CA2265795C - Therapeutic agent with quantitative consumption marker and method of monitoring therapeutic agent consumption - Google Patents

Abstract

Quantitative compliance markers and associated methods for monitoring patien t compliance with medication prescriptions associated with compliance markers have been found to eliminate the need for specific quantitative relationships for each new drug tested. Such compliance markers and methods for monitoring patient compliance utilize pharmacologically inert substances, namely the weak acids benzodiazepines, or non-metabolizable substances in association with an underlying drug at a measurable dosage, so as to correlate compliance marker concentration with underlying medication concentration to determine amount of actual medication ingested.

Description

101520253035W0 98l12557CA 02265795 l999-03- 16PCT/U S97/ 16416THERAPEUTIC AGENT WITH QUANTITATIVE CONSUMPTION MARKERAND METHOD OF MONITORING THERAPEUTIC AGENT CONSUMPTIONTECHNI CAL FI ELDThe present invention relates generally to monitoringpatient compliance with medication prescriptions. Moreparticularly, the invention relates to compositions andpatient compliance usingmethods for monitoringquantitative compliance markers in association withprescribed medications.BACKGROUND OF THE INVENTIONIn the fields of human and animal medicine, psychiatryand animal husbandry, insuring that the patient or animalingests the proper amount of medicine, hormone or nutrientto produce a desired effect is a commonly encounteredproblem. For example, human research has demonstrated thatpatients typically ingest only half the amount ofmedications prescribed by their physicians. Thus, patientsplaced on prescribed medication treatment programs areoften monitored. Both subjective and objective methods areused to identify bothersome symptoms and to implementduring the course of treatment.necessary changesMonitoring generally continues for as long as treatment is101520253035CA 02265795 l999-03- 16WO 98/12557 PCT/US97/16416-2-provided. For example, the Hamilton Anxiety Scale can beused to quantify the amount of anxiety remaining astreatment proceeds for an anxiety—related condition. Ifthe level of residual anxiety decreases significantly, sayfrom the proper prescription of a benzodiazepine drug, likediazepam, then the physician and patient can be assuredthat treatment is efficacious and should be continued.Preferably both quantitative and analytical methodsshould be used to monitor the patient on a repetitive basisto insure that the patient is indeed ingesting theprescribed amounts of medication. Currently, the mostcommon method of monitoring patients for medicationcompliance is clinical observation which involvesindividual counseling and close personal supervision byphysicians. Physicians observe physiological signs andsymptoms such as intoxication, drug withdrawal typicallyoccurring for benzodiazepines, barbiturates and opioids, orresidual signs of illness such as tremor in anxiety,sighing in depression, and nociception in pain syndromes.Physicians also listen to patient complaints regardingdegree of pain relief and evaluate psychological changesover time. This method however is time consuming,expensive and highly subjective. Needless to say, it isfraught with potential errors.Additional compliance information can be obtainedusing qualitative urine monitoring methods such as thestandard laboratory procedure called enzyme-multipliedimmunoassay (EMIT). Utilizing an arbitrary cutoff value,these methods provide the clinician with a simple positiveor negative indication of the possible presence or absenceof a parent drug or its metabolites in a patient’s urine.The parent drug is the prescribed medication itself and themetabolites are those chemical derivatives of themedication which naturally occur upon the patient's bodymetabolizing the medication. These tests do not provide101520253035CA 02265795 l999-03- 16W0 98/12557 PCT/US97/16416-.3-information concerning the time or amount of last drug useor whether or not the prescribed dose of medication wasingested properly, diverted or supplemented. This type oftesting fails to provide any indication as to the actualquantity of drug ingested.Physicians utilizing only clinical evaluation andqualitative urine drug screening test results may developproblems in their treatment methods. Such is often thecase in treating patients who have become biochemicallydependent upon opioids either through prescription orillegal use. Opioid addicts experience great difficultyeliminating their dependency upon such drugs and typicallyenter into extended rehabilitative treatment programs whichutilize prescribed methadone dosages to eliminate opioiddependency. For example, physicians must effectivelyassess the condition of patients on methadone maintenanceprograms in order to adjust dosages and monitor compliance.If a patient is continually testing positive for opioids orcomplains of continuing subjective opioid withdrawalsymptoms, a physician may conclude that the currentlyprescribed dose of methadone is not sufficient to curb thebody's desire for opioids and may increase the prescribeddosage. This highly subjective monitoring method canresult in over-medication with patients being given moremethadone than they require, creating an unnecessaryreliance on methadone. Alternately, physicians sometimesconclude, erroneously, that a patient’s methadone dose issufficient to prevent opioid withdrawal and drug cravingsand deny the patient a further increase sufficient to stopillicit opioid use. Such action can expose the patient tofurther intravenous drug use and the associated negativesocial and medical consequences which can follow such asHIV, hepatitis, and blood poisoning.Similar problems with treatment may arise for patientsprescribed diazepam for longstanding generalized anxiety.101520253035CA 02265795 l999-03- 16W0 98/ 12557 PCT/U S97] 16416-4-Patients may not show improvement in their condition eventhough this therapy is known to be highly efficient. Thismedication is a member of the sedative-hypnotic family ofbenzodiazepines which have been clinically shown to causesedation, hypnosis, decreased anxiety, muscle relaxation,anterograde amnesia and anticonvulsant activity. Apatient, for example, may insist that he or she isingesting the medication as prescribed, and yet claim nosignificant improvement in symptomology. The physiciansuspects that the patient is not ingesting the medicationproperly and perhaps is selling it, and orders aqualitative urine drug screen to verify compliance. Thescreen is reported as positive at greater than 200 ng/mldrug concentration. Since some benzodiazepine is presentthe physician assumes, incorrectly, that the patient iscompliant, but will require additional medication andincreases the daily dose. In truth, the patient isdiverting the majority of his or her dose to the illicitmarket and only ingesting enough drug to test positive onthe drug screen.Patients also commonly visit multiple physicians toobtain similar medication for self-ingestion. Thesepatients desire the intoxicating effects of the medication,but are unable to obtain sufficient quantities from asingle source. Qualitative tests like the EMIT aregenerally not useful in detecting this situation since thequantitative amount of medication concentration in the bodyis not measured.Another monitoring method sometimes used, though mostoften only in research centers, is direct measurement ofparent drug concentrations or active metabolitesconcentrations of the drug in plasma. This method has beenparticularly useful to eliminate illicit opioid use ofpatients on methadone maintenance