Expert design and optimization of ethyl cellulose-poly (ε-caprolactone) blend microparticles for gastro-retentive floating delivery of metformin hydrochloride.

BACKGROUND: Metformin hydrochloride (MH) is an oral anti-hyperglycemic agent belonging to the biguanide class of drugs. OBJECTIVE: The present study involves the formulation and evaluation of gastro-retentive floating microparticles containing MH as a model drug for the prolongation of absorption time. METHODS: Three levels of a three-factor, Box-Behnken design were used to evaluate the critical formulation variables. Microparticles were prepared using a water-in-oil-in-water double-emulsion solvent evaporation method and examined in terms of production yield, particle size, entrapment efficiency, floating ability, morphology, FTIR (Fourier transform infrared spectroscopy), and in vitro drug release. RESULTS: The optimum conditions for preparing MH microparticles were predicted to be the content of ethyl cellulose content (150 mg), poly (Iµ-caprolactone) (150 mg), and polyvinyl alcohol (1 %w/v). The optimized MH microparticles were found to be spherical with a mean size of 350.2 µm. Entrapment efficiency was 58.62% for microparticles. 63.94% of microparticles showed floating properties. The FTIR analysis confirmed no chemical linkage between microparticle components. In vitro release study showed a controlled release for up to 8h. CONCLUSION: These results demonstrated that MH microparticles, as a drug delivery system, may be useful to achieve a controlled drug release profile suitable for oral administration and may help to reduce the dose of drug and to improve patient compliance.