Analysis of morphine and codeine in samples adulterated with Stealth.

Stealth is an adulterant used to avoid detection of drug abuse. The product does have an effect on the ability to detect several drugs of abuse, including the opiates morphine and codeine. It has previously been shown that low concentration (2500 ng/mL morphine) samples adulterated with Stealth tested negative by both Roche OnLine and Microgenics CEDIA immunoassays, but those spiked with higher concentrations (6000 ng/mL of codeine and morphine glucuronide) were positive. Initial results showed confirmation analysis was also sometimes negatively impacted by this adulterant. Urine samples were spiked with 6000 ng/mL of codeine and/or morphine glucuronide to assess the effect of Stealth. Each individual sample was split into separate aliquots. One aliquot of each was adulterated with Stealth following package directions. The samples were then tested by immunoassay and gas chromatography-mass spectrometry (GC-MS). The control and adulterated aliquots were positive by both immunoassays. Results of GC-MS analysis of the Stealth-adulterated aliquots following standard procedures using deuterated internal standards proved unsuccessful in several cases. In 4 of 12 cases (33%), neither the drugs nor internal standards were recovered despite repeated attempts. In one other sample, recovery was dramatically reduced, making accurate quantitation impossible, whereas the unadulterated aliquots of the same samples posed no problem with recovery. Addition of sodium disulfite to the aliquots prior to extraction allowed recovery of the drugs and internal standards from all samples. Analysis of the samples showed the concentration of morphine and codeine decreased in some by as much as 17 and 30%, respectively. In other cases, there was essentially no difference in the concentration seen before and after adulteration, with or without disulfite treatment. Unless the initial concentration of opiate is near the cutoff, samples containing opiates are likely to be immunoassay positive, it is important to consider this procedure as an option for samples that screen positive but the opiates and their respective internal standards are not recovered for GC-MS analysis.

Effects of Stealth adulterant on immunoassay testing for drugs of abuse.

Stealth is an adulterant advertised as being undetectable by adulteration tests. It has been described as peroxidase and peroxide, which, when added to urine samples, are intended to prevent a positive drug test. Characterization of the effect of Stealth on urine samples and immunoassay results was undertaken to assist in detection of this adulterant. Stealth was added to a number of urine matrices, and various parameters were evaluated including pH, specific gravity, color, creatinine, chloride, urea, blood, glucose, and nitrite. Samples were spiked with THC acid metabolite, benzoylecgonine, morphine, secobarbital, PCP, amphetamine, and lysergic acid diethylamide (LSD) then tested by Roche OnLine and Microgenics CEDIA immunoassay reagents. Results of these analyses showed Stealth did not cause the urine sample to exceed any of the monitored parameters including those routinely used in drug-testing laboratories that would indicate adulteration of a sample. It did, however, cause samples positive for the marijuana metabolite (11-nor-delta9-tetrahydrocannibinol-9-carboxylic acid), LSD, and opiate (morphine) at 125-150% of cutoff to screen negative by immunoassay. Adulterating an authentic positive sample provided by a marijuana user caused that sample to screen negative using these immunoassay reagents as well.

Amphetamine, clobenzorex, and 4-hydroxyclobenzorex levels following multidose administration of clobenzorex.

