1H-Pyrrole-1-Heptanoate, 3-Benzoyl-5-(4-Fluorophenyl)-Β,Δ-Dihydroxy-2-(1-Methylethyl)-4-Phenyl-, Calcium Salt, (Betar,Deltar)- (1:1)
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HS Code |
836167 |
| Chemical Name | 1H-Pyrrole-1-Heptanoate, 3-Benzoyl-5-(4-Fluorophenyl)-β,Δ-Dihydroxy-2-(1-Methylethyl)-4-Phenyl-, Calcium Salt, (βR,ΔR)- (1:1) |
As an accredited 1H-Pyrrole-1-Heptanoate, 3-Benzoyl-5-(4-Fluorophenyl)-Β,Δ-Dihydroxy-2-(1-Methylethyl)-4-Phenyl-, Calcium Salt, (Betar,Deltar)- (1:1) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 100g of 1H - Pyrrole - 1 - Heptanoate calcium salt in sealed chemical - grade packaging. |
| Shipping | The chemical "1H - Pyrrole - 1 - Heptanoate, 3 - Benzoyl - 5 - (4 - Fluorophenyl)-β,Δ - Dihydroxy - 2 - (1 - Methylethyl)-4 - Phenyl -, Calcium Salt, (βR,ΔR)-(1:1)" will be shipped in containers suitable for chemicals. Packaged securely to prevent damage, with proper labeling and documentation for safe transport. |
| Storage | Store "1H - Pyrrole - 1 - Heptanoate, 3 - Benzoyl - 5 - (4 - Fluorophenyl)-β,Δ - Dihydroxy - 2 - (1 - Methylethyl)-4 - Phenyl -, Calcium Salt, (βR,ΔR)-(1:1)" in a cool, dry place, away from heat sources and direct sunlight. Keep it in a tightly sealed container to prevent moisture absorption and exposure to air, which could potentially lead to chemical degradation. |
For direct compression of immediate-release tablets containing the 1:1 calcium salt of (βR,δR)-3-benzoyl-5-(4-fluorophenyl)-β,δ-dihydroxy-2-(1-methylethyl)-4-phenyl-1H-pyrrole-1-heptanoic acid, a pre-blending step with anhydrous lactose (Specified Loss on Drying ≤0.5%) and microcrystalline cellulose PH102 is executed in a tumble blender (V-type, 30 rpm, 15 min) at a ratio of 1:4:5 (active : diluent : compression aid). The resulting premix is passed through a 30-mesh (600 μm) oscillating granulator prior to the addition of croscarmellose sodium (3.0 wt%) and colloidal silicon dioxide (0.5 wt%); lubricant-grade magnesium stearate (vegetable source, specific surface area 4.0–5.2 m²/g) is introduced at 1.0 wt% and blended for an additional 3 min only—over-lubrication exceeding 5 min has been observed on production-scale equipment (Manesty Betapress, 16-station B-tooling) to delay disintegration beyond the 15-minute acceptance criterion of USP <701> due to hydrophobic film formation on the calcium salt particles. Compression is carried out on a rotary press with a pre-compression force of 6–8 kN and a main compression force of 12–18 kN, targeting tablet hardness of 6–9 kp (Schleuniger Model 6D) and friability <0.8% per USP <1216>. Content uniformity of the heptanoate calcium salt is verified by HPLC/UV at 244 nm after extraction with a 70:30 v/v acetonitrile–phosphate buffer (pH 7.4); acceptance limits comply with USP <905> Stage 1 testing. A critical processing boundary emerges at relative humidity above 60% at 25 °C, where the dihydroxy-heptanoate moiety absorbs moisture rapidly, necessitating dehumidified air supply and in-process moisture checks by Karl Fischer titration every 30 min. Under these conditions, a validated batch record limits the total holding time of unlubricated blend to 4 hours to prevent pre-degradation of the β,δ-diol array and consequent rogue epimerization at C-3 and C-5. Terminal products are conventionally film-coated with Opadry® II aqueous dispersion (12% w/w solids) in a side-vented coating pan (O’Hara Labcoat II, inlet temperature 65 °C, pan speed 6 rpm) to achieve a 3–4% weight gain; the coating formulation intentionally avoids polyethylene glycol grades with molecular weight below 4000 Da because low-MW PEG plasticisers have been correlated with calcium chelation at the film–core