Preparation, Characterization and Study of the Dissociation of Naproxen from Its Chitosan Salt

Salts of naproxen (NAP) with chitosan (CTS) and reticulated chitosan (CEP) were prepared under optimized conditions to maximize the yield of reaction. The objective was to evaluate the dissociation in water, which can guide studies of release of the drug from biopolymeric salts in pharmaceutical applications. Higher salification was found after 24 h of reaction at 60 °C in a molar ratio 1:1.05 (CTS:NAP, mol/mol), resulting in a degree of substitution (DS) of 17% according to 13C NMR, after neutralization of the –NH2 group of the biopolymer by the carboxylic group of the drug. The presence of NAP salt is evidenced by FTIR bands related to the –NH3+ group at 856 cm−1, a decrease in crystallinity index in XRD diffractograms as well as changes in mass loss ratios (TG/DTG/DTA) and increased thermal stability of the salt regarding CTS itself. The CEPN crosslinked salt presented a DS = 3.6%, probably due to the shielding of the –NH2 groups. Dissociation studies revealed that at pH 2.00, dissociation occurred faster when compared to at pH 7.00 in the non-reticulated salt, while the opposite was observed for the reticulated one

Biohydroxylation of (-)-ambrox®, (-)-sclareol, and (+)-sclareolide by whole cells of brazilian marine-derived fungi.

International audienceA screening was performed using nine marine-derived fungi as biocatalysts and the natural products (-)-ambrox® (1), (-)-sclareol (2), and (+)-sclareolide (3) in order to select the microorganisms able to catalyze the biooxidation of these compounds. It was observed that only the Aspergillus sydowii CBMAI 934, Botryosphaeria sp., Eutypella sp., and Xylaria sp. presented active oxidoreductases and catalyzed the regioselective hydroxylation in the natural products. The hydroxylated metabolites obtained were 1β-hydroxy-ambrox (1a) (14 %, A. sydowii CBMAI 934); 3β-hydroxy-ambrox (1b) (17 %, Botryosphaeria sp.; 11 %, Eutypella sp.); 3β-hydroxy-sclareol (2a) (31 %, Xylaria sp.; 69 %, Botryosphaeria sp.; 55 %, Eutypella sp.); 18-hydroxy-sclareol (2b) (10 %, Xylaria sp.); and 3β-hydroxy-sclareolide (3a) (34 %, Botryosphaeria sp.; 7 %, Eutypella sp.). This is the first report of biohydroxylation of (-)-ambrox® (1), (-)-sclareol (2), and (+)-sclareolide (3) by whole mycelia of marine-derived fungi

Partition of proteins in aqueous two-phase systems based on Cashew-nut tree gum and poly(ethylene glycol)

The partitioning of two proteins, bovine serum albumin (BSA) and trypsin was studied in an aqueous poly(ethylene glycol)(PEG)- Cashew-nut tree gum system. The phase diagram was provided for Cashew-nut tree gum and PEG molecular weight of 1500 at two different temperatures. The influence of several parameters including concentrations of polymers, pH, salt addition and temperature on the partitioning of these proteins were investigated.. The results of this research demonstrated the importance of the protein characteristics for partitioning in aqueous biphasic system.<br>A partição de duas proteínas, albumina de soro bovino (BSA) e tripsina foi estudada no sistema bifásico aquoso Polietileno glicol(PEG) - Goma do cajueiro. O diagrama de fases foi estabelecido para a Goma do Cajueiro e para PEG de peso molecular 1500 em duas diferentes temperaturas. A influência de vários parâmetros na partição destas proteínas, incluindo concentração dos polímeros, pH, adição de sal e temperatura foi investigada. Os resultados desta pesquisa demonstraram a importância das características da proteína na partição em sistemas bifásicos aquosos