[Synthesis and characterization of controlled-release preparation of metronidazole].
To increase the solubility of metronidazole in water in order to increase its bioavailability.A new controlled-release preparation of metronidazole was synthesized by using sodium alginate which had good solubility in water, degradation and characteristics of biocompatibility. The chemical structures of the controlled-release preparation were characterized by FT-IR, 1H-NMR, DSC and SEM. The solubility was assayed according to the National Standard. The inclusion rate and controlled-release effect were assayed by UV spectrum.The inclusion rate could reach maximum under the optimum conditions of molar ratio of 3:1, ultrasonic power of 400 W, and reaction time of 200 s. The solubility of the controlled-release preparation in water increased to 18.99 mg/ml. There was 40% metronidazole released in 12 h in buffer solution.A new controlled-release preparation of metronidazole is synthesized successfully by using sodium alginate and its release rate is satisfactory.