Compound Glycyrrhizin API used in immediate-release tablets is supplied as a ternary mixture of glycyrrhizic acid or its monoammonium salt, glycine, and methionine for oral grades; injectable grade replaces methionine with L-cysteine hydrochloride. A 25 mg glycyrrhizic acid tablet core therefore carries 75 mg of API blend, placing the API at 34–42% w/w in a 180–220 mg core. In production-scale high-shear granulation, the cohesive nature of the glycyrrhizic acid fraction and the low bulk density of the API blend require endpoint control by impeller torque rather than fixed water addition. Batch-to-batch variation in API particle size d90 75–150 µm and bulk density 0.35–0.55 g/cm³ causes granule endpoint drift when water addition is fixed volumetrically. The granulation process uses a 150 L high-shear mixer with binder solution added to an endpoint of 2.0–3.0% product moisture after drying. Microcrystalline cellulose and lactose monohydrate serve as combined fillers at 45–55% w/w, croscarmellose sodium at 3–5% w/w, hydroxypropyl cellulose at 2–4% w/w, and magnesium stearate at 0.5–1.0% w/w. Granulation with aqueous binder above 55°C accelerates methionine oxidation and produces off-white to tan granule discoloration; therefore, the safer process uses a fluid-bed dryer inlet temperature of 45–50°C. After wet milling through a 0.8–1.2 mm Conidur screen, the dried granules are blended and compressed on a rotary press at 8–14 kN main compression force and 2–4 kN precompression to achieve tablet hardness 60–90 N and friability below 1.0% under USP <1216>. Terminal tablet cores are film-coated with an aqueous hydroxypropyl methylcellulose system at pan inlet temperature 60–70°C and spray rate 5–10 g/min/kg to mask the sulfurous odor of methionine. Compliance for this route references ICH Q3D (R2) for elemental impurities, ICH Q3C (R9) for residual solvents, USP <905> and USP <711> for uniformity and dissolution, and 21 CFR 210/211 for finished pharmaceutical cGMP. The terminal dosage form is an immediate-release film-coated tablet for chronic hepatitis or allergic dermatitis indications, with release testing also limited by the capability of the coating pan to maintain inlet air dew point below 10°C to avoid edge chipping during scale-up.

What Limits Capsule Fill Weight Uniformity When Compound Glycyrrhizin Is Roller-Compacted?

Capsule production with this API is selected when patients require dose flexibility or when tablet compression shows lamination due to insufficient plastic deformation of the glycyrrhizic acid fraction. In the roller compaction route, oral-grade Compound Glycyrrhizin API containing methionine is blended at 31–42% w/w of the total fill weight, corresponding to a 75 mg ternary API blend in a 180–240 mg fill weight for a 25 mg glycyrrhizic acid dose. The process is highly sensitive to magnesium stearate level; above 1.0% w/w, granule tensile strength decreases below 1.0 MPa, and capsule dissolution slows because the glycyrrhizic acid-rich granules become hydrophobic. A Gerteis Mini-Pactor or Alexanderwerk WP120 roller compactor operating at roll pressure 4–7 kN/cm, roll speed 3–8 rpm, and gap 2–3 mm produces ribbons with density 1.05–1.25 g/cm³. After comminution through a 0.8–1.25 mm screen, the granules are blended with croscarmellose sodium 2–3% w/w and filled into size 1 or 2 HPMC or gelatin capsules. Weight variation is maintained below ±5% on an MG2 or Bosch capsule filler only when the granule Carr index is below 25 and the Hausner ratio is below 1.25. Because the glycine-containing API blend becomes hygroscopic above RH 60%, the encapsulation suite must be held at 21–25°C and 35–45% RH; failure to control humidity results in sticky granules that bind to dosing pins and produce weight rejection rates above 2%. Compliance standards include ICH Q3D (R2), USP <905> for content uniformity, USP <711> with Apparatus II at 50 rpm for dissolution, USP <701> for disintegration, and 21 CFR Part 211. The terminal dosage form is an immediate-release hard gelatin or HPMC capsule for oral administration. Published data for compound-specific dissolution Q values in capsule form is limited; manufacturers justify acceptance criteria under ICH Q6A based on tablet monographs and bioavailability data.

