ABSTRACT
The use of lipase immobilized on an octyl-agarose support to obtain the optically pure enantiomers of chiral drugs in reactions carried out in organic solvents is a great challenge for chemical and pharmaceutical sciences. Therefore, it is extremely important to develop optimal procedures to achieve a high enantioselectivity of the biocatalysts in the organic medium. Our paper describes a new approach to biocatalysis performed in an organic solvent with the use of CALB-octyl-agarose support including the application of a polypropylene reactor, an appropriate buffer for immobilization (Tris base-pH 9, 100 mM), a drying step, and then the storage of immobilized lipases in a climatic chamber or a refrigerator. An immobilized lipase B from Candida antarctica (CALB) was used in the kinetic resolution of (R,S)-flurbiprofen by enantioselective esterification with methanol, reaching a high enantiomeric excess (eep = 89.6 ± 2.0%). As part of the immobilization optimization, the influence of different buffers was investigated. The effect of the reactor material and the reaction medium on the lipase activity was also studied. Moreover, the stability of the immobilized lipases: lipase from Candida rugosa (CRL) and CALB during storage in various temperature and humidity conditions (climatic chamber and refrigerator) was tested. The application of the immobilized CALB in a polypropylene reactor allowed for receiving over 9-fold higher conversion values compared to the results achieved when conducting the reaction in a glass reactor, as well as approximately 30-fold higher conversion values in comparison with free lipase. The good stability of the CALB-octyl-agarose support was demonstrated. After 7 days of storage in a climatic chamber or refrigerator (with protection from humidity) approximately 60% higher conversion values were obtained compared to the results observed for the immobilized form that had not been stored. The new approach involving the application of the CALB-octyl-agarose support for reactions performed in organic solvents indicates a significant role of the polymer reactor material being used in achieving high catalytic activity.
Subject(s)
Biocatalysis , Enzymes, Immobilized , Fungal Proteins , Lipase , Sepharose , Lipase/chemistry , Lipase/metabolism , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/metabolism , Fungal Proteins/metabolism , Fungal Proteins/chemistry , Sepharose/chemistry , Propionates/chemistry , Stereoisomerism , Kinetics , Esterification , Temperature , Enzyme Stability , Candida/enzymology , Solvents/chemistry , SaccharomycetalesABSTRACT
BACKGROUND: Many OTC drugs are available in non-pharmacy outlets, and as such the risk of overuse and/or improper use of this class of drugs is more likely. In light of this observation, our study was conducted with the aim of exploring opinions on non-pharmaceutical distribution among Polish patients. This study was a part of an informative project to educate patients about the possible risks associated with the use of OTC medicines. METHODS: We conducted a cross-sectional study among Polish patients in which we used an authorial questionnaire, previously tested via content, face validity, and a pilot study. The questionnaire was distributed both electronically and in a traditional form. RESULTS: 'Time saving' had a statistically significant role in the patient's decision about purchasing drugs in a non-pharmacy outlet (p = 0.0052; R = 0.276994). The lack of a pharmacist's consultation/advice (p = 0.0072; R = -0.3290490), improper storage (p = 0.0044; R = -0.238246), risk of overdose (p = 0.0125; R = -0.189564), and the risk of purchasing out-of-date drugs (p = 0.0125; R = -0.145411), as well as the risk of purchasing falsified drugs (p = 0.0265; R = -0.159428), were all associated with the patient's non-willingness to purchase drugs in non-pharmacy outlets. Patients supported the idea of the elimination of non-pharmacy outlet distribution (p = 0.0074; R = -0.195932); they also emphasized that they are advocates of purchasing drugs only in community pharmacies (p = 0.0006; R = -0.238625). CONCLUSION: Patients are aware of the risks associated with buying drugs outside of community pharmacies. They perceived pharmacists as professional health care advisors and supported the fact that OTC drugs should be available only via pharmaceutical distribution.
