A novel device for chronic intracranial drug delivery via microdialysis

A system is described for chronic intracranial drug administration in the rat using a modified in vivo microdialysis probe coupled to an Alzet model 2002 osmotic minipump. The results presented demonstrate that this system can be used for the chronic administration of quinolinic acid with minimal non-specific damage. Each pump delivered approximately 225 microliters of solution over a period of 19-20 days when tested in vitro. The dialysis units were uniform in function, delivering greater than 93% of the [3H]quinolinic acid initially loaded into the minipump. For in vivo analysis of this apparatus the dose of quinolinic acid tested produced extensive destruction of the striatum. The present system allows reliable drug diffusion over a relatively large area without pressure injection variability. In conclusion, we have developed a simple and inexpensive technique for administration of drugs into brain parenchyma with substantial advantages over previously used techniques.