Aseptic ampoule filling with nitrogen-purged aqueous solution

Injectable Compound Glycyrrhizin is supplied as a sterile aqueous solution in 20 mL ampoules, with the API ternary composition adjusted to the injectable grade of glycyrrhizic acid, glycine, and L-cysteine hydrochloride. The manufacturing challenge is the oxygen-induced degradation of L-cysteine hydrochloride and the thermal lability of the solution when terminal steam sterilisation is attempted. The dissolved oxygen limit before filling is held below 0.1 mg/L by purging water for injection with nitrogen for at least 30 minutes; the solution is prepared at 10–25°C because glycyrrhizic acid precipitates at pH below 5.0 and the cysteine fraction oxidizes rapidly above pH 7.5. The pH is adjusted with 0.1 mol/L sodium hydroxide or hydrochloric acid to 6.0–7.0. In a 20 mL ampoule, the API addition is 40 mg glycyrrhizic acid, 400 mg glycine, and 20 mg L-cysteine hydrochloride, giving a total solute concentration near 2.3% w/v. This creates a low-viscosity solution that can be filtered through a 0.22 µm polyethersulfone membrane without measurable flux loss. Aseptic filling is conducted in a Grade A unidirectional airflow zone within a Grade B background, with filling speed 400–600 ampoules/min on a Bausch+Ströbel line. Terminal sterilisation at 121°C for 15 minutes is avoided because the cysteine residue produces a yellow-to-brown colour shift with absorbance at 420 nm above 0.1 AU and unknown degradants that complicate stability. Sterile filtration before filling is the standard control, but the operation must satisfy ICH Q6A decision-tree requirements and demonstrate pre-filtration bioburden below 10 CFU/100 mL in the bulk solution. Compliance standards include USP <1> Injections, USP <788> particulate matter, USP <790> visible particulates, USP <85> bacterial endotoxins, and Ph Eur 5.1.1 sterility. The terminal dosage form is an intravenous or intramuscular injection, with endotoxin limits calculated from the maximum adult daily dose, and the primary container is an amber low-density polyethylene or type I glass ampoule to protect the solution from light.

Granule sachet production cannot tolerate API loadings above 15% w/w without flow control additives

Oral granules are produced for patients who cannot swallow tablets or capsules and for dose adjustment in pediatric or elderly populations. In a fluid-bed top-spray granulation line, oral-grade Compound Glycyrrhizin API containing methionine is sprayed as a suspension or dissolved binder onto a lactose or mannitol substrate. The addition ratio is constrained by the low bulk density of the active mixture: above 15% w/w total ternary API blend, the granule mass becomes cohesive and the fluidization pattern collapses at air velocity below 1.5 m/s. A typical granule formula for a 25 mg glycyrrhizic acid dose in a 1.0 g sachet carries 75 mg API blend, equivalent to 7.5% w/w, with mannitol 70–80% w/w, hydroxypropyl cellulose 2–4% w/w, and citric acid 0.5–1.0% w/w to maintain the acidic microenvironment that protects methionine from oxidation. The granulation process operates at inlet air temperature 50–60°C, spray rate 15–25 g/min/kg, and product temperature 30–35°C, followed by drying to loss on drying below 3.0%. The dried granules are sieved through 0.5–1.0 mm mesh and packaged into aluminium-laminated sachets under nitrogen because moisture ingress above RH 40% in the package headspace produces agglomeration and sulfurous odor. Compliance for this route is anchored to ICH Q3D (R2), ICH Q3C (R9), USP <905> for single-dose weight variation, and 21 CFR Part 211. The terminal dosage form is an oral granule sachet, typically a 1.0 g single-dose stick pack reconstituted in water before administration. Published data for this specific configuration is limited; manufacturers validate blend uniformity under ICH Q2(R2) rather than relying only on pharmacopoeial acceptance values.

When a 25 mg tablet core enters film coating at inlet temperatures above 70°C

Film coating of Compound Glycyrrhizin tablets is not merely cosmetic; the coating layer must mask the sulfurous odor of methionine and protect the core from light and moisture. When a 25 mg core is coated in a perforated pan, inlet air temperature above 70°C can raise the core surface temperature above 60°C, triggering methionine oxidation and browning at the tablet edge. The coating pan is therefore run with inlet air temperature 60–65°C, exhaust air temperature 35–40°C, and spray rate 5–8 g/min/kg. The coating dispersion is an aqueous hydroxypropyl methylcellulose/polyethylene glycol system at 10–12% w/w solids, with titanium dioxide 0.5–1.5% w/w and iron oxide below 0.1% w/w for light protection; addition ratio to core weight is typically 3–4% w/w weight gain. The coating process on a 48-inch pan with 4–6 rpm pan speed and four anti-bearding guns with 0.8–1.2 mm nozzles produces a uniform film below 40 µm thickness. Compliance standards for the coating step include 21 CFR 210/211, ICH Q3C (R9) for residual ethanol or isopropanol if used as co-solvent, and USP <905> for content uniformity after coating; the finished film-coated tablet must pass USP <701> disintegration within 15 minutes in water. Terminal dosage form is a light-protective film-coated oral tablet. A process failure in coating—air velocity above 0.5 m/s at the spray zone—causes orange-peel surface defects that do not affect release but increase visual rejection above 3% in automated inspection.