A double-blind, placebo-controlled trial of modafinil for cocaine dependence

This is a randomized, double-blind, placebo-controlled study of modafinil treatment for cocaine dependence. Patients (N = 210) who were actively using cocaine at baseline were randomized to 8 weeks of modafinil (0 mg/day, 200 mg/day, or 400 mg/day) combined with once-weekly cognitive-behavioral therapy. Our primary efficacy measure was cocaine abstinence, based on urine benzoylecgonine (BE) levels, with secondary measures of craving, cocaine withdrawal, retention, and tolerability. We found no significant differences between modafinil and placebo patients on any of these measures. However, there was a significant gender difference in that male patients treated with 400 mg/day tended to be more abstinent than their placebo-treated counterparts (p = .06). Our negative findings might be explained by gender differences and/or inadequate psychosocial treatment intensity in patients with severe cocaine dependence.

Cocaine and metabolites by LC-MS/MS

Abuse of the stimulant cocaine (COC) is a common problem in the United States and elsewhere. The drug can be used either as the powder or as the free base (crack COC), and causes feelings of alertness and euphoria; both forms of COC are powerfully addictive. The assay described here is designed to detect and quantitate parent COC, its major metabolite benzoylecgonine, and a selection of metabolites that can provide specific information about sample validity (m-hydroxybenzoylecgonine), potential toxicity (norcocaine), route of administration (anhydroecgonine methyl ester), and co-utilization with ethanol (cocaethylene).

Identification of cocaine and its metabolites in urban wastewater and comparison with the human excretion profile in urine

The most relevant human urinary metabolites of cocaine (nine metabolites) were measured in urban wastewater in Italy and USA. A novel analytical method based on liquid chromatography tandem mass spectrometry allowed the identification of ecgonine, ecgonine methyl ester and the pyrolytic derivatives of cocaine in untreated wastewater. The aim of this study was to verify whether the pattern of cocaine metabolites in wastewater reflected the human excretion profile in urine. The performance of the method was good, with recoveries higher than 60% and limits of quantifications in the low ng/L range. The stability in untreated wastewater was assessed for all metabolites and the best storage condition resulted freezing samples immediately after collection and keep them frozen until analysis. All the selected compounds were measured in wastewater at concentrations up to 1.5 μg/L and their weekly loads were calculated during a five weeks monitoring campaign in Milan (Italy). The profiles of cocaine metabolites in wastewater matched with those in human urine reported in the literature, suggesting that measures in wastewater reflect the real human excretion and that wastewater analysis is suitable for assessing drug consumption. Benzoylecgonine was confirmed as the best target for estimating cocaine use by wastewater analysis, while cocaine itself should not be considered because its amount in wastewater is affected by other environmental sources such as transport, handling and consumption. Results suggested that the measurement of other metabolites in combination with benzoylecgonine might reflect 60% of an administered dose of cocaine providing also information on different patterns of use.

Contingency management is efficacious and improves outcomes in cocaine patients with pretreatment marijuana use

BACKGROUND

Marijuana use is common in patients seeking treatment for cocaine use. Nevertheless, few studies have examined effects of marijuana use on treatment outcomes in general, and even fewer with respect to contingency management (CM) treatment, which has been criticized for potentially increasing non-reinforced drug use.

METHODS

Data from three randomized clinical trials of CM versus standard treatment (ST) in cocaine-abusing patients were examined (Petry et al., 2004, 2005a, 2006a; N=393) to assess effects of pretreatment marijuana use on outcomes. Patients were divided into two groups: (1) no self-reported marijuana use (No Pre-M; n=315) and (2) any self-reported marijuana use (Pre-M; n=78) in the 30 days pretreatment.

RESULTS

CM was especially efficacious in enhancing retention in Pre-M patients such that retention nearly doubled among Pre-M patients assigned to CM versus those assigned to ST. In contrast, CM exerted only modest benefits on retention in No Pre-M patients. Pretreatment marijuana use was not related to during-treatment abstinence from cocaine, opioids, and alcohol, or abstinence at a Month 9 follow-up. However, CM treatment and longest duration of abstinence achieved during treatment were significant predictors of Month 9 abstinence. Pre-M patients also evidenced more improvements in drug problems over time when randomized to CM.

