A method of preparing an excipient composition includes forming an aqueous slurry containing a mixture of microcrystalline cellulose in the form of a wet cake and a surfactant, said surfactant being present in an amount from about 0.1% to about 0.5% by weight of the wet-cake microcrystalline cellulose; and drying said slurry to obtain an excipient comprising a plurality of agglomerated particles of microcrystalline cellulose in intimate association with said surfactant. The excipient may be mixed with a therapeutically active agent to form a dosage form. The surfactant provides a hydrophobic boundary at cellulose surfaces, and improves absorptivity of the therapeutically active agent.