Eudraginated polymer blends: A potential oral controlled drug delivery system for theophylline

Abstract

Sustained release (SR) dosage forms enable prolonged and continuous deposition of the drug in the gastrointestinal (GI) tract and improve the bioavailability of medications characterized by a narrow absorption window. In this study, a new strategy is proposed for the development of SR dosage forms for theophylline (TPH). Design of the delivery system was based on a sustained release formulation, with a modified coating technique and swelling features aimed to extend the release time of the drug. Different polymers, such as Carbopol 71G (CP), sodium carboxymethylcellulose (SCMC), ethylcellulose (EC) and their combinations were tried. Prepared matrix tablets were coated with a 5 % (m/m) dispersion of Eudragit (EUD) in order to get the desired sustained release profile over a period of 24 h. Various formulations were evaluated for micromeritic properties, drug concentration and in vitro drug release. It was found that the in vitro drug release rate decreased with increasing the amount of polymer. Coating with EUD resulted in a significant lag phase in the first two hours of dissolution in the acidic pH of simulated gastric fluid (SGF) due to decreased water uptake, and hence decreased driving force for drug release. Release became faster in the alkaline pH of simulated intestinal fluid (SIF) owing to increased solubility of both the coating and matrixing agents. The optimized formulation was subjected to in vivo studies in rabbits and the pharmacokinetic parameters of developed formulations were compared with the commercial (Asmanyl ® ) formulation. Asmanyl ® tablets showed faster absorption (t max 4.0 h) compared to the TPH formulation showing a t max value of 8.0 h. The C max and AUC values of TPH formulation were significantly (p < 0.05) higher than those for Asmanyl ® , revealing relative bioavailability of about 136.93 %. Our study demonstrated the potential usefulness of eudraginated polymers for the oral delivery of the sparingly soluble drug theophylline.

Preparation, characterization and pharmacokinetics evaluation of clarithromycin-loaded Eudragit® L-100 microspheres

“…Eudragit Ò L100 is a gastro-resistant polymer that is soluble in intestinal fluid from pH 6.0 (Sharma et al 2011). It is an anionic polymer synthetized from methacrylic acid and methacrylic acid methyl ester (Emeje et al 2012).…”

Evaluation of the fluid uptake kinetics and drug release from gellan gum tablets containing metronidazole

“…Measurement of liquid uptake has been used primarily for evaluating the effect of polymer-liquid interactions, which enables the release of drug to take place at a constant rate [3]. Fig.…”

“…The method of Emeje et al [3] was used; the study was carried out using a magnetic stirrer assembly (Model LR II Metler) with an attached thermo-regulated hot plate. The dry polymer tablets containing 100% gellan gum (300 mg) were accurately weighed, placed in the dissolution basket and immersed in the dissolution medium (SGF or SIF) maintained at 37 • C in the dissolution vessels.…”

“…A major function of polymers is to stabilize a large amount of water. Various mathematical models have been used to characterize polymer swelling kinetics [3].…”

Nanotechnology in Novel Drug Delivery System

“…The typical size of micelles for pharmaceutical applications ranges from 10-80 nm. [52][53] . The particle range of different nanotechnology techniques are listed in Table 2.…”