TY - JOUR T1 - Improved Delivery Through Biological Membranes XVI Enhancement of the Brain-Specificity of a Dihydropyridine ⇄ Pyridinium Salt Drug Delivery System by Controlled Infusion JF - PDA Journal of Pharmaceutical Science and Technology JO - PDA J Pharm Sci Technol SP - 159 LP - 164 VL - 37 IS - 5 AU - Marcus Brewster AU - Nicholas Bo Bodor Y1 - 1983/09/01 UR - http://journal.pda.org/content/37/5/159.abstract N2 - The quaternary salt berberine can be delivered to the brain by injecting the lipoidal dihydroberberine, which is converted in vivo to berberine. The efflux from the brain of the berberine formed in situ is much slower than its rate of elimination from the general circulatory system. This inherent specificity for the brain of this redox delivery system can further be enhanced by slowly infusing the dihydroberberine instead of an i.v. bolus injection. It was found that by controlling infusion of dihydroberberine, the concentration of berberine (relative to its concentration after i.v. bolus) rose specifically in the brain while it fell in other tissues. It is suggested that a combination of the redox-delivery system with controlled infusion (or other controlled release techniques) will result in maximal brain-specific delivery. ER -