The Preparation Of The Coated Colon Targeted Drop Pill Of Metronidazole

The colon which has a higher pH value and alkalescency has a quite different physiological environment from the beginning of the enteron. So we can package the drug with the pH-rely materials. The drug shouldn't release in the tart environment of the beginning of the enteron, and will release in the colon, thus we can implement the view of colon target.Metronidazole is playing an important role in the healing of colonitis. In this experiment we put it into a colon target preparation to make the metronidazole concentrated in the colon to get a better therapeutic effect.We have to coat the drop pills with acrylic resins water dispersion and investigate the dissolve of the coat and the release of metronidazole in solutions with different pH values. The results showed that the metronidazole release from the drop pill was nearly none in 1h and only approximate 10% after 2h, while the drop pills without coat release their drug up to 100% in 10 minutes. In the pH7.4 buffer, the coat dissolved quickly and disappeared at about 25 minutes, while the release of metronidazole get the maximum sooner. And the coat was investigated dissolving slowly in the pH6.8 buffer .After 4h, the release of metronidazole was 24.13%。After all, the total result of this experiment was satisfactory. The effect we get could consistent with our expectation and the define of the Pharmacopeia. The coated drop pills produced in our experiments have the ability of colon target.