Validated Analytical Methods for the Determination of Drugs Used in the Treatment of Hyperemesis Gravidarum in Multiple Formulations.

Quantitative multicomponent analysis is considered an analytical goal to save time and cost in analysis. Hence, this work aimed to provide sensitive and selective UV-spectrophotometric, chemometric manipulation, and ultra-performance LC (UPLC) methods for the determination of well-known coformulated antiemetics used in pregnancy, namely pyridoxine HCl (PYR), meclozine HCl, and cyclizine. The developed UV-spectrophotometric methods are dual wavelength in ratio spectra and first derivative of the ratio spectra with which PYR was determined selectively at 290.8 nm, whereas the other drugs in a ternary mixture were determined from their ratio spectra using a spectrum of PYR as a divisor in 0.1 M HCl. An ecofriendly partial least-squares regression chemometric method was applied to raw UV absorbance data for the determination of the ternary mixture in a 218-355 nm range using a three-factor, three-level design with water as the green solvent. A gradient UPLC method was developed and successfully resolved the ternary mixture within 5 min. Different ratios of water (adjusted to pH 3 with phosphoric acid) and methanol were delivered at 0.5 mL/min as the mobile phase into a Hypersil Gold C18 column (50 × 2.1 mm, 1.9 µm). The developed methods were successfully applied to different pharmaceutical formulations containing the aforementioned drugs and validated according to the International Conference on Harmonization guidelines. The results obtained were reproducible and reliable and can be applied for routine analysis and QC in laboratories.

Validated Chromatographic Methods for the Analysis of Two Binary Mixtures Containing Pyridoxine Hydrochloride.

Accurate and precise TLC-densitometric and HPLC-diode-array detector (DAD) methods have been developed and validated to resolve two binary mixtures containing pyridoxine hydrochloride (PYH) with either cyclizine hydrochloride (CYH) or meclizine hydrochloride (MEH). In the developed TLC-densitometric method, chromatographic separation of the three studied drugs was carried out on silica gel 60 F254 plates using a developing system containing methylene chloride + acetone + methanol (7 + 1 + 0.5, v/v/v) scanning separated bands at 220 nm. Beer-Lambert law was obeyed in the ranges of 0.2-5, 0.2-4, and 0.2-4 µg/band for PYH, CYH, and MEH, respectively. On the other hand, the developed HPLC-DAD method depended on chromatographic separation on a Zorbax Eclipse C18 column using methanol-KH2PO4 (0.05 M; 90 + 10, v/v; pH 5, with H3PO4 and KOH) as the mobile phase, a flow rate of 1 mL/min, and UV scanning at 220 nm. A linear relationship was obtained between the integrated peak area and the concentration in the ranges of 10-50, 10-50, and 7-50 µg/mL for PYH, CYH, and MEH, respectively. The proposed methods were successfully applied for the determination of the cited drugs in their pharmaceutical formulations. Statistical comparison with the reported methods using Student's t- and F-tests found there were no significant differences between the proposed and reported methods for accuracy and precision.

Application of adsorptive voltammetry for the detection of sub-nano molar cyclizine in biological fluids and tablets using fast Fourier transform continuous cyclic voltammetry in a flowing system.

An easy and fast Fourier transform continuous cyclic voltammetric technique (FFTCV) for monitoring of ultra trace amounts of cyclizine in a flow-injection system has been introduced in this work. The potential waveform, which was applied continuously on an Au disk microelectrode (12.5 microm in radius) consisted of the potential steps for cleaning, accumulation and potential ramp. The proposed detection method has some advantages, the greatest of which are as follows: first, it is no longer necessary to remove oxygen from the analyte solution and second, this is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. The detection limit for cyclizine was 1.8 ng ml(-1). The relative standard deviation (RSD) of the proposed technique at 5.0 x 10(-7) was 2.0 for 10 runs. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the cyclizine were considered. The proposed method was applied to the determination of cyclizine in a pharmaceutical preparation.

A capillary zone electrophoresis (CZE) method for the determination of cyclizine hydrochloride in tablets and suppositories.

Current compendial methods of assay for the analysis of cyclizine tablets involve the use of UV spectrophotometry. Since this is a non-selective technique its application to more complex dosage forms, such as suppositories, is unlikely to be appropriate. There is therefore a need for the development of a highly specific quantitative analytical method, such as high performance liquid chromatography (HPLC) or capillary electrophoresis (CE). The latter technique was chosen in view of some specific advantages over HPLC, such as the use of relatively non-toxic aqueous buffers, as opposed to organic solvents, which obviates the use of expensive HPLC grade solvents making CE more cost effective. Cyclizine was analyzed in 50mM phosphate buffer (pH 2.3) and run at an applied voltage 25 kV. Detection sensitivity was enhanced by using a wavelength of 200 nm and samples were loaded hydrodynamically onto an uncoated fused-silica capillary (60 cm x 50 mm i.d.). Chlorcyclizine was used as the internal standard and resolution of both compounds was achieved in less than 7 min. Stress testing was undertaken in order to investigate the appearance of breakdown products. The method has the requisite accuracy, selectivity, sensitivity and precision to assay cyclizine in tablets and suppositories. Degradation products resulting from the stress studies did not interfere with the detection of cyclizine and the assay is thus stability-indicating.

