Lizhong Powder Veterinary Grade API is a spray-dried, multi-component botanical active pharmaceutical ingredient intended for incorporation into tablets, injections, capsules, powders, granules, premixes, and solutions. The manufacturer’s specification dossier designates model LZP-VG-100 for oral solid and dry-mix applications, and model LZP-VG-200 for liquid and parenteral use after additional purification. The extract ratio is stated as 4:1 for the oral grade and 5:1 for the parenteral grade. The product differs from a crude herb powder in that extraction, vacuum concentration, and spray drying remove insoluble plant cell debris, reduce bioburden, and concentrate marker compounds into a controlled range. The powder is not an excipient; it is an active pharmaceutical ingredient with a multi-component chemical fingerprint.

Routine quality control identifies and quantifies marker compounds by high-performance liquid chromatography. The marker set includes 6-gingerol, glycyrrhizic acid, and atractylenolide I. Because the product is a complex botanical matrix, release is not based on a single active entity mass balance. Instead, the HPLC fingerprint similarity must meet an acceptance criterion of 0.95 or greater against the reference chromatogram, and individual marker content must fall within 90%–110% of the label claim. This is a fundamental difference from synthetic single-entity veterinary APIs, which are released by assay of one chemical entity and related-substance profiling.

Pharmacopoeial identity and standardization limits

Release specifications parallel the general methods of the Chinese Veterinary Pharmacopoeia and relevant USP General Chapters. Loss on drying is tested by ChP 2020 <0831> with a limit of 5.0% for LZP-VG-100 and 3.0% for LZP-VG-200. Total ash and acid-insoluble ash are tested by ChP 2020 <2302> and ChP 2020 <2303>; the oral grade allows 5.0% total ash and 1.0% acid-insoluble ash. Heavy metals are tested by ChP 2020 <0821> with a limit of 10 mg/kg for LZP-VG-100 and 5 mg/kg for LZP-VG-200. Arsenic is tested by ChP 2020 <0822>. Microbial enumeration follows ChP 2020 <1105> and ChP 2020 <1106>. The oral grade permits total aerobic microbial count ≤1,000 CFU/g; the parenteral grade permits ≤100 CFU/g. Escherichia coli and Salmonella must be absent in 1 g for both grades. Bacterial endotoxin testing by ChP 2020 <1143> is required for LZP-VG-200 with a limit of <0.5 EU/mg.

During dry blending, the powder’s flow and compressibility are evaluated according to USP <616>. Hausner ratio values between 1.25 and 1.35 are reported for LZP-VG-100, with Carr index between 20% and 26%. These values indicate passable flow that is sufficient for low-speed filling but requires colloidal silicon dioxide or dibasic calcium phosphate in high-speed tablet pressing. On a rotary tablet press equipped with a forced feeder, tablet blends containing 25–35 wt% API and 0.5 wt% glidant maintain weight variation below 2.0% at press speeds up to 40 rpm. Direct compression at higher API loadings is not recommended because fibrous botanical residue increases ejection force and can cause capping at compression pressures above 25 kN.

For wet granulation, the API is dry-mixed with fillers and granulated with purified water or a 2–5 wt% polyvinylpyrrolidone solution. Product temperature during fluid-bed drying is controlled at 40–45°C; inlet air temperature is set at 65–75°C. Thermal exposure above 60°C for more than 4 h reduces 6-gingerol content by approximately 8%–12% based on forced degradation data. Therefore, the dryer is not operated at higher inlet temperatures even when moisture throughput is limited. Capsule filling at 20,000 capsules/h on a dosator machine requires a granule bulk density of 0.60–0.75 g/mL to avoid inconsistent fill weight. For direct powder filling, the fine particle fraction below 45 µm should remain below 15% to minimize segregation and dusting.

