Biomedical subjects

F F Mao

Publications and source records attributed to F F Mao.

8 recordsLinked to original sources

PubMed1992

[Studies on the dissolution and bioavailability of trimethoprim-sulfadiazine-sulfamethoxazole tablets].

A reverse-phase high performance liquid chromatographic method was established for the simultaneous determination of trimethoprim (TMP), sulfadiazine (SD) and sulfamethoxazole (SMZ) in dissolution media. Meanwhile, another reverse-phase high performance liquid chromatographic method was developed for the simultaneous determination of the three drugs mentioned above and their metabolites, N4-acetyl-SD and N4-acetyl-SMZ in serum. The in vitro dissolution and in vivo bioavailability of two commercial trimethoprim-sulfadiazine-sulfamethoxazole tablets (A and B) were studied. Drugs were released far more rapidly from A than from B. Significant difference (P less than 0.001) was observed between the T50 s of the same active principles released from A and B. The in vivo processes of all three active principles in 8 healthy subjects taking two tablets each could be described by one-compartment model with first-order absorption and elimination. Compared with A, the relative bioavailabilities of B were 0.83, 0.73 and 0.78 for TMP, SD and SMZ, respectively. Drugs were absorbed more rapidly from A than from B.

Adult↗

PubMed1990

[Studies on the bioavailability of nitrendipine tablet].

The problem of nitrendipine tablets manufactured in China is its low bioavailability. To solve this, a new tablet formulation was developed by using milling method to increase its relative bioavailability. The commercially available conventional tablet A (Nanjing factory) and C (a Hebei factory) and the new tablet formulation D were compared with the reference tablet B (Bayer Company, West Germany) in vitro and in vivo. The determination of nitrendipine in vivo was carried out by GC-MS. The pharmacokinetic parameters of nitrendipine in vivo were estimated by using the nonlinear least square computer program on the basis of the compartment model (zero order dissolution, first order absorption). The bioavailability of A, C and D relative to B was 31.8%, 72.2% and 138.9% respectively. The new tablet formulation D is superior to the imported tablet B in both the extent and rate of absorption.

Biological Availability↗

PubMed1989

[Development and pharmacokinetic study of metoprolol tartrate controlled-release tablet remaining-floating in stomach].

An oral controlled-release system (M-HBS) of metoprolol was developed based on the hydrodynamically balanced controlled drug delivery system. It was found that the in vitro release characteristics showed basically first-order kinetics (K'r = 0.1651 h-1); a tentative two-year expiration date on M-HBS was established; the gamma-scintiphotographic study after oral ingestion showed that M-HBS was retained in human stomach for longer time (5-6 h) than the conventional metoprolol tablet (1-1.5 h). The blood concentration-time course of M-HBS was demonstrated to fit a one-compartment model with apparent first order absorption and first order elimination. The parameters were calculated using a NONLIN computer program with the values of Ka, K, Vd, tmax, cmax, being 0.1944 h-1, 0.1867 h-1, 2.813, 5.247 h, 125.1 ng/ml, respectively. Moreover, the fraction of the dose absorbed from M-HBS in vivo well correlated with dissolution rate in vitro.

Adult↗

PubMed1988