programs. It is knownfrom analytical studies using venous blood samples obtained1015202530CA 02265795 l999-03- 16WO 98/12557 PCT /US97I 16416-5-from stable patients that plasma methadone concentrationsranging from 150 - 600 ng/ml are necessary. This directmethod of testing is not very practical since it requiresthe use of time consuming, expensive, and highly technicalanalytical procedures such as high pressure liquidchromatography and gas chromatography/ mass spectrometrysince active and inactive metabolites must be quantifiedseparately. Additionally, for many patients the obtainingof plasma samples is invasive, offensive and difficult dueto inadequate venous access. Medical professionals mustalso be concerned about their own health safety in doingthis since they are exposed to blood products from patientgroups which can have a high prevalence of hepatitis andHIV infection. Therefore, such procedures are primarilyconducted in research centers and not generally utilized instandard maintenance programs.Another problem commonly encountered by pharmaceuticalcompanies occurs whenever they are comparing the clinicalefficacy of a potential, new medication versus a placebo.For example, in clinical trials new medications appear tobe two to three times as effective as a placebo, i.e.,placebo response rates can range from 20-30% while drugresponse rates range from 60-80%. One explanation for whynew medications are not more effective is that many testsubjects are not taking their prescribed doses. The endresult is that ‘many’ medications with undesirable side-effects, as formulated for the study, may appear not to beefficacious and be inappropriately dropped from researchonly because subjects are not ingesting sufficient drug toobserve the desired effects. other medications may end upbeing clinically prescribed at higher doses than necessary,increasing morbidity and mortality, because the researchersthink the subjects are taking more medication than theyactually are.1015202530CA 02265795 l999-03- 16W0 98/ 12557 PCT/US97/16416-5-Researchers have proposed several solutions to thisproblem. For instance, drug compliance in a researchsetting has been monitored by counting the residual pillsremaining following a course of treatment. In this regardthe use of a tablet container which incorporates a recorderthat records each opening of the container is described inthe scientific literature. However, the technique ofresidual pill counting is not necessarily indicative ofpill ingestion.Another method of drug compliance monitoring which isdisclosed in scientific literature involves addingsecondary substances to medication which presence can bequalitatively detected in blood work and other bodilyfluids. In this regard, some researchers have addedingredients like riboflavin to pills and looked for theingredient in the patient's serum, urine, or feces.However, testing serum necessitates additional labor andcare since it requires a blood sample to be taken.Furthermore, since ingredients like riboflavin are commonlyfound in food, beverage, and multivitamins, they arenormally also present in urine independent of anysupplemented riboflavin. The normal presence of suchingredients in the urine therefore leads to false positivereadings during testing. Additionally, no accuraterelationship has been determined between the presence ofthese markers in the urine and the amount of medicationtaken.As an alternative solution, researchers have addedrelatively harmless amounts of a second medication to pillsfor this purpose. However, the addition of this type ofingredient again only indicates that patients are takingsome pills. Depending on the half-life of these secondarymedications, researchers may only be able to tell if thepatient ingested the medication recently. Furthermore,101520253035CA 02265795 l999-03- 16W0 98/12557 PCT/U S97/ 16416-7-research with "second medication" type markers has focusedon serum testing for verification.While methods now exist for determining complianceusing quantitative urine monitoring that are useful forinsuring that patients are obtaining adequate body levelsof specific drugs, as disclosed in the applications earliercited, these methods require the development of specificanalytical methods tailored for measuring each specificdrug and its metabolites. Often these methods are notavailable in a clinically useful manner in the earlydevelopment of new drugs.While providing useful information relative to patientstatus and treatment compliance, the clinical monitoringmethods described above, i.e. clinical interviews withpatients, direct plasma drug measurement, qualitative urinedrug screening, residual tablet counting, and quantitativeurine drug screening for each drug ingested, each havedistinct drawbacks which limit their usefulness inexperiments and treatment plans. Therefore, it is seenthat a need remains for a predictable method of monitoringpatients who have been placed on potentially abusable anddangerous maintenance medications or new experimental drugsfor compliance therewith. A need remains for a method ofmonitoring drug ingestion which is not invasive to thepatient and which does not require a predeterminedmathematical relationship specific for each. drug beingmonitored. To help prevent continued medication misuse andbetter optimize patient medication dose, it would beadvantageous for patients to have a facile bodily fluid,such as urine, regularly and quantitatively monitored forthe presence of the medication. It would be furtherdesirable not to have to rely on the distinctivepharmacokinetics of each medication in such monitoring buton the pharmacokinetics of only a standard compliancemarker or a series of compliance markers. Such a101520253035CA 02265795 l999-03- 16W0 98/12557 PCT/US97/16416._8_monitoring method would help physicians both in prescribingadequate doses of medication and in monitoring patients toinsure that they were ingesting the prescribed amounts.Obtaining a fluid sample like urine would not be invasiveto the patient or a safety risk to the health careprovider.Furthermore, a need remains for a composition whichincludes an easily measurable quantitative compliancemarker and a therapeutic agent, in which the consumptioncompliance marker readily passes through the renal systemwith little or no pharmacological effect on the patient.Accordingly, it is to the provision of such improvedmethods and compositions that the present invention isprimarily directed.SUMMARY OF INVENTIONA composition and method has been developed forparticular‘ use in clinical drug evaluation studies fortracking compliance of patients on prescription medications(therapeutic agents) by using compliance markers(quantitative consumption markers) in association with themedications, which consumption compliance markerconcentrations can be accurately measured in the urine.Upon a determination of the compliance markerconcentration, a correlation. is ‘made to ‘the amount ofactual medication ingested. only a small number ofmathematical relationships need be determined betweenmarker intake and urine output, rather than developingunique relationships for each and every drug tested.Moreover, quantitative relationships exist between theamount ingested and the amount appearing in the urine as afunction of physical parameters such as patient weight,lean body’ mass, age, urine pH, urine specific gravity(which may be measured by a refractometer, hydrometer orchemical methods), or other equivalent parameters related1015202530CA 02265795 l999-03- 16W0 98/ 12557 PCT/US97/16416-9..to dissolved urinary solids such as urine osmolality. Thisis especially useful in clinical trials of new, potentiallyuseful