Clobenzorex (Asenlix) is an anorectic drug used as part of a weight-management program. The drug is metabolized by the body to amphetamine, which is then excreted in the urine, thus causing difficulty in interpretation of amphetamine-positive drug tests. Previous studies have shown that the parent drug and several metabolites are excreted in urine. Clobenzorex itself has been detected for as long as 29 h following administration of a single dose. However, the parent drug was not always detected in samples that contained amphetamine at > or =500 ng/mL, the administrative cutoff for a positive result. Consequently, the parent compound clobenzorex is not ideal for ascertaining whether the drug was the origin of the amphetamine. Several metabolites of clobenzorex have been shown to be detected for a longer period of time than the parent. One of these, a hydroxy metabolite, was shown to be detected for an extended period of time. In a study of urine samples provided following administration of a single 30-mg dose of this drug, 4-hydroxyclobenzorex could be detected for up to 91.5 h. More significantly, that study showed all samples that were positive for amphetamine also contained detectable amounts of 4-hydroxyclobenzorex. This metabolite proved to be easily detected and was typically found at higher levels than amphetamine in urine samples positive for amphetamine long after clobenzorex itself could no longer be detected. The present study analyzed samples from a controlled multidose administration (30 mg of clobenzorex daily for seven days) for the presence of 4-hydroxyclobenzorex. The analytical procedure used acid hydrolysis followed by liquid-liquid extraction and gas chromatographic-mass spectrometric analysis with monitoring of ions at m/z 125, 330, and 364 for 4-hydroxyclobenzorex and its 3-Cl regioisomer, which was used as an internal standard. Peak concentrations of 4-hydroxyclobenzorex ranged from 17,786 to 99,044 ng/mL. Most importantly, this study also found that all samples that contained amphetamine at > or =500 ng/mL also contained detectable amounts of this hydroxy metabolite (LOD 10 ng/mL), making it a valuable tool in differentiating use of clobenzorex from illicit amphetamine use.

Differentiation of clobenzorex use from amphetamine abuse using the metabolite 4-hydroxyclobenzorex.

Clobenzorex (Asenlix) is an anorectic drug metabolized by the body to amphetamine, thus causing difficulty in the interpretation of amphetamine-positive drug tests. Previous studies have shown the parent drug and several metabolites are excreted in urine. Clobenzorex itself has been detected for as long as 29 h postdose using a detection limit of 1 ng/mL. Despite this fact, several amphetamine-positive samples (> or = 500 ng/mL) contained no detectable clobenzorex. Thus, the absence of clobenzorex in the urine does not exclude the possibility of its use. To more definitively assess the possibility of clobenzorex use, evaluation of another metabolite was considered. One study reported the presence of unidentified hydroxy metabolites of clobenzorex for as long as amphetamine was detected in some subjects. To assess the viability of using a hydroxy metabolite to confirm the use of clobenzorex in samples containing amphetamine, 4-hydroxyclobenzorex was synthesized for this study. This metabolite proved to be easily detected and was typically found at levels higher than amphetamine in amphetamine-positive urines, long after clobenzorex itself was no longer detected. Samples obtained from a controlled single-dose study involving the administration of clobenzorex (30 mg) were analyzed for the presence of the 4-hydroxy metabolite. The analytical procedure used acid hydrolysis followed by liquid-liquid extraction and analysis with gas chromatography-mass spectrometry by monitoring ions at m/z 125, 330, and 364. 4-Hydroxyclobenzorex and its 3-Cl regioisomer were used in the identification and quantitation of the metabolite. Peak concentrations of 4-hydroxyclobenzorex were found at approximately 1:30-5:00 h postdose and ranged from approximately 5705 to 88,410 ng/mL. Most importantly, however, all samples that contained amphetamine at > or = 500 ng/mL also contained detectable amounts of this hydroxy metabolite (LOD 10 ng/mL), making it a valuable tool in differentiating use of clobenzorex from illicit amphetamine use.

Dental caries history in nine children with chromosome 18p deletion syndrome.

Chromosome 18p deletion syndrome is caused by the deletion of a portion of genetic material on the short (p) arm of chromosome 18. Many of 100 prior case reports in the medical literature describing the dental health of subjects with this syndrome reported multiple caries associated with the syndrome. At the third annual international conference of The Chromosome 18 Registry & Research Society, dental examinations were carried out on nine children with chromosome 18p deletion syndrome and five of their unaffected siblings. The dental examination included an intra-oral evaluation of coronal decay and filled permanent teeth surfaces (DFS) and decayed and filled primary tooth surfaces (dfs) using a mouth mirror, explorer, and a high-intensity fiber optic light. An evaluation of the data revealed that five of nine children with 18p deletion syndrome (56%) were free of tooth decay or a history of tooth decay. Four of the nine (44%) had tooth decay or a history of tooth decay. The prevalence of decay was quite similar in the genetically unaffected siblings. Three of the five (60%) unaffected siblings of the children with 18p were free of tooth decay, whereas two of the five (40%) had tooth decay. One of the affected children had a missing mandibular left central incisor. None of the children had abnormally shaped teeth. The caries pattern seems to be similar to that reported in the NHANES III data collected in the United States from 1988-1991. Analysis of these preliminary data suggests that the risk for caries in chromosome 18p deletion syndrome may be lower than previously reported.

