Water-soluble supramolecular complexes formed from a water soluble block copolymer and at least one associative gelling adjuvant. The copolymer includes at least two blocks of polyethylene oxide and at least one block of polypropylene oxide. The adjuvant has a water solubility less than 0.5 g/100 ml at 20° C. When combined with water, the complexes form a transparent reversely thermo-reversible hydrogel or solution that may be repeatedly hydrated and dehydrated. The hydrogel exhibits improved gelling efficiency and enhanced solubility and/or stability for sparely soluble and insoluble pharmaceutical agents. The complexes are useful in a variety of pharmaceutical and cosmetic products and applications and may be combined with an effective amount of a cosmetic, medicament, or diagnostic in a solid dosage form.
