Percutaneous absorption of butylparaben through guinea pig skin in vitro.

Percutaneous absorption of aqueous butylparaben through guinea pig dorsal skin was studied using a diffusion chamber. Polysorbate 80 increased the solubilized concentration but decreased penetration of the preservative. Polyethylene glycol 400 also reduced the amount of penetration. Propylene glycol was less effective than polyethylene glycol 400. Preservative activities of these systems on several microorganisms were evaluated on agar plates. The relationship between the butylparaben penetration and preservative activity is discussed.