Effect of Betong Watercress and Phenethyl Isothiocyanate on N-Demethylation of Caffeine in Rats

Purpose: To investigate the effect of Betong watercress and phenethyl isothiocyanate (PEITC) on the N-demethylation of caffeine (CF) in ratsMethods: Male Wistar rats were subjected to 2 phases of experiment. Phase I, they received a single oral dose of CF (10 mg/kg), while in phase II, they were pretreated with the following regimens: 10 mg/kg  fluvoxamine, i.p.; a single oral dose of 2, 10, and 20 mg/kg PEITC; 2, 10, and 20 mg/kg PEITC, once daily for five days; single oral dose of 800 mg/kg Betong watercress; 800 mg/kg Betong watercress once daily for five days, before receiving the same dose of CF as in phase I. Serum concentrations of CF and its metabolites after 3 h of CF administration were measured. Caffeine metabolic ratios (CMRs) and ratio of serum  concentration of metabolites to that of CF were calculated and compared.Results: CMRs were decreased by a single pretreatment \with fluvoxamine (30 – 40%), PEITC (2 - 20 mg/kg) (40 – 55%), and Betong watercress (9 – 22%). The decreases caused by 10 and 20 mg/kg PEITC were significantly greater than those by fluvoxamine. CMRs were also decreased after five days of pretreatment with all doses of PEITC (43 – 69%) and Betong watercress (28 – 44%). The reduction in metabolic ratio after single- and multiple PEITC pretreatments was dose- and time-independent.Conclusion: Betong watercress and PEITC inhibit N-demethylation of CF in rats. Such an effect indicates that they have inhibitory activity on CYP1A2 and CYP2C.Keywords: Watercress, Phenethyl isothiocyanate, Caffeine,  N-demethylation, Fluvoxamine, Cytochrom

Solid phase extraction method for determination of mitragynine in urine and its application to mitragynine excretion study in rats receiving caffeine

Purpose: To develop a solid phase extraction (SPE) method that utilizes reverse-phase high performance liquid chromatography (RP-HPLC) to determine mitragynine (MG) in rat and human urine, and to investigate the influence of caffeine (CF) on urinary excretion of MG in rats.Methods: A two-dimensional wash-elute study was conducted using Oasis® HLB cartridge. The optimized SPE procedures consisted of washing with 5 and 70 % methanol containing 2 % ammonium hydroxide and eluting with methanol containing 2 % acetic acid. The SPE-HPLC method was validated according to United States Food and Drug Administration guidelines. Two groups of rats were used for the study and received an oral administration of either alkaloid extract (AE) of kratom (100 mg/kg), or AE (100 mg/kg) combined with CF (25 mg/kg). The 24-h urine samples after administration were analyzed using the developed method for the content of MG excreted.Results: Validation indicate good linearity (r > 0.9991) and high precision in rat (1.18 - 5.97) and human urine (0.67 - 3.41). Accuracy for rat and human urine ranged from -9.11 - 19.64 and -7.20 - 13.72 %, respectively. Recovery of MG ranged from 92.75 - 100.83 %. Co-administration of AE and CF significantly increased urinary excretion of MG.Conclusion: The developed SPE method is simple, fast and reliable, and can be suitably applied to pharmacokinetic studiesKeywords: Mitragynine, Mitragyna speciosa, Solid phase extraction, Caffeine, Urin

Solid-phase extraction for determination of caffeine and its dimethylxanthine metabolites in rat urine using high performance liquid chromatography and its application

A solid-phase extraction (SPE) method for use with high performance liquid chromatography to measure caffeine (CF) and its metabolites in rat urine was developed and validated. Oasis HLB cartridges were used and washed with water, 1% acetic acid: 3% methanol-water (0.5:99.5 v/v), and 1% ammonium hydroxide: 3% methanol-water (0.5:99.5 v/v), respectively, and eluted with methanol:acetronitrile (80:20 v/v). Method validation showed good linearity (r>0.9990) over all calibration ranges for CF and its metabolites. The method was precise (1.0–17.6%RSD) and accurate (-13.8–(+) 16.0%DEV). The SPE method resulted in a high recovery for all analytes (72.9-98.9%). The lower limits of quantification were 0.1 µg/ml (PX), 0.25 µg/ml (CF and theophylline), and 0.5 µg/ml (theobromine and 1,3,7-trimethyluric acid). This method was successfully applied to determine the urinary profiles of CF and its metabolites, and the caffeine metabolic ratios in rats receiving a single oral dose of CF

An overview of recent developments in the analytical detection of new psychoactive substances (NPSs)

