Mahuang Tingli Powder Veterinary Grade API for Tablets / Injections / Capsules / Powders / Granules / Premix / Solutions is a standardized botanical active pharmaceutical ingredient derived from the traditional Chinese veterinary formula Mahuang Tingli San. The material is prepared from the aerial parts of Ephedra sinica Stapf and the seed of Descurainia sophia (L.) Webb ex Prantl or Lepidium apetalum Willd., extracted by aqueous decoction, concentrated, and dried by spray drying or vacuum drying. The finished API is a free-flowing, beige-to-light-brown powder with a characteristic Ephedra odor and is intended solely for incorporation into veterinary dosage forms after appropriate formulation and, where required, further purification. A representative procurement model designation is MHTL-API-60/200/EPE, in which 60 denotes the nominal aqueous extract ratio, 200 denotes the upper D90 particle-size target in micrometres, and EPE denotes the ephedrine-positive extract class. The finished API is not a finished dose form and is not intended for human use.

The powder is standardized to marker alkaloid content rather than to crude botanical weight, because seasonal variation in Ephedra alkaloid concentration and Tinglizi seed polysaccharide content can otherwise produce unacceptable batch-to-batch variability. At relative humidity above 60%, the hygroscopic oligosaccharide fraction of the extract increases the angle of repose beyond 40°, leading to die-filling defects on rotary tablet presses. Pre-drying at 45–55 °C until loss on drying is below 8.0% is required before dry blending, direct compression, or premix preparation in facilities without dehumidified dispensing suites.

What Release Specifications Govern the Veterinary-Grade API?

The release specification is established by the manufacturer and verified lot-by-lot with the methods shown in Table 1. Compliance with these parameters does not substitute for finished-dose stability testing, but it provides the baseline for blending calculations and sterile-filtration feasibility.

For feed-premix applications, maximum limits for heavy metals and arsenic are cross-checked against the destination market’s feed-safety legislation; the ICP-MS method detection limit is typically below 0.1 mg/kg, which permits reliable compliance even in compound-feed dilution scenarios. Aerobic plate counts are performed after reconstitution because the dried powder matrix can reduce recovery if directly plated. Residual solvent screening is included when vacuum drying is used; the certificate of analysis should state that solvent residues are not detected at a reporting limit of 50 mg/kg by headspace GC-FID.

Particle-Size Distribution, Extract Ratio, and Blend Uniformity

Laser diffraction data for typical spray-dried lots show a D10 of approximately 15–25 µm, D50 of 70–110 µm, and D90 below 200 µm. The span value, defined as (D90-D10)/D50, is usually between 1.8 and 2.4; tighter spans may be specified for direct compression because a broad size distribution increases segregation potential. The extract ratio of 60:1 is a nominal manufacturing input-output ratio, but the pharmacologically relevant lot parameter is the total alkaloid assay, not the extract ratio alone. For tablet and capsule formulation, blend uniformity is assessed according to USP 905; acceptance is typically 90.0–110.0% of the target label claim with relative standard deviation not more than 5.0% for a 10-unit sampling plan.

In capsule filling, volumetric dosator and tamping-pin machines require bulk-density compensation because the powder’s tapped density can shift from 0.45 g/cm³ to 0.65 g/cm³ depending on spray-drying chamber outlet temperature and residual moisture. Volumetric filling without assay-adjusted fill weight can therefore generate alkaloid content variation above ±10%. Preblending with 0.5% magnesium stearate for not more than 10 min reduces sticking in tamping pins, but over-lubrication can delay dissolution by forming hydrophobic films on the granule surface. For tablets, direct compression with microcrystalline cellulose and dicalcium phosphate dihydrate is performed on a rotary press with 10 mm flat-faced tooling at 60–80 N hardness. Friability is kept below 1.0%. Granulation drying uses a fluid-bed dryer with inlet air no higher than 55 °C because ephedrine alkaloids can volatilize above 60 °C. Final granule moisture is targeted at 3.0–5.0% before compression.

