Gastro Retentive Research Articles

가바펜틴을 함유한 위체류성 정제의 제조 및 용출 평가

The objective of this investigation was to develop a gastro-retentive(GR) dosage form of gabapentin and was to evaluate of its dissolution characteristics. GR tablet consists of expandable core tablet matrix and semi-permeable membrane coating. Poloxamer 407 and sodium bicarbonate were used to prepare the core matrix. Polyvinly acetate dispersion (Kollicoat ) and polyvinyl alcohol-polyethylene glycol copolymer ((Kollicoat )) were employed to form the semi-permeable membrane. The GR tablets significantly expanded up to fivefold in simulated gastrointestinal fluids with no apparent damage of the coating membrane over 12 hours. Also, the swelling rate was controllable with the amount of sodium bicarbonate. The drug release was observed to be substantially sustained based on coating level. The release rate of gabapentin from the GR tablet was gradually slowed down as the coasting amount was increased. The gabapentin GR tablet with 8% coating level showed a pseudo-zero order release kinetics over 12 hours. These results suggest that this swellable GR tablet system having semi-permeable membrane coating can be applicable for hydrophilic drug substances like gabapentin.

Preparation of a Matrix Type Multiple-Unit Gastro Retentive Floating Drug Delivery System for Captopril Based on Gas Formation Technique: In Vitro Evaluation

A gastro retentive floating drug delivery system with multiple-unit minitab's based on gas formation technique was developed in order to prolong the gastric residence time and to increase the overall bioavailability of the drug. The system consists of the drug-containing core units prepared by direct compression process, which are coated with three successive layers of an inner seal coat, effervescent layer (sodium bicarbonate) and an outer gas-entrapped polymeric membrane of an polymethacrylates (Eudragit RL30D, RS30D, and combinations of them). Only the system using Eudragit RL30D and combination of them as a gas-entrapped polymeric membrane could float. The time to float decreased as amount of the effervescent agent increased and coating level of gas-entrapped polymeric membrane decreased. The optimum system floated completely within 3 min and maintained the buoyancy over a period of 12 h. The drug release was controlled and linear with the square root of time. Increasing coating level of gas-entrapped polymeric membrane decreased the drug release. Both the rapid floating and the controlled release properties were achieved in the multiple-unit floating drug delivery system developed in this present study. The analysis of the parameter dissolution data after storage at 40 degrees C and 75% RH for 3 months showed, no significant change indicating the two dissolution profiles were considered to be similar (f2 value is more than 50).

Gastro-retentive Dosage Form for Improving Bioavailability of Cefpodoxime Proxetil in Rats

Cefpodoxime proxetil (CP) is a prodrug with poor oral bioavailability because of its metabolism to Cefpodoxime acid (CA) in luminal contents and intestinal epithelial cells. In the present investigation, regional variability in different segments of the gastrointestinal tract vis-à-vis solubility and metabolism were investigated, and the results indicated potential for a gastro retentive (GR) dosage form. Suitability of a GR dosage from for CP and finally in vivo efficacy were investigated. Thereafter, an effervescent floating GR dosage form was developed for CP and evaluated in rats. The GR dosage form improved the oral bioavailability of CP significantly by about 75%, hence providing a proof-of-concept. The Tmax value increased to 1.43+/-0.24 h from 0.91+/-0.23 h of pure drug, while Cmax values of 4735+/-802 ng/ml and 3094+/-567 ng/ml were obtained for the GR dosage form and pure drug respectively.

Effect of Hydrophobic Polymers on the Gastro Retention Time and <i>In vitro</i> Release of Ciprofloxacin HCl from Co-matrix Tablets

The present study was conducted to investigate the effect of different polymers on the release profile and bio-adhesive strength of a water soluble drug, ciprofloxacin HCl from different percentages of Eudragit RS PO and Kollidon SR based co-matrix tablets. Matrix formulations were prepared by direct compression method. The bioadhesive property was investigated in terms of retention time following in vitro wash-off method. The concentrations of polymers were varied to investigate whether these variations can cause any change in release of ciprofloxacin HCl molecule and bio-adhesion property or not. In most of the cases it is found that Eudragit RS PO based co-matrix tablets release greater percentage of active drug and that bio-adhesive strength of Kollidon SR and xanthan gum based co-matrix tablets were significantly better. Finally it was revealed that xanthan gum provided optimum bioadhesion functioning as a synergist in co-matrices and comply the USP specification as a most suitable controlled release polymer. Key words: Gastro retention time; direct compression; ciprofloxacin HCl; Eudragit RS PO; Kollidon SR; xanthan gum. DOI: http://dx.doi.org/10.3329/dujps.v9i2.7893 Dhaka Univ. J. Pharm. Sci. 9(2): 97-102, 2010 (December)

Comparison of Gastro Retention Time and <i>in vitro</i> Release Profile studies of Ciprofloxacin HCl from Co-matrix Tablets of Hydrophilic Polymers

Controlled release co-matrix tablets of Ciprofloxacin HCl were prepared with different types of bioadhesivepolymers e.g. Methocel K4M, Methocel K 15M CR and Methocel K 100LV, Povidone K-30, and Xanthangum. Tablets prepared by direct compression method were subjected to in-vitro drug dissolution study for 8 hours ina simulated gastric fluid media using USP dissolution apparatus II with 50 rpm at 37±0.5ºC. The bio-adhesiveproperty was investigated in terms of retention time following in-vitro wash-off method. The concentrations ofpolymers were varied to investigate whether these variations can cause any change in release of Ciprofloxacin HClmolecule and bio-adhesion property or not. In most of the cases it is found that Methocel K4M and MethocelK100LV based co-matrix tablets release greater percentage of active drug than Methocel K15M CR based co-matrixtablets. Bio-adhesive strength of Methocel K15M CR and Xanthan gum based co-matrix tablets was proved to bemaximum followed by Methocel K4M and Xanthan gum based co-matrices. Whereas Methocel K100LV andXanthan gum based co-matrices showed little or poor muco-adhesion. Methocel K4M, K15M CR and Xanthan gumbased formulations showed nearly zero-order release, on the other hand Methocel K100LV and Xanthan gum basedformulation showed a burst release within one hour of dissolution. Finally it was revealed that Xanthan gum providedoptimum bio-adhesion functioning as a synergist in co-matrices and comply the USP specification as a most suitablecontrolled release polymer.Key words: Gastro retention time; Direct Compression; Ciprofloxacin HCl; Methocel K4M; Methocel K15M CR;Methocel K100LV; Xanthan gum.DOI: 10.3329/dujps.v8i1.5338Dhaka Univ. J. Pharm. Sci. 8(1): 67-73, 2009 (June)