New psychoactive substances (NPSs), sometimes referred to as “legal highs” in more colloquial environments/ the media, are a class of compounds that have been recently made available for abuse (not necessarily recently discovered) which provide similar effects to the traditional well studied illegal drugs but are not always controlled under existing local, regional or international drug legislation. Following an unprecedented increase in the number of NPSs in the last 5 years (with 101 substances discovered for the first time in 2014 alone) its, occasionally fatal, consequences have been extensively reported in the media. Such NPSs are typically marketed as ‘not for human consumption’ and are instead labelled and sold as plant food, bath salts as well as a whole host of other equally nondescript aliases in order to bypass legislative controls. NPSs are a new multi-disciplinary research field with the main emphasis in terms of forensic identification due to their adverse health effects, which can range from minimal to life threatening and even fatalities. In this mini-review we overview this recent emerging research area of NPSs and the analytical approaches reported to provide detection strategies as well as detailing recent reports towards providing point-of-care/in-the-field NPS (“legal high”) sensors

Effects of Mitragynine and a Crude Alkaloid Extract Derived from Mitragyna speciosa Korth. on Permethrin Elimination in Rats

Detoxification and elimination of permethrin (PM) are mediated by hydrolysis via carboxylesterase (CES). Mitragyna speciosa (kratom) contains mitragynine (MG) and other bioactive alkaloids. Since PM and MG have the same catalytic site and M. speciosa is usually abused by adding other ingredients such as pyrethroid insecticides, the effects of MG and an alkaloid extract (AE) on the elimination of PM were investigated in rats. Rats were subjected to single and multiple pretreatment with MG and AE prior to receiving a single oral dose (460 mg/kg) of PM. Plasma concentrations of trans-PM and its metabolite phenoxybenzylalcohol (PBAlc) were measured. The elimination rate constant (kel) and the elimination half-life (t1/2 el) of PM were determined, as well as the metabolic ratio (PMR). A single and multiple oral pretreatment with MG and AE altered the plasma concentration-time courses of both trans-PM and PBAlc during 8–22 h, decreased the PMRs, delayed elimination of PM, but enhanced elimination of PBAlc. Results indicated that PM–MG or AE toxicokinetic interactions might have resulted from the MG and AE interfering with PM hydrolysis. The results obtained in rats suggest that in humans using kratom cocktails containing PM, there might be an increased risk of PM toxicity due to inhibition of PM metabolism and elimination

Enantioselective HPLC-UV method for determination of eslicarbazepine acetate (BIA 2-093) and its metabolites in human plasma

Eslicarbazepine acetate (BIA 2-093) is a novel central nervous system drug undergoing clinical phase III trials for epilepsy and phase II trials for bipolar disorder. A simple and reliable chiral reversed-phase HPLC-UV method was developed and validated for the simultaneous determination of eslicarbazepine acetate, oxcarbazepine, S-licarbazepine and R-licarbazepine in human plasma. The analytes and internal standard were extracted from plasma by a solid-phase extraction using Waters Oasis® HLB cartridges. Chromatographic separation was achieved by isocratic elution with water–methanol (88:12, v/v), at a flow rate of 0.7 mL/min, on a LichroCART 250-4 ChiraDex (β-cyclodextrin, 5 μm) column at 30°C. All compounds were detected at 225 nm. Calibration curves were linear over the range 0.4–8 μg/mL for eslicarbazepine acetate and oxcarbazepine, and 0.4 – 80 μg/ mL for each licarbazepine enantiomer. The overall intra- and interday precision and accuracy did not exceed 15%. Mean relative recoveries varied from 94.00 to 102.23% and the limit of quantification of the assay was 0.4 μg/mL for all compounds. This method seems to be a useful tool for clinical research and therapeutic drug monitoring of eslicarbazepine acetate and its metabolites S-licarbazepine, R-licarbazepine and oxcarbazepine

Prevalence of potential drug interactions in an Iranian general hospital

The hazards of prescribing many drugs, including side-effects, drug-drug interactions and difficulties of compliance have long been recognized as particular problems when prescribing. This study estimates the rate and factors associated with potential drug-drug interactions in prescriptions from wards of An Iranian General Hospital. Data were retrieved from the pharmacy of a general hospital (200 beds) during one year period 2010. Potential drug-drug interaction were identified using a computerized drug-drug interaction database system (Prescription Analyzer 2000, Sara Rayane Co., Iran). Patients of both genders and 15 years-old or more were included in this study. Prescriptions with two or more drugs prescribed were selected during one year period 2010. Gender number of drugs and therapeutic drug classes on prescriptions were explored as associated factors to drug-drug interaction. The overall prevalence of potential drug-drug interaction was 20.3%. The risks of severe potential drug interactions were relatively high and the rate of potential drug-drug interaction was significantly higher in women (60.6%) and the patients aged over 60 years old (57.1%). The frequency of the potentially severe drug-drug interaction was 10.8% with digoxin-furosemide as the most common interacting pair (5.91%). A positive correlation was found between drug-drug interaction, patient′s age, number of drugs and drugs acting on cardiovascular system. So cardiology women inpatients, age more then 60 years old, and patients prescribed digoxin and angiotensin-converting enzyme inhibitors should be closely monitored for adverse outcomes from drug-drug interaction