Development of Theophylline Microbeads Using PregelatinizedBreadfruit Starch (Artocarpus altilis) as a Novel Co-polymer for Controlled Release

Abstract

Purpose: The aim of this study was to prepare formulations of theophylline microbeads usingpregelatinized breadfruit starch (Artocarpus altilis, family Moraceae) in combination withsodium alginate and chitosan at various polymer: drug ratios. Microbead formulations forcontrolled delivery of theophylline would be better alternatives to conventional dosage formsfor optimized drug therapy.Methods: The native and pregelatinized starches were characterized for morphology (scanningelectron microscope), crystallinity (Fourier transform intra-red spectroscopy, FTIR and X-raydiffractometer, XRD), thermal flow (differential scanning colorimeter), density and flowproperties. Theophylline microbeads were prepared by ionic gelation and characterized usingsize, swelling index, entrapment efficiency and time required for 15% and 50% drug release (t15and t50 respectively).Results: FTIR and XRD spectra revealed the orderly arrangement of granules of the semi-crystallinebreadfruit starch was disrupted on gelatinization. The viscosity and flow of pregelatinized starchwere enhanced. Theophylline microbeads were near spherical in shape with size range 1.09± 0.672 to 1.58 ± 0.54 mm. FTIR and XRD spectra confirmed there was no drug-polymerinteraction. Microsphere size, swelling increased while entrapment and dissolution time (t50)reduced with polymer: drug ratio. The entrapment efficiency ranged from 30.99 ± 1.32 to 78.50± 2.37%. Optimized formulation, starch: alginate ratio 3:1 at polymer: drug ratio of 2:1, gave aprolonged dissolution time (t50 = 8.40 ± 1.20 h).Conclusion: Breadfruit starch was suitable as a copolymer for the controlled delivery oftheophylline in microbeads which could serve as a substitute to synthetic polymers in drugdelivery.

Keywords: Chitosan, Controlled release, Microbeads, Pregelatinized breadfruit starch, Sodium alginate, Theophylline