Design and Evaluation of Oral Gastroretentive Folic Acid Floating Tablets

Abstract

Folic acid is a water soluble vitamin of the B-complex group used in prevention of NTD (an acronym for neural tube defect)–a general term that describes a variety of congenital anomalies resulting from abnormal neurulation during early development of the central nervous system. Folic acid has an half life of 3.5 h and therefore, the present investigation was concerned with the development of oral gastroretentive floating tablets of folic acid, which after oral administration were expected to prolong the gastric residence time and improve the bioavailability of the drug as well as its half life. Drug-polymer compatibility studies by FTIR gave conformation about their purity and showed no interaction between drug and selected polymers. Various formulations were developed by using release rate controlling and gel forming polymers like HPMC (K4M, K15M, K100M) and Carbopol 934 by direct compression method with the incorporation of sodium bicarbonate as gas generating agent. All the formulations had a floating lag time between 33 and 47 s and floated on dissolution medium for more than 12 h. Swelling studies indicated significant water uptake and contributed in drug release. From among all the developed formulations, formulation F5 prolonged the drug release for longer period of time and it was selected as the best formulation. F5 was found to be stable during stability studies conducted according to ICH guidelines (30 ± 2 °C / 65 ± 5% RH and 40 ± 2 °C / 75 ± 5% RH) for two months. F5 satisfied physicochemical parameters, floating properties, swelling index and in vitro drug release profile requirements for a floating drug delivery system.