Effect of polymer ratio on the quality of a co-processed excipient of prosopis gum and crab shell chitosan

Purpose: To assess the effect of polymer ratio on the quality of a novel co-processed excipient of prosopis gum and crab shell chitosan.Methods: The physicochemical properties (DSC thermogram, powder flow properties, porosity and swelling index as well as pH, viscosity and adhesive strength of 2 % w⁄v dispersions) of prosopis gum, chitosan and the three grades of co-processed excipient of prosopis gum and crab shell chitosan (Prosochit® 201, Prosochit® 101 and Prosochit® 102) were determined.Results: The three grades of the co-processed excipient of prosopis gum and crab shell chitosan (Prosochit®) were characterized by one endothermic transition each with peaks at 180 oC, 179 oC and 178 oC for Prosochit®201, Prosochit®101 and Prosochit®102 respectively. Flow properties increased with increase in proportion of chitosan. The porosity of the three grades of the new excipient was not significantly different from that of prosopis gum. Swelling indices of prosopis gum, chitosan, Prosochit® 201, Prosochit® 101 and Prosochit® 102 were 1135.53%, 14.00%, 726.33%, 677.33% and 514.00% respectively. The viscosity also decreased with increase in the proportion of chitosan. The new excipient had higher adhesive strength compared to the individual constituents (prosopis gum and crab shell chitosan).Conclusion: Prosochit® is superior to its individual constituents as a tableting excipient but its suitability for liquid formulation is reduced by increase in the proportion of chitosan.Keywords: Polymer ratio, Crab shell chitosan, Prosopis gum, Prosochit®