Drugs for youth via Internet and the example of mephedrone.

Recently a new class of "designer drugs" has emerged on the drugs abuse market, known as "legal highs". Such drugs are legal to use and possess, and legal to supply. Mephedrone, a central nervous system stimulant, is the most widely experienced "legal high". This review presents any available information about psychoactive properties, safety profile, clinical data, and legislation of the new "legal high" and emphasizes the role of Internet with mephedrone's expansion. Available data were collected by various literature search engines and World Wide Web. All valuable information about psychoactive properties, safety profile and clinical data for mephedrone and its use as "legal high" were managed to spot and summarise. Internet plays a significant role for the distribution of "legal highs", becoming one of the major "drug market". Adolescents and young adults who are curious about drugs may search on the Internet and thereby become exposed to thousands of sites that expound upon the positive effects of drugs and downplay or deny any negative effects. Use of mephedrone is mainly a youth phenomenon. The hazardous side-effects are strong desire to re-dose, uncomfortable changes in body temperature and heart rate, hallucinations and psychosis.

Validated GC/MS method for the simultaneous determination of clozapine and norclozapine in human plasma. Application in psychiatric patients under clozapine treatment.

A sensitive and specific GC/MS method for the determination of clozapine (CLZ) and its major metabolite norclozapine (NCLZ), in plasma has been developed, optimized and validated. Specimen preparation includes solid-phase extraction of both analytes using Bond-Elut Certify cartridge and further derivatization with TFAA. Clozapine-d8 was used as internal standard for the determination of CLZ and NCLZ. Limits of detection were 0.45 ng/mL for CLZ and 1.59 ng/mL for NCLZ, while limits of quantification were 1.37 ng/mL for CLZ and 4.8 ng/mL for NCLZ, as calculated by the calibration curves. The calibration curves were linear up to 600 ng/mL for CLZ and NCLZ. Absolute recovery ranged from 82.22% to 95.35% for both analytes. Intra- and interday accuracy was less than 7.13% and --12.52%, respectively, while intra- and interday precision was between 9.47% and 12.07%, respectively, for CLZ and NCLZ. The method covers all therapeutic range and proved suitable for the determination of CLZ and NCLZ not only in psychiatric patients but also in forensic cases with clozapine implication.

Spice drugs as a new trend: mode of action, identification and legislation.

The present review highlights the existing monitoring and legislation status of synthetic cannabinoids in "Spice" products and alert research community about the identification and risk assessment problems of these compounds. Available data were collected by various literature search engines. All valuable information about psychoactive properties, safety profile, clinical data and detection problems for synthetic cannabinoids and their use as "herbal highs" were managed to spot and summarise. "Spice" contains synthetic cannabinoids that bind to cannabinnoid-like receptors and they are stronger than natural cannabis. Chronic abuse of "Spice" has linked with signs of addiction syndrome and withdrawal symptoms similar to syndromes observed in cannabis abuse. These cannabinoids can be considered as new products to be added to the list of "designer drugs". Although it remains unclear where and how the actual production of the herbal mixtures takes place, it is evident that producers are purposely risk the health of consumers to skim high profits. Only recently a number of countries in Europe, as well as in US and Canada banned the use of these substances. The difficulty in identification of related compounds leads to the necessity for the availability of reference standards in order to aid toxicological analyses.

Investigation of the identification point system adaptation in cocaine, benzoylecgonine and ecgonine methyl ester using a single quadrupole mass spectrometer.

At present, no official criteria exist for drug identification using single quadrupole mass spectrometers although the European Union (EU) criteria for compound identification have been adopted. These criteria are evaluated with respect to the confirmation of cocaine and its metabolites by single quadrupole liquid chromatography/mass spectrometry (LC/MS) and problems are highlighted. Spiked samples, proficiency testing samples, certified reference materials and samples from real cases that had screened positive for cocaine derivatives by immunoassay were subjected to confirmation by LC/MS using single ion monitoring with in-source fragmentation. The EU criteria for compound identification were applied for the confirmation of cocaine, benzoylecgonine and ecgonine methyl ester. The use of the identification point (IP) system in spiked, proficiency testing samples and certified reference materials provided acceptable results in all cases while in some cases real positive samples did not provide acceptable results. Failure to meet the EU criteria was attributed to low fragmentation at the lower concentrations and the ion suppression effect while both factors affected compliance with the IP system. The identification of cocaine and its metabolites was considerably improved by using a combination of ammonium formate and formic acid as the LC mobile phase. It appears that poor in-source fragmentation in single quadrupole LC/MS and ion suppression may constitute a problem with drug identification when implementing the IP system in real samples, resulting in false negative results. Further investigation is needed for the use of such IP systems to be suitable for use in LC/MS methods.

Application of the ion pair concept to the n-octanol-water partitioning of cefepime and cefpirome.

