Vasoactive cocktails for erectile dysfunction: chemical stability of PGE1, papaverine and phentolamine.

Abstract

Vasoactive cocktails are widely used in diagnosing and treating erectile dysfunction, especially in poor responders to prostaglandin E1 (PGE1). However, very little information as to their chemical interactions and stability is available, despite the huge amount of published work regarding their clinical efficacy. Obviously, medical and legal problems are involved. We analyzed four kinds of vasoactive cocktails, composed of papaverine, phentolamine and PGE1 in different combinations, using High Performance Liquid Chromatography analysis after 5 to 60 days of storage at temperatures between 2 and 8C. SPSS MANOVA analysis and a t-test for paired samples were used for statistical purposes. Papaverine and phentolamine concentrations showed no significant variations during the 2 month study, ranging from a minimum of 96.75+/-1.20 to a maximum of 103.00+/-0.20% of the starting values. In the same period, PGE1 showed an accelerated degradation profile, reaching concentration values, after 60 days, of 76.00+/-2.28% and 70.20+/-2.02% when added to phentolamine or papaverine respectively and 70.00+/-2.40% with both. Papaverine and phentolamine are characterized by chemical stability when blended together or with PGE1. Papaverine and/or phentolamine increase the naturally occurring degradation of PGE1 in physiological solution. This effect is most evident in the first 10 days. Papaverine has the greatest deteriorating effect on PGE1. A safe and proper use of these cocktails should take into account the variations of PGE1 concentration.