Development and Release Behavior of Impermeable PVA-wall Microcapsules in Cosmetics

Abstract

The structure and diffusion behavior of impermeable PVA (polyvinyl alcohol)-wall microcapsules containing a hydrophobic moisturizing agent as a core substance in a facial cleanser was investigated.
Recently, new materials are necessary in cosmetics, creating new functions. But sometimes these kinds of materials are unstable in the final product.
The crystalline PVA microcapsules were prepared by an improved salt coacervation method incorporating a water-soluble polymer. The mean particle size of 300μm is required in terms of the product appearance and the feeling while in use. Microcapsules, which have the mean wall thickness of 3μm, were selected because they satisfy the product design of not breaking at production and breaking while in use.
The PVA microcapsules are much more stable in a facial cleanser containing surface active agents than widely-used gelatin-wall microcapsules.
Good correlations were found between the diffusion coefficient of the moisturizing agent in microcapsule walls, led by the release curves, and the crystallinity of PVA-walls, led by the DSC method. This indicates that the existence of rigid crystalline parts improves the impermeability of materials.