In vitro Evaluation of PEGylated-Mucin Matrix as Carrier for Oral Delivery of Metformin Hydrochloride

Purpose:To formulate metformin hydrochloride-loaded PEGylated-mucin microparticles and evaluate their in vitro properties.
Method: Three different formulations of metformin hydrochloride (MTH) (PEG-M1, PEG-M2 and PEG- M3) were prepared using PEGylation method. PEG-8000 and snail mucin, in a ratio of 1:3, were PEGylated together using solvent interaction principle. Loading of MTH into the matrix was by diffusion method and the microparticles characterized for particle size, zeta potential, polydispersity index, stability and in vitro release in phosphate buffer (pH 7.4).
Results: Maximum yield and encapsulation were 97 and 87 % respectively. Zeta potential was -37.7, - 42.3 and -46.2 mV for PEG-M1, PEG-M2 and PEG-M3 with a corresponding polydispersity index (PDI) of 0.320, 0.374 and 0.398, respectively. Particles size was 85, 115, and 145 μm for PEG-M1, PEG-M2 and PEG-M3, respectively, and they showed a unimodal distribution. Drug release was biphasic and exhibited controlled release pattern with maximum release of 92 % in 18 h compared to 81 % in 6 h for the conventional formulation.
Conclusion: Extended release metformin hydrochloride formulations were successfully developed using PEGylated mucin matrices.

Keywords
Drug delivery; Extended release; Polyethylene glycol; Mucin PEGylation; Encapsulation; Zeta potential; Polydispersity index