Caffeine (CAF) levels in instant regular coffees, instant decaffeinated coffees, and instant teas are determined and compared using spectrophotometric and gas chromatographic methods of determination. Modification of a previously reported spectrophotometric assay for CAF in biological fluids is necessary to reduce interference from theophylline (THP) and theobromine (THB). Readjustment of the b...

High-throughput screening (HTS) involves testing of compound libraries against validated drug targets using quantitative bioassays to identify 'hit' molecules that modulate the activity of target, which forms the starting point of a drug discovery effort. Eicosanoids formed via cyclooxygenase (COX) and lipoxygenase (LOX) pathways are major players in various inflammatory disorders. As the conve...

A direct-reading spectrophotometric assay for acyl-CoA oxidase activity is described. The assay is based on the strong absorption at 300 nm of deca-2-trans,4-cis-dienoyl-CoA, the product of oxidation of dec-4-cis-enoyl-CoA. By use of this assay, acetyl-CoA, CoA and FMN were found to be inhibitors of acyl-CoA oxidase, but with distinctly different kinetic characteristics.

The lack of a rapid and quantitative autophagy assay has substantially hindered the development and implementation of autophagy-targeting therapies for a variety of human diseases. To address this critical issue, we developed a novel autophagy assay using the newly developed Cyto-ID fluorescence dye. We first verified that the Cyto-ID dye specifically labels autophagic compartments with minimal...

Acetylcholine is an essential neurotransmitter found throughout the nervous system. Its action on postsynaptic receptors is regulated through hydrolysis by various carboxylesterases, especially cholinesterases (ChEs). The acute toxicity of organophosphate (OP) compounds is directly linked to their action as inhibitors of ChE. One widely used assay for evaluating ChE activity is a spectrophotome...

This presented paper deals with application of three multivariate calibration methods methods for simultaneous spectrophotometric determination of two active substances in combined pharmaceutical formulation, composed of rutin (RU) and ascorbic acid (AA). The multivariate methods are classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS). The results...

A spectrophotometric method for the determination of chlorine,bromine or iodine ion by using1,5-bis(6-methy1-4-pyrimidyl)carbazone has been established.The ranges of determination were0.355-3.55ppm of Cl-,0.799-7.99ppm of Br and1.27-12.7ppm of F.The proposed method could be applied to the analyses of various halogen-containing organic compounds, including sulfur-containing compounds.Eleven comm...

Three rapid, simple and accurate analytical methods for the determination of citalopram in tablets were developed. The capillary zone electrophoresis (CZE) method was carried out using fused silica capillary with 67 mM phosphate buffer pH 7.0 as the background electrolyte, 30 kV of separation voltage and UV detection at 239 nm. The direct spectrophotometric method was performed by measuring the...

Olmesartan medoxamil (OLM, an angiotensin II receptor blocker), amlodipine besylate (AML, a dihydropyridine calcium channel blocker) and hydrochlorothiazide (HCT, a diuretic of the class of benzothiadiazines) are co-formulated in a single-dose combination for the treatment of hypertensive patients whose blood pressure is not adequately controlled on either component monotherapy. In this work, t...