Bacterial Endotoxins Testing Using Recombinant Alternative Reagents for Veterinary Medicinal Products
Hsun-Lung Chan
Abstract
The bacterial endotoxins test (BET) is a critical quality control step for sterile veterinary medicinal products and has long relied on limulus amebocyte lysate (LAL). Concerns regarding ecological sustainability, supply stability, and inter-lot variability, have driven adoption of non-animal alternatives. The recombinant cascade reagent (rCR), comprising recombinant Factor C, recombinant Factor B, and (pro) clotting enzyme to reconstitute the LAL coagulation cascade, enables quantitative BET. Pharmacopeial adoption of rCR in present is heterogeneous: the United States Pharmacopeia (USP) General Chapter <86> (effective 2025) recognizes BET using recombinant reagents as an alternative to Chapter <85>, with implementation requiring method validation and comparability assessment; the European Pharmacopoeia currently treats rCR as an alternative method; the Japanese and Chinese Pharmacopoeias have no rCR general chapter and likewise require validation and comparability when adopted. This study establishes rCR testing techniques for veterinary products and conducts method validation in line with pharmacopeial principles. Within 0.005–5.0 EU/mL of bacterial endotoxin standards, calibration correlations were (|r|) ≥ 0.980; repeatability coefficients of variation (CVs) at each level were ≤10% based on laboratory control standard. Interference was evaluated by spiking 0.5 EU/mL endotoxin into endotoxin-free water; positive product control recoveries measured by LAL turbidimetric, LAL kinetic chromogenic, and rCR methods ranged 71.02–84.54%, meet the 50–200% acceptance criterion of the pharmacopoeia. Six veterinary monoclonal antibody products were further tested at the maximum valid dilution (MVD), yielding recoveries of 55.97–84.48% with interference-test CVs ≤10%, were consistent with pharmacopeial expectations and laboratory quality controls. Future work will extend matrix-interference and method-comparability studies to a broader set of sterile veterinary dosage forms to confirm the suitability of rCR for veterinary medicinal products.
Development and Prduction of Waterfowl Parvovirus Vaccine
Chun-Hsien Tseng
Abstract
Waterfowl parvovirus infection is caused by goose parvovirus (GPV) or Muscovy duck parvovirus (MDPV) which infecting goslings or ducklings, and it results in high mortality. Clinically manifestations include fibrinonecrotic enteritis, stunted growth, and shortened beak deformities. The virus can propagate in fibroblast cells and embryonated eggs from geese and Muscovy ducks. However, these hosts do not lay eggs year-round, and SPF embryonated eggs are difficult to obtain. Thus, our division has gradually attempted to develop a goose-origin embryo-propagated live attenuated parvovirus vaccine, a duck-origin embryo-propagated inactivated vaccine, a bivalent tissue-culture–derived live attenuated waterfowl parvovirus vaccine, a multivalent live attenuated waterfowl vaccine, and a multivalent waterfowl egg yolk antibody preparation. These vaccines can be used to provide active and passive immunization for breeder and young waterfowl in the industry, protecting ducklings and goslings against both duck- and goose-origin waterfowl parvoviruses. The vaccines and egg yolk antibody preparations mentioned above have demonstrated good safety and efficacy in ducklings, goslings, breeder ducks, and breeder geese. In contrast to embryo-propagated waterfowl parvovirus vaccines, which are limited by seasonal egg production and the difficulty of obtaining SPF eggs, vaccine production via tissue culture can overcome these constraints. Furthermore in combination with egg yolk antibody administration, better protection can be achieved.