Solubility and Stability of Proroxan at Various PH Values

The solubility and stability of the nonselective α-adrenoblocker 1-(2,3-dihydro-1,4-benzdioxin-6-yl)-3-(3-phenyl-1-pyrrolidinyl)-1-propanone hydrochloride (proroxan) at various pH values were investigated. It was established that proroxan solubility was reduced for 3 < pH < 5.5, which corresponded to the protonated species; was uncharacteristic for salts of organic bases; and increased its destruction. It was suggested that this peculiarity of proroxan behavior in aqueous solutions could reflect complexation between its protonated and unprotonated molecules. The results indicated that proroxan preparations using dosage forms and delivery systems that provide its maximum absorption in the stomach must be developed.