CONCLUSIONS

CM was especially efficacious in facilitating retention and improving severity of drug-related problems in those who used marijuana in the month before initiating treatment.

Buprenorphine/naloxone versus methadone in opioid dependence: a longitudinal survey

BACKGROUND AND OBJECTIVES

Buprenorphine and methadone are widely used for the treatment of opioid dependence, but their diversion and/or misuse are frequent. In principle, buprenorphine/naloxone combination therapy should be associated with a lower frequency of drug abuse/misuse than methadone. This study assessed the efficacy of the substitution of buprenorphine treatment with the buprenorphine/naloxone combination in opioid-dependent patients.

MATERIAL AND METHODS

3812 drug-addicted outpatients selected from 10 Italian Public Services for Addiction (Ser.T.) centres in Naples (Italy) were enrolled: 3105 (81.5%) were treated with methadone and 707 (18.5%) with buprenorphine. The buprenorphine treatment was switched to buprenorphine/naloxone (4:1), and the patients were followed for about 1 year. The number of subjects still on treatment after 1 year, their status according to social, educational and toxicologic (assessed by a urine toxicology test) parameters were assessed.

RESULTS

1 year after the therapy switch, the number of patients still on treatment was similarly reduced with methadone (2883; -7.5%) and buprenorphine/naloxone (632; -10.6%; p=0.369). However, in patients treated with buprenorphine/naloxone, a significant improvement was reported in social life status (63% versus 39% of the buprenorphine/naloxone and methadone treated subjects, respectively, were married/cohabiting p<0.001), in the educational level (43% of buprenorphine/naloxone treated versus 32% of the methadone treated subjects obtained at least a high school certificate, p<0.001) and in the toxicological conditions (53% of buprenorphine/naloxone treated subject versus 30% of methadone treated individuals had opioid- and cocaine- negative urine tests, p<0.001).

DISCUSSION

These preliminary data suggest that buprenorphine/naloxone treatment of opioid dependence reduces the percentage of treated subjects similarly to methadone, and is associated with an improvement in social life, educational and toxicological conditions, compared with methadone treatment. However, we cannot exclude a selection bias, i.e. patients who were more likely to stabilize their opiate dependence switched to buprenorphine/naloxone.

Employment-based reinforcement of adherence to depot naltrexone in unemployed opioid-dependent adults: a randomized controlled trial

AIMS

Naltrexone can be used to treat opioid dependence, but patients refuse to take it. Extended-release depot formulations may improve adherence, but long-term adherence rates to depot naltrexone are not known. This study determined long-term rates of adherence to depot naltrexone and whether employment-based reinforcement can improve adherence.

DESIGN

Participants who were inducted onto oral naltrexone were assigned randomly to contingency (n = 18) or prescription (n = 17) groups. Participants were offered six depot naltrexone injections and invited to work at the therapeutic workplace on week days for 26 weeks, where they earned stipends for participating in job skills training. Contingency participants were required to accept naltrexone injections to maintain workplace access and to maintain maximum pay. Prescription participants could work independently of whether they accepted injections.

SETTING

The therapeutic workplace, a model employment-based intervention for drug addiction and unemployment.

PARTICIPANTS

Opioid-dependent unemployed adults.

MEASUREMENTS

Depot naltrexone injections accepted and opiate-negative urine samples.

FINDINGS

Contingency participants accepted significantly more naltrexone injections than prescription participants (81% versus 42%), and were more likely to accept all injections (66% versus 35%). At monthly assessments (with missing urine samples imputed as positive), the groups provided similar percentages of samples negative for opiates (74% versus 62%) and for cocaine (56% versus 54%). Opiate-positive samples were more likely when samples were also positive for cocaine.

CONCLUSIONS

Employment-based reinforcement can maintain adherence to depot naltrexone. Future research should determine whether persistent cocaine use compromises naltrexone's effect on opiate use. Workplaces may be useful for promoting sustained adherence to depot naltrexone.

Randomized, double blind, placebo-controlled trial of disulfiram for the treatment of cocaine dependence in methadone-stabilized patients

This study examined the dose-related efficacy of disulfiram for treating cocaine dependence in methadone-stabilized cocaine dependent participants.

