Compression Window for High-Load Ecliptae Herba Extract Tablets at 45% Relative Humidity

Ecliptae Herba veterinary-grade dried extract is milled to D90 ≤ 75 µm before weighing. Direct compression is restricted to batches with ≤ 6.0% w/w loss on drying and ambient relative humidity below 40% RH because the extract contains hygroscopic polyphenolic fractions. In wet granulation, the extract is dry-mixed with microcrystalline cellulose at a ratio of 1:1.2 in a high-shear granulator with 150 L bowl, impeller speed 120 rpm, and chopper speed 1,800 rpm. Purified water containing 3.0% w/w polyvinylpyrrolidone K30 is sprayed at 350–450 g/min until wet-mass moisture reaches 18–22% w/w. The wet mass is passed through a 1.0 mm square-mesh screen and dried in a fluid-bed dryer with inlet air at 55°C until granulate moisture reaches 2.0–3.5% w/w. Dried granulate is screened through 0.8 mm, then blended with 4.0% w/w crospovidone and 1.0% w/w colloidal silicon dioxide for 10 min; magnesium stearate 0.5% w/w is added last and mixed for 3 min. Compression on a rotary press with 10-mm round concave punches requires 12–18 kN average force, producing tablets with hardness 80–120 N, friability below 1.0% per USP <1216>, and disintegration below 15 min in 0.1 M hydrochloric acid at 37°C per USP <701>. Each 520 mg finished tablet contains 100 mg dried extract equivalent to 500 mg crude herb at a 5:1 extraction ratio. Residual ethanol from extraction is controlled below 0.5% w/w under VICH GL18; elemental impurities are monitored to ICH Q3D levels for veterinary oral products. Alkaline granulating fluids are excluded because wedgeolactone contains a lactone ring that undergoes hydrolytic opening above pH 8.5 during wet massing, causing batch assay loss and peak splitting in HPLC-UV.

In swine and equine injectable presentations, the extract is further clarified into a low-endotoxin, low-lipid concentrate before aseptic processing. The dried extract is dispersed in 20% v/v propylene glycol and 10% v/v polyethylene glycol 400 in water-for-injection, stirred at 40°C for 45 min, cooled to 8–10°C for 12 h, and clarified through a 1.0 µm glass-fibre depth filter followed by a 0.45 µm polyvinylidene fluoride membrane. The filtrate is adjusted to pH 6.8–7.2 with 10 mM phosphate buffer and sterile-filtered through a 0.22 µm PVDF capsule into pre-sterilized type I glass vials. A representative loading is 10% w/w dried extract equivalents, but the final volume per vial must be calculated from the wedgeolactone marker assay on the extract batch. Terminal sterilisation by autoclaving at 121°C for 15 min is unsuitable when wedgeolactone degradation exceeds 2.0% under thermal challenge; for such batches, aseptic filtration alone is selected. The vial headspace is flushed with nitrogen before stoppering with chlorobutyl rubber closures because oxygen-sensitive coumestans can oxidise at the stopper-liquid interface. Compliance testing includes sterility per USP <71>, bacterial endotoxins per USP <85> at a limit of 1.0 EU/mg extract for parenteral use in large animals, particulate matter per USP <788>, and pH per USP <791>. If the clarified solution retains more than 2.0% w/w of chlorophyll-derived lipophilic material, cold filtration may become blocked; published data for this specific configuration is limited and scale-down studies are required.

Why Does Magnesium Stearate Above 0.8% Retard Dissolution in Herbal Extract Capsules?

For hard capsule filling, the extract milled to D90 ≤ 100 µm must be dried below 4.0% w/w moisture and maintained at 35–40% RH during encapsulation. A low-shear tumble mixer with 300 L capacity and 45–55% fill volume is used; the extract is first mixed with 1.0% w/w colloidal silicon dioxide for 10 min to coat hygroscopic surfaces and reduce interparticle adhesion. Magnesium stearate at 0.5% w/w is added as final lubricant; raising the concentration to 0.8% w/w or mixing beyond 7 min produces a hydrophobic film over extract particles, delaying wetting and reducing dissolution of wedgeolactone in USP <711> apparatus 2 at 50 rpm. The blend is filled into size 1 hypromellose capsules at 300 mg nominal fill weight using a dosator machine with 4.0 mm pin compression and 8 N ejector force. Each capsule contains 60 mg dried extract, equivalent to 300 mg crude herb at 5:1. Empty capsule shells with 12–15% w/w moisture are avoided because moisture migration into the extract can cause plug formation in the dosator and gloss change in the capsule body. In-process tests include fill weight at ±5%, disintegration below 15 min in water at 37°C per USP <701>, and moisture by Karl Fischer below 6.0% w/w. Residual solvents are controlled under VICH GL18; the terminal product is packaged in aluminum/aluminum blisters with desiccant to maintain RH <30% in the primary package.

