Sulfamethoxazole Methoxy Pyrimidine Sustained-release Injection Study

The paper studied pharmacokinetic properties in black goats of CO.SMM sustained-release injection ,and tested it's antibacterial activity in vitro ,safety and stability .The objective of the study was to offer some theoretical basis for clinical application and industrial production .Ten healthy black goats were divided into two groups ,five goats as a group . The first group was injected CO.SMM sustained-release injection following single intramuscular administration 60mg/kg , and the second group was injected SMM injection following single intramuscular administration 60mg/kg .Blood samples were collected at different intervals after administration of the injection .Concentrations of SMM and TMP in the plasma were determined by high performance liquid chromatography (HPLC). The concentrations versus time data were analysed using pharmacokinetic program . The concentration-time data of SMM and TMP were respectively described by a one-compartment open model with first-order absorption and a two-compartment open model with first-order absorption after single intramuscular administration of CO.SMM sustained-release injection . The main pharmacokinetic parameters of SMM and TMP in CO.SMM sustained-release injection were as follows .respectively : T_1/2Ka 0.56±0.095h and 0.87±0.15 h, T₁/2 12.20±0.70 h and 13.61±1.78 h, AUC 1065.60±21.83h.ng/mL and 60.24±5.25h.μg/mL, Vd 0.99±0.031L/kg and 19.53±1.67L/kg, CL_B 0.056±0.0037 L/kg.h and 1.00±0.087 L/kg.h, Tmax 2.58±0.35 h and 2.68±0.26 h, Cmax52.27±1.05μg/mL and 3.83±0.095μg/mL. The concentration-time data of SMM was described by a one-compartment open model with first-order absorption after single intramuscular administration of SMM injection . The main pharmacokinetic parameters of SMM in SMM injection were as follows : T_1/2Ka 0.42±0.046 h, T₁/2 1.27±0.068 h, AUC 243.75±12.62h.ng/mL , Vd 0.45±0.025L/kg , CL_B 0.25±0.013L/kg.h , Tmax 1.00±0.061h , Cmax77.06±2.12ng/mL .The results there were significant difference in pharmacokinetic parameters of SMM between CO.SMM sustained-release injection and SMM injection .The T_1/2Ka, Tmax and T₁/2 of the former were higher than the latter ,but the Cmax of the former was lower. These differences indicated that the CO.SMM sustained-release injection was absorbed slowly, and it had sustained-release and long-acting properties .Nine type bacteria were selected to test the in vitro antibacterial activity of CO.SMM sustained-release injection , and to compare with CO.SMM injection and SMM injection . The results showed that the MIC of CO.SMM sustained-release injection was equal to CO.SMM injection , but it's in vitro antibacterial activity was by far higher than SMM injection .These results indicated that CO.SMM sustained-release injection had higher and wider antibacterial action than...