Wanrukang Veterinary Grade API is screened through a 40-mesh sieve before tablet blending. Flowability is determined with a Flodex tester or ring shear cell. The resulting flow function coefficient sets the dry-binder level. When a 10–15% w/w API load is specified for a 200 mg tablet, the remainder is split between microcrystalline cellulose, anhydrous dibasic calcium phosphate, croscarmellose sodium, and 0.5–1.0% w/w magnesium stearate. Particle size is reduced in a cone mill fitted with a 0.8 mm round screen. Bulk density is tuned to 0.45–0.65 g/cm³ by spray-dried lactose addition. Water activity of the final blend is monitored at 25 °C; a value below 0.4 is used to prevent hydrolytic degradation of moisture-sensitive batches. Wet granulation is run in a 250 L high-shear granulator with impeller tip speed 3–6 m/s. The wet mass is dried at 55–65 °C inlet air until loss on drying reaches 1.5–2.5%. Dried granules are compressed on a rotary press fitted with D-tooling. Precompression force is 3–5 kN. Main compression force is held at 8–15 kN, producing tablet hardness of 50–100 N. Ejection force above 2.5 kN triggers additional lubricant or punch surface correction. Tablet weight variation is maintained at ±2.0%. Content uniformity is checked by USP 905 with acceptance value ≤15.0. Disintegration follows USP 701 with a limit of ≤15 min in water at 37 °C. Friability is tested according to USP 1216 using a 100-drop drum; the release limit is ≤1.0%. Residual solvent levels are checked against VICH GL18 by headspace GC when ethanol is used as the granulation solvent. The finished tablets are packed in aluminum/aluminum blisters and labeled for oral administration in the approved target species.

Why capsule fill weight drift occurs when API particle size exceeds 100 µm

Hard gelatin capsule filling uses dosator or tamping-pin technology. Fill weight drift occurs when the API particle size exceeds 100 µm because dosator retention relies on interparticle friction. The API is therefore milled with a jet mill or pin mill to D90 ≤100 µm. A 25 mg active dose in a 250 mg fill weight capsule gives an active load of 10% w/w. Lactose monohydrate or pregelatinized starch forms the filler. Colloidal silicon dioxide is used at 0.5–1.0% w/w to improve flow. Magnesium stearate is limited to 0.5–1.0% w/w to avoid dissolution slowdown. Empty gelatin shell moisture is controlled at 13–16% to avoid deformation. The filling suite is held at 20–25 °C and 35–45% RH. Fill weight is monitored every 15 min on the automatic capsule machine. Weight variation is checked according to Ph. Eur. 2.9.5 or USP 2091. Dissolution is performed at 37 °C in 0.1 N hydrochloric acid using USP 711 apparatus 2 at 50 rpm. Shell brittleness or cross-linking is evaluated after storage at 25 °C/60% RH and 40 °C/75% RH. Packaging in PVC/PVDC blisters with desiccant is adopted when moisture uptake exceeds 1.5% within 24 h. Finished capsule products are used for companion animal oral therapy where unit dosing must be exact.

Preparing a sterile parenteral dose from Wanrukang Veterinary Grade API begins with a solubility screen in Water for Injection, citrate buffer, pH-adjusted WFI, and co-solvent systems. A 5% w/v injectable solution corresponds to 50 mg/mL API. The solution pH is adjusted with 0.1 M sodium hydroxide or hydrochloric acid to the range specified in the product dossier. Osmolality is corrected with sodium chloride to 280–330 mOsm/kg for intramuscular or subcutaneous administration. The compounded solution is clarified through a 0.45 µm prefilter and sterilized through a 0.22 µm PVDF or PES membrane. Terminal sterilization at 121 °C for 15 min is acceptable when forced degradation data show a shift of ≤2.0% peak purity. If the shift exceeds 2.0%, aseptic filtration is selected. Parenteral manufacturing is conducted in an ISO 5 aseptic zone under ISO 14644-1. For terminal sterilization, the autoclave cycle is qualified with Geobacillus stearothermophilus biological indicators. F0 must reach ≥15 min at 121.1 °C. For aseptic filtration, filter integrity is tested by bubble point or diffusion before and after filling. Sterility is confirmed by membrane filtration according to USP 71. Bacterial endotoxins are controlled according to USP 85; the limit is calculated from the maximum species dose and body weight. Subvisible particulate matter is measured by light obscuration according to USP 788. Fill volume is checked per USP 1. Hold time between bulk solution preparation and filling is limited to ≤4 h unless stability and bioburden data support longer. The solution is packaged in Type I glass vials with bromobutyl rubber stoppers. Leak testing by vacuum decay is performed on 100% of critical batch vials. Extractables and leachables are assessed under USP 1663. Published data for this specific configuration is limited beyond the standard pH and co-solvent ranges; forced degradation screening is therefore required for any formula change. Finished injection products are used in veterinary clinics when rapid systemic exposure is required.