Screening for drugs of abuse (II): Cannabinoids, lysergic acid diethylamide, buprenorphine, methadone, barbiturates, benzodiazepines and other drugs.

Requirements for the provision of an efficient and reliable service for drugs of abuse screening in urine have been summarized in Part I of this review. The requirements included rapid turn-around times, good communications between requesting clinicians and the laboratory, and participation in quality assessment schemes. In addition, the need for checking/confirmation of positive results obtained for preliminary screening methods was stressed. This aspect of the service has assumed even greater importance with widespread use of dip-stick technology and the increasing number of reasons for which drug screening is performed. Many of these additional uses of drug screening have possible serious legal implications, for example, screening school pupils, professional footballers, parents involved in child custody cases, persons applying for renewal of a driving licence after disqualification for a drug-related offence, doctors seeking re-registration after removal for drug abuse, and checking for compliance with terms of probation orders; as well as pre-employment screening and work-place testing. In many cases these requests will be received from a general practitioner or drug clinic with no indication of the reason for which testing has been requested. This also raises the serious problems of a chain of custody, provision of two samples, stability of samples, and secure and lengthy storage of samples in the laboratory-samples may be requested by legal authorities several months after the initial testing. The need for confirmation of positive results is now widely accepted but it may be equally important to confirm unexpected negative results. Failure to detect the presence of maintenance drugs may lead to the patient being discharged from a drug treatment clinic and, if attendance at the clinic is one of the terms of continued employment, to dismissal. It seems likely that increasing abuse of drugs and the efforts of regulatory authorities to control this, will lead to the manufacture of more designer drugs. Production of substituted phenethylamines was facilitated by the drug makers' cook book, 'PIHKAL' (Phenethylamines I Have Known And Loved) by Dr Alexander Shulgin and Ann Shulgin, and production of substituted tryptamines is promised in their next book, TIHKAL. Looking to the future, laboratories will need to ensure that they can detect and quantitate an ever-increasing number of drugs and related substances. The question of confidence in results of drugs of abuse testing raised in 1993 by Watson has assumed even greater importance as a result of attention focused on the OJ Simpson trial in Los Angeles. Toxicological investigations are likely to be challenged more frequently in the future. Even if analyses have been performed by GC-MS, there is a need to establish the level of match between the spectrum of the unknown substance and a library spectrum which is considered acceptable for legal purposes. It will also be essential to ensure that computer libraries contain spectra for all substances likely to be encountered in drugs of abuse screening.

Sensitive high-performance liquid chromatographic determination of cyclizine and its demethylated metabolite, norcyclizine, in biological fluids using coulometric detection.

An accurate, sensitive, selective and reproducible high-performance liquid chromatographic method with coulometric detection for the determination of cyclizine and its inactive demethylated metabolite, norcyclizine, in biological fluids has been developed. The drugs were separated using a custom packed reversed-phase C18 analytical column and phosphate buffer (0.05 M, pH 3)-acetonitrile (7:3) as mobile phase. The dual electrode coulometric detector was operated in the "oxidative-screen" mode with the upstream electrode (detector 1) set at 0.55 V and the downstream electrode (detector 2) set at 0.90 V. Serum and urine samples were prepared for analysis by solid-phase extraction, followed by a simple phase-separation step. The limit of quantitation was 1 ng/ml for both cyclizine and norcyclizine in serum and urine.

Fatality resulting from cyclizine overdose.

A case involving an overdose fatality of cyclizine is presented. Toxicological analysis revealed a cyclizine blood concentration of 80 micrograms/mL. The drug was quantified by gas chromatography/mass spectrometry (GC/MS). Qualitative analyses of urine and stomach contents were performed.

[Cyclizine as a drug of abuse?]. / Cyclizin als Rauschdroge?

Two British people going from Amsterdam to Berlin was examined at the borderline near Aix la Chapelle. Customsinspectors found besides a lot of hashish a letter hidden in a pocket lamp concerning drugs received in Amsterdam as remarks to LSD trips. Therefore a white powder found in a little paper in the purse of one person was tested for drugs. Previous examinations at the border failed and after further investigations at the Department of Forensic Medicine including mass spectrophotometry the powder was identified as Cyclizine. The analytical data like mass spectrum are described. This compound used many years for the prevention and treatment of motion sickness is off the market because of suggested teratogen effects. Previous reports about LSD-like symptoms after ingestion of large amounts of Cyclizine as the environment the powder was found let us suppose that some people will know about psychotic effects at high doses of this drug not being an inhibited narcotic.

Blood and urine concentrations of cyclizine by nitrogen-phosphorus gas-liquid chromatography.

Gas-liquid chromatography with nitrogen-phosphorus detection was used to analyze blood and urine from a volunteer who ingested 50 mg of cyclizine hydrochloride. A peak blood cyclizine concentration of 69 ng/mL was observed 2 hr after drug administration, and the levels declined thereafter in a biphasic manner, with estimated half-lives of 7 and 24 hr for the early and late phases, respectively. The peak urine cyclizine concentration of 12.5 ng/mL was achieved at 4 hr after administration; only 0.01% of the dose was excreted in the 24 hr urine. Norcyclizine was not observed in blood or urine; however, the detectability of the method for this metabolite is poor relative to the parent drug.