AIMTo evaluate the self-emulsifying ability and dissolution behavior of tretinoin in vitro and the pharmacokinetic behavior in beagle dogs.

METHODSThe self-emulsifying rate was evaluated by determining the intensity of scattered light at different time and the particle size of resultant emulsions after self-emulsifying were observed by optical microscope. The plasma concentrations were determined by HPLC and dissolution and pharmacokinetic behavior of self-emulsifying formulations were evaluated by comparison with commercial capsules.

RESULTSThe area under the curve (AUC) was significantly higher in the tretinoin self-emulsifying formulation group (3048.0 mg x h x L(-1)) than that in the commercial capsule group (1826.0 mg x h x L(-1)). Also, Tmax was smaller in the self-emulsifying formulation group (1.25 h) compared with market products (2 h) and the dissolved amount from self-emulsifying formulations in water at 15 min was much higher (more than 80%) than that of the market products (less than 5%).

CONCLUSIONThe self-emulsifying drug delivery systems can increase drug dissolution in vitro and absorption in vivo significantly.