On broiler farms with high-capacity nipple drinker lines, the concentrated liquid API is normally administered through a proportioning medicator. The incoming barrel is checked for baicalin content, and the dilution factor is set only after the certificate of analysis is reviewed. At a baicalin assay of 3.0 mg/mL, the working concentration in drinking water is 1.0 mL/L to 2.0 mL/L. The stock solution is prepared at 1:50 v/v in a separate tank because direct dosing from the barrel causes pump pulsation and uneven delivery. Free chlorine above 2.0 ppm oxidizes berberine-type alkaloids; the water is therefore held in a carbon-filtered buffer tank until residual chlorine falls below 0.3 ppm. The pH is maintained between 5.8 and 6.5 with a citric acid-sodium citrate buffer. At pH below 4.2, insoluble precipitates form and block nipple drinkers. The prepared solution is discarded after 8 h when ambient temperature exceeds 28°C. The terminal product is a drinking-water medication for flocks; each batch must be released with a microbial limit of aerobic plate count below 1000 CFU/mL and absence of Salmonella in 10 mL. EU Regulation 2019/6 requires that the target species and withdrawal period be stated in the marketing authorisation.

What Compression Parameters Prevent Lamination in Herbal Extract Tablets?

Tablet compression of dry-sprayed Sanhuangweng liquid extract is constrained by the plastic deformation behaviour of the dried solids. When the liquid API is spray-dried onto a maltodextrin-starch carrier to 25% w/w dry solids, the resultant powder is passed through a 0.8 mm screen before dry blending. Direct compression is restricted to an extract load below 20% w/w; above this level, tablet hardness falls and capping increases. Wet granulation with 2.5% w/w hydroxypropyl methylcellulose solution is preferred for extract loads of 20–30% w/w. The granulation is dried to residual moisture below 2.5% w/w. Croscarmellose sodium at 3.0% w/w is added extragranularly to obtain disintegration below 30 s at 37°C. A 16-station rotary press with B-tooling operates between 20 kN and 35 kN. Production batches above 40 kN show lamination. Target tablet hardness of 60–90 N gives friability below 0.8% after 100 revolutions per USP <1216>. Dissolution testing is performed with 900 mL of pH 6.8 phosphate buffer at 50 rpm using USP <711> apparatus II; not less than 75% of labeled baicalin releases within 45 min. The terminal product is an oral tablet for swine, with the dose calculated from bodyweight and the labeled extract quantity.

Injectable formulations built around a herbal decoction-type extract introduce constraints that tablet and premix processes do not encounter. The liquid API as supplied is not sterile and may contain plant-derived polysaccharides, tannins, and pyrogens. Aseptic filtration is the only reliable sterilisation method when the filtered solution has a turbidity below 5 NTU. The extract is first cooled to 2–8°C and held for 12 h to allow suspended mucilage to settle. It is then passed through a 0.45 µm polyethersulfone filter and subsequently through a 0.22 µm membrane under a differential pressure not exceeding 1.0 bar. For isotonicity, sodium chloride is added to 0.9% w/v; pH is adjusted to 5.5–6.5 with diluted hydrochloric acid or sodium hydroxide. Terminal steam sterilisation at 121°C for 15 min is not recommended for this configuration because published stability data for baicalin and berberine under saturated steam are limited, and brown discolouration is observed in some development batches. The finished solution is filled into 10 mL neutral glass vials under nitrogen. Sterility is tested according to USP <71>, bacterial endotoxins according to USP <85>, and sub-visible particles according to USP <788>.

Fluidised-bed granulation yields a low-dust premix for in-feed medication.

A top-spray fluidised bed granulator is charged with 40 kg of a mixed carrier composed of corncob meal and lactose monohydrate in a 4:1 ratio. The liquid API is sprayed at an inlet air temperature of 60–70°C and an outlet air temperature of 35–40°C. The spray rate is maintained between 200 g/min and 300 g/min; higher rates lead to local overwetting and agglomerate formation. The target liquid load is 10% w/w on dry carrier, giving a free-flowing premix that passes through a 0.8 mm sieve. A 5% w/w aqueous polyvinylpyrrolidone K30 solution serves as binder; the total binder volume is divided into three equal portions and added at 10 min intervals to avoid crusting on the filter bags. The granulated premix is dried to final moisture below 3.5% w/w. Mixing uniformity in a double-ribbon blender is tested by near-infrared spectroscopy; the coefficient of variation for baicalin must remain below 5% in 10 sampling points. The terminal product is an in-feed premix for swine and poultry, incorporated at 5–10 kg/t of complete feed depending on the registered dosage. The premix must be released under EU Regulation 2019/6 for medicated feed or under local 21 CFR 558.5 if intended for US medicated feed applications.

Capsule filling limits and hygroscopicity thresholds for companion-animal oral use.

Hard gelatin capsule filling of the spray-dried extract is limited by tap density and moisture sensitivity. The dried powder is milled to a particle size below 0.25 mm and blended with 1% w/w colloidal silicon dioxide to improve flow. The tap density is measured according to USP <616>; target values between 0.45 g/mL and 0.60 g/mL allow reproducible filling on a dosator-type capsule machine. Capsule size 0 is chosen for unit doses up to 350 mg; size 1 is used for lower doses. The powder moisture is held between 3.0% w/w and 4.0% w/w because higher moisture causes gelatin crosslinking and delayed disintegration. Disintegration is tested in water at 37°C with discs according to USP <701>. The finished capsules are tested for uniformity of dosage units according to USP <905>. The terminal product is an oral capsule for cats and dogs under veterinary prescription.

Ruminant oral drench formulations require a higher buffering capacity than poultry drinking water because rumen-reticulum pH is acidic. The drench is prepared by diluting the liquid API to 20% v/v in a vehicle containing 0.5% w/v sodium carboxymethylcellulose and 0.1% w/v potassium sorbate. The viscosity target is 150–300 mPa·s at 25°C to permit passage through a standard drenching nozzle without dripping. Propylene glycol is included at 10% v/v as a co-solvent and mastication-safe carrier. The buffer system uses sodium citrate and citric acid to hold pH between 5.5 and 6.5; this range prevents precipitation of berberine alkaloids during storage at 5°C. Calves, lambs, and kids receive the drench by oral syringe; the dose volume is calculated from the labeled marker content and the target daily intake per kilogram of bodyweight. The terminal product is a viscous oral drench for ruminants, packaged in amber high-density polyethylene bottles.

When pellet feed temperature exceeds 75°C, the carrier-protected powder is selected over the unprocessed liquid.

Thermal exposure during feed pelleting is the main process conflict for this liquid API. Unprotected liquid extract added to the mixer before pelleting degrades sharply when conditioned meal temperature exceeds 75°C; baicalin recovery can fall by more than 15% within 30 min at 85°C. The carrier-protected powder is therefore used for pelleted feed. The powder is prepared by adsorbing the liquid API onto a calcium carbonate-silica blend at 15% w/w; the adsorbent mass is chosen to maintain a free-flowing state. The powder is introduced post-pelleting through a rotary feeder if the pellet die emits pellets above 80°C, or pre-pelleting when conditioning time is below 10 s. The final feed concentration is adjusted to deliver 1.0–2.0 L of original liquid API per tonne of complete feed. Feed homogeneity is confirmed by tracer studies using riboflavin; the coefficient of variation across 12 production samples must remain below 5%. Feed mills producing this product in the EU fall under Regulation EC 183/2005 and EU 2019/4 for medicated feed. The terminal product is a pelleted complete feed or top-dressed premix for food-producing animals.