A gas chromatography-mass spectrometry method for the quantitation of clobenzorex.

Drugs metabolized to amphetamine or methamphetamine are potentially significant concerns in the interpretation of amphetamine-positive urine drug-testing results. One of these compounds, clobenzorex, is an anorectic drug that is available in many countries. Clobenzorex (2-chlorobenzylamphetamine) is metabolized to amphetamine by the body and excreted in the urine. Following administration, the parent compound was detectable for a shorter time than the metabolite amphetamine, which could be detected for days. Because of the potential complication posed to the interpretation of amphetamin-positive drug tests following administration of this drug, the viability of a current amphetamine procedure using liquid-liquid extraction and conversion to the heptafluorobutyryl derivative followed by gas chromatography-mass spectrometry (GC-MS) analysis was evaluated for identification and quantitation of clobenzorex. Qualitative identification of the drug was relatively straightforward. Quantitative analysis proved to be a far more challenging process. Several compounds were evaluated for use as the internal standard in this method, including methamphetamine-d11, fenfluramine, benzphetamine, and diphenylamine. Results using these compounds proved to be less than satisfactory because of poor reproducibility of the quantitative values. Because of its similar chromatographic properties to the parent drug, the compound 3-chlorobenzylamphetamine (3-Cl-clobenzorex) was evaluated in this study as the internal standard for the quantitation of clobenzorex. Precision studies showed 3-Cl-clobenzorex to produce accurate and reliable quantitative results (within-run relative standard deviations [RSDs] < 6.1%, between-run RSDs < 6.0%). The limits of detection and quantitation for this assay were determined to be 1 ng/mL for clobenzorex.

Molecular, morphometric and functional analyses demonstrate that the growth hormone deficient little mouse is not hypomyelinated.

To study the effects of naturally occurring growth hormone deficiency type I on CNS myelination, we compared the myelination of brains from little and wild-type littermate mice using molecular, histological, morphometric, and functional analyses. The little mouse produces only 6-8% of normal levels of growth hormone (GH) and approximately 20% of normal circulating levels of insulin-like growth factor 1 (IGF-1). Our data show that the expression of myelin basic protein (MBP) and proteolipid protein (PLP) of the little brain exhibit the same temporal pattern and amount as that of the wild-type brain. Furthermore, the density and size of myelinated axons and the myelin sheath thickness in the corpus callosum, anterior commissure and the optic nerve are comparable in the little and wild-type brains. These regions are reduced in size in the little mouse brain proportionate to the overall reduction in brain size implying a reduction in the total number of neurons. Therefore, it follows that the total myelin content is reduced, but when normalized to brain size, the myelin concentration is unchanged. Myelin staining patterns of whole brains were identical. Moreover, functional analysis of the visual pathway indicated no difference between the little and control mice. These results are inconsistent with previous reports of hypomyelination in the little mouse and suggest that this form of GH deficiency does not adversely affect the myelination process except possibly through neuronal proliferation. However, since axon size and density are maintained, the neuronal growth may conversely be inherently limited by other restricted brain growth.

Metabolic production of amphetamine following multidose administration of clobenzorex.