medications.It has now been discovered that pharmacologicallyinert quantities of weakly acidic medications, specificallybenzodiazepines, provide quantitative compliance markers inassociation with therapeutic agents. The measurablebenzodiazepines and their metabolites readily pass throughthe renal system into the urine making benzodiazepines andsubstances with similar properties especially suitable ascompliance markers. Preferably a pharmacologically inertquantity of a benzodiazepine, referred to as a"quantitative compliance marker," is added to each unitdose of therapeutic agent, i.e. medication, hormone ornutrient, which quantitative compliance markerconcentration can be measured in the urine. For thepurposes of this application, an inert substance shallinclude biologically inactive substances which are non-metabolizable and pharmacologically insignificant amountsof therapeutic drugs and their metabolites, which can stillbe detected in the urine of a patient.The quantitative compliance marker may be added to amedical formulation by being mixed homogeneously throughoutthe formulation or solution, or as a film or coating on atablet or capsule containing the formulation.Additionally, the marker may be introduced as particulatesin a suspension. If more than one medication has beenprescribed, a separate quantitative compliance marker maybe used in association with each medication. Preferablythe quantitative compliance markers have biological half-lives of between 24 and 48 hours so that they will appearin a urine sample long after ingestion. The quantitativecompliance markers are associated with therapeutic agentsat a predetermined proportion and preferably at a1015202530CA 02265795 l999-03- 16WO 93/12557 PCT/US97/16416sufficiently small dosage to insure the absence ofpsychotropic and physiological effects on the patient.In the method of monitoring therapeutic agentconsumption, random samples of a patient's urine may beanalyzed for the concentration of a quantitative compliancemarker associated with a therapeutic agent. Theconcentration of the quantitative compliance marker thenserves as the basis for both monitoring consumptioncompliance with the prescribed therapeutic agent dosage andto establish the proper medication dosage.In the method of monitoring therapeutic agentconsumption, if appropriate, it is first determined whetherthe urine sample is adulterated as by comparing urine pH,specific gravity, and creatinine level with that of anormal urine sample and the specific values previouslydetermined for the patient. If found to be unadulterated,and probably from the patient being monitored, the rawurine compliance marker concentration is measured alongwith the urine specific gravity or urine osmolality.Once the actual concentration of the compliance markerin the sample is determined (the raw urine compliancemarker concentration), adjustments are made to account forthe affects of variations in certain urinary parametersupon this concentration, by adjusting for the compoundingeffects of urine specific gravity. This is accomplished byaccounting for the difference between the measured specificgravity and a reference specific gravity. An adjustment isalso made to reflect a normalization to a constant patientbody weight such as 70 kg or 154 lbs. This final adjustedcompliance marker concentration is defined as thenormalized urine compliance marker concentration. In thealternative, the normalized urine compliance markerconcentration may be calculated as a function of the urineosmolality, the measured raw urine compliance marker101520253035CA 02265795 l999-03- 16WO 98/12557 PCT/US97/16416-11-concentration and the patient body weight normalized to aconstant value.The normalized urine compliance marker concentrationvalue is then used to determine whether the patient iscompliant by comparing the value of the normalizedcompliance marker concentration to an expected value, forthe purpose of determining whether there is any significantstatistical variance between the two values. By obtainingmultiple urine samples from the patient, once or twice aweek, it is possible to establish an expected baselinenormalized compliance marker concentration against which acurrent or future value can be statistically compared. Anexpected baseline compliance marker concentration for apatient is _the mean normalized compliance markerconcentration from historical values obtained from thepatient. This method of monitoring compliance is dependentupon the assumption that the patient is initially compliantin order to get the expected value. In the alternative,expected ranges of normalized compliance markerconcentrations for specific compliance marker dosages, maybe used for comparison. These ranges are based. on apatient database independent of the subject patient.A corresponding value for the actual medication doseingested is then calculated by multiplying the prescribedmedication dose with the calculated normalized urinecompliance marker concentration, and dividing the productby the expected normalized urine compliance markerconcentration.BRIEF DESCRIPTION OF DRAWINGSFig. 1 is a graph of reverse urine creatinineexcretion factor (RUCEF) versus urine volume productionrate factor (UVPRF) showing their substantially linearrelationship.101520253035CA 02265795 l999-03- 16WO 98/12557 PCT/US97/16416-12-Fig. 2 is a graph of urine volume production ratefactor (UVPRF) versus specific gravity factor (SGF) showingtheir substantially linear relationships.Fig. :3 is a graph of urine production rate versusurine specific gravity factor (SGF) using independent dataand showing their substantially linear relationship.Fig. 44 is a graph of urine production rate versusspecific gravity ratio (1.030/urine SG).Fig. 5 is a graph of urine creatinine concentrationversus urine production rate showing the inverserelationship between urine creatinine and urine productionrate, forming a hyperbola.Fig. £5 is a graph of urine volume production ratefactor versus urine specific gravity factor, showing aslope of one and a zero intercept and demonstrating theirsubstantially linear relationship.Fig. 7 is a graph of normalized urine compliancemarker concentration versus daily compliance marker dosedemonstrating their substantially linear relationship.DETAILED DESCRIPTIONSpecifics of CompositionA specified amount of the quantitative compliancemarker benzodiazepine is added to each unit dose oftherapeutic agent, i.e. medication, hormone or nutrient,which marker can be measured in the urine. For thepurposes of this application, an inert substance includesbiologically inactive substances which are non-metabolizable, and pharmacologically'insignificant.amountsof therapeutic drugs and their metabolites, which can stillbe detected in the urine of a patient. Preferably theinert substances are not normally found in urine and arenot normally ingested as food or drink or as a medicine.Also the inert substances are preferably weak acids so thatthey are unaffected by urine pH and pass through the renal101520253035)wo és/1255;:CA 02265795 2004-02-19PCTIUS9'IIl6416-13-system without resorption. Additionally, there aremathematical relationships between weak acids with pK(dissociationm constants) values less than. 4, and theirindividual active and inactive metabolites.Benzodiazepines, such as the alprazolam Xanaainfind theValimgy which aretherapeutic for treatment ofconditions, are especially suited as markers because theirdiazepam normally prescribed asagents anxiety relatedurinary excretion is not dependent upon urine pH, as areweak bases, because they are completely ionized at thetypical urine pH range of 4.5-8.5. This insures completeclearance