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Although the formulation of effective topical drug delivery system is one of the most sophisticated pharmaceutical preparations, it has attracted researchers due to many medical advantages associated with it. Topical drug delivery systems can act superficially on skin surface, locally in dermal layer of the skin or transdermally to provide successful delivery of drug molecules to the systemic circulation avoiding the traditional problems and limitations of conventional routes of drug delivery. Many novel formulations have been utilized topically to enhance either permeability or drug targeting to a specific layer of the skin such as Liposomes, ethosomes, transfersomes, niosomes and catezomes. The main problem with all of these formulations is that there is no distinct barrier between the targeting and localization action to a certain layer of the skin and the transdermal action to the circulation of these preparations. Any minimal change in the formulation could transform it from a local targeting preparation to a systemic one. This article deals with the innovations pertaining to the use of various types of liposomal preparations and liposomal like preparations for topical drug delivery and the patents associated with it.

In this paper a hybrid finite element method is applied in evaluation of the stress intensity factors K I and KII of unidirectional fiber reinforced composites. In order to satisfy the stress singularity at the crack tip a singular super-element based on a modified complementary energy principle is developed. The stress and displacement fields in the super-element are expressed in terms of polynomials of two complex variables ~1 and ~ in the transformed ~-plane. The stiffness matrix of the super-element was determined by using a line integral along the boundary of the super-element. The displacement vector was expressed in terms of the element nodal displacement vector (q } and a properly selected shape function defined along the element boundary.Numerical results for K 1 and K n of glass-epoxy and graphite-epoxy unidirectional composites with cracks along the diameter of a circular cut out as well as elliptical cut outs were evaluated.