The interpretation of urine drug-testing results can have important forensic and legal implications. In particular, drugs that are metabolized to amphetamine or methamphetamine or both pose significant concerns. In this study, clobenzorex, an anorectic drug that is metabolized to d-amphetamine, was administered to five subjects. Each subject took 30 mg daily for seven days, and individual urine samples were collected ad lib for 14 days beginning on the first day the drug was administered. Urine pH, specific gravity, and creatinine values were determined for each sample. Gas chromatography-mass spectrometry (GC-MS) was used to determine the excretion profile of amphetamine and clobenzorex using a standard procedure for amphetamines with additional monitoring of ions at m/z 118, 125, and 364 for the detection of clobenzorex. Peak concentrations of amphetamine were found at 82 to 168 h after the first dose and ranged from approximately 2900 to 4700 ng/mL amphetamine. The use of a regioisomer (3-Cl-benzylamphetamine) as internal standard allowed for accurate quantitation of the parent drug. Peak concentrations of clobenzorex were found at 50 to 120 h after the first dose and ranged from approximately 8 to 47 ng/mL clobenzorex. However, in many samples, clobenzorex was not detected at all. This analysis revealed that the metabolite, (amphetamine) is present in much higher concentrations than the parent compound, clobenzorex. Yet even at peak amphetamine concentrations, the parent was not always detected (limit of detection 1 ng/mL). Thus, in the interpretation of amphetamine-positive drug-testing results, the absence of clobenzorex in the urine sample does not exclude the possibility of its use.

Simultaneous determination of amphetamine, methamphetamine, methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA), and methylenedioxyethylamphetamine (MDEA) enantiomers by GC-MS.

A method is described for the simultaneous determination of the ratio of l- and d-enantiomers of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) in urine. The assay uses liquid-liquid extraction followed by derivatization with trifluoroacetyl-l-prolyl chloride (l-TPC) and analysis by gas chromatography-mass spectrometry. The assay was developed using prepared samples containing varying concentrations of each of the analytes over a range of percentages of each enantiomer. Results showed the method to provide accurate and reliable results in samples containing > or = 10 ng/mL amphetamine and methamphetamine and > or = 25 ng/mL MDA, MDMA, and MDEA. The assay was used to analyze urine samples from subjects of a controlled MDMA study. Results for each of the eight subjects showed a greater percentage of the l-enantiomer of MDMA initially, and the percentage increased with time postdose. Analysis of the metabolite MDA revealed that the proportion of d-enantiomer was initially greater than the l-enantiomer followed by a gradual increase in the proportion of l-enantiomer until it exceeded the amount of the d-enantiomer. In all cases, the l-MDA exceeded the d-MDA within the first 36 h postdose.

Amphetamine and fenproporex levels following multidose administration of fenproporex.

Drugs that are metabolized to amphetamine or methamphetamine are potentially of significant concern in the interpretation of positive drug-testing results for amphetamines. A number of different drugs have been reported to produce amphetamine in the urine of users. One of these compounds, fenproporex, has been shown to be metabolized to amphetamine, and previous reports indicated the parent compound could be detected at low levels for up to 48 h. Administration of fenproporex for seven days (one 10-mg dose per day) to five healthy volunteers resulted in amphetamine being detected in the urine of all subjects. Peak concentrations of amphetamine ranged from approximately 2850 to 4150 ng/mL. Amphetamine could be detected (> or = 5 ng/mL) in the urine for up to nearly 170 h after the last dose. Analysis of the metabolically produced amphetamine showed the presence of both enantiomers, which can be helpful in the differentiation of some illicit amphetamine use from the use of this precursor drug. In addition, evaluation of the enantiomeric composition of the metabolite (amphetamine) can be a valuable tool in the interpretation of time since last dose. More significantly, all samples that contained amphetamine at a concentration of > or = 500 ng/mL were shown to also contain detectable amounts of the parent compound.

Metabolic production of amphetamine following administration of clobenzorex.

Many of the anorectic drugs that are metabolized to amphetamine and/or methamphetamine pose significant concerns in the interpretation of amphetamine-positive drug testing results. One of these drugs--clobenzorex--has been shown to produce amphetamine. Thirty milligrams of clobenzorex hydrochloride, in the form of a single Asenlix capsule (Roussel, Mexico), were administered orally to five human volunteers with no history of amphetamine, methamphetamine or clobenzorex use. Following administration, urine samples (total void volume) were collected ad lib for seven days and pH, specific gravity and creatinine values were determined. To determine the excretion profile of amphetamine and parent drug, samples were extracted, derivatized, and analyzed by gas chromatography/mass spectrometry (GC/MS) using a standard amphetamine procedure with additional monitoring of ions at m/z 91, 118, 125 and 364 for the detection of clobenzorex. Peak concentrations of amphetamine were detected at 4 to 19 h postdose and ranged from approximately 715 to 2474 ng/mL amphetamine. Amphetamine could be detected (> 5 ng/mL) in the urine in one subject for up to 116 h postdose. GC/MS was also used to determine the enantiomeric composition of the metabolite, amphetamine. This analysis revealed the metabolically derived amphetamine was only the d-enantiomer. This differs from previous literature which indicates clobenzorex is the racemic N-orthochlorobenzyl derivative of amphetamine.

