The pharmaceutical compositions described herein include a suspension which comprises an admixture in solid form of a therapeutically effective amount of a therapeutic agent and at least one salt of a medium chain fatty acid and a hydrophobic medium, e.g. castor oil or glyceryl tricaprylate or a mixture thereof. The pharmaceutical compositions described herein contain medium chain fatty acid salts and are substantially free of alcohols. The pharmaceutical compositions may be encapsulated in a capsule. Methods of treating or preventing diseases by administering such compositions to affected subjects are also disclosed.