Huanglian Granules Veterinary Grade API is a standardized dried extract of Rhizoma Coptidis prepared as a granular active pharmaceutical intermediate for downstream manufacture of tablets, injections, capsules, powders, granules, premixes, and solutions. The product is supplied under model designation HL-VET-API-G-2207 for the spray-dried granular form and HL-VET-API-G-2210 for the vacuum-dried granular form with reduced residual solvent. It is not a final dosage form and is not labelled as sterile. The granule contains the native protoberberine alkaloid fraction, including berberine hydrochloride, palmatine hydrochloride, jatrorrhizine, and coptisine, in a dried extract matrix. Release criteria are set for total protoberberine alkaloids calculated as berberine hydrochloride, individual berberine hydrochloride content, loss on drying, acid-insoluble ash, heavy metals, arsenic, residual solvents, and microbial load. Because the same granule cannot simultaneously meet all finished-form requirements, the model code, particle-size cut, and endotoxin burden are selected before drying. Tablet and capsule grades are milled to a volume mean diameter of 80–150 µm; premix grades are sieved to 150–420 µm to reduce segregation in mash feed; injection grades require further depyrogenation and sterile filtration after dissolution, because the intact granule is not injectable.

Specification Profile and Pharmacopoeial Alignment

Because the granule is a multi-alkaloid botanical intermediate, the release profile is divided into chromatographic composition, inorganic safety, and microbiological quality. The method platform is high-performance liquid chromatography with diode-array detection for alkaloid quantification, combined with compendial limit tests. The following table lists representative release criteria used when the product is ordered as a non-sterile veterinary API.

When the intended use is injection, an additional bacterial endotoxin criterion of <0.50 EU/mg is applied to the solution before filling, not to the dry granule as shipped. The dry granule is not depyrogenated by default. Because contract granulation conditions can shift total alkaloid recovery, each lot should be confirmed against the certificate of analysis before use in finished-product manufacture.

For injectable formulations, the limiting factor is not alkaloid content but the combination of bacterial endotoxin burden, insoluble particulate matter, and cold-water dissolution behaviour. The dry granule is manufactured as a non-sterile intermediate; therefore, direct reconstitution and aseptic filling without depyrogenation is outside its operational boundary. Injection-grade manufacture requires dissolution in heated water at 60–80 °C, pH adjustment to 3.0–4.0 with a pharmaceutically acceptable acid, activated-carbon treatment at 0.1–0.3% w/v for 20–30 min, followed by filtration through 0.45 µm and 0.22 µm membrane filters and terminal sterilisation only after degradation studies. Sterile filtration removes insoluble extract matrix but not all endotoxin; depyrogenation must be demonstrated by bacterial endotoxin testing per CPV 2020 1143. The pH-dependent stability of berberine hydrochloride in aqueous solution is the principal reason that autoclaving profiles must be developed for each formulation. Published degradation data for this specific multi-alkaloid granule in injectable vehicles are limited, so forced degradation and photostability studies are required before a terminal sterilisation cycle is selected.

When the Granule Is Intended for Tablet or Capsule Blending

Tablet and capsule manufacture exposes the granule to compaction stress, flow constraints, and moisture-related defects. Direct compression is possible only when the granule has a tapped density of 0.45–0.65 g/mL, an angle of repose below 35°, and a loss on drying below 5.0%. If loss on drying exceeds 5.0%, punch sticking and picking are observed on rotary tablet presses; if moisture falls below 1.0%, capping and lamination become more frequent. A typical direct-compression matrix blends the granule with microcrystalline cellulose at 20–40% w/w, crospovidone at 2–5% w/w, colloidal silicon dioxide at 0.5–1.5% w/w, and magnesium stearate at 0.5–1.0% w/w. For wet granulation, a high-shear mixer or fluid-bed granulator is used; the binder solution is sprayed at product temperature 30–40 °C, and the drying inlet air is maintained at 60–70 °C to avoid thermal degradation. Tablet disintegration is controlled to ≤15 min in 0.1 M hydrochloric acid using the apparatus described in CPV 2020 0921. Capsule filling requires a granule with a Carr index below 25 and consistent bulk density to maintain fill weight variation within ±5%. After compression or encapsulation, the finished product should be protected from light because berberine-related alkaloids undergo photolytic fading.

Across the seven finished-form routes, the same granule lot can be used only after verifying a small set of grade-specific parameters. The following matrix summarises the critical granule property for each route.

In mash feed and mineral premixes, the principal failure mode is segregation, not chemical instability. The spray-dried granule is hygroscopic and should be stored below 60% relative humidity; above this threshold, the surface may cake and the sieve profile may shift. Premix grades are typically blended with ground corn, rice hulls, or calcium carbonate carrier to a target total alkaloid concentration determined by the veterinarian and the target species. Published dosing data for this specific granule across all veterinary species are limited; the inclusion rate must be derived from the assayed total alkaloid content and the prescribed berberine dose. To reduce segregation, the granule is sieved to 150–420 µm, and the carrier particle-size distribution is matched so that the mean diameter ratio is not greater than 3:1. Batch-to-batch variation in particle-size span above 1.8 has been observed to cause alkaloid assay drift at the top and bottom of V-blender discharge. Sampling plans should therefore include at least 3 positions at discharge after 15 min of blending.

Solution Preparation and pH-Dependent Solubility Constraints

Aqueous reconstitution of the granule does not yield a true solution at ambient temperature. The granule matrix disperses partly, but the native protoberberine alkaloids remain largely associated with extract components at neutral pH. Oral solution preparation therefore uses heated water at 60–80 °C, pH adjustment to 3.5–5.0, and where permitted, a co-solvent system of propylene glycol or glycerol at 10–30% v/v. The resulting liquid should be clarified through a 0.45 µm filter before filling into amber glass or opaque plastic containers. For injectable solutions, a 0.22 µm sterilising-grade filter is used only after depyrogenation and only when the formulation has been shown to be stable at the selected pH and temperature. The pH must not be adjusted with strong alkali because berberine salts can precipitate as the free base above pH 6.0. Light protection is mandatory for all liquid forms because the protoberberine chromophore is light-sensitive. Residual particulate matter in solution should be monitored by light obscuration per CPV 2020 0903; if the count exceeds 25 particles/mL at ≥10 µm, the clarification step is inadequate for the chosen vehicle.

A direct substitution of crude Huanglian powder is not microbiologically equivalent

Relative to crude Rhizoma Coptidis powder, the granular API differs in standardised alkaloid content, microbial burden, heavy-metal load, and particle-size regularity. Crude powder can vary in berberine content by more than 2-fold depending on geographic origin, harvest year, and drying method; the granulated API is normalised by blending extract lots to the release range. The granular form also reduces total aerobic microbial count from values that can exceed 10⁴ CFU/g in poorly dried botanical material to ≤10³ CFU/g. Compared with purified berberine hydrochloride, the granule retains palmatine, jatrorrhizine, and coptisine, which may alter the pharmacological response, but the multi-alkaloid matrix has lower aqueous solubility and higher hygroscopicity than the isolated salt. Compared with human-grade Coptis extract, the veterinary-grade API is controlled under veterinary-specific residual solvent and elemental impurity assessments aligned with VICH GL18 and the receiving jurisdiction’s veterinary pharmacopoeia. Human-grade extract is not automatically suitable for veterinary use because species-specific excipient tolerances, residue limits, and target daily doses differ. The granule is not interchangeable with feed-grade herbal powders that lack a full release specification; for inclusion in medicated feed, only lots with a certificate of analysis covering assay, heavy metals, residual solvents, and microbial limits should be accepted.