Azacitidine Seacross 25 mg/mL Powder for suspension for injection Pharma Grade API for Tablet / Capsule / Granule / Injection, Oral & Injectable is a chemically defined 5-azacytidine drug substance, CAS 320-67-2, molecular formula C8H12N4O5, and molar mass 244.21 g/mol. The material is supplied as a white to off-white powder with a compendial purity profile intended for downstream manufacture of hypomethylating-agent dosage forms. The same active pharmaceutical ingredient can be allocated to injectable presentations for myelodysplastic syndromes and related myeloid malignancies, or to oral presentations for acute myeloid leukaemia maintenance, provided the selected lot meets route-specific microbial and particulate controls. The injectable and oral drug products are not interchangeable because dose-normalised exposure, dosing frequency, and approved indications differ. Release control covers assay, related substances, residual solvents, water content, elemental impurities, bacterial endotoxins, and particulate matter using harmonised Ph. Eur. and USP methods; injectable allocation is differentiated by bacterial endotoxin control of ≤0.1 EU/mg and particulate-matter compliance with Ph. Eur. 2.9.19 after reconstitution.

Aqueous hydrolysis is the dominant degradation route for 5-azacytidine. The dry API remains stable in sealed moisture-barrier packaging, but once suspended in water for injection, degradation accelerates with temperature and with pH excursions outside the neutral window. Reconstituted azacitidine injection is therefore not a solution; it is a suspension with a finite hold time on the label of the reference product: 1 h at 25 °C or 8 h at 2–8 °C. The powder-for-suspension presentation is not pre-formulated for patient use; it is an unformulated pharmaceutical-grade API that must be further processed by aseptic powder filling or by oral solid-dosage unit operations before administration.

What differentiates this Seacross 25 mg/mL powder-for-suspension grade from conventional lyophilised azacitidine?

Conventional azacitidine injection is a finished single-dose vial containing 100 mg of lyophilised azacitidine with mannitol as a bulking agent, reconstituted with 4 mL sterile water for injection to yield 25 mg/mL. The Seacross material described here is not the finished vial; it is an unformulated drug substance supplied in bulk. Compared with oral-only azacitidine API, the Seacross grade carries parenteral-grade endotoxin and particulate specifications. Compared with injectable-only API, the material is also controlled for particle-size distribution and polymorphic form required for reproducible tablet, capsule, and granule manufacturing.

This dual-use specification reduces the need to qualify two separate API suppliers when a manufacturer develops an injectable suspension and an oral maintenance form from the same chemical entity. Injectable allocation requires additional endotoxin and particulate release data. The API is supplied in pharmaceutical-grade low-density polyethylene bags inside aluminium foil laminate pouches with desiccant to maintain water content below 1.0%; transfer to Grade D or Grade C dispensing suites follows validated cytotoxic handling procedures.

Specification limits, residual solvent thresholds, and particulate control

Release and stability specifications are established under ICH Q6A, ICH Q3C, and ICH Q3D. The following control template applies to dual-use lots allocated to injectable processing; oral-only lots may use a reduced endotoxin-testing frequency after process validation, but the impurity and residual solvent limits remain unchanged.

The residual solvent profile is synthesis-dependent. Azacitidine produced through protected cytidine intermediates may retain dimethyl sulfoxide, acetonitrile, or ethanol; when present, the certificate of analysis reports ethanol ≤5000 ppm, dimethyl sulfoxide ≤5000 ppm, and acetonitrile ≤410 ppm against ICH Q3C option 1 permitted daily exposure limits. The exact solvent profile depends on the validated crystallisation and drying train; the ICH Q3C limits remain the regulatory ceiling.

Polymorphic form is monitored because amorphous and alternative crystalline phases can show different intrinsic dissolution rates and hygroscopicity. The API is released as the thermodynamically favoured crystalline phase, confirmed by X-ray powder diffraction against a reference pattern; amorphous content is controlled below 10% by modulated differential scanning calorimetry or dynamic vapour sorption. The accepted limit is form-specific and is derived from solubility and bioavailability studies under ICH Q6A decision tree 4.

The principal organic impurities include cytosine, cytidine, and ring-opened hydrolysis products. HPLC methods with ultraviolet detection at 254 nm separate azacitidine from its degradation products; any unspecified impurity is limited to ≤0.10% and total impurities to ≤1.0% under ICH Q3A thresholds. For oral azacitidine at 300 mg/day, the ICH Q3A reporting threshold is 0.05% because the maximum daily dose is below 2 g/day.

