Pasteurella Vaccine Veterinary Grade API is released as a live attenuated freeze-dried antigen plug, an inactivated whole-cell suspension, or a detoxified toxoid concentrate. It is specified by importers for tablets, injections, capsules, powders, granules, premix, and solutions, but registered downstream usage in Pasteurella vaccination programs is concentrated in injectable suspensions, lyophilized drinking-water powders, and liquid toxoid products. Tablet and capsule vaccine presentations are not currently established commercial categories for Pasteurella multocida or Mannheimia haemolytica biologicals; development activity has not produced a registered oral solid-dosage Pasteurella vaccine in the major regulatory jurisdictions. The following application scopes therefore exclude non-validated solid oral formats and focus on production-scale veterinary biological processes where the API has demonstrable batch release data.

Heat-stable lyophilized fowl cholera drinking-water vaccine with stabilizer-limited cake morphology

The live Pasteurella multocida API for flock-level oral vaccination is handled as a lyophilized plug in Type I glass vials. Formulation addition at compounding is typically 5.0% w/v sucrose, 1.5% w/v gelatin, 2.0% w/v N-Z amine, and 0.02 M potassium phosphate buffer, with the live API concentrate added at 25–40% v/v of the final bulk. The post-reconstitution potency target is 1×10⁷–8×10⁸ CFU per dose, and freeze-dried cake moisture is released only when loss on drying is below 3.0% w/w. Compliance for the live product is anchored to 9 CFR 113.64; seed lot identity and extraneous-agent freedom follow 9 CFR 113.27, and diluent sterility follows Ph. Eur. 2.6.1. Production-scale fermentation is terminated at mid-log phase with an optical density of 0.8–1.2 to preserve capsular antigen expression. If the culture exceeds 1.5 OD₆₀₀, capsular polysaccharide release changes the amorphous matrix, lowers the glass transition temperature, and can extend primary drying by 6–10 h in 10 mL tubing vials. The lyophilization program uses a freezing ramp of 0.5 °C/min to -45 °C, a vacuum setpoint of 80–120 mTorr, and primary drying shelf temperature at -18 °C. Product temperature is kept below the collapse temperature of the amorphous phase, as defined by freeze-drying microscopy. Edge-vial meltback over 1 mm from the heel is observed when the ramp exceeds 0.5 °C/min or when the condenser load exceeds 80% of rated capacity. Stoppers are seated under vacuum; vial headspace moisture is confirmed by Karl Fischer and is required to remain below 0.4% w/w for 18 months at 2–8 °C. The terminal product is a 1000-dose drinking-water presentation or a 100-dose wing-web presentation. The powder plug is reconstituted in non-chlorinated water at the farm; it is not a tablet, granule, or premix, and direct contact with chlorinated water above 0.5 ppm free chlorine reduces viable count.

In bovine haemorrhagic septicaemia programs, aluminum hydroxide-adjuvanted inactivated bacterin is built from formalin-inactivated whole-cell Pasteurella multocida serotype B:2 or E:2 biomass. The final API incorporation is 20–35% v/v of the concentrated inactivated suspension, aluminum hydroxide gel is added at 20–30% v/v, and thiomersal is permitted only in multidose containers at 0.01% w/v. The adsorption pH is clamped between 6.8 and 7.2; if the pH falls below 6.2, aluminum hydroxide gel begins to dissolve, releasing adsorbed antigen and increasing ionic aluminum in the supernatant. The release is confirmed by centrifugation and protein assay of the aqueous phase; batch release potency is evaluated by mouse potency under 9 CFR 113.118. On production floors, formaldehyde addition at 0.3–0.5% v/v to the inactivation vessel generates a measurable temperature rise of 1.5–2.0 °C within 30 min. The jacket temperature is set 2 °C below target 37 °C to avoid antigen degradation above 39 °C, a threshold associated with depressed seroconversion in vaccine-challenge batches. Following inactivation, residual formaldehyde is neutralized with sodium metabisulfite and diafiltered against phosphate-buffered saline to a free formaldehyde concentration below 0.05% w/v, verified by a chromotropic acid method. Inactivated biomass is concentrated by continuous disc-stack centrifugation at 12,000 × g, washed twice, and blended with aluminum hydroxide gel through a static mixer at 60–100 rpm rather than a recirculating homogenizer. The final suspension must meet Ph. Eur. 2.6.14 bacterial endotoxin limits appropriate to the bovine dose. The filled terminal product is a ready-to-use injectable suspension in 100 mL or 250 mL vials, administered subcutaneously to cattle and buffalo at 2–3 mL per dose.

Why does high-shear emulsification desorb Pasteurella multocida toxoid from aluminum hydroxide in swine atrophic rhinitis vaccines?

