Swine Pasteurella multocida Vaccine, Live (Strain EO630) Veterinary Grade API for Tablets / Injections / Capsules / Powders / Granules / Premix / Solutions

Swine Pasteurella multocida Vaccine, Live (Strain EO630) Veterinary Grade API is a lyophilized live antigen concentrate derived from the EO630 master seed of Pasteurella multocida. The product is manufactured as a pure live antigen concentrate for further formulation into immunological veterinary products intended for swine. The designation “for Tablets / Injections / Capsules / Powders / Granules / Premix / Solutions” identifies downstream formulation routes that may be considered by the marketing authorization holder; it does not indicate that all listed matrices are approved, stable, or suitable for the live organism without route-specific validation. Each final dosage form must be qualified under its actual manufacturing process because the viability of Gram-negative bacterial cells is sensitive to desiccation, oxygen, shear, temperature, and osmotic shock.

The EO630 strain identity is controlled at the master seed and working seed stages. Identity testing includes colony morphology on tryptic soy agar supplemented with 5% sheep blood, Gram-stain reaction as a Gram-negative coccobacillus, biochemical profiling, and strain-specific polymerase chain reaction. Capsular typing by slide agglutination with reference antisera is used to support the antigenic identity of the seed lot. Production lots are expanded in liquid medium under controlled pH and dissolved oxygen; the harvest is concentrated, formulated with stabilizers, and lyophilized. The final lyophilized cake is a white to off-white porous plug that disperses rapidly upon reconstitution. Model designation is Strain EO630. The API is supplied in glass vials with butyl rubber closures and aluminum overseals. Fill volume, viable count per vial, and residual moisture are batch-specific and declared on the certificate of analysis. The product is not a final vaccine and lacks use directions, diluent, and target species safety data for any particular presentation.

Production of the EO630 antigen involves scale-up from a characterized working seed lot through pre-culture and production fermenter. Fermentation medium typically contains animal-free peptones, yeast extract, and glucose; pH is maintained at 6.8–7.4, dissolved oxygen at 20–40% air saturation, and temperature at 37 ± 1°C. The culture is harvested in late logarithmic phase because stationary-phase cells may exhibit altered surface antigen expression and reduced freeze-drying survival. Continuous centrifugation at 8,000–12,000 × g is used for harvest concentration, followed by washing with chilled buffer at 4–8°C. High-pressure homogenization must not be used because it disrupts Gram-negative outer membranes. Downstream tubing and filters should be selected for low binding of bacterial cells, and peristaltic pumping should be set to avoid cavitation and foaming.

What release specifications apply to the EO630 lyophilized cake?

Release testing combines identity, potency, purity, and safety parameters. Representative release criteria are listed in Table 1. The limits are presented as industrial reference values for live bacterial lyophilized APIs; the approved specification for a given registration must be consulted because strain-specific and formulation-specific ranges may differ.

Viable count is the critical potency parameter. The enumeration method uses multiple dilutions plated in duplicate or triplicate to reduce counting uncertainty; acceptance is based on the geometric mean of countable plates. The spread-plate method for bacterial counts typically has an intra-laboratory repeatability of approximately ±0.3 log10 CFU/g. Overage calculations should not rely on nominal count alone; the lower confidence limit of the release assay must remain above the minimum potency claim throughout shelf life. The lyophilized API is typically overfilled to compensate for loss during storage and downstream formulation, but the overage should not exceed the registered upper potency limit.

During lyophilization, the product temperature is maintained below the collapse temperature of the stabilizer system. A typical sucrose-based formulation for live Gram-negative vaccines has a collapse temperature between −32°C and −35°C. The primary drying shelf temperature is ramped from −40°C to −10°C over 36–48 h, followed by secondary drying at 20–25°C under vacuum ≤ 0.1 mbar. Residual moisture above 3.0% w/w increases molecular mobility in the dried cake, depresses glass transition temperature, and shortens shelf life. Batch-to-batch variance in residual moisture across shelf positions, particularly edge vials, can be as high as ±0.5% w/w; segment sampling across the lyophilizer shelf is therefore used during process validation. Vials with partially collapsed cake or shrinkage should be rejected because collapse indicates local product temperature exceeded the collapse temperature and viability may be reduced.

Stabilizer selection is critical for freeze-drying survival. Sucrose or trehalose at 5–10% w/w total solids are common protective matrices. Mannitol alone can crystallize and damage cell membranes; combinations of sucrose and sodium glutamate or sucrose and dextran are often used. The glass transition temperature of the maximally freeze-concentrated matrix should be above −40°C for acceptable storage stability. Residual moisture and glass transition are measured by differential scanning calorimetry. For injectable solutions, the cake is reconstituted with sterile physiological saline or the approved diluent at 15–25°C in a Class II biological safety cabinet or equivalent controlled environment.

For injectable solutions, the reconstituted suspension should be used within 2 h when held at ambient temperature; longer holding requires stability data because live Pasteurella multocida viability declines rapidly outside 2–8°C. For drinking-water or premix application, the concentrated suspension is diluted into non-chlorinated water. Free chlorine at 0.2–0.5 mg/L can inactivate non-spore-forming Gram-negative bacteria; if chlorinated water is unavoidable, neutralization with sodium thiosulfate at 1.0 g per 100 L may be validated, but the buffer should not raise water pH above 7.2. Preservatives suitable for inactivated vaccines should not be assumed compatible with live EO630. Phenol and benzalkonium chloride at common antimicrobial concentrations can reduce live-cell viability; multi-dose presentations require preservative compatibility data generated specifically for the live strain.

