Design development and evaluation of oral sustained release in situ floating gel as a carrier for stomach specific drug delivery of anti ulcer drug

Abstract

The present thesis is entitled as Design, Development and Evaluation of Oral Sustained Release In Situ Floating Gel as a Carrier for Stomach Specific Drug Delivery of Anti ulcer Drug . Gastroretentive drug delivery systems are used to administer drugs with narrow absorption window in the upper gastric region at a controlled rate. The raft formation mechanism provides an important benefit over gastric preservation methods based on floating structures, the use of medications as a liquid dosage medium, and then in situ gelation of the solution for a sustainable drug release in the high GI Tract. newlineSeveral difficulties are faced in designing controlled release systems to achieve better absorption and enhanced bioavailability for drugs that are incompletely absorbed. One of such difficulties is the inability to target the dosage form in the desired area of the gastrointestinal tract due to variability in gastric transit time. Small intestinal transit time is also an important parameter for drugs that are incompletely absorbed. newlineIt has been suggested that compounding narrow absorption window drugs in a unique pharmaceutical dosage form with gastroretentive properties would enable an extended absorption phase of such drugs. After oral administration, such a dosage form would be retained in the stomach and release the drug there in a sustained manner, so that the drug could be released continuously to its absorption sites in the upper gastrointestinal tract. newlineNizatidine is a histamine H2-receptor antagonist. It is widely prescribed in active duodenal ulcers, gastric ulcers, ulcerative esophagitis, gastroesophageal reflux disease (GERD), heartburn and erosive esophagitis. However, the recent failure of proton pump inhibitors to prevent night-time gastric acid surge (which is associated with high nocturnal histamine newlineconcentration) and side effects from other H2 receptor antagonists (gyanacomastia) brings open a new door for delivery of nizatidine at specific times in relation to onset of symptom. newline