A study on factors affecting the preparation and in-vitro evaluation of mucoadhesive propranolol HCl suppositories


Propranolol HCl is a beta-adrenoreceptor blocking drug which is subjected to extensive first pass metabolism after oral administration. In this study, attempts were made to prepare mucoadhesivesuppositories composed of 80mg (4%) propranololHCl by fusion method using fatty base,witepsolW-35 or water soluble bases polyethylene glycol (PEG) 4000 and mucoadhesivepoloxamer 188. Physical characteristics and dissolution profiles of the prepared formulas were studied. The results showed that all the prepared formulas have acceptablephysical characteristics regarding weight variation, hardness, and melting time. The release of drug from the prepared suppositories was found to be affected by the type of suppository base and additives. Fastest release was obtained with witepsolW-35 followed by PEG 4000 then poloxamer 188. Addition of carbopol 934 as a mucoadhesive polymer in a concentration of 1% or 2% to witepsol W-35 or PEG 4000 bases , retard the release of drug to unacceptable limit due to formation of an insoluble complex with the drug. On the other hand, the release of drug was enhanced by addition of propylene glycol to poloxamer 188 based suppositories in a concentration of 25% or 30% to a required limit for sustained release preparations that follow zero order kinetics.Furthermore, these last formulas were found to have mucoadhesive property. Therefore, the results suggest that propylene glycol-poloxamer 188 mixture is a promising base for preparation of sustained release solid mucoadhesive propranolol HCl suppositories.