after glomerular filtration in the kidneys, sincethesequantities by’ the renal tubules of the kidneys. Fordrugs are not absorbed or secreted in greatinstance, Valium could serve as a marker at a dosage rangeof 1—10mg a day, depending on the individual patient.Advantageously, while the benzodiazepine family’ ofmedications are absorbed fully’ by the digestive tract,being very lipophilic in neutralized form, they are notsignificantly’ metabolized by the liver. Consequently,simple relationships exist between oral intake and urineoutput, as corrected for patient weight and urine specificgravity. Moreover, if the compounds are psychotropicallyand physiologically inactive at low doses, their ingestionwill not adversely affect the patient. Therefore it ispreferable that pharmacologically inert quantities of abenzodiazepine be used as a marker.A benzodiazepine quantitative compliance marker may beadded to a medical formulation by being mixed homogeneouslythroughout the formulation or as a film or coating on atablet or capsule formulation.Additionally, the marker may be mixed in in solution orintroduced as particulates in a suspension. If more thancontaining theone medication has been prescribed, a separate quantitativecompliande marker may be used in association with each1015202530CA 02265795 l999-03- 16W0 98/ 12557 PCT/U S97/ 16416_14—medication. Preferably the markers have biological half-lives of between 24 and 48 hours so that they will appearin a urine sample long after ingestion.A general example using this type of quantitativecompliance marker, is the following:A clinical examination shows that a patient needs toingest three pills of medication a day. If 0.5 mgs of along-acting inactive metabolite of alprazolam or diazepam(having plasma half-lives greater than 24 hours) is addedto each pill as a compliance marker, each compliant patientwill have a specified and constant amount of the compliancemarker in each urine sample. The average amount measured,as normalized for urine specific gravity, and a constantpatient body weight, will be directly related to the numberof pills ingested, for instance 120 concentration unitsassuming each pill contains 40 concentration units.Persons taking only 2 pulls will have 80 concentrationunits, and persons taking only 1 pill will have 40concentration units. Having this data, a pharmaceuticalcompany can then create dose-response curves for the drugsince they will have patients taking different amounts ofdrugs due to variations in compliance.A second general example is the following:A quantitative compliance marker is used in amethadone concentrate at a constant ratio, i.e., onecompliance marker per ten methadone. Therefore the amountof methadone ingested will be proportional to the amount ofcompliance marker taken. Consequently, taking less or moremethadone than prescribed will show up as less or moremarker in the urine, thus helping to eliminate diversion ofa drug to a second individual or supplementing of apatient's drug intake from another source. In this way anumber of distinct markers may be used to monitor thecompliance of a variety of medications.101520253035CA 02265795 l999-03- 16W0 98/ 12557 PCT/US97/16416-15-Other inert substances may also serve as markers inthe following method of monitoring consumption compliancewith therapeutic agents. For example, the barbituratephenobarbital may be used as a compliance marker inconjunction with other prescribed medications, providingthe dosage of the compliance marker is low, and there is nodrug cross-reactivity with the prescribed medication orother medication that the patient is currently taking.Specifics of MethodA patient is initially prescribed a medication anddose based on several factors. These ordinarily includethe severity and duration of illness, amounts and types ofmedications previously used, current or previousphysiological and/or physical dependence upon otherprescription or illicit drugs, previous medical history,patient sex, pregnancy status, patient weight and ingestionof other therapeutic medications. Often medication dose isadjusted upwardly until a patient no longer complains ofresidual signs and symptoms of his or her psychiatricand/or medical illness, is no longer experiencingwithdrawal signs and symptoms if on a medication-replacement taper to abstinence program, or loses his orher desire to use illicit medications if a substance abuseproblem exists. Medication dose is increased per publishedand accepted standard medical protocols for each family ofpsychiatric and medical drug, usually "x" mg every fewdays. A compliance marker is associated with theprescribed medication at a preestablished ratio so that asthe patient takes his/her prescription, he/she also takesa correlative amount of the compliance marker.Testing for AdulterationIn certain circumstances it. may be appropriate tofirst test for adulteration of urine samples. Such. a101520253035CA 02265795 l999-03- 16W0 98/ 12557 PCT/US97/ 16416-16....circumstance may be appropriate in drugrehabilitation/addiction treatment settings. If this isnecessary, a supervised, spot sample of urine should befirst collected from a patient. The urine sample iscollected by simply providing the patient with a standardurine collection bottle into which he or she can urinate.Alternatively, a sample can be collected by catheterizationor withdrawn from a urine collection bag. only severalmilliliters of urine are required for analysis. With thissampling method, it is not necessary to record the volumecollected or completely void the bladder. Loss of aportion of the sample is also not detrimental as long as asufficient sample remains for analysis.Several properties of the urine are measured toevaluate whether the urine is adulterated, adulterationbeing the altering by a patient of his or her urine in aneffort to prevent detection of illicit drug use ordiversion of a drug. Adulteration typically isaccomplished by adding foreign substances to the urine suchas salt, bleach, or vinegar. Many patients attempt todilute amount of drugs in the urine sample by drinkinglarge quantities of water or by adding water to the sample.Adulteration may also occur by substituting anotherperson's urine for the patient's own urine, includinginstillation of foreign urine into the patient's bladder.In checking for adulteration, urine pH is measured, aswith the use of a pH Data Logger type meter available fromOakton, to see if it is within the normally expected pHrange of 4.5 to 8.5. Urine specific gravity is alsomeasured to see if it is within the normal range of 1.004to 1.035 units. A Digital Urinometer by Biovation may beused for this test. Creatinine, an end product of glycineand arginine metabolism excreted through the kidneys, ismeasured to evaluate renal function. The creatinine levelin human urine usually ranges from 8 to 500 mg/dl, the101520253035CA 02265795 l999-03- 16WO 98112557 PCT/US97/ 16416-17..range being affected by variables such as age, sex, diet,lifestyle and geographic location. creatinine levelsgenerally are homeostatically maintained by the body at aconstant value for each individual patient over his or herlifetime. Creatinine levels may be determined on nmnydifferent analyzers, including a TDX REA creatinine Systemavailable from Abbott Laboratories. All of these tests arehelpful in establishing normally expected ranges for eachpatient and the overall population of patients.Once pH, specific gravity, and creatinine level valuesfor the spot urine sample are obtained for a particularpatient, comparisons can be made between the sample inquestion and values previously measured (if alreadyavailable) both for the patient and for normals