Allergen Extract Selection and Handling
ÎThe maintenance concentrate should be formulated to deliver a dose considered to be therapeutically effective for each of its constituent components. The maintenance concentrate vial is the highest concentration allergy immunotherapy vial (eg, 1:1 vol/vol vial). The projected effective dose is called the maintenance goal. Some subjects unable to tolerate the projected effective dose will experience clinical benefits at a lower dose. The maintenance dose is the dose that provides therapeutic efficacy without significant adverse local or systemic reactions and might not always reach the initially calculated projected effective dose. This reinforces that allergy immunotherapy must be individualized. (A)
Proteolytic Enzymes and Mixing
ÎStudies designed to investigate the effect of combining extracts with high proteolytic activity, such as cockroach and mold/fungi, with extracts such as pollen, dander, and dust mite, have demonstrated a significant loss of potency with some of these extracts. Separation of extracts with high proteolytic enzyme activities from other extracts is recommended. It might be necessary to prepare two or more vials to provide allergen immunotherapy containing an optimal dose of each component while avoiding allergen extract combinations that might result in degradation of some or all of the components. (B)
Allergen Immunotherapy Extract Handling Storage
ÎAllergen immunotherapy extracts should be stored at 4ºC to 8ºC to reduce the rate of potency loss. (B)
ÎExtract manufacturers conduct stability studies with standardized extracts that expose them to various shipping conditions. It is the responsibility of each supplier or manufacturer to ship extracts under validated conditions that are shown not to affect the product's potency or safety adversely. (C)
Allergen Extract Expiration Dates
ÎIn determining the allergen immunotherapy extract expiration date, consideration must be given to the fact that the rate of potency loss over time is influenced by several factors separately and collectively, including (1) storage temperature, (2) presence of stabilizers and bactericidal agents, (3) concentration, (4) presence of proteolytic enzymes, and (5) volume of the storage vial. (D)
Allergen Extract Dilution Labeling and Nomenclature
ÎSerial dilutions of the maintenance concentrate should be made in preparation for the build-up phase of immunotherapy. (D)
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