interface, resulting in delayed disintegration in stability batches stored at 40 °C/75% RH over 6 months. Accelerated stability protocols follow ICH Q1A(R2) guidelines with testing intervals at 0, 1, 2, 3, and 6 months; significant degradation products arising from double-bond formation between the β- and δ-hydroxyls are monitored and controlled at ≤0.2% per ICH Q3B(R2). The active calcium salt is never dry-blended with amine-bearing excipients (e.g., chitosan, basic butylated methacrylate copolymer) because Maillard-type condensation involving the heptanoate carbonyl has been detected under thermomechanical stress during prolonged tableting campaigns exceeding 8 hours.Can This 1,3-Diol Calcium Salt Function as a Chiral Resolving Agent for Racemic Carboxylic Acid Intermediates?In preparative-scale enantiomeric resolution of racemic non-steroidal anti-inflammatory drug intermediates (e.g., 2-arylpropionic acids), the heptanoate calcium salt is exploited as a diastereomeric salt-forming selector in a mixed-solvent crystallisation system. The free acid of the (βR,δR)-isomer is first liberated from the 1:1 calcium salt by partitioning between dichloromethane and 0.5 M aqueous hydrochloric acid at 0–5 °C; the dichloromethane phase is washed until the aqueous layer registers pH 6.8–7.0 and concentrated under reduced pressure (40 °C bath, 72 mbar) to an oil that crystallises upon seeding with authentic (βR,δR)-free acid. A racemic target acid (e.g., (R,S)-flurbiprofen) is dissolved in acetonitrile–water (85:15 v/v) and treated with 0.55 molar equivalents of the (βR,δR)-free acid at 50 °C under nitrogen; controlled cooling at a ramp of 0.2 °C/min to 8 °C precipitates a crystalline diastereomeric complex whose composition is subsequently verified by chiral HPLC (Chiralpak AD-H, 250 × 4.6 mm, hexane–ethanol–trifluoroacetic acid 95:5:0.1, 1.0 mL/min). The isolated diastereomeric salt is recrystallised from isopropyl acetate–cyclohexane (1:2 v/v) to upgrade the diastereomeric excess (de) to >99.0%. After hydrolysis of the salt with 0.2 M sodium hydroxide and re-acidification, the liberated (S)-flurbiprofen exhibits an enantiomeric excess of >99.5% by the same HPLC method, while the resolving agent is recovered as the calcium salt by addition of 0.5 equivalents of calcium acetate monohydrate in aqueous methanol and filtration; the recovered calcium salt shows an XRPD pattern matching the original form (Form A) and retains resolving efficiency over three successive cycles. This procedure is operationally bounded by the requirement to keep the free acid strictly anhydrous before the salt-forming step—residual water content above 0.1% (w/w) induces a competing hydration that depresses the de of the precipitated complex to <85%. Industrial-scale trials on a 500 L glass-lined vessel with a retreat-curve impeller (85 rpm) have reproduced laboratory results when the cooling jacket temperature profile is maintained within a ±1 °C tolerance band; deviations exceeding 2 °C have caused oiling-out phenomena and emulsion formation, requiring additional silica-gel filtration and reducing isolated yield from a typical 88–92% to <60%. Occupational exposure limits are benchmarked against the compound’s OEL of 5 µg/m³ (8-hour TWA) based on a calcium salt surrogate.When introduced as a synthetic building block in a continuous-flow platform for atorvastatin-type frameworks, the heptanoate calcium salt bypasses the classical ester-amide exchange sequence. The calcium salt (1.0 eq based on heptanoate monomer) is suspended in anhydrous tetrahydrofuran (10 volumes) and activated with pivaloyl chloride (1.05 eq) and triethylamine (1.2 eq) at -15 °C under a nitrogen cap to form a