Tight Moisture Control Prevents Premix Segregation and Tablet Die Filling Defects

Premix production is carried out by staged geometric dilution onto ground corn cob or lactose monohydrate carriers. The API D50 should be within a 1:4 ratio of the carrier D50; larger mismatches promote percolation segregation during conveying and pile formation. The powder has a Hausner ratio of approximately 1.20–1.40 at or below 8.0% loss on drying. A Hausner ratio above 1.45 indicates that moisture has raised interparticle cohesion and that the powder should be re-dried before dispensing. High-shear granulation with polyvinylpyrrolidone K30 in purified water or ethanol is controlled by impeller torque endpoint rather than fixed time. Drying is maintained at 50–55 °C to limit alkaloid loss; because published retention data for this specific dual-plant extract matrix are limited, a pilot-scale total alkaloid assay before and after drying should be performed when starting a new granulator train.

For powder dose forms, the API is diluted with lactose monohydrate and dispensed as an oral powder; dry mixing in a V-blender at 60% fill volume with an intensifier bar speed not exceeding 1,500 rpm gives acceptable homogeneity. Extended mixing beyond 20 min can generate static charge and should be avoided unless the humidity is held constant at 45–55% RH.

When Injectable Solutions Are Prepared From the Powder

The powder is not directly injectable. For injectable formulations, the API is reconstituted in water for injection, acidified to pH 4.5–5.5 with dilute hydrochloric acid, and clarified by cold storage at 2–8 °C for 12–24 h followed by centrifugation. The clarified solution is passed through 0.45 µm and 0.22 µm polyethersulfone membrane filters and filled under aseptic conditions. Terminal sterilization at 121 °C for 15 min may be applied only after confirming that total alkaloid assay and pH remain within specification; the Descurainiae Sophiae-derived polysaccharide fraction can otherwise hydrolyze and alter viscosity. Because the botanical powder is not inherently pyrogen-free, bacterial endotoxin testing according to USP 85 is mandatory for injectable solutions. Particle counts should meet USP 788 limits for small-volume parenterals.

For oral solutions, the API can be dissolved or suspended in purified water with an appropriate preservative such as potassium sorbate at 0.1–0.2%. The pH is adjusted to 4.5–5.5; above pH 6.0, the free base can precipitate. Tannin-rich flavoring extracts and high-ionic-strength saline vehicles should be avoided because they cause alkaloid complexation or salting-out precipitation. Compatibility testing by visual inspection and particle-size analysis is required before locking the formula.

The Dual-Plant Standardization Profile Separates This API From Simple Ephedra Alkaloid Extracts

This veterinary-grade API differs from the dispensary powder Mahuang Tingli San in three ways: the dual-plant marker profile is standardized, the particle-size distribution is controlled for solid-dose blending, and the heavy-metal and microbial limits are tightened for multi-route formulation. Table 2 summarizes the practical consequences for formulators.

Formulators should not substitute a simple ephedra-only extract for this API unless the target indication has been explicitly limited to ephedrine-mediated bronchodilation and the Descurainiae Sophiae component is not required. The Descurainiae Sophiae seed contributes mucilaginous polysaccharides and flavonoid markers; their absence changes both the rheological behavior of wet granulations and the extraction residue profile. No published equivalence data for this specific veterinary-grade configuration are available; therefore, bioequivalence between this dual-plant API and a single-ephedra extract cannot be assumed.

Because the powder is a botanical extract, residual aflatoxin B1 and ochratoxin A are controlled when the product is intended for feed-premix use; typical acceptance is ≤ 10 µg/kg for aflatoxin B1 and ≤ 50 µg/kg for ochratoxin A by immunoaffinity-column HPLC with fluorescence detection. These limits are derived from feed-safety legislation and are not stated as API monograph values for all markets. The powder should not be combined with strong oxidizing agents or with ammonia-releasing alkaline granulation aids, because the free alkaloid base can be released and volatilized. Storage is at 15–25 °C in sealed aluminium-laminate bags with desiccant; shelf life is normally 24 months from the date of manufacture when unopened, but open-bag revalidation should be performed after 30 days in humid conditions.