DEVELOPMENT AND IN-VITRO CHARACTERISATION OF CHITOSAN LOADED PACLITAXEL NANOPARTICLE

ABSTRACTObjectives: To meet the above aim the following objectives are undertaken: (1) Preparation of paclitaxel (PTX) loaded nanoparticles by differenttechniques, (2) In-vitro evaluations of the drug loaded nanoparticles and selection of optimized batch.Methods: PTX loaded chitosan nanoparticles were prepared by Ionic-crosslinking technique. In this technique, chitosan was dissolved in 0.25%v/vacetic acid solution. To this above solution 0.84%v/v, glutaraldehyde solution was added dropwise under high-speed homogenizer at 17000 rpm for1 hr.Result: Particle size of prepared nanoparticle formulations was found to be 345.175±5.66-815.125±8.355 nm with low PDI between 0.456. Themaximum entrapment of drug was found to be 88.57±2.533% with formulation F5. In-vitro release studies of the F5 formulation showed 57.8±1.735%release of drug after 24 hrs.Conclusion: The prepared nanoparticles were evaluated for its particle size, zeta potential, drug entrapment efficiency, in-vitro drug release study,and surface morphology studies by scanning electron microscopy. The results of Fourier transform infrared studies of 1:1 physical mixture of drug andexcipients confirmed the absence of incompatibility. Thus, the study concludes that PTX loaded nanoparticles were developed successfully by ioniccrosslinking method, which is expected to enhance the oral bioavailability of PTX.Keywords: Paclitaxel, Nanoparticles, Chitosan, Ionic-crosslinking, In-vitro release

Bacterial protein HU dictates the morphology of DNA condensates produced by crowding agents and polyamines

Controlling the size and shape of DNA condensates is important in vivo and for the improvement of nonviral gene delivery. Here, we demonstrate that the morphology of DNA condensates, formed under a variety of conditions, is shifted completely from toroids to rods if the bacterial protein HU is present during condensation. HU is a non-sequence-specific DNA binding protein that sharply bends DNA, but alone does not condense DNA into densely packed particles. Less than one HU dimer per 225 bp of DNA is sufficient to completely control condensate morphology when DNA is condensed by spermidine. We propose that rods are favored in the presence of HU because rods contain sharply bent DNA, whereas toroids contain only smoothly bent DNA. The results presented illustrate the utility of naturally derived proteins for controlling the shape of DNA condensates formed in vitro. HU is a highly conserved protein in bacteria that is implicated in the compaction and shaping of nucleoid structure. However, the exact role of HU in chromosome compaction is not well understood. Our demonstration that HU governs DNA condensation in vitro also suggests a mechanism by which HU could act as an architectural protein for bacterial chromosome compaction and organization in vivo

Condensation of oligonucleotides assembled into nicked and gapped duplexes: potential structures for oligonucleotide delivery

The condensation of nucleic acids into well-defined particles is an integral part of several approaches to artificial cellular delivery. Improvements in the efficiency of nucleic acid delivery in vivo are important for the development of DNA- and RNA-based therapeutics. Presently, most efforts to improve the condensation and delivery of nucleic acids have focused on the synthesis of novel condensing agents. However, short oligonucleotides are not as easy to condense into well-defined particles as gene-length DNA polymers and present particular challenges for discrete particle formation. We describe a novel strategy for improving the condensation and packaging of oligonucleotides that is based on the self-organization of half-sliding complementary oligonucleotides into long duplexes (ca. 2 kb). These non-covalent assemblies possess single-stranded nicks or single-stranded gaps at regular intervals along the duplex backbones. The condensation behavior of nicked- and gapped-DNA duplexes was investigated using several cationic condensing agents. Transmission electron microscopy and light-scattering studies reveal that these DNA duplexes condense much more readily than short duplex oligonucleotides (i.e. 21 bp), and more easily than a 3 kb plasmid DNA. The polymeric condensing agents, poly-l-lysine and polyethylenimine, form condensates with nicked- and gapped-DNA that are significantly smaller than condensates formed by the 3 kb plasmid DNA. These results demonstrate the ability for DNA structure and topology to alter nucleic acid condensation and suggest the potential for the use of this form of DNA in the design of vectors for oligonucleotide and gene delivery. The results presented here also provide new insights into the role of DNA flexibility in condensate formation

Insights into the Role of Nucleic Acid Structure and Topology in Controlling Condensation

DNA condensation is a fundamental process in all living organisms. The highly abundant nucleoid-associated proteins, HU and IHF, present in bacteria, have been shown to play an important role in shaping the nucleoid. However, the exact mechanism is not well understood. In this thesis, we have demonstrated that both HU and IHF guide DNA to condense into linear bundle-like structures in presence of cellular condensing components, but the proteins alone do not condense DNA into densely packed structures. Our results suggest a mechanism by which HU and IHF could act as architectural proteins during in vitro and in vivo DNA condensation. More recently, DNA condensation has attracted much attention for its relevance in optimizing artificial DNA delivery systems for gene therapy. The research presented in this dissertation provides in depth biophysical studies that demonstrate how local modulations in the nucleic acid structure can be used to control both the size and the morphology DNA condensates. We describe a novel strategy for improving the condensation of oligonucleotides that is based on the self-organization of half-sliding complementary oligonucleotides into long duplexes (ca. kb) with flexible sites at regular intervals along the duplex backbones, in the form of single-stranded nicks or single-stranded gaps. Our results also provide new insights into the role of DNA flexibility in condensate formation and suggest the potential for the use of this DNA structure in the design of vectors for oligonucleotide and gene delivery.Ph.D.Committee Chair: Hud, Dr. Nicholas V.; Committee Member: Doyle, Dr. Donald F.; Committee Member: Harvey, Dr. Stephen; Committee Member: Lyon, Dr. Andrew; Committee Member: Wartell, Dr. Roger M

Studies on Piparwar Open Cast Mines of North Karanpura Coalfield

This paper deals with the study on coal deposits of Piperwar block of north Karanpura coalfield. A detailed geological map with its geological features in relation to the exposed rock has been prepared. The litholog of borehole up to a depth of 67 m is prepared to observe the geological characteristics and the decomposition of coal seams. The coal deposits with a view to find out its grade, quality and reserves have been studied and a general data about the environmental condition of desolation of sediments and deposition of coal has been presented. The structural units and where ever interesting features observed are photographed. The rank and grade of coal is interpreted based on the present study. However, more boreholes in the unexplored areas of the coalfield are required for the preparation of an elaborated geological map