5-Nitrofurfural Diacetate Pharma Grade API for Tablet / Capsule / Granule / Injection, Oral & Injectable, catalogue model 5-NF-DA-PH-1025, is supplied as a white-to-pale-yellow crystalline powder for controlled pharmaceutical manufacturing. The product is chemically identified as (5-nitrofuran-2-yl)methylene diacetate, CAS 92-55-7, molecular formula C9H9NO7, and molar mass 243.17 g/mol. Its geminal diacetate group protects the aldehyde position of 5-nitrofurfural, reducing oxidation, polymerisation, and aldehyde-associated discoloration during storage and handling. The material is used in tablet, capsule, granule, and injectable manufacturing chains not as a direct antimicrobial active, but as a controlled pharmaceutical intermediate for nitrofuran active substances such as nitrofurantoin and furazolidone. Direct administration of the diacetate form lacks an official pharmacopoeial monograph or validated clinical endpoint. The grade differs from unprotected 5-nitrofurfural by lower aldehyde reactivity, and from finished nitrofurantoin or furazolidone APIs by the absence of an antimicrobial pharmacophore in the diacetate form. Standard release specifications include assay ≥99.0% on the anhydrous basis, water ≤0.5%, residue on ignition ≤0.1%, and a melting range of 92–95°C. The product is packaged in sealed HDPE drums with desiccant and should be stored at 15–25°C protected from light.

Which compendial tests define release for the 5-NF-DA-PH-1025 grade?

Because no specific monograph for 5-nitrofurfural diacetate appears in current Ph. Eur. or USP–NF collections, release is controlled by an internal specification cross-referenced to Ph. Eur. general chapters. The certificate of analysis reports appearance, identity, assay, water content, residue on ignition, related substances, residual solvents, elemental impurities, and, for parenteral-grade orders, bacterial endotoxins and sub-visible particulates. HPLC assay is performed on an octadecylsilyl silica gel column, 250 × 4.6 mm, 5 µm, with a mobile phase of methanol and 0.1% phosphoric acid at 65:35 v/v, flow rate 1.0 mL/min, UV detection at 254 nm, and injection volume 10 µL. System suitability requires resolution ≥2.0 between 5-NF-DA-PH-1025 and free 5-nitrofurfural. Identification by infrared absorption is performed against a qualified reference spectrum, and HPLC retention time concordance is used as a secondary identification. The material is not automatically equivalent to a certified pharmacopoeial reference standard and should not be used as such without qualification against a traceable primary standard.

The residual solvent limits follow ICH Q3C Option 1 concentrations for Class 3 solvents declared in the manufacturing route. Elemental impurities are assessed per ICH Q3D, with results reported against the permitted daily exposure for the intended oral or parenteral route. Stability samples stored in sealed HDPE containers at 40°C/75% RH for 6 months show assay loss below 0.5% and water uptake below 0.2%; open-container exposure at 60% RH can raise water content above 1.0% within 4 h, supporting immediate closure and desiccant use.

Manufacturing of tablets and capsules from the derived active usually begins with conversion of 5-NF-DA-PH-1025 in organic media rather than direct compression. In a typical conversion step, the diacetate is dissolved in acetone at 40–50°C, treated with the appropriate nitrogen reagent according to the target nitrofuran, and stirred until HPLC indicates residual diacetate ≤0.5% area. The resulting active is isolated, dried under reduced pressure at ≤50°C, and then processed into tablets or capsules. Direct compression of unmodified 5-NF-DA-PH-1025 into a finished dosage form is not a recognised pharmaceutical procedure because the diacetate would not provide an antimicrobial active. For granule manufacture, dry blends containing the derived active and common fillers such as microcrystalline cellulose and lactose monohydrate are granulated using an aqueous binder at 10–12% w/w; granule moisture is dried to ≤2.0% w/w before tableting. High-shear granulation on a 10 L Diosna P1/6 mixer at impeller speeds of 300–500 rpm and chopper speeds of 1,000–2,000 rpm is suitable for the derived active, but the diacetate intermediate should not be exposed to acidic water at pH below 3 because hydrolysis regenerates free 5-nitrofurfural and increases related substances. Tablet compression is performed on a rotary press at 30–60 rpm; hardness is maintained at 50–80 N for tablets based on derived nitrofurantoin. Dissolution testing follows Ph. Eur. 2.9.3 or USP <711> for the specific final API, not for the diacetate intermediate. Encapsulation of derived nitrofurantoin from 5-NF-DA-PH-1025 via low-shear blending uses bin speeds of 10–15 rpm for 20 min; blend uniformity is confirmed by HPLC with acceptance value ≤15% relative standard deviation. Capsule filling on a Zanasi 12E or MG2 Planeta machine at 40,000–80,000 capsules/h requires moisture content ≤2.0% w/w to prevent powder adhesion and diacetate hydrolysis if residual diacetate is present.