DESIGN

One hundred and sixty-one cocaine- and opioid-dependent volunteers were entered into a 14-week, double blind, randomized, placebo-controlled clinical trial at two sites.

METHODS

Participants were stabilized on methadone during weeks 1-2 and received disulfiram at 0, 62.5, 125 or 250 mg/day during weeks 3-14. All participants also received weekly cognitive behavioral therapy. Thrice-weekly urine samples and weekly self-reported drug use assessments were obtained.

RESULTS

Baseline subject characteristics, retention and drug use did not differ across groups. Outcome analyses were performed on those who participated beyond week 2. Opioid-positive urine samples and self-reported opioid use did not differ by treatment group. The prevalence of alcohol use was low prior to and during the trial and did not differ by treatment group. Cocaine-positive urines increased over time in the 62.5 and 125 mg disulfiram groups and decreased over time in the 250 mg disulfiram and placebo groups (p < 0.0001). Self-reported cocaine use increased in the 125 mg disulfiram group relative to the other three treatment groups (p = 0.04).

CONCLUSIONS

Disulfiram may be contraindicated for cocaine dependence at doses <250 mg/day. Whether disulfiram at higher doses is efficacious in reducing cocaine use in dually cocaine and opioid dependent individuals needs to be determined.

Extended voucher-based reinforcement therapy for long-term drug abstinence

OBJECTIVE

To determine whether longer durations of voucher-based reinforcement therapy (VBRT) increase long-term abstinence compared to standard durations.

METHODS

Cocaine-abusing or dependent methadone-maintenance patients (N = 130) were randomized to receive either Standard (12-week; n = 62) or Extended (36-week; n = 68) VBRT. Participants provided 3 urine samples weekly during VBRT, and each cocaine-negative sample produced a voucher exchangeable for goods and services.

RESULTS

Extended VBRT produced longer durations of self-reported continuous abstinence during study Year 1 (M = 74 vs. 46 days; F(1,128) = 5.23, P = 0.024), but not during Year 2. However, each week of abstinence during Year 1 was associated with an increase of 9.19 days of abstinence during Year 2, regardless of study condition (t(1) = 4.92, P < 0.001).

CONCLUSIONS

Longer-duration VBRT can increase abstinence during VBRT, but may not maintain it afterwards. However, longer during-treatment abstinence begets later abstinence suggesting that further research regarding this relationship is needed.

Contingency management and levodopa-carbidopa for cocaine treatment: a comparison of three behavioral targets

New data support use of levodopa pharmacotherapy with behavioral contingency management (CM) as one efficacious combination in cocaine dependence disorder treatment. A potential mechanism of the combined treatment effects may be related to dopamine-induced enhancement of the saliency of contingently delivered reinforcers. Evidence to support this mechanism was sought by evaluating levodopa-enhancing effects across distinct CM conditions that varied in behavioral targets. A total of 136 treatment-seeking, cocaine dependent subjects participated in this 12-week, randomized, placebo-controlled trial of levodopa (vs. placebo) administered in combination with one of three behavioral CM conditions. In the CM-URINE condition, subjects received cash-valued vouchers contingent on cocaine-negative urine toxicology results. In the CM-ATTEND condition, the same voucher schedule was contingent on attending thrice weekly clinic visits. In the CM-MEDICATION condition, the same voucher schedule was contingent on Medication Event Monitoring Systems- and riboflavin-based evidence of pill-taking behavior. Primary outcomes associated with each CM target behavior were analyzed using generalized linear mixed models for repeated outcomes. CM responding in the CM-ATTEND and CM-MEDICATION conditions showed orderly effects, with each condition producing corresponding changes in targeted behaviors, regardless of medication condition. In contrast, CM responding in the CM-URINE condition was moderated by medication, with levodopa-treated subjects more likely to submit cocaine-negative urines. These findings specify the optimal target behavior for CM when used in combination with levodopa pharmacotherapy.

