An Emerging Era in Topical Delivery: Organogels

Semisolid preparations for external application to skin have gained much demand, since it is easily absorbed through the skin layers. Many novel topical dosage forms have been discovered, among which organogels appears to play an important role. Organogels are thermodynamically stable, biocompatible, isotropic gel, which not only give localised effect, but also systemic effect through percutaneous absorption. Although different types of gelator molecules are being used for the development of organogels, both egg and soya lecithin are mainly focused. The purity of lecithin is also considered to be an important factor in gelation. Apart from lecithin, non-ionic surfactant based microemulsion gels and pluronic organogels are also being developed. Compared to conventional topical dosage forms, these novel formulations are found to be more advantageous and efficient. In future, organogels can give way to many promising discoveries in the field of topical dosage forms. The current review aims at giving an idea about organogels, its applications and importance in topical delivery. *Corresponding author, Mailing address: Vedha Hari B.N Email: [email protected] Article History:-----------------------Date of Submission: 29-03-2012 Date of Acceptance: 13-04-2012 Conflict of Interest: NIL Source of Support: NONE R e v i e w P a p e r C o v e r e d i n I n d e x C o p e r n i c u s w i t h I C V a l u e 4 .6 8 f o r 2 0 1 0 Int. J. Drug Dev. & Res., April-June 2012, 4 (2): 35-40 Covered in Scopus & Embase, Elsevier 35 most effective dosage forms for localized drug delivery and these include creams, ointments, pastes, gels etc. Several novel drug carrier systems have been evolved, which offer sustained release of the drug or which provide a stable environment for the incorporation of APIs. The various properties which make semisolid dosage forms in demand are smooth texture, elegant appearance, non-grittiness, nongreasiness, non-irritating nature, miscibility with the skin secretion, ease of application, prolonged stability etc. Among the different topical applications available, gels have attained keen importance due to its easy absorption trough skin layers. There has been much advancement in the field of topical delivery and many novel formulations have evolved. The novelty in ointments is related to its bases, eg: enhancement in absorption of water, high permeation and prevention of evaporation of moisture from the skin, inclusion of ingredients that prevent skin irritation and so on. They are even safer to use, compatible with a wide range of drugs and also release the drug in a controlled manner. In addition to ointments, the other novel semisolid dosage forms include creams incorporated with microspheres, produced by emulsion method for prolonged release and retention on skin, emulsion containing liquid paraffin as creams, creams with lipid nanoparticles which contains fats and oils, like liquid and semisolid paraffin which produces a high degree of occlusiveness, thereby preventing a rough feeling on application to the skin. Novel discoveries have also been done on gels, which have been explained below in detail. The objective of this review is to give an insight into the importance of topical drug delivery, the advancements made and also to give an idea about the novel semisolid preparations, emphasising mainly on organogels. TYPES OF CONVENTIONAL TOPICAL DOSAGE FORMS 1. Ointments They are soft semisolid preparations containing medicaments which are used for external application to the skin. It may be dermatological, ophthalmic, rectal, depending upon the area to which it is applied.