The present invention relates to pharmaceutical formulations comprising as active compound Suvorexant, or its salts, or its metabolites or derivatives, thereof and pharmaceutical excipients, process for the preparation thereof and pharmaceutical compositions containing them. The pharmaceutical formulations of the present invention possess instantaneous redispersibility, increased apparent solubility and permeability, no observable food effect with respect to immediate absorption and more predictable plasma concentration throughout the night and next morning. The invention also relates to methods of manufacturing the pharmaceutical formulations and pharmaceutical compositions containing them according to the invention, their uses and methods of treatments using the pharmaceutical formulations and their pharmaceutical compositions.