Gas chromatographic determination of residual levels of tert.-butanol from lyophilized liposomal formulations.

The use of liposomal formulations is rapidly gaining popularity in pharmaceutical research and development. Their preparation often involves the use of organic solvents such as tert.-butanol to dissolve lipophilic lipids. To improve the physicochemical stability of the liposomes, lyophilizing the product is one of the best available means. A gas chromatographic method for the determination of tert.-butanol residual levels in lyophilized liposomes, employing sec.-butanol as internal standard, using a flame ionization detector (FID) detector and a cross-linked dimethylpolysiloxane capillary column, was developed. The method described is simple, sensitive, rugged, reliable and reproducible and requires less time than other reported methods for the quantitation of tert.-butanol; it also has pharmaceutical applications.