Influence of non ionic surfactants on the release characteristic of wax-matrix ibuprofen granules formed by thermal technique

Abstract

This study was carried out to investigate the influence of non ionic surfactants (polysorbate 80 or sorbitan monooleate) on the release characteristics of wax-ibuprofen matrix granules. Ibuprofen-wax matrix granules were prepared by melt granulation technique. This was formed by triturating ibuprofen powder (100 g) with 20 g of carnauba wax with varying concentrations of non ionic surfactant i.e. polysorate 80 or sorbitan monooleate (0-10 %w/w), and then screened through sieves. The content of carnuaba wax in each formulation was 16.7 %w/w. The granules were evaluated for flow and packing properties. The formed granules were then encapsulated and the in vitro dissolution profile, release kinetics and mechanism were studied. The tap and bulk densities were not affected by the presence of any of the non ionic surfactants as there was no statistically significant difference between these values irrespective of the type and concentration used (P>0.05). All the granules were free flowing with angles of repose <20 °. The dissolution rate increased with increase in concentration of the non ionic surfactants. However, the  influence was more with polysorbate 80 as it was more hydrophilic compared with sorbitan monooleate. For instance, at a concentration of 5 %w/w, the dissolution rates were 10.1 and 8.8 %h ^-1 for polysorbate 80 and sorbitan monooleate respectively. There was no significant difference between their release profiles (P>0.05). All the formulations fitted into Korsmeyer and Peppas model and the release exponents (n) were between 0.49 and 0.86. This indicates that release of ibuprofen wax matrix followed anomalous transport, often termed first-order release. Non ionic surfactants influenced the release of drugs from the system studied hence, controlled amount of non ionic surfactant can be used to effectively enhance and modulate the release of drugs from such system.

Keywords: Ibuprofen, non-ionic surfactants, dissolution profile, wax matrix, release mechanism

Journal of Pharmaceutical and Allied Sciences, Vol. 7 No. 5 (2010)