The ion pair concept was applied for the assessment of lipophilicity of cefepime and cefpirome. Octanol-water distribution coefficients were determined in presence of different concentrations [X-] of sodium octanesulphonate. The log Dx values within the linear part of the log Dx/[X-] relationships were extrapolated to log Do values corresponding to the partitioning in absence of the counter ion. Measurements were feasible at pH values close to the isoelectric points of the acidic and basic functions. In that pH range the conduction of the experiments in presence of the hydrophobic counter anion facilitated the partitioning of the two cephalosporins to octanol, circumventing the problems arising from their high hydrophilicity. This procedure could not be applied at lower pH, possibly due to a further drastic decrease in the 'intrinsic' lipophilicity or to reduced ion pairing potential of octanesulphonate, and at higher pH due to the disruption of the zwitterionic structure. Extrapolated log Do values were compared to actual log D measurements performed for a reference quinolinium compound and for cefpirome. Extrapolated retention factors log kw close to the isoelectric point were also determined by reversed phase HPLC and compared to the log Do values.

Bioequivalence evaluation of two brands of glimepiride 4 mg tablets in healthy subjects.

OBJECTIVE: This paper describes a bioequivalence study with two oral glimepiride (4 mg) tablets formulations. The reference preparation was Solosa/Aventis Pharmaceuticals Inc., USA, and the test preparation was Glimepiride/Specifar, Athens, Greece. SUBJECTS, MATERIAL AND METHODS: The study design was open, randomized, two-period, two-sequence, two-treatment with crossover involving 24 healthy male and female subjects. All subjects completed the study. Glimepiride plasma concentrations were measured utilizing a sensitive, reproducible and accurate HPLC method. Pharmacokinetic parameters used to assess bioequivalence were AUC(0_last), AUC(0-inf) for the extent of absorption and Cmax and tmax for the rate of absorption. Statistical evaluation of Cmax, AUC(0_last), and AUC(0-inf) was done after semilogarithmic transformation using a two-way analysis of variance (ANOVA). Tmax values were tested using the distribution-free Hodges-Lehman interval. RESULTS AND CONCLUSION: The parametric 90% confidence intervals for ratio T/R ranged from 90.60-108.00% (point estimate 98.90%) for AUC(0-last), 90.70-107.90% (point estimate 98.90%) for AUC(0-inf) and 86.70-103.70% (point estimate 94.80%) for Cmax, respectively. Based on the results of tmax, Kel and t(1/2), there were no statistically significant differences and the two glimepiride preparations are equivalent with respect to rate and extent of absorption as defined by the European Union bioequivalence requirements.

Investigation of the retention/pH profile of zwitterionic fluoroquinolones in reversed-phase and ion-interaction high performance liquid chromatography.

The retention/pH profiles of three fluoroquinolones, ofloxacin, norfloxacin and ciprofloxacin, was investigated by means of reversed-phase high performance liquid chromatography (RP-HPLC) and reversed-phase ion-interaction chromatography (RP-IIC), using an octadecylsilane stationary phase and acetonitrile as organic modifier. Sodium hexanesulphonate and tetrabutylammonium hydroxide were used as sources of counter ions in ion-interaction chromatography. The retention/pH profiles under in RP-HPLC were compared to the corresponding lipophilicity/pH profiles. Despite the rather hydrophilic nature of the three fluoroquinolones positive retention factors were obtained while there was a shift of the retention maximum towards more acidic pH values. This behavior was attributed mainly to non-hydrophobic silanophilic interactions with the silanized silica gel material of the stationary phase. In ion-interaction chromatography the effect of counter ions over a broad pH range was found to be ruled rather by the ion pair formation in the mobile phase which led to a drastic decrease in retention as a consequence of the disruption of the zwitterionic structure and thereupon the deliberation of a net charge in the molecules. At pH values at which zwitterionic structure was not favored both the ion-exchange and ion pair formation mechanisms were assumed to contribute to the retention.

Bioequivalence evaluation of 2 brands of cefuroxime axetil 250 mg tablets in healthy human volunteers.

