The pH Analysis of Papaverine-Phentolamine and Prostaglandin E ₁ for Pharmacologic Erection

Abstract

Although papaverine-phentolamine preparations are being employed for pharmacologic erection programs across the nation, their chemical properties have not been described in the literature. We found that the pH of papaverine-phentolamine solution in all concentrations tested remained less than 4.0. Attempts to buffer the solution resulted in a precipitate at a pH greater than or equal to 5.0. The pH of prostaglandin E1 was less than 5.0 but could be easily buffered to pH 7.4 or even 10.75 and remained stable. The effect of an acidic solution on corporal connective tissue and smooth muscle meshwork is unknown. We believe that buffering by blood will lead to the precipitation of papaverine-phentolamine and may cause primary intracorporal scarring. Extravasation or improper injection into the subcutaneous tissue exposes the mixture to blood and may secondarily result in additional scarring for the same reason. Therefore, prostaglandin E1 may be a more appropriate agent for penile injection.

Cavernous oxygen tension in the patients with erectile dysfunction

“…Although, it is said that papaverine may have signi®cant in¯uence on cavernous blood gas analyses, 14 our results of cavernous pO 2 is similar to results of electroerection, visual-tactile sexual stimulation and intracavernosal injection of the PGE 1 3,10,13 which have no adverse effects on cavernous pH.…”

Intracavernous Alprostadil

“…However, there have been a few reports of syncope and other systemic events.l 41 ,95] The nature and incidence of adverse events reported in elderly users of intracavernous alprostadil are similar to those found in the general populationJ47, 48] The frequency of adverse events associated with intracavernous alprostadil use is affected by a number of factors, possibly including the pH of the formulation, [33,45,50,67,[96][97][98] the dose, [44,51] the amount of training patients receive [67,99] and the type of injection device. However, there have been a few reports of syncope and other systemic events.l 41 ,95] The nature and incidence of adverse events reported in elderly users of intracavernous alprostadil are similar to those found in the general populationJ47, 48] The frequency of adverse events associated with intracavernous alprostadil use is affected by a number of factors, possibly including the pH of the formulation, [33,45,50,67,[96][97][98] the dose, [44,51] the amount of training patients receive [67,99] and the type of injection device.…”

Comparison of the Effects of Papaverine versus Prostaglandin E(1) on Penile Blood Flow by Color Duplex Sonography

“…The pH of papav erine is less than 4.0. Buffering by the blood will lead to the precipitation of papaverine and may cause primary intracorporéal scarring when injected into the corpus cavemosum [10]. Repeated injections might cause fibro sis of the penile shaft.…”

“…Other actions include the subsi dence of inflammation, the inhibition of platelet aggre gation, the protection against tissue damage and the sta bilization of proteases [1]. The pH of PGEi was less than 5.0 but could be easily buffered to pH 7.4 or even 10.7 and then remained stable [10]. Some authors reported that it may be metabolized locally and that 70% of cir culating PGEi is cleared through the lungs [13], The rapid decline of circulating PGEj might minimize the systemic side effects and the incidence of priapism.…”