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 hepathic encephalopathy by the use of a pharmaceutical formulation as claimed.
