Release from transdermal delivery systems. Application of a new non isothermic method to Trans-Ver-Sal patches.

In this paper a new non isothermic method for the determination of the release drug rate constant (k) from a transdermal delivery system is proposed. The new method was applied to transdermal patches Trans-Ver-Sal. The results obtained prove to be able to release salicylic acid of transdermal system and the effectiveness of the new method propose.

Fast rolitetracycline stability determination by spectrophotometer variable-temperature kinetic experiments.

The pseudo-first order rate constant for the hydrolysis of rolitetracycline as a function of temperature was obtained by performing variable-temperature kinetic experiments. The results are in agreement with those obtained at constant-parameter kinetics but saving experimental time and chemicals.

Variable pH kinetics: an easy determination of pH-rate profile.

The complete pH-rate profile of the hydrolysis reaction of aspirin, requiring many experiments in the past, was obtained by a single variable-parameter kinetic experiment carried out by varying the hydrogen ion concentration. The experiment was carried out spectrophotometrically, reading automatically absorbance, pH, and temperature inside the reaction vessel. The results obtained by the fast processing of the kinetic profile are identical to those obtained under the same conditions but using traditional constant-pH kinetic runs. This method provides the possibility of reducing the amount of time and chemicals usually spent in collecting kinetic data in such mechanistic studies by nearly two orders of magnitude.

Hydrolysis of aspirin studied by spectrophotometric and fluorometric variable-temperature kinetics.

Pseudo-first-order rate constants for the hydrolysis of acetylsalicylic acid as a function of temperature have been obtained by variable-temperature kinetic experiments. A method, based on a generalization of non-isothermal analysis, has been used that takes advantage of the capabilities of modern data collection and processing systems. Both spectrophotometric and, for the first time under non-isothermal conditions, fluorometric measurements have been carried out. The results obtained are identical to those obtained under the same conditions but using traditional constant-temperature kinetic runs. This provides the possibility of reducing the amounts of time and chemicals usually spent in collecting kinetic data in mechanistic studies in solution by an order of magnitude.