Quantitative structure-activity relationship and cytotoxicity.

Lipases from two different sources Candida rugosa (CRL) and Burkholderia cepacia (BCL) were formulated as enzyme precipitated and rinsed with organic solvents, organic solvent rinsed enzyme preparation, cross-linked enzyme aggregates (CLEAs) and protein coated micro-crystals (PCMCs). These various enzyme formulates were evaluated for the kinetic resolution of (+/-)-1-phenylethanol in ionic liquid [Bmim][PF(6)] by transesterification with vinyl acetate. Of all the enzyme forms evaluated EPRP and PCMC in the case of CRL showed the best results with 26 % (E value=153) and 53% (E value=79) conversion, respectively, at 35 degrees C in 24h. Carrying out this conversion with PCMC at lower temperature of 25 degrees C further improved the E value to 453 (with 44% conversion in 12h). For BCL the acetone-rinsed enzyme preparation (AREP), CLEA and PCMC performed equally well with % conversion of 50 and 99 ee(p) (%) (E value >1000) in just 2h, whereas, the free lipase gave only 8% conversion.

Benzyl Alcohols↗

PubMed2006

Chemoenzymatic dynamic kinetic resolution of rac-1-phenylethanol in ionic liquids and ionic liquids/supercritical carbon dioxide systems.

Continuous dynamic kinetic resolution processes in different ionic liquid/supercritical carbon dioxide biphasic systems were carried out by simultaneously using both immobilized Candida antarctica lipase B (Novozym 435) and silica modified with benzenosulfonic acid (SCX) catalysts at 40 degrees C and 10 MPa. SCX was seen to act as an efficient heterogeneous chemical catalyst for the racemization of (S)-1-phenylethanol in different ionic liquid media ([emim][NTf(2)], [btma][NTf(2)] and [bmim][PF(6)]). Coating both chemical and enzymatic catalysts with ILs greatly improved the efficiency of the process, providing a good yield (76%) of (R)-1-phenylethyl propionate product with excellent enantioselectivity (ee = 91-98%) in continuous operation.

Benzyl Alcohols↗

PubMed2006

Electronic speckle pattern interferometry: a novel non-invasive tool for studying drug transport rate through free films.

In this work, Electronic Speckle Pattern Interferometry (ESPI) is presented as a non-invasive tool to study drug transport in controlled release systems. ESPI is shown to be a feasible tool to measure drug film permeability via comparison with an ordinary diaphragm cell. A specially designed cuvette was used in the release study: the polymeric film separated the donor and the receiving chambers of the cuvette to create a diffusion cell with no mixing in the two chambers. Thus, the cuvette mimicked a coated system immersed in a stagnant bulk liquid. Concentration profile data were obtained for the two compartments. Using these data, it was possible to visually discriminate between a film subject only to diffusion and a film subject to diffusion as well as osmotic effects. Moreover, using the concentration profile data collected at different time intervals, it was possible to follow the film properties in terms of drug permeability, thus studying how drug permeability depended on drug concentration. Compared to other measuring techniques, ESPI offers the advantages that no invasive measurements are needed, and that no sampling and calibration are required. Furthermore, the permeability can be measured with no influence of mass transfer in the boundary layers.

Benzyl Alcohols↗