Ф-order kinetics of photoreversible-drug reactions

Quantitative assessment of photostability and photostabilisation of Fluvoxamine and its design for actinometry

“…11 It involves only the cumulative observed absorbances A λirr=λobs tot of the medium which have been measured under the observation (l λ obs ) and not the excitation (l λ irr ) condition (with l λ obs being the optical path length of the monitoring light inside the sample). These optical path lengths (l λ irr and l λ obs ) are not necessarily equal for a given experiment, and the absorbance of the medium under the excitation conditions (i.e.…”

“…This condition is easily met by reducing the values of either the initial concentration of species A or the optical path length for irradiation, l λ irr . 10,11 3.1.2 Isosbestic irradiation equations. In the case where monochromatic irradiation of the solution is realised at an isosbestic point, λ irr = λ isos (only a few isosbestic points are usually present on the electronic spectra of AB(2Φ) reactions), the general integrated rate-law of AB reaction systems has been obtained through a closed-form integration, 25 as…”

Modeling and Elucidation of the Kinetics of Multiple Consecutive Photoreactions AB 4 (4Φ) With Φ-order Kinetics. Application to the Photodegradation of Riboflavin

“…The methodology previously developed to model the kinetics of unimolecular 12 and reversible 13 photoreactions is employed here for AB 4 (4) reactions. In principle, the method is based on proposing a template set of equations that hold the -order kinetics character in their mathematical formulation (the log-exp function), then modify these equations until a good fitting is obtained for a variety of simulated traces of the studied systems, that were independently generated by Runge-Kutta numerical integration (RK-5).…”

“…9,10 As a closedform integration of the systems of differential equations relative to photoreactions is not generally possible, 11 a method was devised to derive validated semi-empirical integrated rate-laws for such reaction systems. 12,13 This approach was applied here, for the first time,…”

Quantification of Unimolecular Photoreaction Kinetics: Determination of Quantum Yields and Development of Actinometers—The Photodegradation Case of Cardiovascular Drug Nisoldipine

“…Φ-order kinetics is a recently developed approach useful for the investigation and characterisation of unimolecular and reversible photodegradation reactions of drugs [1][2][3][4][5][6][7]. It has been proven to be more suitable for the description of drugs' photoreactivity than the classical treatments based on zeroth, first, and second reaction orders [1][2][3][4].…”