Comparative human study of ibuprofen enantiomer plasma concentrations produced by two commercially available ibuprofen tablets

Twelve healthy male subjects participated in a two-way Latin square crossover study in which the treatments were a single 400 mg generic ibuprofen tablet (Tablet A) or a single 400 mg MOTRIN Tablet (Tablet B). Blood samples were drawn at various times through 12 h after dosing and plasma samples were assayed for ibuprofen enantiomers with a stereospecific capillary gas chromatographic procedure. Concentration-time data for both enantiomers were in agreement and indicated that drug was absorbed much more quickly from Tablet B than from the Tablet A; enantiomer Tmax values were less than 1.3 h from Tablet B but longer than 4 h from the Tablet A (p less than 0.001). Also, maximum enantiomer plasma concentrations from the Tablet B were about 50 per cent of the peak concentrations observed from Tablet A (p less than 0.001). The total extent of drug absorption appeared to be the same in both products. These data clearly indicate that the two tablets are not bioequivalent with respect to either ibuprofen enantiomer.