Films were formulated by solvent-casting technique using EC, HPMC E15 and Eudragit RLPO as polymers and dibutyl phthalate as the plasticizer in both the layers. Apart from routine technical parameters, the bilayer films were evaluated for unfolding behaviour based on the mechanical shape memory of polymers. The capsulated zigzag folded film was shown to unfold in the gastric juice and provided drug release up to 12 h in the simulated gastric fluid. The X-ray study revealed that the GRDDS was retained in the stomach for up to 6± 0.5 h in fasting condition and 8 h in fed state validating the design. In an effort to design a controlled-release, expandable GRDDS; Biswas et al . (2014) fabricated a drug delivery system of carvedilol using HPMC and psyllium. Mass swelling ratios at equilibrium were higher for batches containing psyllium which rendered them buoyant in the simulated gastric fluid within 9 min and maintained the structural integrity for a maximum period of 23.8±0.97 h. The batch with HPMC K15M and psyllium in the ratio 2:1 exhibited Fickian type swelling mechanism. The drug diffused out through the gel barrier around the swollen matrix slowly via diffusion/relaxation controlled transport. Release retardant effect of psyllium was manifested in high values of t 50% and t 80% of 7.8 0.59 and 16.1±0.26 h, respectively, for the optimized batch. Bio/Mucoadhesive systems They bind to the gastric epithelial cell surface, or mucin, and extend the GRT by increasing the intimacy and duration of contact between the dosage form and the biological membrane. The epithelial adhesive properties of mucin have been applied in the development of Gastro retentive drug delivery systems (Sarojini, Manavalan, 2012). Pathak, Mishra and Mishra (2013) developed gastroretentive mucoadhesive films of captopril by using polymers like EC, HPMC and carbopol 934P and glycerine(plasticizer) for treatment of hypertension. The release kinetics followed Korsmeyer-Peppas model. FIGURE 2 - Folding pattern of film for gastroretentive bilayer film of furosemide. (Darandale, Vavia, 2012.)
GRDDS for antihypertensive therapy Braz. J. Pharm. Sci. 2017;53(3):e00173 Page 9 / 15 The optimized formulation showed best mucoadhesive strength and a drug release of 99.06% at 24th hour. In another report on captopril; Pawar, Lalitha and Ruckmani (2015) prepared gastroretentive captopril loaded alginate beads by ionotropic gelation method using sodium alginate in combination with natural gums containing galactomannans (Senna tora seed gum, guar gum and locust bean gum) in the presence of calcium chloride. From the entrapment efficiency and drug release studies, it was concluded that galactomannans in combination with sodium alginate show sustained release property. The optimized formulation showed satisfactory sustained release for 12 h and the release was governed by swelling of the polymer followed by drug diffusion through the swollen polymer and slow erosion of the beads.
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- Summer '18
- EDQWR EDWEDF
- drug release, Braz. J. Pharm, GRDDS