The present invention is directed to a novel pharmaceutical formulation comprising 3α-ethynyl-3β-hydroxyandrostan-17-one oxime in an amount of 0.1-10% by weight of the total weight of the composition; and a vehicle comprising (a) 45-100% of a monoester; (b) optionally up to 51% of a diester; and (c) optionally up to about 10% of a triester. Also claimed is a method for the treatment of medical conditions such as hypersomnia and hepatic encephalopathy by the use of a pharmaceutical formulation as claimed.