Objective: To determine the stability of the extracts of wheat flour, egg white and peanuts in glycerin and aqueous formulation.
Methods: Extracts were prepared in GMP conditions at BIOCEN, Cuba from defines raw materials and subjected to diafiltration. Three pilot batches of each extract were stored at 4°C, in aqueous or 50% glycerin formulation and were sampled at 0, 15 days, 1, 2 and 3 months and 0, 3, 6, 9, 12, 18 y 24 months, respectively. The possible degradation was monitored by total protein content (Lowry) and content of glycerin (USP). Preservation of integrity of the most relevant allergens was checked by SDS-PAGE. Allergenicity was verified using patient IgE sera by Western blotting and sterility was determined at the beginning and end of the study. Acceptance limits matched those used for product release.
Results: After 24 months no deviations of quality specifications were detected in any parameter for glycerin formulation. Preservation of antigen's integrity was stable at the time of study, in addition preserving its allergenicity/antigenicity. Sterility testing showed that products were sterile during the study. Regression analysis of protein content and protein composition, indicated no significant trend towards degradation of the same (p = 0.05) either in glycerin or aqueous formulation during the study period.
Conclusions: This study demonstrated the stability of allergenic extracts in glycerin and aqueous formulation during 24 months and 3 months, respectively, as a basis for approval of a reliable expiration period. This period ensures the quality and safety in terms of stability of these products for the diagnosis of food allergy to wheat flour, egg and peanuts.
To determine the stability of the extracts of wheat flour, egg white and peanuts in glycerin and aqueous formulation.