EFFECT OF 2-HYDROXYPROPYL-BETA-CYCLODEXTRIN ON THE STABILITY OF PROSTAGLANDIN E(2) IN SOLUTION

The potential use of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) i n the stabilization of prostaglandin E(2) (PGE(2)) was investigated. I nclusion complexation of PGE(2) with HP-beta-CyD was estimated by circ ular dichroism spectroscopy. The effect of HP-beta-CyD on the dehydrat ion rate of PGE(2) and the isomerization rate of PGA(2) was examined b y comparing the rate constant of PGE(2) alone with that of the inclusi on complex of PGE(2) with HP-beta-CyD in each buffered solution. The d ehydration rate of PGE(2) and the isomerization rate of PGA(2) under a cidic conditions were decreased by HP-beta-CyD, while the rates under basic conditions were increased, probably due to positive catalytic ef fects on the reactions. The retardation of the dehydration and isomeri zation rates at low pH might be the effect of inclusion complexation w ith HP-beta-CyD.