An evaluation of the diagnostic accuracy of liquid chromatography-tandem mass spectrometry versus immunoassay drug testing in pain patients

BACKGROUND

Immunoassay screening is used by pain physicians to determine compliance with controlled substances. Because clinical use of pain medications is different from illicit drug use, there is a need to evaluate the level of diagnostic accuracy of this procedure for the pain patient.

OBJECTIVE

To compare the results of automated screening by immunoassay with analysis by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) in identifying pain patients using illicit drugs and pain patients excreting low concentrations of their prescribed medications.

STUDY DESIGN

A diagnostic accuracy study.

METHODS

Urine samples from 4,200 pain patients were tested by immunoassay and LC-MS/MS for the following drugs and metabolites: Amphetamine, Methamphetamine, Alpha-hydroxyalprazolam, Lorazepam, Nordiazepam, Oxazepam, Temazepam, Cannabinoids, Cocaine, Methadone, Methadone Metabolite, Codeine, Hydrocodone, Hydromorphone, Morphine, Propoxyphene, and Norpropoxyphene.

RESULTS

In a number of patients negative immunoassay findings were superseded by positive results on analysis by Mass Spectrometry. These were termed false negative results. The greatest failures were for the benzodiazepines (28%) and for cocaine (50%).

LIMITATIONS

The study was limited by the lack of complete demographics for the cohort and because only one immunoassay diagnostic product was used. It was also limited because not all drugs react the same in the immunoassay.

CONCLUSIONS

We show that in general, immunoassay screening results are accurate, although as shown in this study there are many false negative observations. The use of LC-MS/MS technology significantly decreases the number of false negative results.

Randomized trial of continuing care enhancements for cocaine-dependent patients following initial engagement

OBJECTIVE

The effects of cognitive-behavioral relapse prevention (RP), contingency management (CM), and their combination (CM + RP) were evaluated in a randomized trial with 100 cocaine-dependent patients (58% female, 89% African American) who were engaged in treatment for at least 2 weeks and had an average of 44 days of abstinence at baseline.

METHOD

The participants were from intensive outpatient programs, which provide 10 hr per week of group counseling. The CM protocol provided gift certificates (maximum value $1,150; mean received = $740) for cocaine-free urines over 12 weeks on an escalating reinforcement schedule, and weekly individual RP sessions were offered for up to 20 weeks. Average number of RP sessions attended was 3 in RP and 13 in CM + RP.

RESULTS

Generalizing estimation equation analyses over 18 months postrandomization showed significant effects for CM (but not RP) on urine toxicology and self-reported cocaine use (p = .05), with no significant CM x RP interactions. Secondary analyses indicated CM + RP produced better cocaine urine toxicology outcomes at 6 months than treatment as usual, odds ratio [OR] = 3.96 (1.33, 11.80), p < .01, and RP, OR = 4.89 (1.51, 15.86), p < .01, and produced better cocaine urine toxicology outcomes at 9 months than treatment as usual, OR = 4.21 (1.37, 12.88), p < .01, and RP, OR = 4.24 (1.32, 13.65), p < .01. Trends also favored CM + RP over CM at 6 months, OR = 2.93 (0.94, 9.07), p = .06, and 9 months, OR = 2.93 (0.94, 9.10), p = .06. Differences between the conditions were not significant after 9 months.

CONCLUSIONS

These results suggest CM can improve outcomes in cocaine-dependent patients in intensive outpatient programs who have achieved initial engagement, particularly when it is combined with RP.

Tunable detection sensitivity of opiates in urine via a label-free porous silicon competitive inhibition immunosensor

Currently, there is need for laboratory-based high-throughput and reliable point-of-care drug screening methodologies. We demonstrate here a chip-based label-free porous silicon (PSi) photonic sensor for detecting opiates in urine. This technique provides a cost-effective alternative to conventional labeled drug screening immunoassays with potential for translation to multiplexed analysis. Important effects of surface chemistry and competitive binding assay protocol on the sensitivity of opiate detection are revealed. Capability to tune sensitivity and detection range over approximately 3 orders of magnitude (18.0 nM to 10.8 muM) was achieved by varying the applied urine specimen volume (100-5 muL), which results in systematic shifts in the competitive binding response curve. A detection range (0.36-4.02 muM) of morphine in urine (15 muL) was designed to span the current positive cutoff value (1.05 muM morphine) in medical opiate urine screening. Desirable high cross-reactivity to oxycodone, in addition to other common opiates, morphine, morphine-3-glucuronide, 6-acetyl morphine, demonstrates an advantage over current commercial screening assays, while low interference with cocaine metabolite was maintained. This study uniquely displays PSi sensor technology as an inexpensive, rapid, and reliable drug screening technology. Furthermore, the versatile surface chemistry developed can be implemented on a range of solid-supported sensors to conduct competitive inhibition assays.

