Abstract: Disclosed herein is a process for preparing a highly concentrated allergenic intermediate from a dilute allergen extract. This process involves providing a crude extract comprising biological material from an allergenic source, where the biological material comprises a solid phase portion and a liquid phase portion; concentrating the crude extract using pervaporation; adjusting the pH of the concentrated crude extract to 4.0-5.0; treating the concentrated extract with a ketonic solvent to form a precipitate; and recovering the precipitate by filtration to obtain a highly concentrated allergenic intermediate.

Abstract: Disclosed herein are methods for the preparation of allergenic extracts. In one embodiment, the methods are carried out without having to adjust the pH of the extraction phase. The methods provide efficient recovery of allergenic extract from allergenic source material.