Use of trona as a permeation enhancer for ointments prepared with beeswax extracted from native honeycombs

This work studied the effect of trona on the release and permeation of salicylic acid from ointments formulated with beeswax processed from native honeycombs. Pure trona was obtained by re-crystallisation. The test (extracted) beeswax was characterized using standard physicochemical procedures. Trona was incorporated into salicylic acid ointment at concentrations of 0.5 - 2.0 %w/w and the ointments evaluated. Consistencies of the ointments were determined by penetrometry while release studies were carried out by studying diffusion of salicylic acid from the ointments on ferric chloride agar. The permeation of salicylic acid from optimised ointments was also studied. Results obtained indicated that the physicochemical properties of the beeswax processed from native honeycombs compared favourably with the standard beeswax. Release enhancement by trona was in the order: 0.5 %w/w > 1.0 %w/w > 1.5 %w/w > 2.0 %w/w while in the permeation experiment, enhancement was mostly observed at trona concentrations of 1.5 %w/w and 2.0 %w/w. Trona could be used as a release and permeation enhancer in salicylic acid ointments.