toascertain whether the urine sample is adulterated. If noadulteration is found, a data base is created or extendedfor the patient so that a basis of comparison exists forfuture spot urine samples. Of the three measures, urinarycreatinine level is generally the most useful indicator asto whether the spot sample is that of the patient or ofsomeone else. If it is not necessary to test foradulteration of urine samples, then random urine samplesare simply obtained from the patient to be analyzed in thefollowing manner.Measurement of Specific Gravity or osmolalityOnce a representative urine sample has been obtained,specific gravity (SG) is measured for the urine at roomtemperature, (22-23 degree C) which typically ranges from1.004 to 1.035 for normal urine. A Digital Urinometer byBiovation may be used for this test. Occasionally, urinesamples may exhibit artificially elevated specific gravityvalues. This situation occurs whenever the urine containsa significant amount of protein, such as in the nephroticsyndrome, and/or glucose, as in diabetes mellitus.101520253035CA 02265795 l999-03- 16W0 98/12557 PCT/US97/ 16416-18-Occasionally, this can also occur when urinary cleared,radiopaque dyes are used for diagnostic purposes.osmolality measurement may therefore be preferred inlieu of specific gravity measurement in order to avoidthese inflated values, since osmolality values are lessdramatically affected by the presence of glucose andprotein in the ‘urine, and since there is a ‘recognizedrelationship in scientific literature that exists betweenurine osmolality and urine specific gravity. Furthermore,osmolality values are not sensitive to temperaturevariations as are specific gravity values.Measuring Raw Urine Compliance Marker ConcentrationThe unadulterated. sample is next analyzed for rawurine compliance marker concentration, preferably usingfluorescence polarization immunoassay (FPIA) technology.In this regard an Abbott TDX or ADX Analyzer may beprofitably employed. other standard analytical methods mayalso be used such as chromatography or other types ofimmunoassay. The value, u, obtained is the raw urinecompliance marker concentration expressed in ng/ml. Ifappropriate, the value u includes the compliance markermetabolite concentration in the urine as well. Metabolitesare those substances which result from the body'smetabolism of the compliance marker.The raw urine compliance marker concentration, u, isnext converted to a :normalized. urine compliance markerconcentration, nu, as discussed below. A historicaldatabase is then created for these values.Calculating Normalized Urine Compliance MarkerConcentrationParameters of a patient’s urine, such as pH andspecific gravity, vary from one day to the next dependentupon the type and quantities of foods and beverages101520253035CA 02265795 l999-03- 16W0 98/ 12557 PCT/U S97/ 16416-19-ingested. Additionally, individuals metabolize endogenoussubstances, as well as medications, at different rates.Due to variations in these daily urine parameters,concentration levels for creatinine, other endogenouscompounds, and drug metabolites can vary over time. Sincemany endogenous compounds and drugs are weak acids undernormal conditions of urine pH, significant tubularresorption does not occur and renal clearance is primarilythe result of glomerular filtration. For these compounds,the major variable responsible for observed variations inurine metabolite and drug concentrations is tubularresorption or excretion of free water. The kidneysregulate urine production rates so to maintain normal bloodpressure and blood osmolality. This property of thekidneys is indicated by the urine specific gravity, aphysical variable relating’ to urinary solids and ‘urinevolume production rate. A mathematical relationship hasbeen discovered to exist between urine compliance markerconcentrations and urine specific gravity, which herein isgiven by the specific gravity normalized compliance markerconcentration, nu.It is now realized that renal excretion rates (mg/dl)for drugs and urine metabolites are relatively constant forany patient during a typical day. This constancy has nowbeen experimentally verified by examining the renalexcretion rates of methadone, benzodiazepines, other drugsand creatinine and other endogenous metabolites as afunction of urine volume production rate. For example,sequential, complete and timed (1-8 hours holding periods)aliquots of urine for 12 compliant control subjects werecollected over 24 to 72 hour periods. For each urinealiquot, urine volume production rate (ml/min), specificgravity and creatinine concentration (mg/dl) (as the testedsubstance) were determined. Using this data, adimensionless, linear relationship was found to exist, that101520253035CA 02265795 l999-03- 16WO 98/12557 PCT/US97/16416-.20..is the same for all patients, between a urine volumeproduction rate factor (UVPRF) and a reverse urinecreatinine excretion factor (RUCEF). For each individual,control, urine collection period, the UVPRF is defined bythe ratio of urine volume production rate for each urinealiquot collected, v, to the urine volume production ratefor the most concentrated sample in the collection periodwith a specific gravity usually near 1.030 (ie thatspecific gravity of a normal urine sample at roomtemperature, typical of a morning void ), v’,UVPRF = v/v’. (1)Similarly, in this example, RUCEF factor is defined by theratio of the creatinine concentration of the mostconcentrated urine aliquot with a specific gravity usuallynear 1.030, u’, to the creatinine concentration for eachurine aliquot collected, u,RUCEF = u’/u. (2)This linear relationship is shown in Figure 1. The bestfit linear regression line is given by the expression,RUCEF = 0.942-UVPRF + 0.121 (3)u’/u = 0.942-v/v’ + 0.121 (4)where statistical evaluation results in an adjusted squaredmultiple R = (L985, a standard error of the estimate =0.242, and a F—ratio = 4965.Therefore, contrary to the traditional teachings ofthose skilled in the art, urine drug and metaboliteconcentrations, u, are inversely related to the volume ofurine produced by the kidneys, v, clearly demonstrating1015202530CA 02265795 l999-03- 16W0 98/12557 PCT/US97/16416-21-that the product (u-v) is constant at any particular timepoint and urine pH.Since (u-v) at any time is a constant, steady—statevalue, it follows that from Equation (4) some empiricalmathematical relationship must exist between u and v suchthat given an arbitrary urine volume production rate v’ andan equivalent u’ at a reference point (a specific gravityof 1.030):{u'v}mwml= {u"V'}aLmo (5)or upon rearrangement for u’ gives,u’ = u-(v/v’) (6)where the products given in Equation (6) are those measuredfor a spot urine sample collected with an actual specificgravity and a corrected specific gravity typical of amorning void of 1.030.Using controlled urine collections, a urine volumeproduction rate v’ of 0.44 ml/min for persons withreasonably normal renal functions at a specific gravity of1.030 was initially measured. A specific gravity factor isthen calculated by the equation (rsg - 1.000)/(msg -1.000), where rsg is the reference specific gravity, whichin this case is equal to 1.030, and where msg is themeasured specific gravity. The specific gravity factor isan adjustment of the measured specific gravity value toaccount for the difference between the measured specificgravity value and a reference specific gravity value.It has been found that a linear relationship existsbetween the urine volume production rate factor and thespecific gravity factor, (SGF) as shown in Figure 2 andgiven as follows:101520253035CA 02265795 l999-03- 16W0 98/12557 PCT/US97/16416.