Modafinil does not serve as a reinforcer in cocaine abusers

The purpose of this double-blind, randomized, outpatient study was to evaluate the reinforcing and subjective effects of modafinil (200, 400, or 600 mg) in cocaine abusers. Twelve participants (2 female, 10 male) completed this study, consisting of 3 blocks of 7 sessions; each block tested a difference dose of modafinil. During the first 2 sessions of each block, participants "sampled" 1 of the doses of modafinil, and placebo. These doses of modafinil and placebo were available for the subsequent five choice sessions of the block. In each choice session, participants had an opportunity to administer active or placebo capsules. Modafinil administration did not differ from placebo administration, and subjective-effects ratings were not systematically altered as a function of modafinil dose. Results suggest that modafinil does not have abuse liability in cocaine abusers.

The association between cocaine use and treatment outcomes in patients receiving office-based buprenorphine/naloxone for the treatment of opioid dependence

Cocaine use in patients receiving methadone is associated with worse treatment outcomes. The association between cocaine use and office-based buprenorphine/naloxone treatment outcomes is not known. We evaluated the association between baseline and in-treatment cocaine use, treatment retention, and urine toxicology results in 162 patients enrolled in a 24-week trial of primary care office-based buprenorphine/naloxone maintenance. Patients with baseline cocaine metabolite-negative urine toxicology tests compared with those with cocaine metabolite-positive tests had more mean weeks of treatment retention (18.3 vs. 15.8, p = .04), a greater percentage completed 24 weeks of treatment (50% vs. 33%, p = .04) and had a greater percentage of opioid-negative urines (47% vs. 34%, p = .02). Patients with in-treatment cocaine metabolite-negative urine toxicology tests compared with cocaine metabolite-positive patients had more mean weeks of treatment retention (19.0 vs. 16.5, p = .003), a greater percentage completed 24 weeks of treatment (60% vs. 30%, p < .001), and had a greater percentage of opioid-negative urines (51% vs. 35%, p = .001). We conclude that both baseline and in-treatment cocaine use is associated with worse treatment outcomes in patients receiving office-based buprenorphine/naloxone and may benefit from targeted interventions.

Quantitation of cocaine, benzoylecgonine, ecgonine methyl ester, and cocaethylene in urine and blood using gas chromatography-mass spectrometry (GC-MS)

Cocaine, a stimulant, is a commonly abused drug. Cocaine and its metabolites are measured in various biological specimens for clinical and forensic purposes. Urine or plasma or serum is spiked with deuterated internal standards cocaine-d3, benzoylecgonine-d3, ecgonine methyl ester-d3, and cocaethylene-d3 and buffered with phosphate buffer. The drugs in the sample are extracted by cation-exchange solid phase extraction. The drugs from the solid phase cartridge are eluted and the eluent is dried under the stream of nitrogen. The residue is incubated with pentafluoropropionic acid anhydride and pentafluoropropanol to form pentafluoropropionyl derivatives of ecgonine methyl ester and benzoylecgonine. Cocaine and cocaethylene are refractory to derivatization. The extract is dried, reconstituted in ethyl acetate, and injected into gas chromatography mass-spectrometry analyzer. Quantitation of the drugs in the samples is made, using selected ion monitoring, from a 3-point calibration curve.

