Development and validation of a liquid chromatographic method for the determination of related substances in verapamil hydrochloride

Method development and validation study for quantitative determination of 2-chloromethyl-3,4-dimethoxy pyridine hydrochloride a genotoxic impurity in pantoprazole active pharmaceutical ingredient (API) by LC/MS/MS

A sensitive and selective liquid chromatographic-tandem mass spectrometric (LC/MS/MS) method was developed and validated for the trace analysis (>1 ppm level) of 2-chloromethyl-3,4-dimethoxy pyridine hydrochloride a genotoxic impurity in pantoprazole sodium drug substances. LC/MS/MS analysis of 2-chloromethyl-3,4-dimethoxy pyridine hydrochloride was done on Hypersil BDS C18 (50 mm × 4.6 mm) 3 μm column and 10 mM ammonium acetate in 1000 mL of water was used as buffer. The mobile phase used was in the ratio of buffer-acetonitrile (79:21, v/v). The flow rate was 1.0 mL/min and elution was monitored at 210 nm. The method was validated as per International Conference on Harmonization (ICH) guidelines. LC/MS/MS is able to quantitate up to 0.3 ppm of 2-chloromethyl-3,4-dimethoxy pyridine hydrochloride.

Detection, isolation and characterization of principal synthetic route indicative impurities in verapamil hydrochloride

Two unknown impurities were detected in verapamil hydrochloride bulk drug using isocratic reversed-phase high performance liquid chromatography (HPLC). These impurities were isolated by preparative HPLC. Spectral data for the isolated impurities were collected. Based on the spectral data derived from two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy and mass spectrometry (MS), impurity-1 and impurity-2 were characterized as 2-(3,4-dimethoxyphenyl)-3-methylbut-2-enenitrile and 2-(3,4-dimethoxyphenyl)-2-isopropyl-3-methylbutanenitrile, respectively.

Spectrophotometric method for the determination of verapamil hydrochloride in pharmaceutical formulations using N-bromosuccinimide as oxidant

A rapid, simple and sensitive validated visible spectrophotometric method has been described for the assay of verapamil hydrochloride either in pure form or in pharmaceutical formulations. The method involves the oxidation of the verapamil hydrochloride with N-bromosuccinimide in perchloric acid medium at room temperature, leading to the formation of a yellow colored product, which absorbs maximally at 415 nm. Under the optimized experimental conditions, the color is stable up to 45 min and Beer's law is obeyed in the concentration range of 10.0-200.0 microg ml(-1) with molar absorptivity and Sandell's sensitivity of 2.55 x 10(3) l mol(-1) cm(-1) and 0.192 microg cm(-2) per 0.001 absorbance unit, respectively. The method has been successfully applied to the determination of the drug in commercial dosage forms. Statistical comparison of the results with those of a reference method by means of point and interval hypothesis shows excellent agreement and indicates no significant difference in accuracy and precision. Results of analyses were optimized and validated statistically and through recovery studies. The experimental true bias of all samples is smaller than +/-2%.

An overview of the recent trends in development of HPLC methods for determination of impurities in drugs

An extensive survey of the literature published in various analytical and pharmaceutical chemistry related journals has been conducted and the high-performance liquid chromatography (HPLC) methods which were developed and used for determination of process-related impurities in drugs have been reviewed. This review covers the time period from 1995 to 2001 during which around 450 analytical methods including all types of chromatographic and hyphenated techniques were reported. HPLC with UV detection was found to be the technique of choice for many workers and more than 200 methods were developed using LC-UV alone. A critical analysis of the reported data has been carried out and the present state-of-art of HPLC for determination of impurities of analgesic, antibiotic, anti-viral, anti-hypertensive, anti-depressant, gastro-intestinal and anti-neoplastic agents has been discussed.

Preparation and in vitro evaluation of modified release ketoprofen microsponges

Microsponges containing ketoprofen and Eudragit RS 100 were prepared by quasi-emulsion solvent diffusion method. The effects of different mixing speeds, drug-polymer ratios, solvent-polymer ratios on the physical characteristics of the microsponges as well as the in vitro release rate of the drug from the microsponges were investigated. All the factors studied had an influence on the physical characteristics of the microsponges. In vitro dissolution results showed that the release rate of ketoprofen was modified in all formulations.