Published on July 19, 2014
PowerPoint Presentation: pH- Controlled drug loading and release from biodegradable microcapsules Journal: Nanomedicine (Impact Factor- 7.647) By Ashani Basu Al Ameen College of Pharmacy PowerPoint Presentation: Introduction Abbreviations Aim of the study Material & Methodologies Results Conclusion PowerPoint Presentation: . . . Introduction Polyelectrolyte microcapsules are used as potential drug carriers. For biomedical application biodegradable polyelectrolyte microcapsules are mainly used. PSS, PAH etc. are mainly used for this. Proteins, polypeptides etc. are generally used on the colloids such as calcium carbonate, melamine formaldehyde etc. for the formation of multilayered shells. PowerPoint Presentation: . . . Abbreviations Content Abb. Poly- L lysine hydrobromide PLL Chondroitin Sulfate sodium salt CS Glycine Sodium carbonate Na 2 (CO)3 Calcium nitrate tetra hydrate Bovin serum albumin labeled with fluorescence isothiocyanate (FITC-BSA) EDTA Ethylene di amine tetra acetic acid GA Glutaraldehyde PowerPoint Presentation: . . . Aim of the study T o develop biodegradable microcapsules with controllable loading and release capabilities for drug delivery applications. PowerPoint Presentation: Materials PLL CS Glycine Sodium Carbonate Calcium nitrate tetrahydrate FITC-BSA EDTA Quartz slides 0.05 M glycine solution of pH 5.5 PowerPoint Presentation: . . . Methodology PowerPoint Presentation: Preparation of CaCO3 microparticles integrated with CS Mineralization of NaCO 3 & Ca(NO 3 ) 2 solutions suspended with CS 100 mL 0.33 M Ca(NO 3 ) 2 Sol. + 2 mL 10% (w/v) CS sol. + 100 mL 0.33 M Na 2 (CO) 3 (rapidly poured under agitation) CaCO 3 microparticles formed & collected through centrifugation CS content in the microparticles were measured by ICP- OES 0.5 g of CaCO3(CS) microparticles were dissolved in 5 mL HCL acid & 10 mL HNO3 Supplemented with deionized water to 50 mL Sol. Heated @ 118 º C for 2.5 hours & cooled to ambient temp. Deionized water was added to bring the sol. Vol. back to 50 mL sol. Was analyzed by ICP- OES PowerPoint Presentation: PLL- CS multilayer assembly & microcapsule preparation PLL & CS were alternatively assembled onto CaCO 3(CS) microparticles CaCO3(CS) particles rinsed twice with glycine incubated in 1 mg/ mL PLL sol. For 10 mins. Again washed 3 times for 1 minute followed by centrifugation @ 5000 rpm for 30 seconds Incubate the microparticles in CS solution & repeat the deposition of PLL & CS PLL- CS multilayers with desired no. of layers on CaCO3(CS) microparticles PowerPoint Presentation: Template shell particles were subjected to cross- linking using GA & particles were treated with glycine sol. To eliminate aldehyde groups. Rinsed the microparticles with deionized water & transferred to 0.1 M EDTA sol. For 1 hour for decompose the CaCO 3 template Microcapsules integrated with CS were obtained Washed for 3 times . . . Cont. PowerPoint Presentation: FITC-BSA was studies as model drug The pH was maintained (range- 3.4- 5.0) certain quantity of microcapsules mixed with 200 μ L 1mg/mL FITC- BSA incubated at certain temperature for 12 hours @ certain temp. followed by centrifugation (3500 rpm for 5 minutes) FITC –BSA quantified by using UV spectrophotometer The loading was confirmed by Zeiss LSM 510 confocal laser scanning microscope PowerPoint Presentation: . . . Release profile of BSA from CS- integrated microcapsules After the previous step, microcapsules were mixed with 1 μ L PBS at pH 7.4 or 1 ml HCL at pH 5.0 Incubated with gentle shaking. 200 μ L aliquot of supernatants was taken out & mixed with PBS or HCL solution absorbance taken at 458 nm & cumulative release was calculated. Statistical analysis of the release profile at different pH were also calculated. PowerPoint Presentation: . . . Bullet Points CaCO3 microparticles integrated with CS were prepared. LBL was applied to form multilayered shells on the particles. After dissociation of CaCO3 particles, polyelectrolyte microcapsules were obtained. Integration of CS inside the capsules was intended to alter physical properties & it will also control the drug loading & release via pH. A model drug was used & investigated. PowerPoint Presentation: . . . Discussion PowerPoint Presentation: Fig: The loading of drug varied with pH. Maximum loading was at pH 3.8 & minimum was at pH 5. PowerPoint Presentation: The loading of model drug in microcapsules was confirmed by confocal laser microscopy. High fluorescence intensity was observed in microcapsule core. PowerPoint Presentation: FITC-BSA cumulative release from CS-integrated microcapsules versus incubation time. (A), Release profiles at pH values 7.4, 5.0, and 1.0. The inset is the release of FITC-BSA at pH 7.4 for up to 5600 minutes. PowerPoint Presentation: ( B ), Release of FITC-BSA at 30 and 65 minutes. (⁎)Release was significantly different between the pH values tested. Release was conducted at 37°C at pH7.4 (○), 5.0 (△), and 1.0 (□) solutions. PowerPoint Presentation: Fig: Scanning electron microscope images of (PLL-CS ) microcapsules cross-linked for 24 hours using GA at a concentration of (A) 0.05% (v/v ), ( B) 0.1% (v/v), (C) 0.5% (v/v), (D) 1% (v/v), and (E) 5% (v/v). PowerPoint Presentation: . . . Conclusion PowerPoint Presentation: . . . Conclusion A biodegradable drug delivery system with controllable loading & release capabilities is produced. A new strategy to load charged drug molecules in polyelectrolyte microcapsules for triggered/ sustained release. The drug loading was better at lower pH & the release of the drug was faster at the higher pH. Cs integrated biopolymer microcapsules seem promising for controlled drug delivery & other related applications.