Synthesis and Characterization of Enzymatically Produced Resistant starch coated Drug Microspheres and their Antimicrobial Potential

Abstract

The aim of the present research was to synthesize and characterize enzymatically produced resistant starch coated drug microspheres,for the colon targeted delivery of Ciprofloxacin (Cipro).Resistant starch (RSIII) was produced by the debranching of maize flour using microbial amylase and pullulanase enzymes isolated and purified from Bacillus licheniformis.The single emulsion evaporation method was used for the synthesis of the microspheres,by the dropping of organic phase containing RS(III) and drug in dimethyl sulfoxide (DMSO) into aqueous solution containing 0.5% tween 80 as stabilizer under stirring.The encapsulation efficiency of 86.73% was found.The size and polydispersity index (PDI), was measured and analyzed by Dynamic Light Scattering (DLS),X-ray Diffraction (XRD) analysis indicated that crystalline form of Ciprofloxacin is completely transformed into amorphous form and drug is encapsulated in resistant starch. The light microscopy and Scanning Electron Microscopy (SEM) showed that the different flat, compact block like structures of Resistant Starch were converted into the spherical microparticles, while Fourier Transform Infrared Spectroscopy (FTIR) results showed chemical and electrostatic interactions between the RS(III) and Ciprofloxacin used for the preparation of microspheres.Antimicrobial potential was measured by agar well diffusion method against E.coli and S.aureus.For in vitro drug release studies, RS(III) coated drug microspheres were incubated in simulated gastric fluid, intestinal fluid and colonic fluid, respectively.RS(III) remain stable and retarded drug release in stomach and small intestine,about 5% of drug was released in(stomach)acidic medium while at pH 7.8 drug release was about 52%.Release profile of drug from microspheres was evaluated by using various kinetic models these models showed concentration dependent sustained drug release.Drug release studies have shown that the enzymatically produced resistant starch could deliver the drug to the colon.These results indicate that the resistant starch prepared by bacterial enzymes can be used as a potential drug carrier in colon-targeted drug transport system.