http://precedings.nature.com/users/2e949dcb9773b7c8ee705bb728cc72ea/ Documents posted by Girish Gupta Nature Publishing Group en Nature Precedings http://precedings.nature.com/images/header_logo.gif http://precedings.nature.com http://dx.doi.org/10.1038/npre.2009.2812.1 A novel formulation of paclitaxel (PTX) has been developed by providing multilayer assembly over drug loaded porous CaCO3 microparticles (CaCO3 MP) using combination of biocompatible and biodegradable polyelectrolytes (PE’s). PTX was encapsulated into the nanopores of preformed CaCO3 MP prepared by the co-precipitation method. Infrared (IR) and X-ray diffraction (XRD) provides evidences that PTX has been encapsulated into nanopores of CaCO3 MP and not crystallized on the surface. PTX loaded CaCO3 MP (CaCO3-PTX) was found to be highly stabilized against thermal decomposition as evinced by thermo gravimetric analysis (TGA) indicating decomposition at 600°C and 250°C for CaCO3-PTX and PTX respectively. The multilayer assembly over CaCO3-PTX was effectuated by alternate deposition of protamine sulfate (PRM) and sodium alginate (SA) using LBL technique followed by subsequent core removal [PTX- (PRM/SA)5]. The pay load efficiency of PTX in this system was found to be 78.98±2.14%. The developed system was further evaluated for surface morphology, size and size distribution, surface charge, core removal and layer-by-layer growth due to sequential adsorption of PE’s. The release data of PTX-(PRM/SA)5 was comparable with marketed formulation of PTX (PTX-M) and CaCO3-PTX when performed in simulated intestinal fluid (SIF pH=7.4). The release profile of PTX-(PRM/SA)5 indicates that PEs based multilayer matrix is capable to provide barrier to PTX release as it has been found to follow first order matrix diffusion kinetics with 64±4.8% release within 24 hrs. The t50% of PTX-M, CaCO3-PTX and PTX-(PRM/SA)5 was found to be 70, 90 and 480 minutes respectively. This alternative delivery system of PTX disguised in the form of LBL assembly could have immense application for the treatment of metastasized mammary glands vis-à-vis existing formulation of PTX which is by and large criticized for having certain toxic excipients to be given parentrally. Moreover, the proposed system provides ample of opportunity to modify the surface for targeted application of PTX. http://dx.doi.org/10.1038/npre.2009.2812.1 Thu, 22 Jan 2009 19:08:51 UTC Paclitaxel delivery by micro/nano encapsulation using layer-by-layer assembly doi:10.1038/npre.2009.2812.1 2009-04-20 Nature Precedings 2009-01-22T19:08:51Z Poster Pharmacology http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2548.1 The proposed ultrathin polyelectrolyte nanoreservoir (UPN) was fabricated in two combinations by alternate layering of polyelectrolytes poly (allylamine hydrochloride) along with sodium poly (styrene sulfonate) (PAH/PSS)5 and sodium alginate (PAH/SA)5 using porous calcium carbonate as a template using layer-by-layer adsorption technique with the subsequent template removal at low pH. We studied the possibility whether remnant intact nanoreservoir could be suited for encapsulation as well as delivery vehicle for protein such as bovine serum albumin as a model. To tune biocompatibility with biological cells the assembled surface was modified using pluronic (F-68) by adsorption and possible hydrophobic interaction. The prepared system was characterized for surface morphology, size and size distribution, surface charge, layer-by-layer growth due to sequential adsorption and surface modification. The experimental data obtained by Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) provide evidence for the stepwise surface modification of the films. Further the system was investigated for payload efficiency of proteins, in-vitro release profile, integrity of proteins, cell adhesion and viability against biological cells (murine macrophages cell line J774.1). In both formulations polyelectrolyte composition lead to smooth and spherical nanomatrix, with payload of approx. 72±6% of proteins. Both the systems exhibited biphasic release profile with initial burst release followed by controlled release with overall release of 43.63±4.8% and 44±5.76% in 48h for formulation prepared by combination of (PAH/PSS)5 and (PAH/SA)5 respectively. There was a marked reduction in cell adhesion and improvement in viability upon surface modification. In a nutshell, the proposed system could successfully be used for the delivery of proteins and moreover the system can be tailored to impart desired properties at any stage of layering especially in terms of drug release and to retain the integrity of proteins. http://dx.doi.org/10.1038/npre.2008.2548.1 Fri, 21 Nov 2008 17:24:34 UTC Surface Modified Ultrathin Polyelectrolyte Nanoreservoir for Delivery of Proteins: Evaluation in Terms of Controlled Release and Biocompatibility doi:10.1038/npre.2008.2548.1 2008-11-21 Prabhat Ranjan Mishra Nature Precedings 2008-11-21T17:24:34Z Poster Pharmacology http://creativecommons.org/licenses/by/3.0/