mixed anhydride. After 25 min of ageing, a pre-cooled solution of 4-fluoroaniline or a substituted aniline derivative (1.03 eq) in THF is added in a single portion via a cooled dosing line; the reaction stream is immediately passed through a jacketed static mixer (Kenics KM series, 6 elements) and residence coil (PTFE, 2.0 mm ID × 10 m) at -5 °C with a residence time of 4.5 min. The process stream exiting the coil is quenched inline with 1.0 M methanesulfonic acid (0.5 volumes) to simultaneously cleave residual mixed anhydride and liberate the carboxylic acid motif, followed by phase separation in a membrane separator (Zaiput SEP-10, PTFE membrane 1.0 µm) and countercurrent extraction with ethyl acetate. Concentration of the organic phase under a wiped-film evaporator (55 °C jacket, 35 mbar) yields the target 3-benzoyl-5-(4-fluorophenyl)-2-isopropyl-4-phenyl-1H-pyrrole-1-heptanoic acid amide derivative as a viscous syrup that crystallises from diisopropyl ether–n-heptane (1:3 v/v) in 85–89% isolated yield (HPLC purity 98.2–99.0% area at 254 nm). The process has been validated for kilogram-scale cGMP campaigns (cleanroom ISO 7) compliant with ICH Q7 Sections 8.1–8.5 covering raw material identity testing; calcium content of the starting salt is verified by complexometric titration against 0.01 M EDTA standardised with calcium carbonate primary standard SRM 915b (NIST). An operational incompatibility is noted: contact of the mixed anhydride solution with primary or secondary amines beyond the stoichiometric requirement results in dimeric amide formation via the β-hydroxyl, detectable by LC-MS as a +320 Da adduct; therefore, the exact molar ratio of amine must be controlled by an automated feedback loop using ReactIR 1650 cm⁻¹ monitoring of the carbonyl region and the dispensing pump must be calibrated with a Coriolis mass-flow meter (Endress+Hauser Promass F) to an accuracy of ±0.5% of set point. Residual palladium, iron, and nickel levels in the final amide are tested by ICP-MS per USP <233> with limits of ≤10 µg/g for each element, traceable to the calcium salt’s supply-chain specification sheet.Immobilised Ligand Precursor for Pirkle-Type Enantioselective HPLC PhasesSilica-based chiral stationary phases (CSPs) utilising the (βR,δR)-3-benzoyl-5-(4-fluorophenyl)-pyrrole-heptanoate scaffold as a pendant selector are produced by covalent linkage through the terminal carboxyl function of the free acid. In a typical coupling cycle, aminopropyl-functionalised silica gel (particle size 5 µm, pore size 120 Å, surface density of aminopropyl groups 2.8–3.2 µmol/m²) is slurry-packed in a 250 × 4.6 mm ID stainless-steel column blank and subsequently activated by recycling a solution of disuccinimidyl carbonate (0.15 M in acetonitrile, 0.5 mL/min for 2 h) through the column at ambient temperature. The (βR,δR)-free acid, generated ex situ from the calcium salt by the phase-partition procedure described above, is dissolved in anhydrous dimethylformamide containing 0.2 M 1-hydroxybenzotriazole and 0.2 M diisopropylcarbodiimide and recycled through the pre-activated column at 0.3 mL/min for 14 h; end-capping of residual amino groups is performed with acetic anhydride–pyridine (1:1 v/v in DMF, 0.4 mL/min, 2 h). Elemental analysis of a sacrificial portion of the bonded phase gives a carbon loading increase of 2.1–2.4% C, corresponding to a selector coverage of 0.27–0.30 mmol/g based on the molecular formula of the immobilised ligand. The prepared column is evaluated with the enantiomers of warfarin (mobile phase: acetonitrile–0.1% aqueous formic acid 60:40, 1.0 mL/min, detection at 280 nm) and exhibits a selectivity factor α of 1.38–1.42 and resolution Rs >2.5 