Pharmaceutical compositions that include a drug and/or drug-oligomer conjugate, a fatty acid component and a bile salt component, or a bile salt component without a fatty acid component are described. The drug can be covalently coupled to an oligomeric moiety. The fatty acid component and the bile salt component, when together, can be present in a weight-to-weight ratio of between 1:15 and 15:1 or any value between. Methods of treating diseases in a subject in need of such treatment using the pharmaceutical compositions of this invention are also provided, as well as methods of providing such pharmaceutical compositions.