Study On The Dissolution Of Three Different Metformin Hydrochloride Formations And Bioavailability Of Metformin Hydrochloride Enteric-Coated Tablet

OBJECTIVE: This paper checks the dissolutions of three metformin hydrochloride formations, set up the method for determining the concentration of metformin hydrochloride in serum and study the bioavailability of metformin hydrochloride enteric-coated tablet. METHODS: The effect of different media on the absorption of metformin hydrochloride was checked.By adding the same amount of NaOH the influence of HC1 can be eliminate. The dissolutions of metformin hydrochloride tablets and enteric-coated formations were determined in H2O and in pH7.0 phosphate buffer solution respectively. The concentration of metformin hydrochloride in serum was determined using acetonitrile: 0.01 mol/L(pH7.0) phosphate buffer solution(40:60) as mobile phase, ?Bondapak C18 (10?m. 250 X 4.6mm) as analytical column, 233nm as detective wave. The method was applied to the study of the bioavailability of metformin hydrochloride. RESULTS and CONCLUSIONS: 1.The contents of three different oralmetformin hydrochloride formations were 100.52%, 98.32% and 99.52% respectively; the accumulating dissolution at 45 minetes was97.70%, 98.65% and 95.80% respectively. The statistical analysis indicated that there was significant difference among the dissolution parameters of the three metformin hydrochloride formations. 2. The linear range of the method for determining the concentration of metformin hydrochloride in serum was 0.079-3.97 ?g/ml, the recovery was 92.4-95.5%, the RSD within days was 92.4-95.5%, between days was 3.81-6.58% respectively. 3. The relative bioavailability of the metformin hydrochloride produced by A company was 46.30 ? 32.45% of F0 , 57.43 ?32.09% of F0 comparing to the production produced by B company, indicating that they were non equivalent; The relative bioavailability of the metformin hydrochloride produced by Acompany was 83.20?2.61% of F0 , 86.60?36.41% of F0 comparingto the production produced by C company. The pharmacokinetical study using 3P97 suggested that the metformin hydrochloride in vivo fitted with one compartment model. 4. The clinical trial indicated that there were no significant difference among the three metformin hydrochloride forms in decreasing the glucose for patients.