Prediction of the Chemiluminescent Behavior of Pharmaceuticals and Pesticides

Abstract

The present paper deals with the first attempt to apply molecular connectivity calculations to predict a chemical property with analytical usefulness: the chemiluminescent behavior of substances when reacted with common oxidants in a liquid phase. Preliminary evidence when searching for new direct CL methods consisted of the examination of analyte reaction with a wide range of oxidants and media. This task, which results in time-consuming and trial-and-error expensive procedures, is necessary due to ensure empirical or theoretical rules for CL prediction are available. On the other hand, in quantitative structure-activity relationship studies, molecular connectivity is a topological method capable of describing the structure of a molecule by means of numbers named indices; subsequent regression in relation to the experimental values of the physical, chemical, or biological properties yields a series of functions called connectivity functions. Discriminant analysis was applied to 200 either chemiluminescent or nonchemiluminescent substances found either bibliographically or in an experimental screening. The method used for the selection of descriptors was a stepwise linear discriminant analysis from the Snedecor F-parameter. The classification criterion used was the minimum value of Mahalanobis. The quality of the discriminant function was calculated through the Wilks U-statistical parameter. Finally, the function was applied to a database including of more than 50,000 structurally heterogeneous compounds. The theoretical predictions were faced with the empirical evidence obtained through a continuous-flow manifold.

Validated Chromatographic Methods for Determination of Hydrochlorothiazide and Spironolactone in Pharmaceutical Formulation in Presence of Impurities and Degradants

“…A gas chromatography-mass spectrometry method was also described for the determination of a number of drugs including the proposed compounds (16). Also the chemiluminescent behaviors of both diuretics and other diuretics were studied (17).…”

Spectrophotometric and chemometric determination of hydrochlorothiazide and spironolactone in binary mixture in the presence of their impurities and degradants

“…Gas chromatography-mass spectrometry (GC-MS) method was described for determination of a number of drugs including HCT, SPR and chlorothiazide (HCT process impurity). [16] Lahuerta-Zamora et al [17] studied the chemiluminescent behaviours of several diuretics, including HCT and SPR.…”

Prediction of pKa Values of Extractant Using Novel Quantitative Structure–Property Relationship Models

“…Since the 1970s, many publications have reported the application of quantitative structure–property relationships (QSPR) in describing the physical properties and biological activity of chemicals, – and all results have shown that the QSPR models can clearly indicate the molecular structure of the related chemicals. The common method used in QSPR is the molecular connectivity index (MCI), , and many research papers can be found relating properties of organic compounds using the QSPR model in recent years.…”