-22..UVPRF = v/v’ = 2.43-SGF — 1.43 (7)where the adjusted squared multiple R = 0.856, standarderror of the estimate = 0.787, F-ratio = 482.Substituting Equation (7) into Equation (6) thespecific gravity normalized creatinine concentration, nu,(since we are testing for creatinine) is then calculated byadjusting the actual urine creatinine concentration, u, forcompounding effects of urine specific gravity at 1.030:nu = u’ = u-(v/v’) = u-UVPRF = u-[kpSGF - kg (8)wherein k.is a constant equal to 2.43 and L is a constantequal to 1.43.Using Osmolalitv Measurement In Lieu of Specific GravityMeasurement in CalculationsIt has been noted that specific mathematicalrelationships exist between the rate of urine formation(ml/min) and the concentration of creatinine in the urine.A relationship also exists between these variables andurine specific gravity. Generally, the relationshipsbetween SGF and v/v’ apply to persons with normal renalfunction. However several situations exist in which theSGF, especially when measured by refractometry orhydrometer, is not directly related to v/v’, thus creatinginaccuracies 531 the relationships heretofore described.Such a situation occurs whenever the urine contains asignificant amount of protein and/or glucose. Occasionallythis can also occur whenever urinary cleared, radiopaquedyes are used. for diagnostic ‘purposes. Each of thesecompounds can affect the refractive index or dragcoefficients for a spinning hydrometer. In situations suchas these, the presence of the abnormal components resultsin the specific gravity value being artificially elevated.101520253035CA 02265795 l999-03- 16W0 98/ 12557 PCT/U S97/ 16416For example, protein in the urine, which is mainly albumin,causes the specific gravity to increase by about 0.003units for every 1000 mg of protein/100 ml urine. Thepresence of glucose results in an increase of about 0.004units for every 1000 mg of glucose/100 ml urine. If thepresence of these influencing compounds is not considered,the specific gravity utilized in the correlation isinaccurate. This inaccuracy is readily apparent becausethe v/v’ from the calculated SGF will fall outside of theexpected range, alerting the clinician to a possibleunusual situation. It will appear that the urine specificgravity is too high for the amount of urine produced. Inthis scenario, additional urine tests can be done toquantify the amounts of protein, glucose and radiopaquedyes. Once these figures are obtained, corrections can beapplied to the calculations. For example, another urinesample can be collected after the radiopaque dye is out ofthe urine and numerical corrections to the refractometer orhydrometer specific gravity values can be made for proteinand/or glucose. The corrected specific gravity isdetermined by subtraction so as to remove the effect of theabnormal urine components. Once these corrections aremade, the normally expected relationships between SGF andv/v’ may be noted.However, in lieu of using SGF as a measure of urineconcentrating ability, specific gravity being the mass ofa unit volume of solution/mass of a unit volume of puresolvent, urine osmolality factor (hereinafter UOF) can alsobe used. osmolality is the number of osmotic particles perunit volume of pure solvent. A common relationship existsin scientific literature relating urine osmolality to urinespecific gravity. For instance, urine osmolality, measuredin mOSM, is equal to 37500(SG~1.000). Furthermore, urineosmolality is not temperature sensitive as is urinespecific gravity. The urine osmolality factor is defined101520253035CA 02265795 l999-03- 16W0 98/12557 PCT/US97/16416as the ratio of the urine osmolality at a specific gravityof a reference point, such as 1.030, to the urineosmolality equivalent at the actual urine specific gravity.Using this equation, the following figures may be generatedfor protein/glucose free urines.EXAMPLESMeasured Calculated Measured CalculatedSpecific Specific Osmolality UrineGravity Gravity OsmolalityFactor Factorsample 1 SG 1.003 SGF 10 Osm 112.5 UOF 10sample 2 SG 1.015 SGF 2 Osm 562 UOF 2sample 3 SG 1.030 SGF 1 Osm 1125 UOF 1It is therefore evident from this data that SGF andUOF values are equivalent and either one may be used in theapplication of this invention.Refinement of the Normalized Urine Compliance MarkerEquationsIndependent data was gathered from 96 patients beingfollowed in a renal disease clinic. Data available fromthese patients included 24 hour urine volumes, urinespecific gravity, urine creatinine concentration, serumcreatinine concentration, creatinine clearances measuredfrom 24 hour collections, presence of protein and glucosein urine, urine osmolality, patient sex, age, lean bodyweight, total body weight, height and diagnosis.The independent data was first plotted by urineproduction rate (ml/min) versus various mathematicalformulations of urine specific gravity as illustrated inFigs. 3 and 4. Although several methods exist for plottingspecific gravity or its equivalent, osmolality, on the x-axis, ie, SG ratio=1.030/SG, SGF or even SG, the SGF andUOF relationship are preferable.101520253035CA 02265795 l999-03- 16W0 98Il2557 PCT/US97/16416-25-As a further example for demonstrating in greaterdetail the inverse relationship between urine creatinineand urine volume production rate, urine creatinineconcentration was plotted against urine production raterevealing a hyperbola in Fig. 5.Figure 6 plots the ratio v/v’ using v’ equal to 0.58ml/min against SGF. Plotting this data gives a slope of oneand a zero intercept. Data gathered from normal subjectssupports this same conclusion.These functions differ from functions describedearlier in that v’ is now equal to 0.58 and v is now equalto SGF -v’ as compared to previous formulations where v wasequal to (2.43 - SGF-1.43) - v’, where v’ equals 0.44. Therefined normalized equation may be expressed generally asfollows (normalized to a specific gravity of 1.030):nu = u’ = u-(v/v’) = u-UVPRF = u-SGF (9)The equation for nu (9) may be further normalized toadjust for a standard patient body weight such as of 70 kgor 154 lbs. This normalized value for nu may be reflectedin the following equation:nu = u’ = u-(v/v’) = u-SGF-(WGT/K) (10)where WGT is equal to patient body weight, and K is aconstant equal in this case to 154 lbs. It should be notedthat this equation may be normalized to any reference valuefor specific gravity or weight.Comparison of nu Value With Established ValuesThe normalized urine compliance marker concentrationis then compared to established values for the patient. Byobtaining multiple urine samples from a patient, once ortwice a week, it is possible to establish an expectednormalized compliance marker baseline against which a101520253035CA 02265795 l999-03- 16W0 98/12557 PCT/US97/16416-25-current or future value can be statistically compared. Theexpected normalized compliance marker baseline is the meannormalized compliance marker value from historical patientdata. This method of monitoring compliance is dependentupon the assumption that the patient is initially compliantin order to get the expected value. In the alternative,expected ranges for normalized compliance markerconcentrations from independent patient databases may beused for comparison. If any difference between calculatednu and expected nu is not explained by statisticallyacceptable deviation, then the patient is not incompliance. The actual medication dosage ingested may thenbe calculated as:(prescribed medication dose)-(calculated nu)expected nuSpecific Examples and Supporting Data Using MethodSeveral methadone patients were independentlyprescribed diazepam for anxiety disorders. These patientswere utilized to determine if