Water-soluble powder dispersion and the D90 cut-off in high-throughput poultry lines

For drinking-water medication, the API is dry-blended with dextrose monohydrate or lactose to produce a water-soluble powder. A 20% w/w powder delivers 200 mg/g. Hard-water solubility is tested at a 2 mg/mL target concentration in pH 7.2–8.0 water. If clarity falls below target, sodium carbonate or citrate buffer is included. The blend is milled to D90 ≤150 µm so that a 1 kg sachet disperses within 60–90 s under 150 rpm mechanical stirring in a 1,000 L dosing tank. Total hardness above 200 mg/L as CaCO3 is managed with citric acid to avoid calcium-API precipitate formation. Blending uniformity is verified by sampling 10 points from the V-blender; target coefficient of variation is <5.0%. Loss on drying is checked by USP 731; target is <1.0%. The reconstituted solution is held under normal drinking water conditions and sampled at 0, 2, 4, and 8 h; API content must remain within 90–110% of initial. Medicated water lines are flushed after treatment to a residual API level below 0.1 ppm before switching to plain drinking water. Packaging line residue is validated to a carryover limit of ≤10 ppm of API in the next product. End products include 100 g, 500 g, and 1 kg foil-lined sachets used in poultry or swine water medication.

Granules are selected over powders when dust containment and flow into measuring scoops become unreliable. Wanrukang Veterinary Grade API is sprayed with a povidone K30 binder solution in a fluid-bed granulator at inlet air 60–70 °C. Active content is set by the approved dose; a 5% w/w granule contains 50 mg/g. The wet granules are dried to moisture content <1.0%. The dried mass is passed through an oscillating sieve; the target cut is between 20-mesh and 60-mesh, and fines below 15% are recycled. Loss on drying is checked against USP 731. Bulk density is adjusted to 0.5–0.7 g/cm³ for stick-pack filling. Granule friability is measured in a friabilator with 100 rotations; target weight loss is <5%. Dissolution is performed at 37 °C in 900 mL purified water with paddle speed 50 rpm according to USP 711 apparatus 2. Stability samples are stored at 25 °C/60% RH and 40 °C/75% RH in aluminum-lined pouches. Bulk material is transferred with vacuum conveyors to limit dust exposure below 1 µg/m³ in the packing room. Finished forms include in-water granules for calves and oral dosing granules for small animals.

When a 20% w/w premix is diluted at farm level, segregation becomes a finished-feed risk

For medicated feed, the API is manufactured into a premix on a carrier such as calcium carbonate, wheat middlings, or soybean hulls. A 5% w/w or 20% w/w premix is prepared and then diluted in a ribbon mixer at the feed mill. The target level in complete feed is fixed by the approved daily dose and feed intake. Under 21 CFR 226, a Type A medicated article is limited to the level set in the approved product dossier. In the EU, the intermediate product is covered by EU Regulation (EU) 2019/4. Mixer homogeneity is validated by assaying 10–12 grab samples per batch; the coefficient of variation between samples must remain <5.0%. Carryover control is implemented under EU Regulation (EU) 2019/4 and 21 CFR 225. Cleanout sampling must show residual API below the validated carryover limit before a non-target feed is produced. Segregation risk rises when the API-carrier particle size difference exceeds 300 µm; sieve analysis is therefore mandatory for each carrier lot. A 1:100 dilution of a 20% w/w premix requires active content calculation for the complete feed dose. After final mixing, samples are pulled from the discharge by an automatic sampler and analyzed by HPLC or LC-MS/MS. Final feed is tested for particle size, moisture, and active content before release; retained samples are stored for the shelf life plus 12 months. The premix is packed in multi-wall paper bags with a moisture barrier. The finished medicated feed is labeled with species restriction, withdrawal period, and storage instruction.

Oral solutions require a fully dissolved API in a vehicle composed of purified water, propylene glycol, and a nonionic surfactant such as polysorbate 80. Propylene glycol content ranges from 5–30% v/v based on solubility data. If ethanol or benzyl alcohol is used, the residual content is checked against VICH GL18 for Class 3 solvents. A 1 g/100 mL oral solution contains 10 mg/mL API. Benzoic acid or potassium sorbate is added at 0.05–0.2% w/v for preserved multi-dose containers. Preservative efficacy is tested according to Ph. Eur. 5.1.3 at 0, 7, 14, and 28 days. The pH is adjusted to keep the API ionized and soluble. Precipitation is checked after 72 h at 2–8 °C and at 25 °C/60% RH. Light stability is tested under ICH Q1B conditions; amber PET or glass bottles are used when photodegradation exceeds 2.0% after 1.2 million lux-hours and 200 Wh/m² UV exposure. Specific gravity is set to 0.98–1.05 g/mL to support reliable volumetric dosing. Dosing accuracy is verified by delivered-dose weight; target is ±5% of label claim. Finished oral solutions are used as drench solutions, liquid feed additives, or pump-dose formulations for swine and poultry.