AIM: To prepare a slow -- released carbomer matrix gel which contains metronidazole and lincomycin hydrochlorideand to work out its quality control standard. METHODS: The contents of metronidazole and lincomycin were measured by spectrophotometry. RESULTS: The mean recovery rate of metronidazole was 99.27% and RSD of metronidazole was 1. 15%. Themean recovery rate of lincomycin hydrochloride was 100. 17% and RSD was 2.22%. CONCLUSION: Under the experimentalcondition, the matrix did not interfere the measure...