it would be possible tocompound a particular "marker" chemical in a set ratio tomethadone such that one could tell how many doses ofmethadone each patient took. If the "marker" concentrationin the urine satisfied specified statistical requirementsas to the concentration level measured, then one would besure that the patient did not ingest extra doses or divertmethadone by not taking the full dose. These experimentswere designed as follows:Experiment £1 QueryDoes normalized urine concentration of compliancemarker correlate with doses of the underlying drugmethadone given to patient?101520253035CA 02265795 l999-03- 16W0 98/ 12557 PCT/U S97ll6416-27-Stages of Experiment £11. A fixed diazepam/methadone hydrochloride mixtureratio was chosen (1 mg diazepam per 15 mg methadone HCL).Methadone-marker solutions were prepared by addingsufficient diazepam liquid (10 mg/ml concentrate) tomethadone concentrate (50 mg/ml) so as to manufacture unitsamples containing either (4mg diazepam/70 mg methadone) or(8 mg diazepam/120 mg methadone) such that the final volume(including water, color and flavor) of each dose was 15 ml.2. To insure compliance with protocol for thisexperiment, three rehabilitated and compliant patients(each having been in methadone treatment for several years)were chosen for this experiment. Two patients ingestedmethadone 30 mg p.o. every 12 hours (half a bottle eachtime) and one patient ingested methadone 60 mg p.o. every12 hours (half a bottle each time). on a random basis,each patient was asked to provide an observed urine samplefor analysis prior to being given his or her daily dose.Each patient came to the office at least twice a week topick up medication, ingest half their dose and beinterviewed. Each experiment was conducted for a two monthperiod. During this period, the only sources of methadoneand diazepam available were given in the test site.3. Diazepam was measured by FPIA normalized to aurine specific gravity of 1.030 and a total body weight of154 lbs:nu concentration = (u)(SGF)(wgt/154)10152025303540CA 02265795 l999-03- 16W0 98/ 12557 PCT/US97l 16416_28_4. Results.PRESCRIBED COMPLIANCEMEDICATION MARKERMEAN NU FORCOMPLIANCE MARKERP-1 methadone 30mg diazepam 2mgp.o. q12h p.o. qlzhsoo (so 90, cv 13%)P-2 methadone 60mg diazepam 4mgp.o. q12h p.o. q12h1068 (so 233, cv 22%)P-3 methadone 30mg diazepam 2mgp.o. q12h p.o. q12h499 (so 73, cv 15%)Expected. ratio of marker P-1/marker P-3 should. be1.00; actual ratio observed was 1.00. Expected ratio ofP-2/marker P—1 or P-3 should be 2.00; actual ratio was2.13.Experiment £2 QueryWhat happens if a patient were to ingest extramethadone from another source also containing compliancemarker?Stages of Experiment £21. For this experiment, patient P-3 was utilized.In order to simulate a patient ingesting twice as muchmethadone (underlying drug) each day (also with compliancemarker), patient P-3 was given his standard methadone dosefor several weeks prior to and following a one week changein the amount of compliance marker (2 mg diazepam per 15 mgmethadone HCL) included in his normal 60 mg daily methadonedose so as to simulate "double dosing." Included in thefollowing chart are sequential nu diazepam urine values forthe pre-change period, simulation of "double dosing" andpost-change period.1015202530CA 02265795 l999-03- 16W0 98/12557 PCT/US97/16416._ 2 9 ..Date: marker status: nu diazepam:02-19-96 post-change 534 ng/ml02-09-96 post-change 48202-02-96 post-change 40401-31-96 post-change 59101-26-96 double marker 1163marker returned to1 mg/15 mg methadone01-22-96 double marker 59701-19-96 pre-change 450marker increased to2 mg/15 mg methadone01-16-96 pre-change 51901-03-96 pre-change 39512-29-95 pre-change 51612-26-95 pre-change 34412-22-95 pre-change 591If the patient was "double dosing" one would expect tosee (after about a week, since the average half-life of thediazepam metabolites is about 48 hours) at the end of aweek, a compliance marker concentration about twice thebaseline concentration. Expected concentration would beabout 1000 ng/ml, while concentration observed was 1163ng/ml. Therefore, if this patient had been non-compliantand getting methadone from another clinic, doctors wouldhave been able to intervene.Experiment £3 QueryWhat happens if a patient were to divert a portion oftheir daily doses?Stages of Experiment £31. For this experiment, patient P-2 was utilized.In order to simulate a patient diverting half of her dailyCA 02265795 l999-03- 16W0 98/ 12557 PCT/US97/16416-30-methadone (has take—homes with one clinic visit a week), aprotocol similar to experiment #2 was done exceptcompliance marker was decreased to 0.5 mg diazepam per 15mg methadone HCL.1015202530If a patient were diverting half of their take-homedoses, one would expect to see a decrease in the complianceDate: marker status: nu diazepam:02-09-96 post—change 1019 ng/ml02-06-96 post-change 104402-02-96 post-change 107301-30-96 post-change 109801-26-96 half marker 445increase marker to1 mg/15 mg methadone01-23-96 half marker 67301-19-96 half marker 997decrease marker to0.5 mg/15 mg methadone01-16-96 pre-change 104401-12-96 pre-change 97801-09-95 pre-change 102901-05-96 pre-change 89601-02-96 pre-change 1210marker concentration of half after a week or so.indeed what happened.Experiment £4 QueryHow to establish expected values for normalized urinecompliance marker concentrations ?Based on data gathered from over 50 patients observed overa four—year period, expected ranges for several normalizedurine complianceestablished.For example, when diazepam is utilized asiamarkerconcentrations ‘haveThis is101520253035CA 02265795 l999-03- 16W0 98/ 12557 PCT/U S97/ 16416—3 1-compliance marker, the expected normalized value for urinediazepam—like immunoreactivity is 125 ng/ml/mg’ diazepammarker ingested. Statistical ranges for acceptable lowsand highs have been established as being between 75 to 175ng/ml/mg diazepam marker ingested. The linear correlationbetween normalized urine compliance marker concentrationand daily compliance marker dose is illustrated in Fig. 7.Using preestablished data for normalized urine compliancemarker concentration will eliminate the need to establishhistorical data bases for each individual patient.It thus is seen that methods and compositions are nowprovided for monitoring patients who have been placed onmedication maintenance programs or have been participantsin experimental drug programs. The method utilizes acompliance marker concentration from evaluation of patienturine samples by FPIA to determine normalized urinecompliance marker concentrations. Normalized urinecompliance marker concentration can then be compared to anexpected normalized urine compliance marker concentration.The actual drug dose ingested may then be calculated todetermine compliance with the prescribed medication dose.The methods and compositions are clinically practicalwithout high laboratory testing cost, the invasiveness ofwithdrawing blood, and the added exposure to medicalprofessionals of patient blood having high probability ofhepatitis and HIV infection. Furthermore, the methods andcompositions do not require multiple equations to calculatenormalized concentration values, or the consideration ofnumerous pharmacokinetics variables for each ‘medicationbeing monitored.While this invention has been described in detail withparticular references to preferred embodiments thereof, itshould be understood that many modifications, additions anddeletions may be made thereto, in addition to thoseexpressly recited without departure from the spirit andCA 02265795 l999-03- 16WO 98/12557 PCT/US97/16416-32-scope of the invention as set forth in the followingclaims.

