Artefact formation in the determination of residual solvents according to a method of the European Pharmacopeia

Static headspace gas chromatographic method for quantitative determination of residual solvents in pharmaceutical drug substances according to European Pharmacopoeia requirements

A static headspace (HS) gas chromatographic method for quantitative determination of residual solvents in a drug substance has been developed according to European Pharmacopoeia general procedure. A water-dimethylformamide mixture is proposed as sample solvent to obtain good sensitivity and recovery. The standard addition technique with internal standard quantitation was used for ethanol, tetrahydrofuran and toluene determination. Validation was performed within the requirements of ICH validation guidelines Q2A and Q2B. Selectivity was tested for 36 solvents, and system suitability requirements described in the European Pharmacopoeia were checked. Limits of detection and quantitation, precision, linearity, accuracy, intermediate precision and robustness were determined, and excellent results were obtained.

Validation of a generic analytical procedure for determination of residual solvents in drug substances

A generic analytical procedure for determination of residual solvents in drug substances is described and validated. The procedure is based on methods described in the European and United States parmacopeias, but is faster than the compendial procedures. It is applicable both during drug development and for quality control in commercial manufacture. The method is accurate, linear and shows a satisfactory level of precision. The solvents included in the validation comprise the five class 1 solvents, 17 out of 27 class 2 solvents, 17 out of 27 class 3 solvents and three unclassified solvents according to ICH guideline Q3C. The solvents can be detected and quantified at levels at or below the ppm limits given in the guideline. In most cases the quantification limit is in the lower ppm range. A strategy is proposed to choose between water or N,N-dimethyl formamide as a diluent. The need for re-validation of the method, mandatory for quantitative procedures according to the European Pharmacopeia, is minimised when using the generic procedure.