Formulation And In-Vitro Evaluation Of Theophylline Hydrochloride Effervescent Floating Tablets: Effect Of Polymer Concentration On Tablet Buoyancy

Objective: This study was undertaken to formulate a floating drug delivery system of theophylline hydrochloride using different concentrations of a chosen polymer and then investigate how polymer concentration affects buoyancy and drug release properties of the tablets. Methods: Hydroxypropyl methylcellulose (HPMC) at different concentration levels of 15% (F1), 20% (F2) and 30% (F3) was used to form the three formulation batches of floating tablets. Wet granulation method was used for the granule preparation while Sodium bicarbonate and citric acid were used as the gas generating agent. The physical properties of the granules and the floating tablets were evaluated. Also determined were the physicomechanical properties, buoyancy and swelling characteristics of the tablets. The in vitro drug release study was carried out according to the USP I (basket method) for 8h in 900 ml 0.1N HCl at 50 rpm. Samples withdrawn at the regular predetermined time were analyzed spectrophotometrically at a wavelength of 271 nm and data obtained statistically analyzed by one-way analysis of variance (ANOVA). The differences between means were considered significant at P<0.05. Results: The result showed that polymer (HPMC) concentration significantly (p>0.05) increased swelling index and improved floating lag time, it had no significant effect on the total floating time. Percentage drug release at the end of 8 h was 100%, 98.2% and 96.13% for formulation F1, F2 and F3, respectively. All three formulations followed the Higuchi drug release kinetics model and the mechanism of drug release was the non Fickian diffusion with exponents of 0.46, 0.51 and 0.56 for the respective batch. Conclusion: Batch F3 gave a better-controlled drug release and floating properties in comparison to batch F1 and F2 thus Polymer concentration influenced the onset of floating and controlled the release of Theophylline.

Development of a new single unit dosage form of propranolol HCl extended release non-effervescent floating matrix tablets: In vitro and in vivo evaluation.

The objective of the present investigation was to develop extended release non-effervescent floating matrix tablets of Propranolol Hydrochloride (PPH) to extend the gastric residence time (GRT) and prolong the drug release after oral administration. Different viscosity grades of Hydroxypropyl methylcellulose (HPMC) polymers such as HPMC K4M, HPMC K15M and HPMC K100M were used as drug release retardants. Glyceryl behinate (Compritol 888 ATO) and Glyceryl monosterate (Precirol ATO 5) were used as low density lipids in order to get the desired buoyancy over a prolonged period of time. The drug excipients compatibility study was carried out by using Differential Scanning Calorimetry (DSC). All the formulations were prepared by direct compression technique. The prepared tablets were evaluated for their physical characters, in vitro drug release and in vitro buoyancy. The release and floating property depends on the polymer type, polymer proportion, lipid type and lipid proportions. The drug release profiles of all the formulations were subjected to Zero order, First order, Higuchi and Peppas kinetic models, and the optimized formulation (F7) followed the Peppas model (R2= 0.987) with non-Fickian diffusion mechanism(n>0.5). The optimized formulation was subjected for in vivo radiographic studies in healthy human volunteers (n=3). These studies revealed a mean gastric residence time of 5±1.73 h (n=3).

A review on gastroretentive drug delivery system.

Oral controlled release and site specific drug delivery system has been of great interest in pharmaceutical field to achieve improved therapeutic advantage. Concept of novel drug delivery system arose to overcome certain aspect related to physicochemical properties of drug molecule and the related formulations. Gastro retentive drug delivery system is one of such novel approaches to prolong gastric residence time, thereby targeting site specific drug release in the stomach for local or systemic effects. This approach is useful particularly for the drugs which have narrow absorption window in the upper part of gastro intestinal tract. In this review we have been discussed various approaches of gastro retentive drug delivery system, such as floating and non-floating systems.

Gastroretentive drug delivery system of a lipid lowering agent.

The objective of this study was to develop mucoadhesive tablets of Simvastatin using natural polymers. Simvastatin has short biological half-life and high first pass metabolism hence which was designed to increase the gastric residence time which prolong the drug release. The tablets were prepared by wet granulation technique using Carbopol-934, guar gum, xanthine gum and chitosin as polymers. Formulations were evaluated for different parameters like hardness, friability, uniformity of weight, swelling characteris-tics, in vitro dissolution and kinetic studies. The dissolution was carried out for 12 hours in which the formulation with guar gum has shown highest dissolution release profile (F9). Thus the present study concludes that mucoadhesive tablets of simvastatin can be a good way to pass the extensive hepatic first pass metabolism and to improve the bioavailability of simvastatin.

Gastroretentive drug delivery system of a lipid lowering agent.

The objective of this study was to develop mucoadhesive tablets of Simvastatin using natural polymers. Simvastatin has short biological half-life and high first pass metabolism hence which was designed to increase the gastric residence time which prolong the drug release. The tablets were prepared by wet granulation technique using Carbopol-934, guar gum, xanthine gum and chitosin as polymers. Formulations were evaluated for different parameters like hardness, friability, uniformity of weight, swelling characteris-tics, in vitro dissolution and kinetic studies. The dissolution was carried out for 12 hours in which the formulation with guar gum has shown highest dissolution release profile (F9). Thus the present study concludes that mucoadhesive tablets of simvastatin can be a good way to pass the extensive hepatic first pass metabolism and to improve the bioavailability of simvastatin.

Formulation and Evaluation of Gastroretentive Floating Tablets of Domperidone Maleate.

The low bioavailability (15%) and good solubility of Domperidone Maleate in acidic pH following oral administration favours development of a gastro retentive formulation. Gastroretentive floating matrix tablets of Domperidone Maleate were successfully prepared with hydrophilic polymers like HPMC K4M, HPMC K15M and HPMC K100M. From the Preformulation studies for drug excipients compatibility it was observed that there was no compatability problem with the excipients used in study. The drug release from most of the formulations follows fickian diffusion. From in-vivo X-ray studies, it was clearly observed that the floating tablets showed a gastric residence of nearly 4.5 hrs in fed state.