In a sterile dry powder filling suite, ceftezole sodium is handled as a crystalline sodium salt with a fill target of 0.5 g or 1.0 g ceftezole per vial, expressed as the anhydrous acid equivalent. The API is pre-sterilized by dissolution, sterile filtration through a 0.22 µm PVDF membrane, controlled crystallization, and aseptic drying. Vials are washed with WFI at 80 °C and depyrogenated in a hot-air tunnel at 250 °C for 30 min. Filling is performed in an ISO 5 unidirectional airflow zone with a mean velocity of 0.45 m/s ± 20%, as described in EU GMP Annex 1. Auger or dosator powder fillers must hold fill weight RSD to ≤ 2.0% at 1.0 g because overdosing increases the ionic load from the sodium salt and underdosing compromises the effective beta-lactam exposure.

The residual moisture specification after filling is controlled by Karl Fischer titration, with a typical in-process ceiling of ≤ 1.0% w/w. This limit is not a compendial value specific to ceftezole sodium; it is based on beta-lactam hydrolysis kinetics observed in sodium cephalosporin powders above water activity 0.3. The filling room relative humidity is maintained below 30% RH, and static charge dissipation through grounded contact parts and ionizing bars is required because low-humidity environments increase electrostatic adhesion and powder bridging in auger fillers. Open-pan hold time is limited to 4 h, and segregated batches are sampled for sterility per USP 71 and bacterial endotoxins per USP 85 using a K/M calculation with K = 5 EU/kg. Terminal steam sterilization is not applied because the beta-lactam ring is heat-labile; the entire route is therefore aseptic processing.

Reconstitution is performed with sterile water for injection or 0.9% sodium chloride. A 1.0 g vial is reconstituted with 10 mL diluent to yield 100 mg/mL ceftezole. The solution pH after reconstitution is within 4.5–6.5. Intravenous infusion is diluted to 10–20 mg/mL in polyolefin or PVC containers and administered through a 5 µm in-line filter if particulate matter is observed. Published compatibility data for ceftezole sodium with lactated Ringer’s and calcium-containing solutions are limited; 0.9% sodium chloride and 5% dextrose are the standard diluents. Prepared solution is stored at 2–8 °C for not more than 24 h unless the hospital pharmacy has generated extension data.

When Lyophilization Replaces Dry Powder Filling for Sterile Parenteral Delivery

When lyophilization is selected instead of dry powder filling, the formulation is designed as a frozen solution containing ceftezole sodium and a crystalline bulking agent. A screening matrix often contains mannitol at 40–60 mg/mL and total solids at 70–110 mg/mL; the API weight fraction falls between 40% and 60% w/w. Published data specific to lyophilized ceftezole sodium cakes are limited. Therefore, thermal characterization by freeze-drying microscopy and differential scanning calorimetry is necessary before cycle design. The target cake should be pharmaceutically elegant, with no collapse or shrinkage at the vial base and no visible meltback.

Process cycle design begins with a shelf freeze to −45 °C, followed by primary drying at −20 °C to −10 °C and chamber pressure of 60–120 µbar. Secondary drying is run at 25–35 °C for 4–8 h until cake moisture measured by Karl Fischer is ≤ 1.0% w/w. The endpoint is confirmed by differential pressure between a Pirani gauge and a capacitance manometer; the pressure differential narrows to ≤ 10 µbar when water vapor flux collapses. Condenser capacity is specified at 2× the calculated total sublimation load to prevent vapor choking in the duct between the chamber and condenser.

The vials are stoppered under vacuum, sealed, and tested for sterility per USP 71, bacterial endotoxins per USP 85, subvisible particulate matter per USP 788, and visible particulate matter per USP 790. Moisture ingress after sealing is limited by bromobutyl stoppers with a moisture vapor transmission rate below 0.1 g/m²/day at 25 °C. Reconstitution time of the lyophilized cake should be ≤ 2 min with 10 mL sterile water for injection. If cake collapse or high residual moisture is observed, the primary drying shelf temperature is reduced by −5 °C increments until collapse disappears, followed by a re-verification of the cycle using a minimum of 3 production-scale batches.

When a tablet dosage form is required, direct compression of ceftezole sodium imposes two immediate constraints: the sodium salt is hygroscopic, and the beta-lactam ring undergoes acid-catalyzed hydrolysis below pH 3.5. A conventional immediate-release tablet is therefore not appropriate unless an enteric coating is applied. The API is milled to a D90 of ≤ 75 µm to support content uniformity under USP 905, with AV ≤ 15.0. The direct-compression matrix contains microcrystalline cellulose PH102 at 35–70% w/w, lactose monohydrate at 15–45% w/w, crospovidone at 2–5% w/w, and sodium stearyl fumarate at 0.5–1.5% w/w.