Detection of amphetamine and methamphetamine following administration of benzphetamine.

Interpretation of urine drug-testing results is a challenging endeavor for several reasons. Effects of pH, dilution, legitimate and illicit sources of the drugs, and, perhaps the most challenging, the possibility of the methamphetamine and/or amphetamine being the result of the use of some other drug. Although it is known that 14 different compounds are metabolized to methamphetamine or amphetamine or both, there is little information on the metabolic profile of many of these compounds, making interpretation of results difficult. Benzphetamine, administered as a single Didrex tablet, was given to 10 subjects (7 male and 3 female) and urine samples collected for the next 7 days. Gas chromatography-mass spectrometry results showed 3 of the 10 subjects did not have a single urine sample that exceeded a 500-ng/mL cutoff for amphetamine or methamphetamine. The other subjects had between one and six samples that tested positive at or above that level. Two subjects excreted more methamphetamine than amphetamine, whereas the other eight excreted greater amounts of amphetamine than methamphetamine. The observed ratio between amphetamine and methamphetamine was significantly different than what would be expected from the use of methamphetamine. Results of this study indicate the metabolism of benzphetamine to desmethylbenzphetamine is a major pathway in the metabolism of the drug. Enantiomer analysis of the methamphetamine and amphetamine revealed only the d-enantiomer. Results of this study add significant information useful to interpret the possibility of benzphetamine as the origin of methamphetamine and amphetamine in urine samples.

Immunoassay analysis of lysergic acid diethylamide.

Screening large numbers of urine samples for drugs of abuse is typically accomplished using immunoassays that allow for processing large numbers of samples without the requirement of sample preparation before analysis. Until fairly recently, screening of lysergic acid diethylamide (LSD) in urine samples could only be accomplished by the use of radioimmunoassays (RIA). Recently, new nonisotopic immunoassays have been developed for the screening of samples for LSD. These assays lend themselves to rapid, high-volume, automated analysis compared with RIA procedures. In order to evaluate the current commercially available assays, samples prepared at known concentrations were tested by each of the assays. In addition, samples from known use of LSD were tested and the performance of each of the assays compared. The assays examined in this study included RIA assays from Roche Diagnostics (Abuscreen) and Diagnostic Products (coat-a-count) and nonisotopic assays from Roche (OnLine), Behring (EMIT), Boehringer Mannheim (CEDIA), and STC (Microplate EIA). Assays that could readily be carried out in a semiquantitative mode (determining concentration based on a calibration curve) were evaluated as to their relative response to the samples tested. All of the assays evaluated identified all of the samples which confirmed positive by gas chromatography-mass spectrometry (GC-MS). Likewise, each of the assays identified some samples which did not confirm as positive by GC-MS.

Detection of amphetamine following administration of fenproporex.

Drugs that are metabolized to amphetamine or methamphetamine are potentially significant concerns in the interpretation of amphetamine-positive drug testing results. A number of different compounds have been reported to produce amphetamine in the urine of users. One of these compounds, fenproporex, has been shown to produce amphetamine. Previous reports indicate that the parent compound can be detected only for a few hours following administration, whereas the amphetamine can be detected for several days. Administration of fenproporex to five healthy volunteers resulted in amphetamine being detected in the urine of all subjects. Peak concentrations of amphetamine were detected at approximately 6-20 h postdose and ranged from approximately 1200 to 2100 ng/mL amphetamine. Amphetamine could be detected (> 5 ng/mL) in the urine for up to 119 h. Analysis of the metabolically produced amphetamine showed the presence of both enantiomers, which can be helpful in the differentiation of some illicit amphetamine use from the use of this precursor drug. More significantly, all samples that contained amphetamine at a concentration of at least 500 ng/mL were shown to also contain measurable amounts of the parent compound.