Because the dried extract has poor cold-water solubility, drinking-water medication in poultry is delivered as a re-engineered powder that does not clog nipple drinkers. The extract is spray-dried onto maltodextrin DE 15 at 25% w/w in a co-current dryer with inlet air at 160–170°C and outlet air at 70–75°C; product temperature must remain below 90°C. The resulting powder is dry-blended with anhydrous dextrose, sodium chloride, and 1.0% w/w food-grade silica to give a free-flowing powder with D50 around 150 µm, tapped density 0.45–0.60 g/mL, moisture ≤ 5.0% w/w, and ≥ 99% particle fraction passing a 500 µm sieve. A 100 g sachet is dispersed into 200 L drinking water to form a slightly turbid suspension; the product is not a true solution, and remaining sediment must be re-suspended before dosing. Solubility of the unconjugated coumestan fraction in water is low, so this presentation is intended for short-term group medication through bell drinkers or tank systems with agitators. Microbiological release testing follows USP <61> for total aerobic count below 10³ CFU/g and USP <62> for absence of Salmonella in 10 g sample; residual solvents are controlled under VICH GL18. Sachets are packed in aluminium/polyethylene laminate and must not be stored above 30°C because hygroscopic maltodextrin absorbs moisture and the powder may cake.

Granule Friability after Fluid-Bed Drying at 55°C with Aqueous Binder

Granules for direct oral administration to calves and foals are produced by top-spray fluid-bed granulation. A 60 kg batch comprises 20 kg dried extract, 28 kg lactose monohydrate 200 M, 10 kg maize starch, and 2 kg povidone K25 as binder. The bed is preheated to 32°C; binder solution at 5.0% w/w solids is sprayed at 120 g/min with atomizing air pressure 2.0 bar and nozzle diameter 0.8 mm. Product temperature is maintained at 32–38°C during spraying to avoid thermal degradation of wedgeolactone. After spraying, the granules are dried at 55°C until moisture is ≤ 3.0% w/w, then cooled to 20°C and passed through a 0.5 mm screen. Friability is measured on a Roche friabilator at 25 rpm for 4 min; acceptable weight loss is below 2.0%. Bulk density is controlled between 0.35–0.55 g/mL. A 2.0 g sachet contains 100 mg dried extract equivalent to 500 mg crude herb at 5:1. The terminal sachet is sealed in aluminium/polyethylene laminate after nitrogen flushing. Uniformity of content per USP <905>, moisture by Karl Fischer, and residual solvents by VICH GL18 are performed on finished lots. Granules must not be exposed to steam sterilization or prolonged storage above 25°C; accelerated stability at 40°C/75% RH for 3 months is used as a stress condition, but long-term stability remains batch-dependent.

When Acid-Pelleted Feed Premixes Contact Ecliptae Herba Extract at 60°C

In feed premix distribution for swine and poultry, a stepwise dilution procedure is used to avoid segregation of the low-dose botanical extract. The extract is first adsorbed onto calcium carbonate at a ratio of 1:4 w/w for 15 min in a ribbon blender to produce a concentrated carrier premix. This concentrate is then diluted with wheat middlings to a final extract content of 2.5% w/w in the veterinary premix. The finished premix is intended for inclusion into complete feed at 2–5 kg/tonne, although final inclusion depends on target marker intake and must be confirmed by the veterinarian. Mixing homogeneity is tested by sampling 10 points across the blender and measuring wedgeolactone content; the coefficient of variation must be below 5.0%. Pelletizing acidic complete feed above 60°C may accelerate degradation of coumestans and increase moisture-driven extract stickiness; therefore, premix addition is preferably made post-pelleting onto cooled pellets via a spraying or coating system. If the premix must be extruded, the temperature profile in the conditioner should not exceed 55°C and the feed pH should remain between 5.5 and 7.0. Acidic feed matrices below pH 4.5 can demethylate the wedgeolactone aglycone during storage, shifting the HPLC-UV marker peak and causing apparent assay loss. Compliance with ISO 22000:2018 prerequisite programs and GMP+ BA2 feed safety assurance is expected for commercial distribution. The terminal container is a 25 kg paper bag with inner polyethylene liner; pack size is chosen to match farm consumption within 3 months because herbal extract premixes absorb moisture and may develop clumping under tropical storage.

An oral solution based on 10% w/w dried extract, 20% v/v propylene glycol, 10% v/v glycerin, and preserved water is prepared in a stainless-steel jacketed vessel. The extract is first dissolved in the propylene glycol/glycerin phase at 40°C under low-shear agitation for 60 min; purified water at 35°C is then added slowly to avoid precipitation. The pH is adjusted to 4.8–5.2 with citrate buffer to suppress microbial growth and improve wedgeolactone stability. Preservatives potassium sorbate 0.1% w/w and sodium benzoate 0.1% w/w are incorporated; however, sorbate can be oxidized by traces of peroxidase in poorly clarified batches, leading to brown discoloration and loss of preservative activity. The solution is filtered through a 10 µm polypropylene filter and filled into 100 mL amber PET bottles fitted with dosing pumps. Final product specifications include pH 4.8–5.2, density 1.04–1.08 g/mL, total aerobic microbial count below 10³ CFU/g, and yeast and mould below 10² CFU/g per USP <61>. This presentation must not be mixed with alkaline rehydration solutions or hard water containing high calcium carbonate levels, because flocculation of polyphenolic acids may occur. Terminal product is stored below 25°C and protected from light; freeze-thaw cycling is avoided because propylene glycol-water phases can separate in sub-zero shipment conditions, requiring re-dispersion before dosing.