In situ ophthalmic gel for treatment of eye disease

Eye is one of the organs that is well protected; therefore giving medicine to the eye is difficult because of several natural barriers. These barriers include the change of tears blinking, tear production and drainage from the nose to the eye all of which take away most of the medicine that is put in the eye with drops (usually less than five percent) and the medicine stays only a few minutes. Because of this only a small amount of the medicine reaches the place in the eye is taken up by the eye tissue and the amount that actually works is low. This low working amount means that many doses are needed. A better way than eye drop is to use in-situ forming gels. In-situ forming gels stay liquid when they are applied and then they change into a gel after they meet a trigger such as a change in pH, temperature or salt level. When in-situ forming gels are formed in the eye in-situ forming gels stays there longer than drops do so the medicine stays inside the part of the eye for a longer time the amount that works increases the dose needed goes down and the eye gets better faster. This review looks at how in-situ ocular gels are made what natural barriers exist, how the gel is made and which polymers and helper substances are used. The review also talks about how the gel's made how its quality is checked how mathematical models help predict how the medicine leaves the gel and how these gels are useful for many types of medicine. The review also shows the bad sides of in-situ gels how they are regulated today and where new research could go. The review gives examples of gels that use polymers like Carbopol hydroxypropyl methylcellulose, gellan gum, sodium alginate, xanthan gum, ethylcellulose, chitosan and poloxamer. These polymers are used to make gels that respond to pH, salt or temperature. They aim to treat eye infections caused by bacteria and fungi. The medicines that are put in these gels include drugs such as ciprofloxacin, ofloxacin, moxifloxacin and besifloxacin as well as drugs for glaucoma. Special care is taken to examine how in-situ forming gels looks, how clear it is, its pH, how thick it's how well in-situ forming gels turns into a gel, how much medicine it holds, its flow behavior, how well it sticks to the eye how fast the medicine comes out that in-situ forming gels is sterile has the right salt balance stays stable and how the eye tolerates it. The review also looks at systems that combine different polymers and two triggers or that add tiny particles to get around many of the problems, with ordinary eye drops. These new systems let the medicine stay in the eye longer and get deeper into the eye tissue. Therefore in-situ forming gels appear to be ways to deliver medicine. They can make the treatment of eye problems better by keeping the eye surface from getting damaged making more medicine work and needing fewer doses.