Enantiomeric composition of amphetamine and methamphetamine derived from the precursor compound famprofazone.

Fourteen different metabolic precursors of amphetamine or methamphetamine have previously been identified. Many of these drugs are available only by prescription and several are only available in some parts of the world and not in others. One of these drugs, famprofazone, is available over-the-counter which complicates the interpretation of methamphetamine urine drug testing results. To assist in the interpretation of typical laboratory results, a study was conducted to determine the enantiomeric composition of the methamphetamine and amphetamine produced from the metabolism of famprofazone. Fifty mg of famprofazone was administered to a volunteer followed by collection of urine for the next 6 days. The resulting quantity, enantiomeric composition and percent conversion from famprofazone to the product amphetamine and methamphetamine was determined. The results showed the amphetamine and methamphetamine to include both the d- and l-enantiomers. Percent conversion and peak concentrations were similar to those reported in previous studies.

The pharmacokinetics of oxytocin as they apply to labor induction.

OBJECTIVE: Our purpose was to determine the relationship among plasma oxytocin levels, metabolic clearance rate of oxytocin, and uterine activity in gravid women undergoing labor induction. STUDY DESIGN: Ten women receiving oxytocin for labor induction and agreeing to participate had blood sampled before initiation of oxytocin and at different levels of uterine pressure. Samples were analyzed with 200 microliter extracts from 1 ml of plasma with an oxytocin radioimmunoassay. The intraassay coefficient of variation was < 3%. Sensitivity of the assay was 1.5 pg/ml. Pharmacokinetic parameters including plasma levels and metabolic clearance rates were calculated. Data were analyzed with the paired t test and linear and logistic regression. RESULTS: Mean oxytocin levels and metabolic clearance rates were 26.6 pg/ml and 7.97 ml/min. There was no correlation between changes in oxytocin level and metabolic clearance rate. Increases in infusion rates were correlated with increases in oxytocin levels (r = 0.71, p < 0.001). Cervical dilatation and uterine contraction pressures did not correlate with oxytocin levels. CONCLUSION: Peripheral plasma levels of oxytocin may not accurately reflect uterine activity or progress in labor. Plasma levels of oxytocin may merely reflect the rate of oxytocin infusion.

Evaluation of internal standards for the analysis of amphetamine and methamphetamine.

Deuterium-labeled analogues are available for a variety of drugs, but the amphetamines (amphetamine and methamphetamine) have more options available than any other drug. The analytical method and circumstances of its use can have a significant impact on the decision of what is the best internal standard to use. More than one method can give acceptable results; however, some circumstances can make a given internal standard a poor choice for a particular analysis. Increased choices of available candidates make the evaluation of an internal standard even more difficult. Thorough evaluation of the available options is a major undertaking and is presented here to assist laboratories in selection of the most appropriate internal standard for their individual needs. All commercially available deuterated analogues to amphetamine and methamphetamine were evaluated as part of this study. in addition, nonisotopically labeled propylamphetamine was also evaluated for comparison purposes. The compounds were analyzed underivatized and derivatized with trifluoroacetic anhydride, pentafluoropropionic anhydride, heptafluorobutyric anhydride, and 4-carbethoxyhexafluorobutyryl chloride on HP-1, HP-5, and DB-I 7 capillary columns. Mass spectral analysis revealed that several of the internal standards were not viable for monitoring ions typically associated with selected ion monitoring analysis of amphetamine and methamphetamine. These included amphetamine-d3 (1-phenyl-2-aminopropane-3,3,3-d3) and amphetamine-d5 (phenyl-d5), neither of which exhibits three unique ions. The d3 standard shares the common ion at m/z 91, acid d5 (phenyl) shares the base peak ion with derivatized amphetamine. Although methamphetamine-d6 and methamphetamine-d10 show three unique ions, they do not allow monitoring of the ion fragments typically used for methamphetamine. Evaluation of the limit of detection, linear range, and within-run and between-run variability was accomplished for each viable internal standard.