The Pasteurella multocida toxoid (PMT) component used in sow vaccination is a detoxified protein that is combined with Bordetella bronchiseptica bacterin and, in some formulations, erysipelas antigen. The final PMT addition is 5–15% w/v of the concentrated toxoid bulk, with aluminum hydroxide gel at 20–30% v/v and isotonic saline to volume; the dose target is 0.5–1.5 mg PMT protein per 2 mL intramuscular dose. Residual formaldehyde after detoxification is maintained below 0.74 mg/mL, determined by a validated derivatization HPLC method after 2,4-dinitrophenylhydrazine reaction. Batch safety is secured under 9 CFR 113.100; sterility follows Ph. Eur. 2.6.1. Production-scale detoxification uses formaldehyde 0.4–0.6% v/v at 35–37 °C for 14–21 days; the vessel is blanketed with nitrogen to limit oxidation. The toxoid is concentrated and diafiltered through a 30 kDa tangential-flow membrane; transmembrane pressure is kept below 1.0 bar to avoid shear-induced aggregation. Final blending must avoid rotor-stator energy above 3000 rpm, because high-shear homogenization has been observed to desorb PMT from aluminum hydroxide surfaces and release free toxoid into the aqueous phase; this was associated with a 10–20% reduction in antibody induction in in-house potency assays. The process specification therefore uses a magnetically coupled bottom impeller at 80–120 rpm. The terminal product is a 50 mL or 100 mL injectable suspension for intramuscular administration to gilts and sows.

When Pasteurella multocida antigen is combined with Mannheimia haemolytica and Histophilus somni fractions in feedlot respiratory vaccines, the finished injectable is an oil-adjuvanted suspension. The aqueous antigen phase is added at 30–40% v/v to the oil phase, which comprises light mineral oil and mannide oleate emulsifier at 5–10% v/v of the total formulation, with the remainder to volume. The combined Pasteurella multocida and Mannheimia haemolytica potency is standardized to a minimum of 1×10⁹ CFU equivalent per dose; final emulsion viscosity at 20 °C is 20–60 cP. Compliance for the inactivated bacterial fraction follows 9 CFR 113.100; sterility of each component is verified by Ph. Eur. 2.6.1 before blending. Before homogenization, the aqueous phase is adjusted to pH 7.0 and sterile-filtered through a 0.45 µm prefilter and 0.2 µm final membrane. The downstream process runs through an inline rotor-stator homogenizer at 6000–10,000 rpm, with the emulsion recirculated through a plate heat exchanger to keep the bulk below 35 °C. Droplet size after emulsification is held at D50 2–5 μm and D90 below 8 μm; larger droplets have been associated with excessive injection-site reactions, while submicron droplets accelerate antigen release from the water-in-oil matrix and shorten duration of immunity. Air entrainment during inline homogenization is controlled by a back-pressure valve set at 1.5–2.0 bar; without back-pressure, cavitation in the fill line increases fill-weight variation beyond ±1.5%. The terminal product is a ready-to-use injectable emulsion in 50 mL or 250 mL vials for cattle.

Emulsion-stabilized bivalent ovine/caprine pasteurellosis antigen concentrates

Bivalent sheep and goat pasteurellosis vaccines are formulated with inactivated Pasteurella multocida and Mannheimia haemolytica serotypes isolated from pneumonic cases. The aqueous pooled antigen is incorporated at 40–50% v/v into a mineral oil adjuvant containing anhydromannitol octadecenoate ether surfactant at 8–12% v/v of the oil phase. Each 1 mL dose is standardized to contain at least 2×10⁹ inactivated cells of each fraction before emulsification. The applicable monograph is Ph. Eur. 0062, with batch release requiring sterility under Ph. Eur. 2.6.1 and freedom from abnormal toxicity under Ph. Eur. 2.6.9. Process control centers on the primary emulsion ratio and droplet size. The aqueous antigen phase is added to the oil phase at 20–25 °C under rotor-stator high shear, with droplet size held at D50 2–5 μm. If the D50 falls below 1 μm, the emulsion becomes too stable and may delay antigen presentation; above 8 μm, the emulsion destabilizes in the vial and forms a visible oil layer. Production-scale batches use an inline homogenizer with a cooling jacket set to 15 °C to offset shear-induced heating of 5–10 °C. The oil phase is sparged with nitrogen to reduce oxidation; if shear-induced heating exceeds 35 °C, mannide oleate may oxidize and lower emulsion stability. The terminal product is a ready-to-inject water-in-oil emulsion for subcutaneous use in sheep and goats, typically in 50 mL or 100 mL vials.

For rabbit breeding units, pasteurellosis bacterin production uses a purified inactivated Pasteurella multocida serotype A:3 or A:12 antigen. The final suspension for injection is compounded at 20–25% v/v antigen concentrate with 0.9% w/v sodium chloride and 0.2 mg/mL potassium phosphate buffer; aluminum hydroxide gel is added at 15–20% v/v. For rabbit products, thiomersal is omitted to avoid species-specific intolerance, and the batch is preserved by aseptic filling rather than chemical preservative. The terminal product is a 0.5 mL subcutaneous dose for breeding does and bucks. Manufacturing uses fastidious media containing yeast extract and heat-inactivated horse serum at 2–5% v/v; serum is pre-screened and heat-inactivated at 56 °C for 30 min to reduce mycoplasma risk. Production batches are inactivated with formaldehyde 0.4% v/v at 30 °C for 24 h, followed by neutralization with sodium metabisulfite and diafiltration against phosphate-buffered saline. Sterility is confirmed by Ph. Eur. 2.6.1; potency is evaluated by active mouse protection or serological response according to in-house methods. The process is a low-shear tank blend rather than an emulsion, which retains the particulate character of the alum-adsorbed bacterin. The filled product is a small-volume multi-dose vial for rabbit producers, not a powder or tablet.