Thesis (M.Sc.)--Chulalongkorn University, 1997

The relative bioavailability of gemfibrozil comparing between the local manufactured product and the original product was studied in Thai male subjects. Before start the experiment, the pharmaceutical equivelence of both products were determined in vitro and confirmed for the statistically nonsignificant differences of their contents of active ingredient, uniformity of dosage units, disintegration time and dissolution time (p>0.05). A single oral 600 mg dose of gemfibrozil was given to twelve healthy male volunteers, age ranged from 18 to 40 years old via a randomized crossover design, elapsing one week as a washing period. The blood samples were collected just before drug administration and following the administration up to 12 hours. Serum was separated and kept frozen for subsequent analysis within one week via the developed isocratic reversed-phase HPLC. The concentration-time profiles of gemfibrozil in Thai subjects exhibited the monoexponential declined in which the elimination rate constant (Ke) was determined to be 0.6307+_0.1353 hr -1. Gemfibrozil was absorbed at the rate constant (Ka) of 0.8415+_0.1819 hr -1. The maximum gemfibrozil concentration detected in serum (Cmax) was 39.35+_9.420 mg/L at time (Tmax) 1.99+_0.364 hrs. The area under the concentration time curve from time zero to infinity (AUC0-alpha) was 108.93+_23.028 mg/L.hr. No statistically significant differences were observed for Ka, Cmax, Tmax and AUC0-alpha values between the local manufactured and original product (p>0.05). The relative bioavailability of gemfibrozil was calculated to be 1:1.09. Therefore, it is possible to be concluded that gemfibrozil from either product was bioequivalence in term of rate and extent of absorption into systemic circulation.