Development and validation of two simple, rapid, precise, accurate and sensitive UV spectrophotometric methods for the simultaneous estimation of Rosuvastatin calcium and Aspirin in bulk and in capsule dosage form. The methods are based on the measurement of absorbance of Rosuvastatin calcium and Aspirin at 241nm and 296nm respectively. The linearity of the calibration curves for Rosuvastatin c...

A new method for phenotyping human serum arylesterase (EC 3.1.1.2) is described and evaluated. The aromatic esters, phenyl acetate and 4-nitrophenyl acetate, were compared as substrates for spectrophotometric measurement of arylesterase activity. A method for arylesterase phenotyping, based upon inhibition of the enzymatic hydrolysis of 4-nitrophenyl acetate by phenyl acetate, was developed. Th...

We compared a spectrophotometric screening test measuring faecal porphyrin concentration with an HPLC method. There was a good overall correlation between both methods although some scatter was observed. ROC plot analysis of the screening test leads to a cut-off value of 35 nmol porphyrin per g faeces, wet weight with a sensitivity of 97% and a specificity of 96%. These results indicate that th...

An enzyme immobilization technique has been developed to determine the concentration of biological compounds. This technique has been applied to penicillinase and urease, which are crosslinked as very fine films directly onto the sensitive ends of pH glass electrodes, thereby dispensing with the need of an on-line enzyme reactor. The biosensor is incorporated in an FIA system within a magnetica...

A multiwavelength spectrophotometric (WApH) titration method for determinatio constants (pΚa values) of ionisable compounds developed previously was applied derivatives of pharmaceutical interest. Specifically, UV absorption spectra of the drug the course of a pH-metric titration using an optical device based on a fibre optics dip pr diode array detector. Target factor analysis was applied to d...

Both assays are accepted reference methods for measurement of lactate dehydrogenase (LDH) activity (2-4). At pH 7.4, pyruvate -* lactate (P -* L) activity is about three times lactate -+ pyruvate (L P) activity, because equilibrium favors formation of lactate. Normal range for the P -* L assay is 130-265 spectrophotometric units at 25#{176} (3); normal range for the L P assay is 40-98 units at ...

Ultraviolet spectrophotometry is widely used for the analysis of theophylline in blood, for purposes of monitoring therapy, and for pharmacokinetic studies. Phenobarbital, a component of common oral theophylline preparations, interferes with assays now in use. The modification of the method of Schack and Waxler [J. Pharmacol. Exp. Ther. 97, 283 (1949)] presented in this paper eliminates barbitu...

A simple, rapid and highly sensitive spectrophotometric method is developed for the determination of risperidone in tablet formulation. The method is based on the oxidation of drug using potassium permanganate in alkaline medium and excess potassium permanganate oxidizes 1,10-phenanthroline Fe(II). The measurement of decrease in absorbance of 1,10-phenanthroline Fe (II) was done at 415 nm. The ...

Anthocyanin pigments readily degrade during processing and storage of foodstuffs, which can have a dramatic impact on color quality and may also affect nutritional properties. Total anthocyanin pigment content and indices for polymeric color and browning are easily measured with simple spectrophotometric methods. Once individual pigments are identified, their changes can be monitored by high-pe...