The dissolution rate of zinc pyrithione.
Synopsis A method of measuring and correlating the rate at which zinc pyrithione dissolves during a shampoo is described. The rise in zinc concentration of a solution in a stirred vessel following the introduction of a dose of zine pyrithione suspension was measured as a function of time using atomic absorption spectrophotometry. An analysis of the mass transfer processes occurring during the dissolution of a suspended solid in a stirred vessel was used to correlate the concentration-time measurements. The analysis allows a calculation of the characteristic solution time, the mass transfer coefficient and the diffusion coefficient for the system. In this way the effect of changing shampoo formulation can be systematically studied.
Davies
T W
TW
Department of Chemical Engineering, University of Exeter, Exeter EX4 4QF, Devon, UK.