Simultaneous liquid chromatography-mass spectrometry quantification of urinary opiates, cocaine, and metabolites in opiate-dependent pregnant women in methadone-maintenance treatment

Opiates, cocaine, and metabolites were quantified by liquid chromatography-mass spectrometry (LC-MS) in 284 urine specimens, collected thrice weekly, to monitor possible drug relapse in 15 pregnant heroin-dependent women. Opiates were detected in 149 urine specimens (52%) with limits of quantification (LOQ) of 10-50 microg/L. Morphine, morphine-3-glucuronide, and/or morphine-6-glucuronide were positive in 121 specimens; 6-acetylmorphine, a biomarker of heroin ingestion, was quantifiable in only 7. No heroin, 6-acetylcodeine, papaverine, or noscapine were detected. One hundred and sixty-five urine specimens (58%) from all 15 participants were positive for one or more cocaine analytes (LOQ 10-100 microg/L). Ecgonine methylester (EME) and/or benzoylecgonine were the major cocaine biomarkers in 142. Anhydroecgonine methylester, a biomarker of smoked cocaine, was positive in six; cocaethylene and/or ecgonine ethylester, biomarkers of cocaine and ethanol co-ingestion, were found in 25. At the current Substance Abuse Mental Health Services Administration cutoffs for total morphine (2000 microg/L), codeine (2000 microg/L), 6-acetylmorphine (10 microg/L), and benzoylecgonine (100 microg/L), 16 opiate- and 29 cocaine-positive specimens were identified. Considering 100 microg/L EME as an additional urinary cocaine biomarker would identify 51 more positive cocaine specimens. Of interest is the differential pattern of opiate and cocaine biomarkers observed after LC-MS as compared to gas chromatography-mass spectrometry analysis.

A randomized clinical trial of methadone maintenance for prisoners: results at 12 months postrelease

This study examined the impact of prison-initiated methadone maintenance at 12 months postrelease. Males with pre-incarceration heroin dependence (N = 204) were randomly assigned to (a) Counseling Only: counseling in prison, with passive referral to treatment upon release; (b) Counseling + Transfer: counseling in prison with transfer to methadone maintenance treatment upon release; and (c) Counseling + Methadone: counseling and methadone maintenance in prison, continued in the community upon release. The mean number of days in community-based drug abuse treatment were, respectively, Counseling Only, 23.1; Counseling + Transfer, 91.3; and Counseling + Methadone, 166.0 (p < .01); all pairwise comparisons were statistically significant (all ps < .01). Counseling + Methadone participants were also significantly less likely than participants in each of the other two groups to be opioid-positive or cocaine-positive according to urine drug testing. These results support the effectiveness of prison-initiated methadone for males in the United States. Further study is required to confirm the findings for women.

Comparison of urine results concerning co-consumption of illicit heroin and other drugs in heroin and methadone maintenance programs

Urine samples of patients from a heroin maintenance program (HMP) and a methadone maintenance program (MMP) were chromatographically analyzed 1 month before and 6 and 12 months into treatment for the presence of classical markers of heroin use as well as for the presence of markers for illicit heroin abuse. Furthermore, the samples were immunochemically tested for cannabinoids, cocaine metabolites, amphetamine, methylendioxyamphetamines and benzodiazepines. A co-consumption of illicit heroin (HER) in the HMP was determined to be 50% but was significantly lower compared to the MMP with a co-use of 71%. The incidence was high because not only acetylcodeine (AC) as a very specific marker was considered but also other marker substances for illicit HER use. Amphetamines played only a minor part in both collectives, and the proportion of HER and methadone patients using cocaine was similar and decreased during treatment. Also, the benzodiazepine use decreased, and cannabis use was high in both collectives during treatment. Considering only the AC in the present study, a co-use of illicit HER in the HMP was similar to previous reports concerning HER-assisted treatment programs. If additional marker substances were examined, the suspicion of a co-use of illicit HER is markedly enhanced.

Individual and community risk factors and sexually transmitted diseases among arrested youths: a two level analysis

High rates of infection for chlamydia and gonorrhea have been noted among youths involved in the juvenile justice system. Although both individual and community-level factors have been found to be associated with sexually transmitted disease (STD) risk, their relative importance has not been tested in this population. A two-level logistic regression analysis was completed to assess the influence of individual-level and community-level predictors on STD test results among arrested youths processed at a centralized intake facility. Results from weighted two level logistic regression analyses (n = 1,368) indicated individual-level factors of gender (being female), age, race (being African American), and criminal history predicted the youths' positive STD status. For the community-level predictors, concentrated disadvantage significantly and positively predicted the youths' STD status. Implications of these findings for future research and public health policy are discussed.

