Disclosed is a self-microemulsifyable anhydrous base composition, comprising: (a) propofol, which is not dissolved in oil and(b) a nonionic surfactant having the structure of [POE(n)] subm-R- Rwhere POE is a polyoxyethylene moiety of -mer number n, and having m of these POE functional groups attached to R where the value of m is one to three where R is a linking moiety selected from glyceryl, sorbitan, ester, amino, or ether functions where R is a hydrophobic moiety consisting of saturated or unsaturated alkyl or alkylphenyl groups and where the structure of the non-ionic surfactant is further defined by a ratio of A, the total number of POE -mer units in the surfactant given by the product of -mer number n and total PEG chain number m per molecule, to B, the number of carbons in the hydrophobic functional group R, the ratio of A/B being in the range of 1 to 2 or in the range of 0.7 to 4 and wherein the nonionic surfactant is included in the base composition in a concentration of eight (8) parts by weight or more of the nonionic surfactant to one (1) part by weight of propofol and with the base composition not containing any co-surfactant or co-solvent the composition may further comprise:(c) a water-immiscible solvent which is a biocompatible monoester, diester or triester and (d) ethanol.
