In fixed-time artificial insemination programmes applied to cow-calf operations across tropical and subtropical rangelands, injectable equine chorionic gonadotrophin is incorporated at progesterone device withdrawal rather than as a feed or drinking-water additive because ruminal and intestinal proteolysis degrade the glycoprotein before systemic absorption. The injectable solution is formulated to 1000 IU/mL in 20 mM phosphate buffer at pH 6.8–7.2 with 0.9% w/v sodium chloride; the per-animal dose in fixed-time AI protocols is generally 300 IU administered intramuscularly as 0.30 mL. Compliance for the finished injectable is anchored to Ph. Eur. monograph 0498 for equine serum gonadotrophin for veterinary use, the sterility test method of Ph. Eur. 2.6.1, endotoxin limits of Ph. Eur. 2.6.14, primary container requirements of ISO 8362-1:2018, and Commission Regulation (EU) No 37/2010 Table 1 classification as a substance for which no maximum residue limit is required. Downstream production involves hydration of the API powder in chilled water for injection at 2–8°C under low-shear stirring below 150 rpm to avoid foaming, pH adjustment with dilute hydrochloric acid or sodium hydroxide to pH 7.0, sterile filtration through a 0.22 µm hydrophilic PVDF capsule filter, and filling into 20 mL Type I borosilicate glass vials under Grade A laminar air flow with nitrogen overlay. The finished pack configuration is a 20 mL multi-dose vial containing 1000 IU/mL eCG, typically used by on-farm artificial insemination teams at a rate of 0.30 mL per cow at progesterone device removal.

What Governs Reconstitution Time and Residual Moisture in Lyophilized eCG for Ovine Herd Use?

Lyophilized eCG powders for ovine and caprine synchronization are prepared as single-dose vials because the liquid glycoprotein develops soluble aggregates and loses ovarian weight-gain activity when stored above 8°C for more than 72 h; the lyophilized format shifts the failure mode from aggregation to reconstitution behaviour. The formulation addition ratio is set at 400 IU eCG per vial with 20 mg mannitol, 2 mg dibasic sodium phosphate, and sufficient water for injection to produce a 2 mL fill before freeze drying; after reconstitution with 2 mL water for injection, the nominal concentration is 200 IU/mL. Compliance includes Ph. Eur. monograph 0498, the manufacture of sterile products under Ph. Eur. 5.1.1, residual moisture by Ph. Eur. 2.5.12 with acceptance limit below 1.0% w/w, sterility by Ph. Eur. 2.6.1, and container quality by ISO 8362-1:2018. The production line uses a stainless-steel lyophilizer with shelf temperature control at −40°C for the freezing step, primary drying at −25°C and 80–100 µbar chamber pressure for 18–24 h, secondary drying at +25°C until the chamber pressure drops below 20 µbar; partially stoppered vials are seated with nitrogen backfill before leaving the lyophilizer. The output of this line is a 6 mL Type I tubing vial containing a white to off-white lyophilized plug equivalent to 400 IU eCG, supplied with a 2 mL WFI diluent ampoule or prefilled syringe for intramuscular administration in sheep and goats at sponge removal.

For replacement gilts that fail to exhibit standing estrus by 7.5–8.0 months of age, co-formulated equine chorionic gonadotrophin and human chorionic gonadotrophin are administered as a single intramuscular injection to induce follicular maturation and ovulation without requiring detection of natural estrus. The addition ratio in this porcine application is 400 IU eCG and 200 IU hCG per 5 mL dose, yielding an eCG concentration of 80 IU/mL and an hCG concentration of 40 IU/mL in a phosphate-buffered saline vehicle at pH 7.0–7.4. Compliance relies on Ph. Eur. monograph 0498 for the eCG component, Ph. Eur. monograph 0496 for the hCG component, Ph. Eur. 2.6.1 sterility, Ph. Eur. 2.6.14 bacterial endotoxin limits, and ISO 8362-1:2018 Type I glass vial certification. Downstream production follows a two-stage compounding sequence in which hCG is dissolved first in a cooled buffer tank at 2–8°C under 100 rpm paddle mixing for 15 min, eCG is then added and mixed for an additional 10 min, and the solution is sterilized by filtration through a 0.22 µm PVDF membrane before aseptic filling into 5 mL Type I glass vials at a line speed of 30–40 vials/min; no terminal heat sterilization is applied because both glycoproteins are heat-labile. The primary pack configuration is a 5 mL single-dose vial containing 400 IU eCG and 200 IU hCG, intended for intramuscular injection in gilts under veterinary supervision.

High-Potency eCG Solutions for Multiple Ovulation in Embryo Transfer Programmes

In embryo transfer donor programmes, the addition of eCG at 2000–3000 IU per donor is used to promote recruitment of a cohort of ovarian follicles after a progesterone priming phase, but the high-potency solution must be formulated without preservatives to avoid local irritation at the injection site. The formulation addition ratio is 1000 IU/mL in 20 mM sodium phosphate buffer at pH 6.8–7.2 with 0.9% w/v sodium chloride; each donor receives 2.0–3.0 mL intramuscularly according to breed and ovarian reserve assessment. Regulatory compliance is established by Ph. Eur. monograph 0498, Ph. Eur. 2.5.12 for residual moisture of the API powder, Ph. Eur. 2.6.1 sterility, Ph. Eur. 2.6.14 endotoxin limits, and Commission Regulation (EU) No 37/2010 Table 1 classification as a substance for which no maximum residue limit is required. Production of the high-potency solution occurs on a dedicated small-batch filling line; after pH adjustment to 7.0, the bulk solution is filtered through a 0.22 µm polyethersulfone membrane, filled into 10 mL Type I glass vials with nitrogen overlay, and immediately transferred to a cold room at 2–8°C. The resulting pack instrument is a 10 mL single-use vial containing 1000 IU/mL eCG, intended exclusively for embryo transfer practitioners and veterinary reproductive specialists.

