The role of various surfactants on the release of salbutamol from suppositories

Salbutamol is a selective beta(2)-adrenoreceptor agonist with different pharmacological effects. In this research because of the simplicity of suppository application in elderly and its higher plasma concentration than tablets as well as its particular indication in premature labour, salbutamol suppositories were prepared. The suppositories were formulated containing 10 mg of the drug and Witepsol H15, the oleaginous soluble base using melting method. To optimize the release rate of drug, different surfactants namely, sodium lauryl sulphate (SLS) as an ionic surfactant and Tween 80 as well as Arlacel 60 as non-ionic surfactants with different HLBs were chosen. The effect of surfactant concentration on the release rate of salbutamol from suppositories were also investigated. All prepared formulations fulfilled the specifications set down in British Pharmacopoeia. The results showed that Tween 80 (2%w/w) and SLS (0.75%w/w) caused an increase in dissolution rate of salbutamol from suppositories. As anionic surfactants, such as SLS, cause greater damage on mucosa than non-ionic surfactant, such as Tween 80, this study recommended that Tween 80 could be added in suppository formulation in order to increase the dissolution rate of salbutamol. It was also shown that the release rate of salbutamol altered linearly with the amount of Tween 80 in suppository formulations.