Compression runs on a 20-station rotary press with a compression force of 8–16 kN. Tablet hardness is 60–100 N and friability is ≤ 1.0% by USP 1216. The uncoated core disintegrates in 10 min in phosphate buffer pH 6.8. The enteric coating is applied as an aqueous dispersion of methacrylic acid-ethyl acrylate copolymer at 8–12% weight gain. Dissolution testing follows USP 711 with two-stage media: ≤ 10% release after 2 h in 0.1 M hydrochloric acid, then ≥ 80% release after 45 min in pH 6.8 phosphate buffer.

Published pharmacokinetic data for oral ceftezole sodium tablets in humans are limited. The above formulation and process conditions are technical design values for a delayed-release oral dosage form, not a compendial monograph. No marketed oral tablet of ceftezole sodium is referenced. If dissolution failure occurs in the acid stage, coating uniformity must be checked by terahertz imaging or cross-sectional microscopy rather than increasing total coating weight alone, because over-coating shifts the buffer-stage release into a lag phase exceeding 45 min.

What Limits Capsule Fill Weight Uniformity at Low API Weight Fractions?

Capsule filling of ceftezole sodium runs into fill weight variability when the API weight fraction is below 20% w/w because cohesive sodium salt particles segregate from free-flowing diluents. A slugging or dry granulation step is introduced before encapsulation. The granulated material is passed through a 0.8 mm screen and blended with pregelatinized starch at 25–40% w/w, talc at 1–2% w/w, and magnesium stearate at 0.5–1.0% w/w. Final blend flow is measured as Carr index ≤ 25 and Hausner ratio ≤ 1.35 under USP 616.

Encapsulation on a dosator machine uses vacuum of −0.4 bar to −0.6 bar and pin compression to achieve fill weight RSD ≤ 3.0%. Hard gelatin capsules of size 0 are filled to 250–350 mg total powder mass. HPMC shells with moisture content ≤ 7% w/w are selected when the API is exposed to humidity above 60% RH. After filling, the capsules are checked for weight variation, content uniformity per USP 905, and dissolution per USP 711. If moisture uptake after 48 h at 25 °C/60% RH exceeds 1.5%, a desiccant pouch is placed in the final packaging.

Fluid-Bed Granulation Binder Viscosity and Dry Syrup Redispersion

For the dry syrup route, granulation of ceftezole sodium is developed around top-spray fluid-bed processing. Binder solution of hydroxypropyl cellulose is prepared at 2–4% w/w based on dry granule mass. Inlet air temperature is 40–60 °C, product temperature is 25–32 °C, and spray rate is adjusted to keep bed dew point below 10 °C. Finished granule loss on drying is ≤ 1.5% w/w. The granules are sieved through 1.0 mm and blended with sucrose, sodium citrate, xanthan gum, and flavoring agents.

Reconstitution is performed with potable water at 20–25 °C. The sodium citrate buffer targets a pH of 5.0–6.0 after reconstitution because ceftezole sodium degradation accelerates below pH 3.5. The final concentration is generally expressed as 125 mg/5 mL or 250 mg/5 mL ceftezole. Viscosity after reconstitution is 100–300 mPa·s at 25 °C, which allows reproducible pouring while avoiding needle clogging during oral syringe administration.

Stability of the reconstituted syrup is limited by water activity and pH. Published ceftezole sodium dry syrup stability data are limited; a conservative in-use shelf life is 7 days at 2–8 °C, followed by discard. The dry syrup is filled into 60 mL amber glass bottles with 12 mm child-resistant closures. Headspace is flushed with nitrogen to reduce oxidative degradation. Terminal product is tested for moisture by Ph. Eur. 2.5.12, content uniformity, and microbial quality per Ph. Eur. 5.1.4.

At the hospital pharmacy level, ceftezole sodium is received as a sterile powder for reconstitution. The manipulations occur in an ISO 5 primary engineering control located in an ISO 7 buffer area under USP 797. The powder vial is disinfected with sterile 70% isopropyl alcohol and entered with a closed-system transfer device when available. For a 1.0 g vial, 10 mL sterile water for injection is used. After complete dissolution, the solution is transferred into 50 mL or 100 mL 0.9% sodium chloride polyolefin bags to a final concentration of 10–20 mg/mL.

Point-of-care filtration uses a 5 µm in-line filter when visual particulates are present. Subvisible particulate control follows USP 788, with NMT 6000 particles ≥ 10 µm and NMT 600 particles ≥ 25 µm per container for large-volume parenterals. Co-infusion with aminoglycosides through the same lumen is avoided unless documented compatibility data exist. The admixture is stored at 2–8 °C for not more than 24 h; room-temperature storage is limited to 8–12 h unless the pharmacy has completed a stability study.