Preparation of microcapsules for skin allergy testing by the solvent evaporation process.

Polyurethanes and polyvinyl alcohol modified by stearyl isocyanate are used as a matrix for microparticles made by a solvent evaporation process to encapsulate allergenic molecules, with petrolatum used as a neutral vehicle. The encapsulation yields, depending on the agent to be encapsulated, vary from 22 to 45%.