Katarzyna Winnicka, Anna Czajkowska-Kośnik
Nowoczesne postaci leków do oczu
Novel ophthalmic drug delivery systems. Topical application of drugs to the eye is the most popular and well-accepted route of administration for the treatment of various eye disorders. The bioavailability of ophthalmic drugs is, however very poor due to efficient protective mechanisms of the eye. Numerous strategies were developed to increase the bioavailability by prolonging the contact time between the preparation, and therefore the drug, and the corneal/conjunctival epithelium. The most widely developed drug delivery system is represented by the polymeric hydrogels. Hydrogels generally offer a moderate improvement of ocular drug bioavailability despite their favourable bioadhesive properties. One of the disadvantages is that hydrogel may result in blurred vision. In situ activated gel-forming systems seem to be preferred as they can be administered in drop form, create significantly less problems with vision and provide good sustained release properties. Development of vesicular system including micro- and nanoparticles, self-emulsifying drug delivery systems (SEDDS), liposomes, dendrimers and microemulsions is also reviewed. The advantages of this systems are prolonged release of drugs, reduction in dose size, elimination of frequent dosing, non irritant to eyes, biocompatibility and minimum side effects.