When Lizhong Powder Veterinary Grade API Is Selected for Injection Solutions

Parenteral manufacturing imposes stricter requirements on bacterial endotoxin, particulate burden, and aqueous solubility. LZP-VG-200 is processed through additional liquid-liquid extraction, centrifugation, and activated carbon treatment before spray drying. Solutions are prepared by dispersing the powder in water for injection at 35–40°C under low-shear mixing; direct addition to a high-shear mixer without pre-wetting causes lump formation and extends final filtration time from 12 min to 48 min on a 500 L batch. The solution is filtered through 0.45 µm followed by 0.22 µm PVDF membranes. The pH of the final solution is maintained between 5.5 and 6.5. At pH below 4.0, visible precipitation of flavonoid glycosides and polysaccharide complexes may occur; at pH above 8.0, browning and marker loss accelerate.

Thermal sterilization is restricted. Autoclaving at 121°C for 15 min reduces glycyrrhizic acid peak area by 10%–15% and shifts the HPLC fingerprint similarity below 0.90 in unbuffered aqueous solution. Sterile filtration is therefore the preferred method for parenteral preparations. The API should not be mixed with amino acid infusions or amine-based additives unless compatibility is first confirmed, because Maillard-type reactions can consume reducing moieties and lower marker content. Oxidizing agents and strong alkaline buffers are considered incompatible.

For premix and granule production, the LZP-VG-100 grade is incorporated at 2–20 kg/t depending on species and therapeutic dose. The fine particle fraction below 45 µm is kept below 15% to minimize dusting and segregation in twin-shaft paddle mixers. Segregation studies on production-scale mixers with 1,000 kg batch size show that addition of vegetable oil at 0.5 wt% reduces active marker variability from 6.5% to 2.8% relative standard deviation after 10 min mixing. These data support a hold time of 20 min at 25 rpm mixer speed for coated premixes.

For oral solutions and drench products, the LZP-VG-200 grade is preferred because its finer particle size and lower ash content reduce sediment. Solutions at 20 mg/mL are prepared in a co-solvent system of propylene glycol and purified water, chilled to 10°C for 24 h to precipitate high-molecular-weight polysaccharides, and then filtered through 1 µm polypropylene depth media. Without cold settling, visible sediment appears within 72 h at 25°C. The use of cyclodextrin inclusion at 2–4 wt% has been reported to improve clarity, but published stability data for this specific veterinary configuration are limited.

What Separates This API from Crude Powder and Synthetic Single-Entity Materials?

Crude Lizhong powder contains the same botanical species but is not standardized for marker content, and its microbial load can exceed 10,000 CFU/g. The veterinary API specification reduces that burden by one or two log10 units and sets heavy-metal ceilings. In addition, the spray-dried product has controlled particle size, while crude powder has irregular morphology and poor flow. The difference from synthetic single-entity APIs lies in the analytical strategy: a single HPLC peak cannot define potency, so the release method uses fingerprint similarity and multiple marker limits. This multi-component character also means that dissolution testing in 0.1 M hydrochloric acid or phosphate buffer pH 6.8 may not be fully predictive of in vivo absorption; published data for species-specific dissolution-performance relationships are limited.

Packaging in aluminum foil laminate bags with desiccant is specified to maintain residual moisture below 5.0% during storage at 15–25°C and relative humidity ≤60%. The manufacturer’s retest interval is 24 months for unopened containers. Once opened, the material should be used within 30 days or re-tested for moisture and microbial limits before use. The main operational boundary is moisture ingress: at relative humidity above 60%, pre-drying at 40°C for 2 h is recommended before dry blending or tablet compression. If injection-grade material is exposed to ambient humidity, endotoxin and particulate controls may no longer be valid, and the material should be quarantined pending re-evaluation.

Solution and premix manufacturers should treat this API as a hygroscopic, thermally sensitive multi-component system rather than a free-flowing synthetic chemical. Batch-to-batch variance is controlled through fingerprint similarity and marker limits, but process validation must be repeated when the source of botanical raw materials changes. The product is compatible with common oral solid fillers and standard granulation equipment, provided that moisture, thermal exposure, and pH boundaries are maintained within the stated ranges. For parenteral applications, sterile filtration and strict endotoxin control are non-negotiable quality gates, and compatibility with co-administered veterinary drug products must be confirmed before terminal formulation lock.