ABSTRACT
INTRODUCTION: Oral sustained release gastro retentive dosage forms offer several advantages for drugs having absorption from the upper gastrointestinal tract to improve the bioavailability of medications which have narrow absorption window. The aim of the study was to develop a floating bioadhesive drug delivery system exhibiting a unique combination of floatation and bioadhesion to prolong the residence in the stomach using atenolol as a model drug. METHODS: Prior to compression, polymeric blend(s) were evaluated for flow properties. The tablets were prepared by direct compression method using bioadhesive polymer like Carbopol 934P and hydrophilic polymers like HPMC K4M, HPMC K15M, and HPMC K100M. The prepared tablets were evaluated for physical characteristics, bioadhesive strength, buoyancy lag time, swelling index and in vitro drug release studies. RESULTS: The mean bioadhesive strength was found to be in the range of 16.2 to 52.1 gm. The optimized blend (F11) showed 92.3% drug releases after 24 hrs. Whilst, increase in concentration of carbopol 934P, bioadhesive strength and swelling index was increased with slow release. The n values of optimized formulations were found in the range of 0.631-0.719 indicating non-fickian anomalous type transport mechanism. CONCLUSION: The study aided in developing an ideal once-a-day gastro retentive floating drug delivery system with improved floating, swelling and bioadhesive characteristics with better bioavailability.
ABSTRACT
Abstract The aims of this study were to prepare fine famotidine-containing floating-bioadhesive cooperative minitablets and to investigate the possibility of using those minitablets as a delivery system for promoting the oral bioavailability of famotidine. Nine minitablet formulations were designed using hydroxypropylmethylcellulose (HPMC K4M) as release-retarding polymers, Carbopol 971P as bioadhesive materials and sodium bicarbonate (NaHCO3) as gas formers. The prepared 3 ± 0.02 mm minitablets were evaluated in terms of their swelling ability, floating behavior, bioadhesion test and in vitro release. The optimized minitablets (F6) containing HPMC K4M (50.00%, w/w), Carbopol 971P (10.00%, w/w) and NaHCO3 (10.00%, w/w) were found to float in 1 min and remain lastingly buoyant over a period of 8 h in vitro, with excellent bioadhesive properties (20.81 g) and sustained drug release characteristics (T50% = 46.54%) followed one-order model. In addition, plasma concentration-time profiles from pharmacokinetic studies in rats dosed with minitablets showed 1.62-fold (p < 0.05) increased absorption of famotidine, compared to the market tablets XinFaDing®. These studies demonstrated that the multiple-unit floating-bioadhesive cooperative minitablets may be a promising gastro-retentive delivery system for drugs that play a therapeutic role in the stomach.
Subject(s)
Adhesives/administration & dosage , Adhesives/chemistry , Famotidine/administration & dosage , Famotidine/chemistry , Tablets/administration & dosage , Tablets/chemistry , Acrylates/administration & dosage , Acrylates/chemistry , Acrylates/metabolism , Adhesives/metabolism , Administration, Oral , Animals , Biological Availability , Chemistry, Pharmaceutical/methods , Delayed-Action Preparations/administration & dosage , Delayed-Action Preparations/chemistry , Delayed-Action Preparations/metabolism , Drug Delivery Systems/methods , Famotidine/metabolism , Gastric Mucosa/metabolism , Male , Polymers/administration & dosage , Polymers/chemistry , Polymers/metabolism , Rats , Rats, Wistar , Sodium Bicarbonate/administration & dosage , Sodium Bicarbonate/chemistry , Sodium Bicarbonate/metabolism , Tablets/metabolismABSTRACT
The purpose of this study was formulation and in vitro evaluation of floating-bioadhesive tablets to lengthen the stay of glipizide in its absorption area. Effervescent tablets were made using chitosan (CH), hydroxypropyl methylcellulose (HPMC), carbopolP934 (CP), polymethacrylic acid (PMA), citric acid, and sodium bicarbonate. Tablets with 5 percent effervescent base had longer lag time than 10 percent. The type of polymer had no significant effect on the floating lag time. All tablets floated atop the medium for 23-24 hr. Increasing carbopolP934 caused higher bioadhesion than chitosan (p < 0.05). All formulations showed a Higuchi, non-Fickian release mechanism. Tablets with 10 percent effervescent base, 80 percent CH/20 percent HPMC, or 80 percent CP/20 percent PMA seemed desirable.
