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

Purpose: The aim of this study was to prepare formulations of theophylline microbeads using pregelatinized breadfruit starch (Artocarpus altilis, family Moraceae) in combination with sodium alginate and chitosan at various polymer: drug ratios. Microbead formulations for controlled delivery of theophylline would be better alternatives to conventional dosage forms for optimized drug therapy. Methods: The native and pregelatinized starches were characterized for morphology (scanning electron microscope), crystallinity (Fourier transform intra-red spectroscopy, FTIR and X-ray diffractometer, XRD), thermal flow (differential scanning colorimeter), density and flow properties. Theophylline microbeads were prepared by ionic gelation and characterized using size, swelling index, entrapment efficiency and time required for 15% and 50% drug release (t(15) and t(50) respectively). Results: FTIR and XRD spectra revealed the orderly arrangement of granules of the semi-crystalline breadfruit starch was disrupted on gelatinization. The viscosity and flow of pregelatinized starch were 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-polymer interaction. Microsphere size, swelling increased while entrapment and dissolution time (t(50)) 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 a prolonged dissolution time (t(50) = 8.40 +/- 1.20 h). Conclusion: Breadfruit starch was suitable as a copolymer for the controlled delivery of theophylline in microbeads which could serve as a substitute to synthetic polymers in drug delivery.