Preparation of drug: hydroxypropylcyclodextrin complexes by a method using ethanol or aqueous ammonium hydroxide as co-solubilizers

The dissolution of lipophilic drugs in aqueous solutions of hydroxypropylcyclodextrins can be accelerated by the addition of co-solubilizers such as ethanol or ammonia. These co-solubilizers can be removed later, together with water, by evaporation or freeze-drying, leaving drug: hydroxypropylcyclodextrin complexes. The co-solubilizer method was used successfully with steroid drugs (5-anrostene-3β,17β-diol, 4-androstene-3,17-dione, dehydroepiandrosterone, dexamethasone, 5α-dihydrostestosterone, 6-methylprednisolone and testosterone), peptides (gramicidin S) and a macrocylic antibiotic (amphotericin B). The complexes prepared in this manner were amorphous and of satisfactory stability and solubility.