QUALITY EVALUATION OF THE COMMONLY PRESCRIBED ANTIPSYCHOTIC DRUGS (CHLORPROMAZINE & THIORIDAZINE TABLETS) MARKETED IN ETHIOPIA

The purpose of this study was to evaluate the quality of the commonly prescribed imported and locally manufactured antipsychotic drugs (chlorpromazine and thioridazine tablets) that are marketed in drug retail outlets in Ethiopia. Four different sources of Chlorpromazine and two thioridazine tablets were assessed in this investigation. The quality of the samples was examined in seven aspects: percent label amount (assay), weight variation, hardness, percent friability, purity, disintegration time and dissolution rate according to British pharmacopeia (2000) specification. The identity of the tablets was confirmed using FT-IR spectrophotometer. All chlorpromazine and thioridazine samples showed acceptable weight variation as none had percent deviation in weight greater than 5% as stipulated by BP (2000). The mean disintegration times of the products ranged from 4.50 ±0.84 (for chlorpromazine from Cyprus) to more than 60 min (for chlorpromazine Korea). All the tested samples showed active ingredient content with in the acceptable range (from 92.5%-107.5%). Thioridazine 25 mg showed high drug content (107±0.5) and the lowest amount was recorded for chlorpromazine from Cyprus (93.0 ±0.8).  Most of the studied samples showed a good drug release pattern except Chlorpromazine tablets from Korea which did not pass the pharmacopeial specification for disintegration time and dissolution rate studies.  So this specimen does not meet the quality requirements for tablets. This implies that the product may not release a significant amount of the drug on absorption in to the systemic circulation and thus leading to therapeutic failure. Chlorpromazine from Cyprus released the 50 and 70% of the active drugs with in 8.3 and 13.8 minutes respectively, showing a good drug release pattern than the others. Chlorpromazine (Ethiopia) took 19.0 and 31.1 minutes to release 50% and 70% of the drug respectively.