Compounded sterile preparations derived from serum gonadotrophin API powder in veterinary hospital pharmacies fall outside large-scale good manufacturing practice but are still prepared under controlled cleanroom conditions because the final solution is injected intramuscularly and cannot be terminally sterilized. A common compounding formulation uses 500 IU eCG per 1 mL final volume in 0.9% w/v sodium chloride injection, drawn from a sterile API powder vial and passed through a 5 µm filter needle to remove any undissolved particulate; no antimicrobial preservative is added, and the preparation is assigned a beyond-use time of 12 h at 2–8°C. The applicable standard for this process is USP Chapter <797> for low-risk compounded sterile preparations with single-dose vials, supported by FDA 21 CFR 210 and 211 current good manufacturing practice principles for reference materials and by Ph. Eur. monograph 0498 for the API quality. Production in the pharmacy setting includes surface disinfection of the vial stopper, withdrawal of diluent with a sterile syringe, slow injection of diluent into the eCG powder vial along the glass wall to avoid foaming, gentle swirling at room temperature for 30–60 s, drawing into individual 1 mL Luer-lock syringes under an ISO Class 5 laminar-airflow hood, and immediate labeling with species, dose, and expiration time. The dispensed terminal unit is a 1 mL single-dose Luer-lock syringe containing 500 IU eCG, intended for extemporaneous use in small ruminant or camelid reproduction protocols under veterinary prescription.

When Low-Dust Granulated eCG Intermediates Are Used for Aseptic Vial Filling Instead of Micronized Powder

Granulation of eCG with mannitol and trehalose produces a free-flowing intermediate with a particle size distribution of 125–500 µm, which reduces dust generation and improves fill-weight consistency in automated vial filling lines; this is an intermediate for injectable reconstitution, not an oral premix or feed application. The granulation blend is formulated to deliver 500 IU eCG per 100 mg granule fill, with 8% w/w mannitol and 1% w/w trehalose as stabilizers; after reconstitution with 2 mL water for injection, the concentration is 250 IU/mL. Compliance for the granule intermediate references Ph. Eur. monograph 0498, Ph. Eur. 5.1.1 for sterile preparation methods, Ph. Eur. 2.5.12 for moisture determination below 1.5% w/w, and ISO 8362-1:2018 for the final Type I glass vial container. The production process uses dry granulation at controlled relative humidity below 20% RH and a product temperature not exceeding 25°C because aqueous wet granulation would hydrate the glycoprotein and accelerate deamidation; slugging or roller compaction is followed by sieving through 125 µm and 500 µm screens, and the sized granules are filled into 6 mL Type I vials using a gravimetric dosing head. Oral tablets, capsules, granular premix, and medicated feed applications are not appropriate terminal dosage forms for this glycoprotein because pepsin at gastric pH 1.5–3.0 and trypsin at intestinal pH 7.5–8.0 cleave the heterodimeric structure before absorption; the granule intermediate is therefore exclusively a sterile-process starting material. The configured fill outcome is a 6 mL Type I tubing vial containing 100 mg granulated eCG intermediate equivalent to 500 IU, partnered with a 2 mL diluent ampoule for reconstitution into an injectable solution.

In postpartum anestrus of high-yielding dairy buffalo maintained under intensive management in South Asian and Mediterranean production systems, eCG is administered as part of an Ovsynch-based fixed-time AI protocol at the moment of prostaglandin F2α administration, but the injectable must be supplied in packaging that minimizes repeated entry into the vial under farm conditions. The formulation addition ratio for buffalo protocols is 400–600 IU eCG per animal, drawn from a 1000 IU/mL solution as 0.40–0.60 mL; the vehicle is 20 mM sodium phosphate at pH 6.8–7.2 with 0.9% w/v sodium chloride. Compliance includes Ph. Eur. monograph 0498, Ph. Eur. 2.6.1 sterility, Ph. Eur. 2.6.14 bacterial endotoxin testing, ISO 8362-1:2018 for Type I glass vials, and Commission Regulation (EU) No 37/2010 Table 1 for absence of a maximum residue limit for natural protein hormones. Downstream production for this pack format uses a small-batch aseptic filtration skid equipped with a 0.22 µm PVDF cartridge, a mass-flow-controlled nitrogen purge before filling, and 50 mL Type I glass vials closed with chlorobutyl stoppers; the line is validated for filling accuracy at ±1% of target volume. The finished multi-dose veterinary unit is a 50 mL vial containing 1000 IU/mL eCG, supplied to veterinary distributors serving dairy buffalo improvement programmes and typically administered at 0.40–0.60 mL per animal with a sterile disposable needle and syringe.