Direct Tableting of the Unconverted Diacetate and the Absence of a Pharmacopeial Monograph

Pharmacopoeial monographs for nitrofurantoin and furazolidone define assay, related substances, crystalline form, and dissolution; no equivalent monograph exists for 5-nitrofurfural diacetate. Tablets or capsules containing only the diacetate would therefore be outside compendial recognition and would lack a validated antimicrobial endpoint. The compound’s geminal diacetate function masks the aldehyde carbon and cannot serve as the electron-deficient nitrofuran centre required for bacterial nitroreductase activation. This is the primary differentiator from nitrofurantoin monohydrate or macrocrystalline API, which is directly compressible and has pH-dependent dissolution specifications. It also differs from furazolidone API, which is used in specific oral suspensions and tablets with different spectral and chromatographic profiles. The diacetate is therefore handled as a controlled starting material in the synthesis of these active substances, not as a therapeutically equivalent substitute. Analytical methods for the diacetate should not be applied directly to finished nitrofurantoin or furazolidone dosage forms because the chromophores, retention times, and related impurity profiles are distinct. Method transfer between the diacetate and the final nitrofuran API requires separate system suitability solutions, separate impurity marker limits, and separate dissolution media according to the final active monograph.

Residual Free Aldehyde Is a Process Boundary in High-Shear Granulation

Residual free 5-nitrofurfural is a critical process boundary because free aldehyde content can increase related substances in downstream nitrofuran synthesis and in wet granulation hold times. The release specification limits free 5-nitrofurfural at ≤0.05% w/w in the diacetate. During high-shear granulation, aqueous acidic conditions at pH below 3 can partially hydrolyse the geminal diacetate, producing free aldehyde and acetic acid. The process limit is therefore set at granulation pH 4.0–6.5 and product temperature ≤40°C for any intermediate hold step containing residual diacetate. At pH 1.2 and 37°C in aqueous methanol, free 5-nitrofurfural can appear within 2 h; published kinetic data for this exact compound are limited, so forced degradation verification is required before setting manufacturing hold times. Vacuum drying at ≤10 kPa and 40°C for 2 h is used to reduce water and acetic acid after exposure to humid conditions. The limit of free aldehyde is determined by HPLC with UV detection at 254 nm, using a separate reference solution of 5-nitrofurfural at 0.05% relative to the diacetate peak.

When aqueous parenteral vehicles impose hydrolysis limits on the diacetate

Parenteral manufacturing routes that involve 5-NF-DA-PH-1025 require non-aqueous handling because the geminal diacetate is susceptible to hydrolysis in the presence of water. For injectable-grade material, the specification adds bacterial endotoxins ≤0.25 EU/mg by Ph. Eur. 2.6.14 and sub-visible particulates by Ph. Eur. 2.9.19 after dissolution in a non-aqueous diluent. A non-aqueous stock solution in dimethyl sulfoxide may be filtered through a 0.22 µm PVDF membrane before the final synthetic conversion; aqueous injection of the diacetate itself is not supported. Water-based parenteral formulations should be reserved for the finished nitrofuran active after deprotection, purification, and terminal filtration. Autoclaving is not recommended because thermolysis can generate acetic acid and free aldehyde; terminal sterilisation of a non-aqueous solution containing the diacetate has not been validated. The operational boundary for aqueous exposure is pH 4.0–6.5 and temperature ≤40°C, with hold time controlled by forced degradation data. For parenteral-grade process validation, filter compatibility studies with PVDF, PTFE, and nylon membranes at 0.22 µm are required because the solvent system may affect extractables and filter integrity. Liquid-transfer operations should use stainless steel or glass equipment; avoid copper or iron contact because trace metal residues can discolour the product and contribute to related substances.

Material-Specific Differences from Unprotected 5-Nitrofurfural and Nitrofurantoin API

The principal technical distinction between 5-NF-DA-PH-1025 and unprotected 5-nitrofurfural is storage stability. The free aldehyde darkens under ambient storage and may form oligomers; the diacetate can be held at 15–25°C in sealed HDPE containers with desiccant for the assigned retest period. The unprotected aldehyde often requires inert-gas blanketing and refrigerated storage in manufacturing facilities. Compared with nitrofurantoin API, 5-NF-DA-PH-1025 shows higher solubility in acetone and dimethyl sulfoxide but negligible aqueous solubility; published aqueous solubility data for the diacetate are limited. Nitrofurantoin macrocrystals require controlled particle size and crystal habit because dissolution and oral bioavailability are crystal-form dependent. The particle size of 5-NF-DA-PH-1025 is controlled at D90 ≤100 µm for uniform blending and rapid dissolution in synthetic organic stages, not for in vivo dissolution. The product should not be mixed with strong oxidisers, concentrated acids, or primary amines that can cleave the acetate protecting groups or form imines. It is incompatible with aqueous acid at elevated temperatures and with direct steam sterilisation. During analytical method transfers, the diacetate should not be co-injected with free amines or hydrazine reagents because imine formation can depress assay recovery and generate extra peaks in the related substances profile.