under isocratic conditions; column efficiency is >85,000 plates/m for the first-eluting enantiomer. Transport and equilibration of the column are performed in acetonitrile–water (80:20), with a strict preservation protocol specifying storage at 4–8 °C when not in use for periods exceeding 72 h to suppress hydrolysis of the carbamate linkage. The CSP tolerates a mobile-phase pH range of 2.5–6.8; below pH 2.0, leaching of the selector is detected by UV monitoring of the column effluent after 200 column volumes, and above pH 7.2, the silica backbone dissolves progressively. Quality control of each manufactured column lot includes a pressure test at 4000 psi (ca. 27.6 MPa) and a standard resolution mixture; record-keeping aligns with ISO 9001:2015 clause 8.6 release of products. The calcium salt is stored separately under argon at -20 °C to maintain the chiral integrity of the pending free acid—thermal acceleration at 60 °C for 14 days has been shown to reduce enantiomeric purity of the subsequently prepared CSP from >99% ee to 91% ee, as traced by the warfarin separation factor dropping below 1.10.In polylactide compounding, the heptanoate calcium salt is evaluated as a non-toxic heterogeneous nucleating agent because its molecular architecture combines aromatic rigid segments with a polar diol array that can template poly(L-lactic acid) (PLLA) chain folding. The 1:1 calcium salt is dry-mixed with PLLA pellets (NatureWorks Ingeo™ 4032D, weight-average molecular weight 2.1 × 10⁵ g/mol, D-isomer content 1.4%) at loadings of 0.5, 1.0, and 2.0 wt% and compounded in a co-rotating twin-screw extruder (Thermo Scientific Process 11, screw diameter 11 mm, L/D 40) with a barrel temperature profile from 165 °C (zone 1) to 195 °C (die), screw speed 150 rpm, and a throughput of 2.0 kg/h. Extruded strands are pelletised and hot-pressed (190 °C, 5 MPa, 3 min) into 0.5 mm films for isothermal crystallisation studies by differential scanning calorimetry (DSC, Mettler Toledo DSC 3+) under nitrogen flow (50 mL/min). With 1.0 wt% of the calcium salt, the crystallisation half-time (t½) at 130 °C decreases from 18.5 min for neat PLLA to 2.4 min, while the cold-crystallisation peak temperature upon heating at 10 °C/min (ASTM D3418) shifts from 117.6 °C to 98.3 °C. Wide-angle X-ray diffraction confirms a pure α-crystal form with no evidence of β-phase contamination; the nucleation efficiency parameter, calibrated against self-nucleated polymer, reaches 62% at the optimal loading. A nontrivial processing constraint arises when the compound is extruded at barrel temperatures exceeding 205 °C: the calcium salt undergoes a disproportionation side-reaction that releases free pyrrole-acid, evidenced by a pH drop of the water extract (from 6.8 to 4.1) and a concomitant increase in the melt flow index at 190 °C/2.16 kg (ISO 1133-1:2022) from 8.5 g/10 min to 22.3 g/10 min. Consequently, processing recommendations mandate a maximum melt temperature of 195 °C and residence time below 4 min. Residual calcium salt in the final injection-moulded parts (tensile bars, ISO 527-2 type 1A) is quantified by ion chromatography after microwave-assisted acid digestion (EPA Method 3052), and migration into food simulants (10% v/v ethanol at 40 °C for 10 days) is assessed per Regulation (EU) 10/2011; specific migration limits apply depending on the final article’s intended use.Used as a solid-phase extraction reagent for divalent heavy-metal removal, the non-hygroscopic calcium salt shows preferential ion-exchange behaviour toward Pb²⁺, Cd²⁺, and Cu²⁺ in weakly acidic aqueous media. A typical batch treatment for industrial wastewater effluent (initial lead concentration 15 mg/L, pH 5.5) applies