Browsing by Author "Shelma, R."

Now showing 1 - 3 of 3
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    Acyl modified chitosan derivatives for oral delivery of insulin and curcumin
    (JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE, 2010)
    In the present investigation, bioadhesive property of chitosan (CS) was enhanced by the N-acylation with hexanoyl, lauroyl and oleoyl chlorides. The chemical structure of the modified polymer was characterized by FTIR and zeta potential measurements. The swelling ability was evaluated at alkaline pH. Mucin interactions and mucoadhesion experiments were performed under in vitro experimental conditions. Cytotoxicity experiments were employed to confirm the applicability of these particles as drug carriers. Finally in vitro evaluation of hydrophobic and hydrophilic drug release profile at acidic and alkaline pH was also conducted. A strong interaction between CS acyl derivatives and mucin was detected, which was further confirmed by an in situ mucoadhesion experiments with excised intestinal tissue. CS modified with oleoyl chloride showed better mucoadhesion property, as compared to the one modified with lower fatty acid groups. CS derivatives were found non-toxic on L-929 cell lines and provided sustained release of hydrophobic drugs under in vitro experimental conditions. From these studies it seems that hydrophobically modified CS is an interesting system for drug delivery applications.
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    Development of lauroyl sulfated chitosan for enhancing hemocompatibility of chitosan
    (COLLOIDS AND SURFACES B-BIOINTERFACES, 2011)
    Chitosan (CS) has received much attention as a functional biopolymer especially in pharmaceutical applications, but has serious limitations owing to its poor hemo-compatibility property. Present paper focuses on the chemical modification of CS in order to enhance hemocompatibility. Amphiphilic derivative (lauroyl sulfated chitosan, ISCS) was prepared by the inclusion of sulfo group (hydrophilic) and lauroyl group (hydrophobic) to CS backbone and particles were prepared by an ionic-gellation approach. Modification was confirmed by FTIR, NMR and zeta potential measurements and the microparticles were evaluated for its particle size, swelling properties and thermal behaviour. Blood compatibility studies like hemolysis, RBC, WBC, platelet aggregation studies, blood clotting time, protein adsorption and C3 protein depletion assay were carried out for these polymers using standard techniques and cytotoxicity studies were performed to understand its applicability.Negatively charged (-6.06 mV) LSCS submicroparticles (886 nm) were prepared in this study. Blood compatibility studies demonstrated that the amphiphilic modification improved the hemocompatibility of CS. RBC aggregation and hemolysis induced by CS were significantly reduced by this modification. Further amphiphilic modification was effective in reducing the protein adsorption on CS. LSCS derivatives were found to be non-toxic in L929 cell lines. From these studies, it appears that LSCS is a hemocompatible version of CS. (C) 2011 Elsevier B.V. All rights reserved.
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    Submicroparticles composed of amphiphilic chitosan derivative for oral insulin and curcumin release applications
    (COLLOIDS AND SURFACES B-BIOINTERFACES, 2011)
    Amphiphilic polymers for dual drug delivery have been a focus of research in recent years. We have previously developed and characterized Lauroyl sulphated chitosan (LSCS). Here biological characterizations like mucoadhesion, cytotoxicity, calcium binding, tight junction opening and enzymatic degradation studies were performed to understand its applicability. In vitro drug release properties of both hydrophilic insulin and hydrophobic curcumin were carried out. The biological activity and stability of released insulin were also studied. The stability studies of encapsulated curcumin and uptake studies have also been carried out. LSCS showed strong mucoadhesion and 100% of non-toxicity. LSCS could transiently open tight junctions between Caco-2 cells and thus increase the paracellular permeability. LSCS enhanced calcium binding properties and decreased enzymatic degradation rate retaining insulin activity. LSCS could protect curcumin from photodegradation and could also enter into the cells. From release studies, LSCS was found to be a suitable candidate for both drugs. (C) 2011 Elsevier B.V. All rights reserved.