RELEASE OF SALBUTAMOL SULFATE ENANTIOMERS FROM HYDROXYPROPYLMETHYLCELLULOSE MATRICES

The in vitro dissolution profiles of nine sustained-release formulatio ns of (+/-)-salbutamol were determined. The formulations contained chi ral pharmaceutical excipients, such as hydroxypropylmethylcellulose (H PMC) and heptakis (2,6-di-O-methyl)-beta-cyclodextrin (DMCD). The infl uence of the degree of ionization was studied in six formulations that were buffered at different pH values. The quantitative determination of salbutamol enantiomers released by the matrices was carried out usi ng a stereospecific capillary electrophoresis method. The release of s albutamol enantiomers from all formulations was found to be non-enanti oselective. Likewise, the addition of buffering agents to the formulat ion did not provide an enantioselective release of salbutamol enantiom ers from the matrices under the conditions established. (C) 1998 Elsev ier Science B.V.