Abstract:
The aim of this study was to develop and evaluate colon targeted drug delivery system
of Praziquantel for the treatment of schistosomiasis. Natural polysaccharides as
coating material were used for targeting the Praziquantel to the colon. Compression
coating has been found to be useful for colonic drug delivery. Colon targeted tablet
releases the drug at colonic pH; hence absorption and degradation of drug in stomach
has been eliminated. Low solubility of Praziquantel had been enhanced by kneading
method of complexation using β-cyclodextrin. Core tablet was prepared by direct
compression method and coated with guar gum by compression coating to achieve
colon targeted drug release. Effects of all the polymers, with different concentrations,
on physical properties of colon targeted tablet were investigated. To evaluate the
effect of Guar gum and HPMC K4M concentrations, 32 factorial design was
employed and for β-cyclodextrin and Crospovidone, 22 factorial design was
employed. The optimized core tablet with Drug: β-cyclodextrin ratio was 1:0.5; with
5% Crospovidone was disintegrated in less than 1 minute. Coated tablet of guar gum with 42.5% and HPMC K4M with 30% has achieved lag time of 5 hours and up to
97.8% cumulative release in colon within 2.5 hours. The FTIR results reveal that drug
and polymers were chemically compatible. From regression value it revealed that all
formulations followed Hixon Crowell model, which indicates erosion release
mechanism. The developed colon targeted tablet may be effectively used for oral
administration in the treatment of schistosomiasis, thus more amount of drug goes to
the systemic circulation thereby reducing dose.
