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Formulation Optimization of Hydrodynamically Balanced Oral Controlled Release Bioadhesive Tablets of Tramadol Hydrochloride Bhupinder SINGH *, Ashu RANI, BABITA, Naveen AHUJA, Rishi KAPIL University Institute of Pharmaceutical Sciences, UGC Center of Advanced Studies, Panjab University 160 014, Chandigarh, India. * Corresponding author. E-mail: firstname.lastname@example.org (B. Singh) Sci Pharm. 2010; 78: 303–323 Published: Accepted: April 18 2010 April 12th 2010 th
doi:10.3797/scipharm.1001-04 Received: January 6th 2010
This article is available from: http://dx.doi.org/10.3797/scipharm.1001-04 © Singh et al.; licensee Österreichische Apotheker-Verlagsgesellschaft m. b. H., Vienna, Austria. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The directly compressible floating-bioadhesive tablets of tramadol were formulated using varying amounts Carbopol 971P (CP) and hydroxypropylmethyl cellulose (HPMC), along with other requisite excipients. In vitro drug release profile, floatational characteristics and ex vivo bioadhesive strength using texture analyzer were determined, and systematically optimized using a 32 central composite design (CCD). The studies indicated successful formulation of gastroretentive compressed matrices with excellent controlled release, mucoadhesion and hydrodynamic balance. Comparison of the dissolution profiles of the optimized formulation, with optimal composition of CP:HPMC :: 80.0:125.0, with that of the marketed controlled release formulation other indicated analogy of drug release performance with each other. Validation of optimization study using eight confirmatory experimental runs indicated very high degree of prognostic ability of CCD with mean ± SEM of −0.06% ± 0.37. Further, the study successfully unravels the effect of the polymers on the selected response variables.
Drug delivery • Gastroretentive • Mucoadhesive • Experimental design • Floatation
B. Singh et al.:
Amongst various routes to deliver drugs, oral intake has unambiguously been the most sought after by the patients and manufacturers alike. Using the conventional oral dosage forms several drugs have to be administered quite frequently (i.e., 2–4 times-a-day) resulting, therefore, in high fluctuation in plasma drug levels causing saw-tooth kinetics. Controlled release (CR) systems are designed primarily for reducing the frequency of administration by regulating the drug concentration in the target tissue, ensuring patient compliance and consequently improving the efficacy of drugs [1, 2]. However, the development of a CR drug delivery system (DDS) is precluded by its inability to restrain and localize it within the desired region of gastrointestinal (GI) tract, and the highly variable nature of gastric emptying process . The DDS can improve the controlled delivery of the drugs exhibiting an absorption window by continuously releasing the drug for a prolonged period before it reaches the absorption site, thus ensuring its optimal bioavailability [4, 5]. Various approaches including floating systems, bioadhesive systems, swelling and expanding systems and high density systems have been successfully employed to improve the gastric residence time of DDS [6, 7]. Though highly efficient for gastroretention, the floating systems suffer from a major disadvantage that they are effective only when the fluid level in the stomach is sufficiently high. However, as the stomach empties and the tablet is at the pylorus, the buoyancy of the dosage form may be impeded. This serious limitation can be overcome by making the floating system eventually adhere to the mucous lining of the stomach wall ....