Development of modified porous starch as a carrier to improve aqueous solubility

The objective of this work was to improve aqueous solubility of poorly water soluble drugs by a modified porous starch as solid dispersion carrier. The yield of the porous starch was found to be 80%. The flow property of the prepared porous starch was found to be good, with good compressibility index. The particle size of the prepared porous starch were found to be in the range of 53–130μ. There was no possible interaction between prepared porous starch and metronidazole in the solid state, as confirmed by FT-IR spectra and. DSC thermograms. Drug content of all the formulations were found to be in the range between 97-100%. The dissolution profile showed that in solid dispersions prepared by physical mixing process and solvent evaporation method, the dissolution of pure metronidazole is high in comparison with the solid dispersion samples. Whereas in solid dispersions prepared by kneading method, dissolution of pure metronidazole is very low in comparison with the solid dispersion samples of drug with porous starch due to co-habitation of carriers with metronidazole that improved the dissolution rate of the drug. The predicted drug release mechanism for kneading method was by peppas model where the drug release could be by diffusion process. Thus this study confirmed that a porous starch can be developed and utilized as a carrier to improve the aqueous solubility of poorly water soluble BCS class II drugs thereby improving its dissolution rate and bioavailability.