The invention relates to a pharmaceutical composition of acyclovir prodrugs that includes olive oil and a solubilizing agent, for topical use in the treatment of illnesses caused by the Herpes virus. The prodrug used is an alkyl ester, such as acyclovir hexanoate, which can be obtained by esterification with an alkylamide and, more specifically, with ?,?-dimethyldecanamide. The invention additionally relates to a method for obtaining the pharmaceutical composition, that includes mixing an acyclovir prodrug with olive oil, and adding a solubilizing agent and suitable excipients for a formulation for topical use.