the calcium heptanoate at a dose of 0.4 g/L while stirring mechanically in a baffled reactor (200 rpm, 25 °C, 45 min contact). The residual Pb²⁺ concentration determined by flame atomic absorption spectroscopy (EPA Method 239.1) drops to <0.15 mg/L, meeting the EU Urban Waste Water Treatment Directive 91/271/EEC discharge threshold of 0.2 mg/L. Calcium ions are released in a stoichiometry approaching 1:1 (Ca²⁺ released per Pb²⁺ removed), confirming an ion-exchange rather than a simple adsorption mechanism; FTIR analysis of the spent material shows the carboxylate asymmetric stretch shifting from 1558 cm⁻¹ to 1521 cm⁻¹, indicative of a stronger metal-carboxylate coordination. The reagent is effective only when the free-acid content of the supplied salt is below 2 mol%, because free diacid forms soluble lead complexes that increase aqueous-phase lead by 0.3–0.5 mg/L; suppliers typically assay residual free acid by non-aqueous titration with tetrabutylammonium hydroxide (TBAH 0.1 N in methanol) and report the value on the certificate of analysis. Reuse of the spent calcium salt regenerated by stripping with 0.1 M calcium nitrate at pH 4.0 recovers 94–96% of the original capacity over five cycles when the regeneration liquor is preheated to 40 °C to enhance calcium-sodium displacement kinetics. Published data for this specific configuration in municipal wastewater matrices containing humic substances is limited; pilot trials invariably require a pre-filtration step through 0.45 µm membrane cartridges to avoid colloidal fouling of the ion-exchange sites. |
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The substance is identified by the fully systematic nomenclature 1H-pyrrole-1-heptanoate, 3-benzoyl-5-(4-fluorophenyl)-β,δ-dihydroxy-2-(1-methylethyl)-4-phenyl-, calcium salt, (βR,δR)-(1:1). The 1:1 stoichiometry with calcium represents a deliberate deviation from the far more common atorvastatin calcium 2:1 salt, a distinction that modifies counter-ion coordination, crystalline packing energy, and solubility in polar aprotic mobile phases. The product is distributed under a controlled substance identity code tied to its role as a process-related impurity marker in the synthesis of HMG-CoA reductase inhibitors. Its molecular architecture contains the characteristic 3,5-dihydroxyheptanoate chain required for chiral recognition by the enzyme active site, yet substitution of the phenylcarbamoyl moiety with a benzoyl group eliminates the pharmacophore’s acyclic amide linkage, thereby rendering the molecule pharmacologically inert while preserving the steric and electronic features necessary for chromatographic co-elution studies with the active pharmaceutical ingredient (API). The material is supplied as a crystalline powder confirmed by X-ray powder diffraction (XRPD) pattern matching to a reference batch, with differential scanning calorimetry (DSC) indicating a single endothermic melting event at 212 ± 3 °C, as recorded under nitrogen purge at 10 °C/min in a sealed aluminium pan. Laser diffraction particle size analysis reveals a D90 of < 45 µm, a parameter optimised for rapid dissolution in acetonitrile:water diluents used in United States Pharmacopeia (USP) monograph 621 chromatographic procedures. Residual solvent analysis conducted via headspace gas chromatography with flame ionisation detection complies with International Council for Harmonisation (ICH) guideline Q3C Option 1 limits, with specific acceptances of ≤ 410 ppm for acetone and ≤ 60 ppm for dichloromethane. Heavy metals by USP 231 are controlled to ≤ 10 ppm as lead, ensuring suitability as an analytical reference where metal-catalysed degradation pathways must be isolated.