OBJECTIVE: To assess the bioequivalence of 2 oral cefuroxime axetil (250 mg) tablets formulation. The reference preparation was Zinadol/Glaxo Wellcome, England, while the test preparation was cefuroxime axetil/Pharmathen, Athens, Greece. SUBJECTS, MATERIAL AND METHODS: The study was an open, randomized, 2-period, 2-sequence, 2-treatment crossover, involving 24 healthy male and female volunteers. All volunteers completed the study. Cefuroxime axetil plasma concentrations were measured utilizing a sensitive, reproducible and accurate HPLC method. Care was taken through the collection and analysis of the samples due to instability of cefuroxime axetil in light. Pharmacokinetic parameters used to assess bioequivalence were AUC(0-last), AUC(0-inf) for the extent of absorption and Cmax and tmax for the rate of absorption. Statistical evaluation of Cmax, AUC(0-last), and AUC(0-inf) was done using 2-way analysis of variance (ANOVA) after semilogarithmic transformation. Tmax values were tested using the distribution-free Hodges-Lehman interval. RESULTS: The parametric 90% confidence intervals for ratio T/R ranged from 98.91-111.65% (point estimate 105.09%) for AUC(0-last), 99.41-111.78% (point estimate 105.41%) for AUC(0-inf) and 87.61-102.89% (point estimate 94.95%) for Cmax, respectively. Based on the results of tmax, K(el) and t(1/2) there were no statistically significant differences. CONCLUSION: The 2 cefuroxime axetil preparations, examined in accordance with the European Union bioequivalence requirements, are equivalent with respect to rate and extent of absorption.

Assay for the simultaneous determination of acetaminophen-caffeine-butalbital in human serum using a monolithic column.

A fast and sensitive high performance liquid chromatography (HPLC) assay was developed on a C18 monolithic column for the simultaneous determination of acetaminophen-caffeine-butalbital in human serum. Serum samples were treated with a solid phase extraction procedure. The analytes were separated using a mobile phase of 95:5 (v/v) 0.1M potassium phosphate monobasic (pH 2.41)-acetonitrile on the C18 monolithic column with detection at 220 nm. Benzoic acid was used as the internal standard (IS). The method was validated over the range of 1.25-100 microg/ml for each drug and found to be linear (r > 0.995, n = 12) with RSD less than 8.3%. The method proved to be accurate (percent bias for all calibration samples varied from -14.6 to -1.3%) and precise (ranged from 2.9 to 13.4%). The mean percent absolute recoveries from serum were 89.7 +/- 3.6 for acetaminophen, 95.5 +/- 4.5 for caffeine, 99 +/- 5.2 for butalbital and 83.4 +/- 3.9% for the internal standard.

Direct injection HPLC method for the determination of selected benzodiazepines in plasma using a Hisep column.

A direct plasma injection HPLC method has been developed for the determination of selected benzodiazepines (nitrazepam, clobazam, oxazepam, lorazepam). The method uses an analytical hydrophobic shielded phase (Hisep) column equipped with a Hisep guard column, are easy to perform and requires 20 ul of a filtered plasma sample. The chromatographic run time is less than 15 min using a mobile phase of 15:85 v/v acetonitrile-0.18 M ammonium acetate pH 2.5. The method is good for 175 injections before replacement of the guard column. The method was linear in the range 0.5-18 ug ml(-1) (r>0.99, n=6) for the analytes with R.S.D. less than 10.82%. Interday and intraday variability were found to be less than 14%. The limits of detection and quantitation were 0.16 (s/n>3) and 0.5 ug ml(-1) (s/n>10), respectively, for each of the four benzodiazepines.

Direct injection HPLC method for the determination of selected phenothiazines in plasma using a Hisep column.

A direct plasma injection HPLC method has been developed for the determination of selected phenothiazines (promethazine, promazine, chlorpromazine) using a Hisep column. The method is easy to perform and requires 20 microL of a filtered plasma sample. The chromatographic run time is less than 11 min using a mobile phase of 15:85 v/v acetonitrile-0.18 m ammonium acetate pH 5.0 and UV detection at 254 nm. The method is linear in the concentration range 0.1-25 microg mL(-1) (r > 0.99, n = 6) for each analyte with RSD less than 6%. Interday and intraday variability were found to be < or =14%. The limits of detection and quantitation were 0.1 (S/N > 3) and 0.25 microg mL(-1) (S/N > 10), respectively, for each of the three phenothiazines. We can also apply this method to separate three other phenothiazines (ethopromazine, trifluoroperazine, prochlorperazine), although it lacks the selectivity to determine the concentration of all six drugs concurrently. The separation is feasible using these drugs in certain combinations.

Determination of ethylenediamine tetraacetic acid in injection forms by ion-pair chromatography.

A high performance liquid chromatographic method was developed for the determination of ethylenediamine tetraacetic acid (EDTA) in injection forms. The method consists of direct extraction of the samples with ethyl acetate; the organic layers were evaporated to dryness and further diluted to a 0.025% (w/v) copper nitrate in order to achive the formation of the EDTA-copper solution complex. The chromatographic separation was performed on a C8 Hypersil column. The mobile phase consisted of a mixture of acetonitrile-0.015 M tetrabutylammonium hydroxide (10:90, v/v), (pH* 7.0) pumped at a flow rate of 1.5 ml min(-1). The UV detector was operated at 300 nm. Correlation coefficients of the calibration graphs were better than 0.9995, relative standard deviation was less than 2.5%. Detection limit of EDTA was found to be 1.97 microg ml(-1).