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 (ε-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