For oral tablet and capsule development, particle-size distribution and surface energy dominate process behaviour. Milled azacitidine API is specified with D90 ≤25 µm and D50 ≤10 µm for low-dose direct-blend formulations, because the core may contain 100 mg or less of API per unit. Jet milling under nitrogen is preferred over ball milling to limit thermal stress and moisture uptake; high-energy comminution can increase amorphous surface content and accelerate hydrolysis if the material is exposed to ambient humidity. Particle-size distribution is measured by laser diffraction under ISO 13320:2020. Blend uniformity testing under Ph. Eur. 2.9.40 is performed at multiple sampling points across the bin blender discharge. On production rotary presses, magnesium stearate levels above 2.0 wt% are avoided because excess hydrophobic lubricant reduces tablet tensile strength and can delay disintegration.

When injectable and oral unit operations are run against the same API lot

The same API lot can be split between an aseptic injectable campaign and an oral solid-dosage campaign only when the batch was released against parenteral controls and the material has not been exposed to non-sterile equipment without subsequent disposition. In practice, manufacturers allocate dedicated sublots at the dispensing stage because the cleaning burden and contamination risk are higher for injectable processing. Aseptic powder filling requires a Grade A environment with Grade B background, sterilised product-contact parts, and filtered air at 0.22 µm for final sterile-grade operations. The powder is not autoclaved because azacitidine degrades under moist heat; dry-heat depyrogenation is also unsuitable for organic drug substance. Therefore the API must meet endotoxin and bioburden limits before entering the aseptic suite.

Granulation of azacitidine for sachet or capsule filling should avoid high-shear wet granulation unless immediate use is intended, because water addition initiates hydrolysis. Roller-compaction dry granulation is preferred for moisture-sensitive lots; ribbon density is controlled between 1.0 g/cm³ and 1.3 g/cm³ to balance granule hardness and post-milling fines. Published data for this specific Seacross granule configuration is limited; the operating range must be confirmed in the applicant’s process validation.

In injectable compounding, azacitidine API powder is aseptically filled into Type I borosilicate glass vials of 20 mL or 50 mL capacity, stoppered with chlorobutyl or bromobutyl closures, and sealed with aluminium flip-off caps. The vial headspace is flushed with nitrogen to limit degradation. Sterile water for injection is not added during filling; the final suspension is prepared by the healthcare professional immediately before use.

Specific surface area is determined by nitrogen adsorption under ISO 9277:2010; the accepted range is batch-specific and is established during process validation to match the dissolution target of the finished oral formulation. Increases in specific surface area correlate with greater hygroscopicity, so the desiccant load in the moisture-barrier pouch is selected using sorption isotherm data at 25 °C/60% RH.

Microbiological quality for oral solid-dosage API follows Ph. Eur. 5.1.4 or USP <1111>. Injectable allocation additionally requires specified micro-organism testing under Ph. Eur. 2.6.12/2.6.13. Bioburden control prior to aseptic processing is typically ≤10 CFU/g for an injectable API entering an aseptic suite without terminal sterilisation. The exact limit is established in the contamination control strategy and depends on the downstream aseptic powder-filling operation.

Azacitidine is chemically distinct from decitabine, 5-aza-2′-deoxycytidine, despite both being hypomethylating nucleoside analogues. Azacitidine is a ribonucleoside analogue that incorporates into RNA and DNA, whereas decitabine is a deoxyribonucleoside analogue incorporated preferentially into DNA. This mechanistic difference affects dosing, clinical use, and the impurity profile; the two APIs are not interchangeable in compounding or manufacture.

Storage of the API is specified at 2–8 °C in sealed original packaging with desiccant; excursions above 25 °C are limited according to stability data. The API is hygroscopic and should not be held in open containers outside humidity-controlled dispensing booths above 30% RH unless the room is conditioned. Cross-contamination control follows cytotoxic containment standards; dedicated or validated-cleaned equipment, closed transfer devices, and downflow booths with HEPA filtration are used for dispensing. The product is not a terminal-sterilised item; any sterility claim applies only after final aseptic filling and release of the injectable drug product.

Stability testing follows ICH Q1A(R2) for long-term, intermediate, and accelerated conditions. Long-term storage is commonly assigned at 2–8 °C because of hydrolytic sensitivity; accelerated studies at 25 °C/60% RH and 40 °C/75% RH define the permitted excursion windows. Re-test intervals are established from real-time data; typical intervals for moisture-sensitive cytotoxic APIs range from 12 months to 36 months in the original sealed aluminium-laminate overwrap.

The API is manufactured and released under ICH Q7 for active pharmaceutical ingredients. Batch release includes a certificate of analysis, a certificate of origin, and declarations of residual solvent and elemental impurity compliance. Distribution is limited to pharmaceutical manufacturers and qualified research facilities with cytotoxic handling permits.