Cocaine Withdrawal Symptoms Predict Medication Response in Cocaine Users

The purpose of this study was to examine the influence of cocaine withdrawal symptoms on addiction severity and treatment outcomes in methadone stabilized cocaine users who participated in pharmacotherapy trials using gamma-aminobutyric acid (GABA) medications. Subjects who fulfilled DSM-IV cocaine withdrawal criteria (n = 45), compared to those who did not (n = 40), showed a greater increase in cocaine free urines in response to pharmacotherapy with GABA medications. Altogether, our results and previous studies support the clinical utility of cocaine withdrawal symptoms in predicting treatment response to medications, such that low withdrawal severity may predict better treatment response to GABA medications, while high withdrawal severity may predict better response to adrenergic blockers. This hypothesis needs to be tested in prospective clinical trials.

Screening of cocaine and its metabolites in human urine samples by direct analysis in real-time source coupled to time-of-flight mass spectrometry after online preconcentration utilizing microextraction by packed sorbent

Microextraction by packed sorbent (MEPS) has been evaluated for fast screening of drugs of abuse with mass spectrometric detection. In this study, C8 (octyl-silica, useful for nonpolar to moderately polar compounds), ENV(+) (hydroxylated polystyrene-divinylbenzene copolymer, for extraction of aliphatic and aromatic polar compounds), Oasis MCX (sulfonic-poly(divinylbenzene-co-N-polyvinyl-pyrrolidone) copolymer), and Clean Screen DAU (mixed mode, ion exchanger for acidic and basic compounds) were used as sorbents for the MEPS. The focus was on fast extraction and preconcentration of the drugs with rapid analysis using a time-of-flight (TOF) mass spectrometer as the detector with direct analysis in a real-time (DART) source. The combination of an analysis time of less than 1 min and accurate mass of the first monoisotopic peak of the analyte and the relative abundances of the peaks in the isotopic clusters provided reliable information for identification. Furthermore, the study sought to demonstrate that it is possible to quantify the analyte of interest using a DART source when an internal standard is used. Of all the sorbents used in the study, Clean Screen DAU performed best for extraction of the analytes from urine. Using Clean Screen DAU to extract spiked samples containing the drugs, linearity was demonstrated for ecgonine methyl ester, benzoylecgonine, cocaine, and cocaethylene with average ranges of: 65-910, 75-1100, 95-1200, and 75-1100 ng/mL (n = 5), respectively. The limits of detection (LOD) for ecgonine methyl ester, benzoylecgonine, cocaine, and cocaethylene were 22.9 ng/mL, 23.7 ng/mL, 4.0 ng/mL, and 9.8 ng/mL respectively, using a signal-to-noise ratio of 3:1.

[Simultaneous analyses of cocaine and its metabolite benzoylecgonine in urine by LC-MS/MS]

OBJECTIVE

To establish a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous analysis of cocaine (COC) and its metabolite benzoylecgonine(BZE) in urine samples.

METHODS

A single dose of COC (10 mg/kg) was injected intraperitoneally into guinea pigs and urine samples were collected for 7 days. The urine samples were extracted by auto solid phase extraction (SPE), separated by the Allure PFP propyl column with a mobile phase consisting of methanol and 20 mmol/L ammonium acetate buffer [0.1% formic acid (80:20, V/V)], and then analyzed by LC-MS/MS. Multiple reaction monitoring (MRM) mode was used to analyze COC (m/z 304.2-->182.3, m/z 304.2-->150.1) and BZE (m/z 290.2-->168.3, m/z 290.2-->105.0).

RESULTS

COC and BZE showed a fairly good linearity over the range of 2.0-100 ng/mL (r=0.9995). The detection limit was 0.5 ng/mL. The recovery rate was greater than 90% and the deviation of intra- and inter-day precision was less than 6%. BZE was the major target detected in urine samples, and its detection window was longer than COC.

CONCLUSION

This newly developed method shows high sensitivity and selectivity, and is suitable for the simultaneous analysis of cocaine and benzoylecgonine in urine samples.