Microneedle

The stratum corneum of the skin or the sclera/cornea of the eye, the outermost layer of the skin and others has the principal barrier to topically-applied medications. Thus, many therapeutic agents are limited by their inability to reach the systemic circulation. Transdermal delivery of hydrophilic drugs and macromolecular agents of interest is problematic. Therefore, facilitation of drug penetration through this barrier may involve by-pass or reversible disruption of molecular architecture. Microneedles, when used to puncture skin, will by-pass the barrier and create transient aqueous transport pathways of micron dimensions and enhance the transdermal permeability. These micropores are orders of magnitude larger than molecular dimensions, and, therefore, should readily permit the transport of hydrophilic macromolecules. This microneedle based drug delivery system will useful for the eye treatments by avoiding drawbacks of topical administration of drug, multiple drug treatment and other dosage form intended in the eye. This review gives the details of history, various types of microneedles, drug delivery, fabrication methods, manufacturing, evaluation and, importantly, investigations of clinical safety of microneedles.

Eye is a window to the outside world and hence it becomes an important part of our body. Various diseases occurring in the eye cavity are difficult to treat. Some diseases require continuous use of medicine and other requires surgery. Lacrisert, Vitrasert, Mydriasert, Prosert etc. are patented technologies useful in the treatment of eye disorders. In this article brief description of various patented technologies such as Eyegiene kit, Ophtha coils, Versidoser, Microneedle, Implantable MEMS ocular drug delivery system, Ocuseal liquid bandage, Filter paper strips is given.