Due to a sustained drug release, a prolonged therapeutic level of drugs exhibiting a short elimination half-live can be maintained. Consequently the frequency of dosing can be reduced contributing to an improved compliance. The release of drugs out of polymeric carrier systems can be controlled by a simple diffusion process. So far the efficacy of such delivery systems, however, was limited by a too rapid disintegration and/or erosion of the polymeric network [Bernkop-Schnürch, A., Scholler, S., and Biebel, R.G. (2000). Development of controlled drug release systems based on polymer-cysteine conjugates. J. Control. Release, 66, 39-48; Clausen, A.E., and Bernkop-Schnürch, A. (2001) Development and in vitro evaluation of a peptide drug delivery system based on thiolated polycarbophil. Pharm. Ind., 63, 312-317]. By using thiolated polymers this essential shortcoming can be overcome. Because of the formation of inter- and intrachain disulfide bonds during the swelling process, the stability of the polymeric drug carrier matrix is strongly improved. Hence, a controlled drug release for numerous hours is guaranteed. This controlled drug release has also been demonstrated by studies in human volunteers.

Disintegration behaviour of tablets based on polycarbophil (PCP) or sodium carboxymethylcellulose (CMC). Click on the graph to see the improvement in stability by using the corresponding thiolated polymers. [Bernkop-Schnürch, A., Scholler, S., and Biebel, R.G. (2000). Development of controlled drug release systems based on polymer-cysteine conjugates. J. Control. Release, 66, 39-48]