Research Information System
Acta Pharmaceutica Turcica, vol.40, no.3, pp.103-119, 1998 (Scopus)
The purpose of this study was to investigate by in vitro method whether a sorption phenomena took place and in which ratios it occurred when excipients talc, kaolin, microcrystalline cellulose, ethyl cellulose, Aerosil 200, Carbopol 934 having absorbent properties are present in the formulations of drugs containing procaine HCl, ephedrine HCl, caffeine and methylene blue or when excipients are taken concomitantly with these drug while they are present in different formulations. The adsoption of drugs was investigated both in distilled water and pH values where the drugs showed optimum stability. Among the drugs used, under the investigation conditions, ephedrine HCl and caffeine were found not to be adsorbed while procaine HCl and methylene blue were adsorbed to a significant extent. The fitness of results obtained to various adsorption isotherms were investigated and the type of the isotherms that the adsorption fitted was determined and was found that the adsorption of procaine HCl and methylene blue in all cases obeyed the Langmuir isotherm. In order to determine the dimensions of extent of adsorption and to make comparison between the excipients, the adsorption capacities of excipients were calculated and Aerosil 200 wets found to possess the highest adsorptive capacity while ethyl cellulose possessed the lowest. In order to determine the relationship between the adsorption capacities and particle sizes of excipients, the particle sizes of excipients were analysed. Aerosil 200 was found to have the smallest particle size while ethyl cellulose was found to have the biggest. While for ethyl cellulose and Aerosil 200 there was a direct correlation between the particle sizes and adsorption capacities however, the same parallelism is not seen at other excipients.