A stabilized bioadhesive composition containing an alkaline labile drug and a method for its preparation are provided. In one aspect, the composition is a hot-melt extruded (HME) composition comprising a preformed excipient mixture comprising an acidic component and an alkaline thermoplastic matrix-forming material, e.g. polymer. The excipient mixture is formed before blending with an alkaline labile drug. The blend is then hot-melt extruded to form the HME composition. By so doing, the acidic component is able to neutralize or render moderately acidic the excipient mixture. This particular process has been shown to substantially reduce the degradation of an alkaline labile drug during hot-melt extrusion. The excipient mixture softens or melts during hot-melt extrusion. It can dissolve or not dissolve drug-containing particles during extrusion. Various functional excipients can be included in the carrier system to improve process performance and/or improve the chemical or physical properties of the HME composition.
