On rotary tablet press lines processing veterinary APIs, the native Artemisiae Annuae Herba Powder is rarely suitable for direct compression without granulation. The raw powder typically has a Hausner ratio above 1.45 and a bulk density below 0.35 g/cm³, which creates die-filling inconsistency at press speeds above 30 rpm. A pre-compression step is therefore introduced when the herb powder loading exceeds 15% w/w of the tablet core. Wet granulation in a high-shear mixer using 3.0% w/w PVP K30 as binder and purified water as granulation liquid reduces elastic recovery and increases bulk density to 0.52–0.60 g/cm³. Milling through a 1.0 mm conical screen with a Quadro Comil U20 at 1,200 rpm yields granules with D50 between 150 µm and 220 µm. After fluid-bed drying at product temperature 40 °C to final moisture 1.5–2.5%, the granules are blended with microcrystalline cellulose 35.0% w/w, crospovidone 2.0% w/w, colloidal silicon dioxide 0.5% w/w and sodium stearyl fumarate 0.75% w/w in a bin blender for 15 min at 12 rpm. Tablet compression on an instrumented rotary press runs at 12–18 kN main compression force with 6 kN pre-compression; ejection force is kept below 750 N to prevent edge chipping. Hardness is controlled to 5–8 kp, friability to ≤0.8% by USP <1216>, and disintegration to ≤15 min in water at 37±2 °C by USP <701>. The tablet core is adjusted by artemisinin assay so that each 500 mg tablet delivers the intended veterinary dose; assay adjustment factor = 100/label claim artemisinin. If ambient relative humidity exceeds 60%, the milled powder must be pre-dried at 40 °C for 4 h before blending because moisture accelerates both particle agglomeration and artemisinin ring degradation. The finished tablets are coated with a 3.0% w/w hydroxypropyl methylcellulose film to mask bitter terpenoid notes and to reduce dust formation during packaging.

Granulation-derived changes in compression behaviour during scale-up

Parameter	Direct compression	Wet granulation	Method
Bulk density	0.32–0.38 g/cm³	0.52–0.60 g/cm³	USP <616>
Hausner ratio	1.40–1.50	1.15–1.25	USP <1174>
Main compression force	8–12 kN	12–18 kN	instrumented press
Ejection force	>900 N	<750 N	instrumented press
Friability	0.9–1.2%	≤0.8%	USP <1216>
Disintegration time	18–25 min	≤15 min	USP <701>

What Limits Terminal Sterilization of Aqueous Injections Containing Artemisiae Annuae Herba Powder?

Terminal steam cycles of 121 °C for 15 min are avoided when artemisinin is used as the assay marker because the endoperoxide bridge is sensitive to prolonged heat in dilute aqueous solution. Published degradation data for herbal powder decoctions in this specific veterinary configuration is limited, so aseptic filtration is the preferred sterilization route. An aqueous decoction is prepared by extracting the powder in purified water at 85 °C for 120 min at a drug-to-solvent ratio of 1:10, followed by cooling to 25 °C and clarification through 0.45 µm polyethersulfone membrane. The clarified extract is adjusted to pH 6.5–7.5 with monobasic sodium phosphate, and sodium metabisulfite is added at 0.1% w/v as an antioxidant. For multi-dose vials, benzyl alcohol at 1.5% v/v is incorporated before sterile filtration through a 0.22 µm PVDF membrane. The final artemisinin concentration is adjusted to 20–50 mg/mL according to target species; cattle and equine formulations are generally at the upper end, while ovine formulations are at the lower end. Endotoxin is monitored by Ph. Eur. 2.6.14 and held below 0.5 EU/mL; sterility is confirmed by Ph. Eur. 2.6.1. Particulate matter must meet Ph. Eur. 2.9.19 for sub-visible particles, which is why raw unprocessed herbal powder cannot be aseptically filled into injectable solutions without prior extraction and filtration. The solution is stored in amber type II glass vials under nitrogen headspace and protected from light; artemisinin photodegradation is a known failure mode, and unprotected vials can show assay loss above 5.0% after 72 h of direct illumination. The injectable is intended as an adjunct in veterinary piroplasmosis protocols, not as a monotherapy; published clinical data for Artemisiae Annuae Herba Powder injectable solutions in specific parasite species is limited and should be confirmed in farm-level studies.In poultry production, the conversion of the API powder into water-reconstitutable granules must address poor wetting of the herb powder and rapid sedimentation after mixing. A wet granulation process using a fluid-bed granulator with top spray is preferred over high-shear granulation when a low-density, fast-dispersing granule is required. The powder is first milled to D90 ≤75 µm by air-jet milling; this increases active surface area but also raises electrostatic charge, so 0.5% w/w fumed silica is mixed into the dry blend before granulation. The binder solution contains 3.0% w/w povidone K30, 0.5% w/w sodium lauryl sulfate and 0.3% w/w citric acid in purified water, sprayed at 25 g/min into a Glatt GPCG 3.1 with inlet air 65 °C and product temperature 35–38 °C. After drying to residual moisture ≤2.0%, the granules are screened through a 0.8 mm sieve and immediately sealed in aluminium-laminated sachets. Reconstitution at 5 g/L in hard water with 300 mg/L CaCO₃ equivalent produces a uniform suspension when the granule formula includes 0.15% w/w xanthan gum as suspending agent; without xanthan gum, the sedimentation volume falls below 0.4 within 4 h. Dose uniformity in the resulting drinking-water solution is checked by HPLC-UV against an artemisinin reference standard, with acceptance limits of 90–110% of label claim and relative standard deviation not more than 2.0%. The target indication is support during Eimeria coccidiosis challenges in broilers, where water consumption is often elevated but erratic; therefore the drinking-water solution concentration is adjusted to deliver the intended daily artemisinin intake per kg body weight across 24 h. Any batch that fails to disperse within 3 min in standard hard water under manual stirring is rejected.

