PREPARATION OF MICRONIZED IBUPROFEN SUBSTANCE AND ASSESSMENT OF ITS BIOAVAILABILITY

A Buchi B-290 mini spray dryer (Switzerland) designed to dry aqueous solutions or suspensions was used to prepare micronized ibuprofen substance, which differed from the starting substance in terms of decreased crystal size. The bioavailability of ibuprofen given as oral capsules containing micronized ibuprofen substance (crystal size 30 mu m) and capsules containing commercial ibuprofen substance (crystal size 150 mu m) was studied in Chinchilla rabbits. Concentrations of unaltered ibuprofen were measured by reverse-phase HPLC with spectrophotometric detection at 220 nm. Ibuprofen was extracted from rabbit serum by liquid:liquid extraction and averaged 78 %. The detection limit was 0.1 mu g/ml. The bioavailability of micronized ibuprofen was more than twice that of the commercial substance (mean crystal size 150 mu m). There were no differences in the rates of absorption or elimination of ibuprofen from the systemic circulation.