ABSTRACT
The present study has investigated various ways to formulate a bi-layer tablet dosage form containing an immediate release and a sustained release portion of a neuroprotective compound named vinpocetine. The bi-layer matrix tablet was prepared by simple compression of the SR granules and IR granules of vinpocetine. The sustained release effect of vinpocetine was achieved with polymers methocel K15M CR, kollidon SR and carbomer 934P. Physical properties of powders, granules and the finished tablets were evaluated. The drug release study of the tablets was studied for 2 hours in 0.1N HCl followed by 8 hours in pH 6.8 phosphate buffer as media using United States Pharmacopoea (USP) XXII paddle type dissolution apparatus. The effect of above mentioned polymers on vinpocetine release profile was investigated. The MDT values of all the formulations were calculated and correlated with the rate retardation capacity of drug release of the polymers used. The release rate of vinpocetine immediate release layer was found to be influenced little by kollidon CL and direct compressible grade lactose. The release rate, extent and mechanisms of sustained release layers were found to be governed by the nature and the extent of the polymer used in the formulation. Kinetic modeling of dissolution profiles reveled that vinpocetine release mechanism ranges from the anomalous / non – fickian transport to super case II transport in the given situations. These studies indicated that the proper balance between a matrix forming agent and a channeling agent can produce a drug dissolution profile similar to a theoretical dissolution profile will overcome the disadvantages of conventional tablets of vinpocetine.
ABSTRACT
Bi-layer tablets of tramadol hydrochloride were prepared by direct compression technique incorporating an immediate release layer and a sustained release layer. An immediate release layer was successfully designed to release the bolus dose instantaneously. Water soluble Xanthan gum, water insoluble Kollidon SR and Eudragit L 100 were used as carriers in the sustained release layer of the matrix tablet. All the tablets were evaluated for thickness, diameter, weight variation, hardness and friability. The in vitro drug release was studied for eight hour, first two hours dissolution in acidic medium followed by six hour dissolution in buffer medium. Matrix tablet showed a sustained release rate with a controlled fashion as a function of the quantity of polymer used. The in vitro drug release data were fitted with several mathematical models and mean dissolution time along with fractional dissolution time values (T25%, T50% and T80%) were calculated. Xanthan gum was found to be the most effective rate retarding agent compared to Kollidon SR and Eudragit L 100, when used at same ratio in the formulations.
ABSTRACT
Over the past 30 years as the expense and complications involved in marketing new drug entities have increased, with concomitant recognition of the therapeutic advantages of controlled drug delivery, greater attention has been focused on development of sustained or controlled release drug delivery systems. Bilayer tablet is new era for the successful development of controlled release formulation along with various features to provide a way of successful drug delivery system.
ABSTRACT
The purpose of this research study was to establish ziprasidone HCl NR 40 mg and trihexyphenidyl HCl SR 4mg in the form of bi-layer sustained release floating tablets. The tablets were prepared using sodium HPMC K4M / HPMC K15M as bio-adhesive polymers and sodium bicarbonate acting as a floating layer. Tablets were evaluated based on different parameters such as thickness, hardness, friability, weight variation, in vitro dissolution studies, content of active ingredient and IR studies. The physico-chemical properties of the finished product complied with the specifications. In vitro release from the formulation was studied as per the USP XXIII dissolution procedure. The formulations gave a normal release effect followed by sustained release for 12 h which indicates bimodal release of ziprasidone HCl from the matrix tablets. The data obtained was fitted to Peppas models. Analysis of n values of the Korsmeyer equation indicated that the drug release involved non-diffusional mechanisms. By the present study, it can be concluded that bi-layer tablets of ziprasidone HCl and trihexyphenidyl HCl will be a useful strategy for extending the metabolism and improving the bioavailability of Ziprasidone HCl and Trihexyphenidyl HCl.
O propósito deste trabalho foi preparar ziprasidona. HCl NR 40 mg e triexifenidila.HCl SR 4 mg na forma de comprimidos efervescentes bicamada de liberação controlada. Os comprimidos foram preparados utilizando HPMC K4M / HPMC K15M sódico como polímero bioadesivo e bicarbonato como camada efervescente. Os comprimidos foram avaliados quanto a diferentes parâmetros, como espessura, dureza, friabilidade, variação de peso, dissolução in vitro, conteúdo do ingrediente ativo e estudos de IV. As propriedades físico-químicas dos produtos finais cumprem as especificações. A liberação in vitro da formulação foi estudada de acordo com o procedimento de dissolução da USP XXIII. As formulações resultaram em liberação normal, seguida por liberação controlada por 12 h, o que indica a liberação bimodal de cloridrato de ziprasidona dos comprimidos matriz. Os dados obtidos se adequaram aos modelos de Peppas. A análise de valores de n da equação de Korsmeyer indicou que a liberação do fármaco envolveu mecanismos não difusionais. Por este estudo, pode-se concluir que os comprimidos bicamada de ziprasidona.HCl e de triexifenidila.HCl serão um bom caminho para estender o metabolismo e para melhorar a biodisponibilidade de ziprasidona.HCl e de triexifenidila.HCl.