## ABSTRACT A simple, rapid and sensitive analytical procedure for the measurement of celecoxib (CXB) levels in skin samples after __in vitro__ penetration studies was developed and validated. __In vitro__ permeability studies in porcine skin were performed for quantification of CXB at different la
Simultaneous determination of methylxanthines in different types of tea by a newly developed and validated TLC method
✍ Scribed by Claudia Cimpoiu; Anamaria Hosu; Liana Seserman; Mihaela Sandru; Vasile Miclaus
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 190 KB
- Volume
- 33
- Category
- Article
- ISSN
- 1615-9306
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✦ Synopsis
Abstract
The aim of this paper is to develop a new simple, fast and economical method for simultaneous quantitative determination of methylxanthine compounds based on TLC combined with image analysis. To obtain certain results, both extraction and chromatographic separation were optimized. The optimum extraction conditions were maceration in ethanol–water 8:2, v/v. The chromatographic separations were done on the silica gel F~254~ TLC plates developed with chloroform–dichloromethane–isopropanol, 4:2:1 v/v/v. Detection was performed under UV lamp at 254 nm and the evaluation of the chromatographic plate was based on digital processing of chromatographic images. The developed TLC method was validated for parameters such as specificity, linearity and range, LOD and LOQ, precision, robustness and accuracy. This method was then applied for determination of caffeine, theobromine and theophylline in different types of tea, commercially available. Moreover, the content of methylxanthines detected and determined in commercial tea samples can be used as chemical marker in quality control.
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## Abstract A new rapid, sensitive and validated HPLC method has been developed for the determination of methylxanthines and their metabolites in asthmatic patients. The method was initiated by using spiked urine samples on a silica monolithic column as a novel packing material. The mobile phase co