Hyder Aliyar

Efficient Ibuprofen Delivery from Anhydrous Semisolid Formulation Based on a Novel Cross-linked Silicone Polymer Network: An In Vitro and In Vivo Study

The use of silicone as a primary polymer in topical semisolid pharmaceutical formulations is infrequent. Recent development of novel silicone materials provides an opportunity to investigate their drug delivery efficiencies. In this study, an anhydrous semisolid formulation was prepared using a novel cross-linked silicone polymer network swollen in isododecane. Similar formulations were prepared using petrolatum, an acrylic, or a cellulose polymer. All formulations contained 5% ibuprofen (IBP). In vitro permeability was evaluated for all formulations and a commercial product using human cadaver epidermis. The silicone formulation delivered IBP more efficiently than all other formulations in terms of flux, cumulative amount, and percent drug release. The silicone formulation showed the maximum flux of 85.9 μg . cm(-2) . h(-1) and a cumulative IBP release of 261.6 μg in 8 h, whereas the benchmark showed 20.1 μg . cm(-2) . h(-1) and 30.9 μg, respectively. An in vivo study conducted on rats showed calculated blood AUCs of 59.2 and 17.6 μg . h/g (p < 0.003) for the silicone formulation and the benchmark, respectively. The IBP in excised rat skin was 264 ± 59 μg/g for the silicone formulation and 102 ± 5 μg/g for the benchmark. The results obtained from the in vitro and in vivo studies demonstrate efficient topical IBP delivery by the silicone formulation.

Silicone Excipients in Pharmaceutical Drug Delivery Applications

Silicones have been used in medicines, cosmetics and medical devices for over 60 years. Polydimethylsiloxanes (PDMS) are commonly used as an active in many oral antiflatulent remedies and topically applied skin protectant creams, and ointments. The plethora of physical forms and the physio-chemical properties that silicones can display has led to their adoption in a diverse array of healthcare applications in different physical forms including as excipients in topical and transdermal drug delivery systems. Unique characteristics like hydrophobicity, low surface tension, and aesthetics intrinsically associated with silicones offer function and performance to drug delivery products. Recent research investigations support the use of silicone based pressure sensitive adhesives for their skin-friendliness, and also to enhance the efficacy of the drug in the transdermal drug delivery patch products. Similarly, in topical drug delivery applications, silicone based novel excipients have demonstrated their capability in improving drug delivery efficiency. Recent silicone technologies like swollen crosslinked silicone elastomer blend networks, sugar siloxanes, amphiphilic resin linear polymers, and silicone based hybrid pressure sensitive adhesives promise potential performance advantages and improved drug delivery efficacy in topical or transdermal drug delivery systems.