Ascorbic acid loaded polyvinylpyrrolidone tablets are prepared and ascorbic acid release profiles are monitored by the automatic continuous online monitoring of polymerization (ACOMP) system. Three different molecular weights of polymers are used in tablets. Parallel experiments are performed using powder samples. Drug release from tablets is investigated as zeroth and halfth order processes for the dissolution step and a first order process for the diffusion step. Powder samples are investigated on the basis of a first order diffusion model. Kinetic rate constants for the dissolution and diffusion processes are calculated. Release profiles are found to depend strongly on the molecular weights of the polymers. Higher molecular weights are found to slow down both the dissolution and the diffusion processes. Diffusion constants are compared with independent viscosity measurements.