Interpretation of methamphetamine and amphetamine enantiomer data.

Interpretation of drug testing results is a challenging and complex task, particularly when the interpretation can result in establishing legitimate use of a drug or illicit use with all of its attendant complications (i.e., loss of job, criminal prosecution, etc.). One of the more challenging drugs to interpret is methamphetamine. While methamphetamine is a schedule II controlled substance, the l-enantiomer of methamphetamine is found in the Vick's Inhaler, which is a product exempted from control. For this reason, while identification of methamphetamine and amphetamine in the urine of an individual can clearly establish the use of methamphetamine, it does not prove the use of a controlled substance. Use of racemic methamphetamine can make the interpretation even more difficult because of the different metabolism and excretion of l- and d-methamphetamine. Enantiomeric characterization of methamphetamine may not give unequivocal results. Evaluation of experimentally derived and published data from urine samples containing l- and d,l-methamphetamine indicates that use of the enantiomeric distribution of amphetamine affords unambiguous interpretation. Because the l-enantiomer is the only possible finding in an individual who is using the Vick's Inhaler, detection of the d-enantiomer or a mixture of the d- and l-enantiomers clearly establishes the use of a controlled substance. Without a prescription from appropriate medical personnel, this detection would indicate the illicit use of a controlled substance.

The effects of adulterating agents on FPIA analysis of urine for drugs of abuse.

A variety of chemical agents were evaluated to determine their effects on fluorescence polarization immunoassays for drugs of abuse. Sixteen different agents, at concentrations up to 10%, were tested against urine assays for cannabinoids, cocaine (metabolite), amphetamines, opiates, phencyclidine (PCP), and barbiturates. The potential to cause both false positive and false negative results was evaluated, and assays were performed one and seven days after sample adulteration to simulate different collection/testing formats. All six drug assays were susceptible to one or more adulterating agents, but the degree varied considerably between assays. The cannabinoid assay was most susceptible to adulterant-induced false negative results, and the barbiturate assay was most susceptible to false positive results. The remaining assays demonstrated relatively few, but characteristic effects, some of which were attributable to drug degradation and others to assay interference. Although the results of pH measurement on adulterated samples verified its utility in identifying some samples adulterated with interfering agents, other adulterants that cause substantial effects would not be identified by pH measurements alone.

Fluorescence polarization immunoassay detection of amphetamine, methamphetamine, and illicit amphetamine analogues.

The Abbott Diagnostics Amphetamine/Methamphetamine II and Amphetamine Class reagents were evaluated on the Abbott TDx for cross-reactivity to amphetamine and methamphetamine stereoisomers, several of their metabolites, and various illicit analogues, including 2-methoxyamphetamine, 4-hydroxymethamphetamine, 2,5-dimethoxy-amphetamine (DMA), 4-bromo-2,5-dimethoxyamphetamine (DOB), 4-bromo-2,5-dimethoxy-beta-phenethylamine (BDMPEA), 3,4,5-trimethoxyamphetamine (TMA), 3,4-methylenedioxy-amphetamine (MDA) N,N-dimethyl-3,4-methylenedioxy-amphetamine, N-hydroxy-3,4-methylenedioxyamphetamine (N-OH MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), 2,5-dimethoxy-4-ethylamphetamine (DOE), 2,5-dimethoxy-4-methylamphetamine (DOM), and mescaline in concentrations ranging from 100 to 100,000 ng/mL. Results demonstrate the utility of this assay for detection of several of the above compounds; unfortunately many are still not detectable. Significant differences were observed between the Amphetamine/Methamphetamine II and Amphetamine Class reagents, particularly regarding their cross-reactivity to over-the-counter medications. Detection of the drugs amphetamine, methamphetamine, and the illicit analogues is not enhanced with the Amphetamine Class reagents, and unless detection of the over-the-counter compounds is of interest, these reagents are a poor choice compared to the Amphetamine/Methamphetamine II reagents. Cross-reactivity of some of the illicit analogues is such that the assay can reliably be used for the routine screening of these compounds.