Physicochemical Characterization and Evaluation of the Suspending Properties of Boswellia papyrifera Gum in Metronidazole Benzoate Suspension.

Background: Currently, many natural gums are extensively utilized as suspending agents in the formulation of pharmaceutical suspensions. They are easily available, nontoxic, biodegradable, and cost-effective to be used as pharmaceutical excipients. Objective: The present study was aimed at physicochemical characterization and evaluation of the suspending capacity of Boswellia papyrifera gum (BPG) in comparison with sodium carboxy methyl cellulose (SCMC) and tragacanth gum (TG). Methods: The extracted and powdered BPG was subjected to physicochemical properties such as micromeritics, solubility, swelling power, ash value, moisture content, conductivity, pH, and apparent viscosity using standard methods. Metronidazole benzoate suspensions were formulated using various concentrations of BPG, SCMC, and TG (1%-5% w/v). The apparent viscosity, flow rate, sedimentation volume, redispersibility number, pH, and drug content were studied as assessment parameters. Results: The micromeritic studies revealed that BPG exhibited good flow properties. There was also a significant increase in solubility and swelling power of the gum as a function of temperature. The gum had 2.78% ash value and 4.32% moisture content. Conductivity and apparent viscosity of the gum were found to be increased with concentration (p < 0.05). However, the apparent viscosity of BPG was decreased with shear rate (p < 0.05), rendering a pseudoplastic flow property of the gum, which is an ideal characteristic of suspending agents. The suspending capacity of the BPG was found to be comparable to SCMC, but higher than TG. Thus, it can be concluded that BPG could be used as the best alternative to natural and synthetic suspending agents.