When Gelatin Capsule Filling Demands a Narrow Carr Index Window

Capsule filling of standardized Artemisiae Annuae Herba Powder requires blend flow behaviour that remains stable across multiple hopper levels, because the raw herb powder has an angle of repose often above 40° and poor compressibility. The milled powder is pre-blended with 0.5% w/w colloidal silicon dioxide in a diffusion mixer for 10 min and then passed through a 0.5 mm screen to break electrostatic agglomerates. Final blend specifications before capsule filling are Carr index 15–20%, Hausner ratio 1.15–1.25, and angle of repose 30–35°; these limits are determined by USP <1174> powder flow methodology. Hard gelatin capsules are filled on an intermittent-motion capsule machine with dosing disc thickness 2.0 mm and tamping station pressure 0.4–0.6 MPa. Fill weight variation is monitored at 15 min intervals and is rejected if the relative standard deviation exceeds 3.0%. Because artemisinin stability in capsule shells depends on moisture ingress, the capsule fill is stored with silica gel desiccant and the final capsule moisture is held below 5.0% by Karl Fischer titration. The active stratum is calculated from the lot assay; if the powder assays 1.0% artemisinin, a 250 mg capsule delivers 2.5 mg artemisinin per shell. Practitioner protocols for equine and camel piroplasmosis use these capsules in combination with supportive care; however, published controlled trial data for this specific herbal powder capsule configuration is limited, and the absence of a standardized bioequivalence model for artemisinin from whole herb powder should be confirmed before therapeutic substitution. The capsules are not enteric-coated because the target absorption site is the proximal small intestine, but storage above 25 °C accelerates release of volatile oil components and may cause shell softening.Feed mill carryover calculations for artemisinin-containing premixes must start from the lowest inclusion rate that still permits homogeneous distribution. The herbal powder is diluted geometrically in a horizontal ribbon mixer at 80% fill volume using calcium carbonate or wheat middlings as carrier. First blend: 1.0 kg API powder with 9.0 kg carrier for 10 min at 25 rpm. Second blend: the 10 kg premix is added to 90 kg carrier and mixed for 15 min. Final premix target is 10% w/w Artemisiae Annuae Herba Powder, with artemisinin concentration typically 0.1–0.2% depending on raw lot assay. Homogeneity testing uses 10 thief samples taken from different mixer zones after 12 min of final mixing; the coefficient of variation of artemisinin by HPLC-UV must be ≤5.0%. The final feed inclusion rate is 0.5–2.0 kg/tonne complete feed. Above 2.0 kg/tonne, the bitterness of the herb powder reduces feed intake in young lambs and calves, and this palatability cliff is more limiting than any regulatory carryover ceiling. A flush procedure with 5 kg ground corn per batch is established after every premix run to reduce carryover below 0.1% of the subsequent batch. The terminal products are medicated premixes for rabbits, poultry and small ruminants; each label must declare the artemisinin content, species-specific withdrawal period where applicable, and batch-specific assay result. Statements of veterinary authorization should reference the intended regional registration file; absent a specific monograph for this herbal powder, the marketing authorization holder verifies compliance with EU Regulation 2019/6 and relevant VICH guidelines.For oral drench administration, the powder is not suspended directly in water because the resulting coarse particles obstruct standard drench nozzles and cause doser pump failure. A hydroalcoholic extract is prepared by maceration in 40% v/v ethanol-water at room temperature for 72 h, then concentrated under vacuum at 50 °C to a soft extract. The extract is dissolved in a cosolvent system of propylene glycol 20% v/v, polysorbate 80 0.5% v/v and purified water, adjusted to pH 5.0–5.5 with citrate buffer. The final artemisinin concentration is set at 10 mg/mL for small ruminants and calves, and the solution is passed through 0.45 µm nylon membrane to reduce turbidity below 10 NTU. The drench is filled into 100 mL amber PET bottles fitted with low-density polyethylene adapters; headspace is flushed with nitrogen to limit oxidative degradation. Viscosity is held below 50 mPa·s at 25 °C to remain compatible with automatic drenching guns. A photostability test per ICH Q1B is used where applicable; the solution is rejected if assay loss exceeds 5.0% after 24 h exposure to cool white fluorescent light. This route is used when individual animal dosing is required for gastrointestinal nematode support or coccidial challenge in neonatal ruminants, but published efficacy data for oral drench solutions containing Artemisiae Annuae Herba Powder in target species is limited; therefore dosing should be adjusted after veterinary diagnosis and supported by faecal egg count reduction tests.