CORRELATION OF IN-VITRO RELEASE AND IN-VIVO ABSORPTION CHARACTERISTICS OF 4 SALBUTAMOL SULFATE FORMULATIONS

The purpose of this study was to investigate the possibility to develo p different levels of correlation between 'in vitro' dissolution param eters and 'in vivo' pharmacokinetic parameters for four salbutamol sul phate formulations: two commercially available formulations (Ventolin( R) Oral and Volmax(R)) and two sustained-release formulations (SG7 and SG14) developed in our laboratory. A level A correlation of 'in vitro ' release and 'in vivo'. absorption could be set up for individual pla sma level data by means of the deconvolution method. Linear correlatio ns could be obtained when dose fraction released 'in vitro' was plotte d vs. dose fraction absorbed 'in vivo', with correlation coefficients between 0.97 and 0.99 for the formulations studied. A second level of correlation between mean 'in vitro' dissolution time (MDT) and mean 'i n vivo' residence time (MRT) was performed with a correlation coeffici ent of 0.81. Finally, it was also possible to establish a good 'in vit ro'-'in vivo' correlation when the mean dissolution time 'in vitro' an d T-max or C-max 'in vivo' were compared, but it appeared impossible t o establish any correlation between mean dissolution time (MDT) and AU C.