Production of ß -cyclodextrin from pH and thermo stable Cyclodextrin Glycosyl Transferase, obtained from Arthrobacter mysorens and its evaluation as a drug carrier for Irbesartan.

Cyclodextrins (CDs) are carrier molecules produced by cyclization of α-1,4-glucans by Cyclodextrin Glycosyl Transferase (CGTase). These torus shaped molecules have hydrophobic cavity and hydrophilic shell making them useful in pharmaceutical, food, textile, pesticide and cosmetic industries. In this study, culture conditions for the production of CGTase by organism belonging to Arthrobacter genus obtained from a paddy field soil were optimized by single parameter mode. Soluble starch, yeast extract and magnesium sulphate played an important role in CGTase production. Percentage increase in CGTase yield under optimized conditions was 396.77%. The enzyme precipitated by 60% ammonium sulphate was purified using DEAE-sepharose. The molecular weight of the purified protein as determined by SDS-PAGE was 75 kDa. Purified CGTase was thermostable and stable over a wide pH range. Dissolution studies on ß -cyclodextrin-Irbesartan complex revealed that ß -CDs formed were useful in preparing immediate release oral dosage forms.

Effects of 17-alkyl-16,17-dihydrogibberellin A(5) derivatives on growth and flowering in Lolium temulentum.

Several gibberellins in which the 16-methyl group of the 16-epimers of dihydro-GA(5) had been replaced by ethyl, n-propyl and n-butyl were prepared and tested at doses of 1, 5 or 25&mgr;g per plant for their effects on stem growth and flowering of the grass Lolium temulentum. The ethyl and n-propyl derivatives were most inhibitory of elongation, the exo-isomers being more active than the endo-forms. While both isomers of dihydro-GA(5) promoted flowering, among the 17-alkyl analogues, only the exo-ethyl derivative showed significant activity.