The present invention relates to topical bioadhesive formulations comprising low viscosity, non-liquid crystalline, mixtures of: a) at least one neutral diacyl lipid and/or at least one tocopherol； b) at least one phospholipid； c) at least one biocompatible, oxygen containing, low viscosity organic solvent； wherein at least one bioactive agent is dissolved or dispersed in the low viscosity mixture and wherein the pre-formulation forms, or is capable of forming, at least one liquid crystalline phase structure upon contact with an aqueous fluid for use in therapy. The invention additionally relates to the use of a preformulation of the invention in a method for the manufacture of a medicament.
