Stability of protease-rich periplaneta Americana allergen extract during storage: formulating preservatives to enhance shelf life

• Published in: Journal of Clinical Immunology Vol. 27; no. 3; pp. 294 - 301
• Main Authors: Sudha, V Thangam, Srivastava, Deepsikha, Arora, Naveen, Gaur, Shailendra Nath, Singh, Bhanu Pratap
• Format: Journal Article
• Language: English
• Published: Netherlands Springer Nature B.V 01.05.2007
• Subjects: Allergens; Allergens - chemistry; Allergens - immunology; Allergens - metabolism; Animals; Cell Extracts - analysis; Cell Extracts - chemistry; Cell Extracts - immunology; Endopeptidases - metabolism; Enzyme Stability - drug effects; Female; Glycerol; Humans; Hypersensitivity - immunology; Hypersensitivity - pathology; Immunoglobulin E - immunology; Immunotherapy; Male; Periplaneta - enzymology; Periplaneta - immunology; Periplaneta americana; Preservation, Biological - methods; Preservatives; Preservatives, Pharmaceutical - chemical synthesis; Preservatives, Pharmaceutical - chemistry; Preservatives, Pharmaceutical - pharmacology; Proteinase; Proteins; Shelf life; Skin - drug effects; Skin - immunology; Skin - pathology; Specimen Handling - methods; Sucrose; Temperature; Time Factors
• ISSN: 0271-9142; 1573-2592; 1365-2567
• DOI: 10.1007/s10875-007-9078-y

Allergenic proteins in extracts degrade rapidly and lose potency on storage. Hence, formulation of optimum conditions is required to enhance shelf life of extracts for proper allergy diagnosis and immunotherapy. In the present study, allergenic potency of P. americana proteins was evaluated after storage with epsilon-aminocaproic acid (EACA), sucrose, glycerol, pepstatin A, and aprotinin, individually for 1, 3, 6, and 12 months at 4, 25, and 37 degrees C. P. americana extract stored with EACA and sucrose individually retained potency comparable to proteins in standard extract (freeze-dried extract, stored at-70 degrees C) upto 6 months at 4 degrees C. The extracts without preservatives or with glycerol, pepstatin A, aprotinin, or stored at 37/25 degrees C were severely degraded and lost potency by 3 months. A formulation containing a combination of EACA and sucrose enhanced the shelf life of P. americana proteins upto 12 months at 4 degrees C. Hence, EACA and sucrose together show better potential for stabilization of protease-rich extracts.