Formulation, physicochemical characterization and in-vivo evaluation of ion-sensitive metformin loaded-biopolymeric...

The demand on the controlled release of short acting antidiabetic drug, metformin (MT), has been increased dramatically. Thus, boosting the development of new sustained release formulations with contents of multi-micro-scaled particles. This paved the way for the preparation of MT-loaded Gellan gum (GG) microbeads through inotropic gelation technique. The prepared beads were characterized for the following parameters; yield and loading efficiency particle size, particles morphology and topography, swelling behavior, and in-vitro release studies. In view of any possible interactions, differential scanning calorimetry and infrared spectroscopy were performed. As an ultimate evaluation, the relative bioavailability of the sustained release beads was studied in healthy volunteers after oral administration in a fasted state compared to commercially available immediate and extended release tablets using a new validated HPTLC method for MT assay in urine. Results obtained revealed that the formulated Gellan beads were spherical in shape with less smooth surface in the micron range with high yield and entrapment efficiency. In-vitro release studies of the prepared beads were achieved up to 8 h. The prolonged release of MT can be explained through various factors among them; the swelling of the biopolymer and the ionic interaction between the drug and the GG. After oral administration, the AUC(0-24), t(1/2) and t(max) of the prepared beads were of 246.74 ± 26.81 mg, 11.84 ± 2.79 and 7.17 ± 1.75 h, respectively, demonstrating its bioequivalence to the marketed products. In conclusion, the formulated GG microbeads exhibit potentials as an oral sustained release MT system.