Claims (24)

1. A method of monitoring compliance of a patient who has been placed on a medication maintenance program with a prescribed medication dosage, and with the method comprising the steps of:
(a) physically associating a compliance marker with a prescribed medication dosage prior to ingestion, (b) obtaining a sample of the patient's urine, (c) measuring the concentration of the compliance marker and its metabolites in the urine and the urine specific gravity, (d) calculating a normalized urine compliance marker and its metabolite concentration as a function of the measured compliance marker and its metabolite concentration in the urine and the urine specific gravity adjusted to account for the difference between the measured urine specific gravity and a preselected reference urine specific gravity, (e) comparing the normalized urine compliance marker and its metabolite concentration with an expected normalized urine compliance marker and its metabolite concentration for the amount of compliance marker prescribed, as an indication of compliance or non-compliance.

2. The method of claim 1 further including the step:
(f) calculating the amount of prescribed medication actually ingested by multiplying the prescribed medication dose with the calculated normalized urine compliance marker and its metabolite concentration, and dividing the product by the expected normalized urine compliance marker and its metabolite concentration.

3. A method of monitoring compliance of a patient who has been placed on a medication maintenance program with a prescribed medication dosage and having a compliance marker physically associated with the medication at a predetermined dosage, and with the method comprising the steps of:
(a) obtaining a sample of the patient's urine, (b) measuring the concentration of the compliance marker and its metabolites in the urine and the urine specific gravity, (c) calculating a normalized urine compliance marker and its metabolite concentration as a function of the measured compliance marker and its metabolite concentration in the urine and the urine specific gravity adjusted to account for the difference between the urine measured specific gravity and a preselected reference urine specific gravity, (d) comparing the normalized urine compliance marker and its metabolite concentration with an expected normalized urine compliance marker and its metabolite concentration for the amount of compliance marker prescribed, as an indication of compliance or non-compliance.

4. The method of claim 3 further including the step:
(e) calculating the amount of prescribed medication actually ingested by multiplying the prescribed medication dose with the calculated normalized urine compliance marker and its metabolite concentration, and dividing the product by the expected normalized urine compliance marker and its metabolite concentration.

5. The method of claim 3 wherein step (d) the normalized urine compliance marker and its metabolite concentration is calculated in accordance with the equation nu = u.cndot.SGF.cndot.(WGT/K) where nu is the normalized urine compliance marker and its metabolite concentration, a is the measured raw urine compliance marker and its metabolite concentration, SGF is the specific gravity factor of the urine sample calculated from the equation (rsg - 1.000)/(msg - 1.000), where rsg is the preselected reference urine specific gravity, and where msg is the urine measured specific gravity, where WGT is the patient body weight and K is a constant.

6. The method of claim 3 wherein step (b) the concentration of a benzodiazepine and its metabolites are measured.

7. The method of claim 6 wherein the benzodiazepine is diazepam.

8. The method of claim 6 wherein the benzodiazepine is alprazolam.

9. The method of claim 3 wherein step (b) the concentration of a barbiturate and its metabolites are measured.

10. The method of claim 9 wherein the barbiturate is phenobarbital.

11. A method of claim 3 wherein step (b) the concentration of a weakly acidic medication and its metabolites are measured.

12. A method of monitoring compliance of a patient who has been placed on a medication maintenance program with a prescribed medication dosage and having a compliance marker physically associated with the medication at a predetermined dosage, and with the method comprising the steps of:
(a) obtaining a sample of the patient's urine, (b) measuring the concentration of the compliance marker and its metabolites in the urine and the urine osmolality, (c) calculating a normalized urine compliance marker and its metabolite concentration as a function of the measured compliance marker and its metabolite concentration in the urine and the urine osmolality, (d) comparing the normalized urine compliance marker and its metabolite concentration with an expected normalized urine compliance marker and its metabolite concentration value prescribed, as an indication of compliance or non-compliance.

13. The method of claim 12 further including the step:
(e) calculating the amount of prescribed medication actually ingested by multiplying the prescribed medication dose with the calculated normalized urine compliance marker and its metabolite concentration, and dividing the product by the expected normalized urine compliance marker and its metabolite concentration.

14. The method of claim 12 wherein step (c) the normalized urine compliance marker and its metabolite concentration is calculated in accordance with the equation nu = u.cndot.UOF.cndot.(WGT/K) where nu is the normalized urine compliance marker and its metabolite concentration, a is the measured raw urine compliance marker and its metabolite concentration, UOF is the urine osmolality factor of the urine sample defined as the ratio of the urine osmolality at a specific gravity of a reference urine sample to the urine osmolality equivalent at the actual urine specific gravity, where WGT is the patient body weight and K is a constant.

15. The method of claim 12 wherein step (b) the concentration of a benzodiazepine and its metabolites are measured.

16. The method of claim 15 wherein the benzodiazepine is diazepam.

17. The method of claim 15 wherein the benzodiazepine is alprazolam.

18. The method of claim 12 wherein step (b) the concentration of a barbiturate compliance marker and its metabolites are measured.

19. The method of claim 18 wherein the barbiturate is phenobarbital.

20. A method of claim 12 wherein step (b) the concentration of a weakly acidic medication and its metabolites are measured.

21. A method of determining patient compliance, comprising prescribing the ingestion by the patient of an active agent and a marker comprising a benzodiazepine or benzodiazepine metabolite and subsequently analyzing the patient's urine to confirm the presence of said marker and thus the ingestion of said prescribed active agent.

22. The method of claim 21, wherein said marker is pharmacologically inert.

23. The method of claim 21, wherein said marker is diazepam.

24. The method of claim 21, wherein said marker is alprazolam.