Formulation and evaluation of gastro retentive floating tablets of Loratadine

Abstract

Loratadine a long-acting tri-cyclic antihistamine with selective peripheral histamine H1-receptor antagonistic activity, is used for

the symptomatic relief of allergic conditions like runny nose, itchy or watery eyes, sneezing and nasal or throat itching and

chronic urticaria. It is stable in acidic pH, has a narrow therapeutic absorption window in the GI tract and found to be absorbed at

proximal part of small intestine. Thus it is decided to prolong the gastric residence time in terms of making floating gastro

retentive drug delivery system to increase drug absorption and hence bioavailability. In this study Loratadine floating tablets were

prepared by using two different techniques like Effervescent floating tablets and Non Effervescent floating tablets using Ethyl

cellulose, Karaya gum and HPMC K4 M as polymers and gas generating agents like sodium bicarbonate and citric acid and

polypropylene foam powder as a selling agent in non effervescent floating tablets. The tablets prepared by direct compression

technique were evaluated in terms of their pre-compression parameters and post compression characteristics such as physical

characteristics, total buoyancy, buoyancy lag time, swelling index and in vitro release. The best formulation showed no

significant change in physical appearance, drug content, total buoyancy time, buoyancy lag time or in vitro release after storage at

40˚C /75% RH for three months. The in vitro release studies confirmed that the formulation (F15) containing 90 mg of karaya

gum showed sustained drug release (100.02 ±0.18%) for 12 h and remained buoyant for more than 12 h.