In vitro vertical diffusion cell design. Validation of some parameters and cell designed

SESTO CABRAL ME; RAMOS AN; CABRERA CA; KOLLING AI; MANZO RH; VALDEZ JC

Rosario

Congreso; Reunión Internacional de Ciencia Farmacéuticas; 2012

RICIFA

Introduction: In vitro Franz diffusion experiments have evolved into one of the most important methods for researching transdermal drug administration. This type of testing often yields permeation data that has poor reproducibility, even when synthetic membranes are used as barriers, thereby eliminating the variability associated with the use of biological tissue. The objective of this work was to evaluate and validate a system designed on our laboratory for research proposes and compared it to the traditional diffusion system. The parameters, reproducibility and robustness were performed included factors as, stirring conditions, membrane stabilization treatment and temperature variation. Materials and methods: The formulation selected for these trials was a sunscreen cream containing as active pharmaceutical ingredient (AFI) Benzophenone-3(1). This assay was conducted using the vertical diffusion cells designed having a receptor compartment capacity of 10 mL. Cellulose membrane was mounted between the half-cells in contact with receptor fluid and equilibrated. The area available for diffusion was 1.8 ± 0.1 cm2. The temperature fluid in the receptor compartment was 32 ± 3ºC. 0.2 ± 0.05 g sample was placed in the donor compartment. The entire assembly was kept on a shaker (80, 100 and 140 rpm) and then 2 mL of the receptor fluid was withdrawn at regular intervals (2, 4, 6 and 8 h). The OD286 of the solution was measured in a UV spectrophotometer. In parallel the same conditions were reproduced on a USP Franz Diffusion cell and the data obtained were compared. Cumulative amounts of Benzophenone-3 (mg) permeated the unit diffusion surface (cm2) was plotted against time (h). All experiments were performed in triplicate and the results were expressed as mean ± SD. Results: Coefficient of variance ranged from 0.48 to 1.3, with regular, reproducible behavior of all the cells employed. These coefficients are within the interval considered to be acceptable for situations of reproducibility for analytical methods. Robustness was determined by introducing small variations on some parameters stirring velocity between 80 and 140 rpm shown no variation on the release profile. On the other hand at 1 h or more (in the stable state), the method is robust for all the experimental factors analyzed except for temperature; a difference of 3°C is sufficient to increase the quantity of the drug released. When we compared the values g/cm2/h not showed significantly differences between them. Discussion and conclusions: From this study, we conclude that the system designed and the methodology employed is acceptable for release studies with classical topical dosage forms. The method is reproducible and robust for a stirring rate of 90-140 rpm and provided that the test temperature, which is influential, is carefully controlled. References: 1) Jiang R, Roberts MS, Collins DM, Benson HAM. Absorption of sunscreens across human skin: an evaluation of commercial products for children and adults. J. Clin. Pharmacol. 1999; 4 (48): 635?637. 2) Shiow-Fern Ng, Rose JJ, Sanderson FD, Meidan V, Ecleston GM. Validation of a Static Franz Diffusion Cell System for In Vitro Permeation Studies. AAPS PharmSciTech. 2010; 11 (3): 1432-1441.