Comparative pharmacokinetic analysis of novel sustained-release dosage forms of pentoxifylline in healthy subjects.

The pharmacokinetics and relative bioavailability of pentoxifylline, from a new sustained-release formulation (Oxopurin) and from a standard sustained-release formulation (Trental-400), were compared in 8 healthy adult male volunteers. After a single oral dose of 400 mg Oxopurin, a mean maximal plasma concentration (Cmax) of 164 +/- 62 micrograms/l was obtained after 2.2 h (tmax). After an identical dose of Trental-400, a peak plasma concentration of 123 +/- 33 micrograms/l was obtained after 2.4 h. Plasma levels of pentoxifylline were determined by a new HPLC assay which was developed as part of this study and makes possible monitoring plasma levels of pentoxifylline for 14 h after a single dose. The mean relative bioavailability of pentoxifylline from Oxopurin was 1.30 +/- 0.19 relative to that of Trental-400. As the rate and the extent of absorption of pentoxifylline was not significantly different after the administration of the two investigated formulations, it can be concluded that Oxopurin is bioequivalent to Trental-400.