Standardisation follows a monograph-type layout anchored to ICH Q3A(R2) thresholds for unspecified impurities. The key chromatographic purity assay utilises a reversed-phase C18 column (250 × 4.6 mm, 5 µm particle size) thermostatted at 30.0 ± 0.5 °C, with mobile phase A consisting of phosphate buffer pH 7.0 and mobile phase B composed of acetonitrile:tetrahydrofuran (95:5) delivered via a binary pump at a flow rate of 1.2 mL/min under gradient elution. Detection at 244 nm exploits the 4-fluorophenyl π→π* transition, which yields a molar extinction coefficient approximately 12% lower than that of the parent drug, necessitating a relative response factor (RRF) of 0.88 against atorvastatin calcium certified reference standard. System suitability criteria include a resolution of ≥ 2.5 between the (βR,δR)-benzoyl impurity and the nearest-eluting (3R,5R)-atorvastatin peak, tailing factor ≤ 1.8, and peak area relative standard deviation ≤ 2.0% over five replicate injections. The specifications are summarised in the table below.
| Parameter | Method/Standard | Acceptance Criterion |
|---|---|---|
| Assay (anhydrous, solvent-free basis) | HPLC-UV, USP 621 | ≥ 98.5 area% |
| Chiral purity (diastereomeric excess) | Normal-phase HPLC, Chiralpak AD-H, 254 nm, hexane:ethanol:trifluoroacetic acid (92:8:0.1) | Diastereomer (3S,5S) content ≤ 0.5% |
| Water content | Karl Fischer coulometry, USP 921 Method Ia | ≤ 1.5% |
| Residue on ignition (sulfated ash) | USP 281 | ≤ 0.2% |
| Calcium content | Complexometric titration with EDTA | 4.0–4.8% (theoretical for 1:1 salt) |
| Related substances (total) | HPLC as above, area normalisation | ≤ 1.5% |
The calcium content range is diagnostic for the 1:1 stoichiometry; a typical 2:1 atorvastatin calcium exhibits calcium content near 3.3%. This shift in counter-ion ratio impacts both mass balance calculations during forced degradation studies and ion-suppression behaviour when electrospray ionisation mass spectrometry (ESI-MS) is used for peak identification in positive ion mode, where the formation of [M + Ca]2+ adducts alters quantitative linearity below the 0.1 µg/mL threshold.
Integration of this benzoyl impurity into pharmacopoeial system suitability mixtures permits concurrent verification of column selectivity, gradient reproducibility, and detector response linearity for non-UV-active related substances. The compound elutes at a relative retention time (RRT) of approximately 1.32 relative to atorvastatin under the commonly adopted European Pharmacopoeia (Ph. Eur.) monograph 2191 liquid chromatography conditions. Its deliberate inclusion at a concentration corresponding to the ICH Q3A reporting threshold—0.05% relative to the API test concentration of 0.8 mg/mL—enables certification that the analytical system can detect and quantify an impurity with a signal-to-noise ratio exceeding 10:1 when processing a 20 µL injection volume. Routine cross-validation across different LC brands (Agilent 1260 Infinity II, Waters Arc HPLC, Shimadzu Nexera) has shown that the column void volume, dwell volume, and mixer type can shift the RRT by up to 0.03 units. Consequently, a system containing this marker is used to calculate a corrective factor: if the observed RRT deviates from 1.32 by more than ± 0.02, the mobile phase organic-solvent ratio is adjusted by ± 1% tetrahydrofuran to restore selectivity. In laboratories operating under ISO/IEC 17025:2017 accreditation, this practice is documented as a column performance qualification step prior to batch release testing. The marker also reveals early signs of stationary phase dewetting when aqueous buffer exceeds 70% initial composition, manifesting as a shoulder on the leading edge.
