Formulation and invitro evaluation of oral extended release microspheres of aceclofenac using various natural polymers

In the present work, bioadhesive microspheres of Aceclofenac using Sodium alginate along with Carbopol 934, Carbopol 971, HPMC K4M as copolymers were formulated to deliver Aceclofenac via oral route. The results of this investigation indicate that ionic cross-linking technique Ionotropic gelation method can be successfully employed to fabricate Aceclofenac microspheres. The technique provides characteristic advantage over conventional microsphere method, which involves an “all-aqueous” system, avoids residual solvents in microspheres. FT-IR spectra of the physical mixture revealed that the drug is compatible with the polymers and copolymers used. Micromeritic studies revealed that the mean particle size of the prepared microspheres was in the size range of 512-903µm and are suitable for bioadhesive microspheres for oral administration. The in-vitro mucoadhesive study demonstrated that microspheres of Aceclofenac using sodium alginate along with Carbopol934 as copolymer adhered to the mucus to a greater extent than the microspheres of Aceclofenac using sodium alginate along with Carbopol 971 and HPMC K4M as copolymers. The invitro drug release decreased with increase in the polymer and copolymer concentration. Analysis of drug release mechanism showed that the drug release from the formulations followed non-Fickian diffusion and the best fit model was found to be Korsmeyer-Peppas. Based on the results of evaluation tests formulation coded T4 was concluded as best formulation

Functional characterisation of the iron superoxide dismutase gene repertoire in Trypanosoma brucei.

Superoxide dismutases (SOD) are a family of antioxidant enzymes that function by removing superoxide anions from the cellular environment. Here, we show that the African trypanosome, Trypanosoma brucei, expresses four SOD isoforms, three of which we have validated biochemically as iron dependent, a feature normally associated with prokaryotic SODs. Localisation studies reveal that two of the enzymes are found predominantly in a parasite-specific organelle, the glycosome (TbSODB1 and TbSODB2), while the other two are targeted to the mitochondrion (TbSODA and TbSODC). Functional analysis of the SOD repertoire in bloodstream form parasites was performed using an inducible RNA interference (RNAi) approach. Down-regulation of the glycosomal SOD transcripts corresponded with a significant reduction in the corresponding proteins and a dramatic level of cell death within the population. The importance of one of the mitochondrial enzymes (TbSODA) only became apparent when parasites were exposed to the superoxide-generating agent paraquat following induction of RNAi. These experiments therefore identify essential components of the superoxide metabolising arm of the T. brucei oxidative defence system and validate these enzymes as parasite-specific targets for drug design