Implementation and in vitro characterization of calcium-free in situ gelling oral reconstituted suspension for potential overweight treatment.

In this work, oral granules that were easily dissolved in aqueous dispersion, were prepared. These oral suspensions were formulated with sodium alginate (AlgNa), chitosan (CHI) and sodium carboxymethylcellulose (CMC Na). The gels were formulated by pouring the suspensions into 150ml of simulated gastric fluid (SGF) pH 1.2 at 37° C. The in-situ gelling mechanism was based on the ionization states of the three biopolymers as a function of the pH of the medium. Fourier transform infrared analysis of gels confirmed the interactions between alginate and chitosan. According to the scanning electron microscopy analysis, the gels were characterized by a firm and homogeneous structure. The obtained values of the elastic storage modulus, G', varied between 101 to 107 Pa. The eliminated volume of the unabsorbed liquid by the gels fluctuated between 25% and 55% of the total liquid volume. The quality of the gels was improved when a maximum concentration of alginate (4g/100ml), a minimum concentration of chitosan (0.5g/100ml) and a maximum amount of carboxymethylcellulose (4g/100ml) were used. The value of their elastic modulus, G' was around105 Pa and the residual unabsorbed volume of the liquid was 25% of the total liquid volume. According to the obtained results, the prepared gels could induce a feeling of fullness by stimulating the gastric distension and they could potentially be applied as anti-obesity medication.