Open AccessSPECTROPHOTOMETRIC DETERMINATION OF METHYLDOPA IN A DISSOLUTION TEST OF TABLETS USING AN EXTRACT OF RADISH AS A SOURCE OF PEROXIDASE
Author(s) -
Natielle Gianine Bueno,
Airton Vicente Pereira
Publication year - 2015
Publication title -
química nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.214
H-Index - 73
eISSN - 1678-7064
pISSN - 0100-4042
DOI - 10.5935/0100-4042.20150091
Subject(s) - peroxidase , dissolution , methyldopa , chromatography , chemistry , dissolution testing , test (biology) , medicine , biochemistry , enzyme , biology , botany , organic chemistry , blood pressure , biopharmaceutics classification system
An enzymatic spectrophotometric method for the determination of methyldopa in a dissolution test of tablets was developed using peroxidase from radish (Raphanus sativus). The enzyme was extracted from radish roots using a phosphate buffer of pH 6.5 and partially purified through centrifugation. The supernatant was used as a source of peroxidase. The methyldopachrome resulting from the oxidation of methyldopa catalyzed by peroxidase was monitored at 480 nm. The enzymatic activity was stable for a period of at least 25 days when the extract was stored at 4 or -20 ºC. The method was validated according to RDC 899 and ICH guidelines. The calibration graph was linear in the range 200-800 µg mL-1, with a correlation coefficient of 0.9992. The limits of detection and quantification in the dissolution medium were 36 and 120 µg mL-1, respectively. Recovery was greater than 98.9%. This method can be applied for the determination of methyldopa in dissolution tests of tablets without interference from the excipients