In forced degradation studies designed according to ICH Q1A(R2) principles, the benzoyl derivative has been identified as a thermal degradation product formed when atorvastatin calcium is exposed to dry heat at 80 °C for 24 hours in the absence of light. The autoxidation pathway involves initial hydrogen abstraction at the benzylic position of the phenylcarbamoyl group followed by rearrangement and decarbonylative coupling, a mechanism confirmed through 13C isotopic labelling experiments reported in peer-reviewed literature. Under acidic stress conditions (0.5 M HCl, 60 °C, 6 hours), the compound does not degrade further, confirming its stability as a terminal marker; by contrast, the lactone impurity formed by intramolecular esterification of the parent drug exhibits appreciable acid lability, reverting to the dihydroxy acid. Alkaline hydrolysis (0.1 M NaOH, room temperature, 30 minutes) cleaves the benzoyl ester, generating desbenzoyl pyrrole derivatives that co-elute with the solvent front under the reversed-phase gradient. Photolytic exposure according to ICH Q1B options 1 and 2 (UV light 200 Wh/m² and visible light 1.2 million lux hours) results in 12% loss of the parent compound’s fluorophenyl ring integrity, a pathway that this calcium salt impurity faithfully replicates, making it an appropriate surrogate for monitoring packaging-induced photoprotection efficiency in primary container closure systems composed of LDPE bags within aluminium overpouches. Mass balance across all stress conditions remains within 95–105%, provided quantification applies the experimentally determined RRF of 0.88 rather than assuming a default value of 1.00.The table below contrasts this 1:1 calcium salt with two other structurally related entities encountered in the atorvastatin drug substance impurity profile.
| Attribute | Benzoyl impurity, Ca salt 1:1 | Atorvastatin calcium (2:1) | Desfluoro atorvastatin calcium |
|---|---|---|---|
| Molecular formula (free acid equivalent) | C33H30FNO4 | C33H35FN2O5 | C33H36N2O5 |
| Molar mass (Da, free acid) | 523.59 | 558.64 | 540.66 |
| Pharmacopoeial classification | Process impurity, ICH Q3A | Active substance (Ph. Eur. 2191) | Specified impurity (typically Impurity A) |
| Retention behaviour (RRT, C18 system) | ~1.32 | 1.00 | 0.87 |
| Calcium mass fraction | 4.0–4.8% | 3.1–3.5% | 3.2–3.6% |
| Hygroscopicity (DVS @ 25°C, 80% RH) | 1.8% mass gain | 4.3% mass gain | 4.0% mass gain |
| Application intent | System suitability, degradation monitor | API manufacturing | Limit test trace impurity |
The dynamic vapour sorption (DVS) data reveal that the 1:1 calcium salt exhibits markedly lower moisture uptake than the 2:1 salt, attributable to a more compact unit cell with fewer unoccupied coordination sites at the calcium centre. This characteristic reduces the frequency of pre-drying steps; nonetheless, analytical accuracy requires equilibrating the reference standard to ambient humidity conditions for at least 4 hours before weighing if the container has been stored in a desiccator maintained at ≤ 10% relative humidity. Laboratories operating in tropical climates (greater than 70% RH) should employ a glovebox purged with nitrogen to limit adventitious water sorption during sample preparation.
Long-term storage at 2–8 °C in tightly sealed amber borosilicate vials under argon headspace preserves the crystalline integrity and chiral purity over a retest period of 36 months when monitored annually by HPLC and polarimetry. Accelerated stability studies at 40 °C / 75% RH for 6 months in the primary packaging show no detectable racemisation above the 0.2% limit, as verified by chiral stationary phase analysis. The substance is incompatible with strong transition-metal oxidisers; contact with ferric chloride in solution generates a coloured charge-transfer complex that interferes with UV detection, and exposure to potassium permanganate in acetone leads to oxidative cleavage of the pyrrole ring. Mixing with amine-functionalised polymers or silanes during formulation of solid dispersions for solubility enhancement is contraindicated, as the terminal carboxylate calcium ion bridge undergoes ligand displacement, releasing free acid that can disproportionate into the lactone. Safety data sheets (SDS) prepared in accordance with the Globally Harmonized System (GHS) classify the solid as a skin sensitiser Category 1B (H317) based on local lymph node assay data, and eye irritation Category 2A (H319). Engineering controls including fume hoods with face velocity ≥ 0.5 m/s and nitrile examination gloves are mandatory during handling. Waste disposal must comply with regional pharmaceutical waste incineration regulations, as aqueous discharge into a biological treatment system would introduce a fluorinated aromatic compound with a predicted logarithmic octanol-water partition coefficient (log P) of 4.2, indicating potential for bioaccumulation.