When Formulation Routes Include Tablets, Capsules, and Oral Powders

Tableting of live bacterial concentrates introduces compaction shear, thermal stress, and surface adhesion losses. Direct compression of the lyophilized powder blended with microcrystalline cellulose having a median particle size of 100 µm and 1.0% w/w magnesium stearate can be performed on a rotary press fitted with 8 mm flat-faced punches. Compaction pressures above 100 MPa may reduce live-cell count by more than 2 log10 CFU/g; therefore compression runs should be bracketed at 40 MPa, 80 MPa, and 120 MPa and viability retested at each pressure. Published data for EO630 in this specific configuration is limited, and tablet viability cannot be assumed from powder viability.

Capsule filling into HPMC size 3 shells avoids the high shear of tableting but requires powder flow control and environmental relative humidity below 30% RH. Granules produced by twin-screw wet granulation with water at an L/D ratio of 20:1 and barrel temperature 20–25°C may preserve viability if exit moisture remains below 5% w/w and drying inlet air does not exceed 35°C. Fluid-bed drying at 30–35°C with top-spray granulation is generally less destructive than high-shear wet granulation. Dry powder carriers intended for premix should have water activity ≤ 0.3 and moisture ≤ 5% w/w. Low-shear tumble blending with geometric dilution is preferred because live lyophilized powders can segregate from coarse carrier granules and create potency non-uniformity.

Excipients for the final dosage form must be screened for toxicity to the live organism. Bulking agents such as lactose monohydrate are generally compatible if moisture is controlled. Mannitol may be used in injectable lyophilized formulations but can form crystalline phases that reduce cell survival if not combined with a disaccharide. Polyvinylpyrrolidone and hydroxypropyl methylcellulose may be used as binders for granules; their aqueous solutions should be cooled to 20–25°C before addition. Magnesium stearate at 1.0% w/w can delay disintegration of compressed tablets and should be used at the lowest effective concentration. Disintegrants such as sodium starch glycolate may function below 2.0% w/w without marked viability loss.

For tablets and capsules intended for oral administration, pharmacopoeial tests such as disintegration per Ph. Eur. 2.9.1 or USP <701> are necessary but insufficient; the dosage form must also release viable cells in the target gastrointestinal segment. Dissolution apparatus with simulated gastric fluid is not directly predictive of bacterial viability unless viability is enumerated at each time point. A sequential pH shift method simulating gastric pH 3.0 for 1 h followed by intestinal pH 6.8 for 2 h may be used for formulation screening. Gastric pH in weaned piglets is generally between 3.0 and 4.5; unprotected Gram-negative cells may lose 3–5 log10 viability within 30 min at pH ≤ 3.0. Enteric capsules with pH-sensitive coatings or feed matrices that buffer gastric contents can be considered, but EO630-specific oral survival data is limited.

Attenuation Markers and Differential Characteristics Against Inactivated Bacterins

Live EO630 is differentiated from inactivated Pasteurella multocida bacterins by retention of limited in vivo replication and by presentation of native surface antigens to the host immune system. The attenuated strain is expected to induce both humoral and cell-mediated responses; inactivated bacterins primarily stimulate antibody responses against somatic and capsular antigens. Unlike inactivated bacterins, which commonly require adjuvants such as aluminum hydroxide or oil-in-water emulsions to enhance antibody responses, the live EO630 antigen does not require a depot adjuvant. This reduces injection-site reactivity but increases the need for strict cold-chain control. The comparative position is summarized in Table 2; the table is qualitative because host-route, antigen mass, and vaccination schedule influence measured performance.

Antimicrobial therapy with agents active against Pasteurella multocida should be avoided for 5 days before and 7 days after administration of the live product unless the approved label provides different withdrawal times. Compatibility with in-feed antibiotics must be established through controlled challenge studies; tetracyclines and β-lactams at feed-use concentrations are known to inhibit Pasteurella multocida. Published data for EO630 in the presence of specific medicated premix combinations is limited.

Target animal safety is evaluated in the final formulated vaccine, not in the API alone. Safety studies in the target species should follow the current VICH target animal safety guideline and should include overdose, repeated single dose, and concurrent administration if label claims include mixing with other products. Published data for EO630 in such protocols is limited.

Storage of the unopened lyophilized cake is at 2–8°C protected from light. The reconstituted solution must not be frozen. Temperature excursions above 25°C require review of the manufacturer’s stability data; exposure above 37°C is particularly damaging to live-cell viability. Distribution packaging should include validated phase-change panels or insulated containers with temperature monitors. Once the vial seal is broken, the contents should be used in one working session; retained reconstituted material is not recommended because viability loss is time- and temperature-dependent.

Manufacturing of the live API should be performed under veterinary biological good manufacturing practice with test methods performed by laboratories accredited to ISO/IEC 17025:2017. The production facility should maintain segregated areas for live biological agents. Waste and decontamination procedures should be validated to inactivate Pasteurella multocida; recommended disinfection includes steam sterilization at 121°C for 15–20 min or validated chemical disinfectants effective against Gram-negative bacteria.