Sildenafil citrate (SC), commonly known as Viagra, is the oral drug of choice for erectile failure despite well-known issues of lengthy waits for the effects to take hold, and the short amount of time it lasts when it does start to work.
However writing in the International Journal of Nanotechnology, the team - Yosra Elnaggar, Magda El-Massik, and Ossama Abdallah – propose a transdermal delivery system which gets into the blood stream quicker than having to be ingested.
And if the researchers succeed, the new method could mean a longer-lasting medication than the oral dosage, of which 70 per cent is wasted when it is metabolized by the liver without having any effect.
The solution of a transdermal based form of sildenafil is one which has been approached before.
However it has always been challenged by the drug’s amphoteric nature, low oil and water solubility, pH-dependent characteristics and poor membrane permeability.
But by impregnating in nanoemulsion based systems that can cross membranes easily with SC the team believe they can use nanomedicine to solve the issue.
The researchers examined two types of nanocarrier – one forming a emulsion with the drug using a surfactant compound to allow the lipid molecules and drug to mix, and the other a self-emulsifying nanocarrier that has its own inbuilt surfactant.
They found that the self-emulsifying form of the mix worked successfully, which shows promise for a new Viagra patch.
The authors wrote: “In this paper, relevance of nanomedicine to improve SC characteristics and transdermal permeation was assessed.
“Nanoemulsion elaborated could significantly enhance transdermal permeation of SC with higher initial permeation and prolonged release.”