The biopharmaceutical properties of solid dosage forms : the in vitro characteristics of phenylbutzaone tablets

Many researchers have attempted to resolve the problems associated with the claims that generic drugs are therapeutically inactive. The objective of this study was to investigate one drug - phenylbutazone - and to determine the overall quality of 23 brands of this drug on the Canadian market. Potency, content uniformity and availability of the drug from the dosage form were investigated. A spectrophotometric method suitable for the analysis of individual phenylbutazone .tablets was developed. This method involved the extraction of the drug from the tablets with alcohol, appreciate dilution with distilled water and spectrophotometric analysis of the aqueous solution. The dissolution and disintegration characteristics of twelve products were studied by two different methods. The official disintegration test described in the Food and Drugs Regulations and a stirrer method similar to that outlined by Levy and Hayes (31) were used. The results of individual tablet assay showed that four products would be rejected on the basis of potency or content uniformity. Two other products, although complying with official requirements, would appear to show questionable characteristics. Two products would be rejected on the basis of disintegration times while six others demonstrated excessive variability in their disintegration characteristics. The official disintegration apparatus was rejected for dissolution studies. A modified version of the apparatus described by Levy and Hayes (31) was considered adequate for this investigation. The dissolution profiles indicated that one product would be classified as "excellent"; seven as "good" and four as "poor" with respect to drug release in vitro. Preliminary studies indicate that there may be a definite correlation between in vitro dissolution and in vivo availability (as measured by drug content in the blood). This abstract represents the true content of the thesis submitted.Pharmaceutical Sciences, Faculty ofGraduat