mPEG Methotrexate, PEG methotraxate - MW 5000 Da

Cat. No.: M163999

GRADE & PURITY MW 5000 Da

Storage

Room temperature

Shipped In

Normal

Overview

Methotrexate PEG derivatives are a class of bioactive PEGs that can be used to for drug discovery or bioassay development. Methotrexate, also called MTX, amethopterin, is an antimetabolite and antifolate drug. It is used in treatment of cancer, autoimmune diseases, ectopic pregnancy, and for the induction of medical abortions. It acts by inhibiting the metabolism of folic acid. Pegylated methotrexate provides better water solubility. Nanocs can provide other methotrexate PEG derivatives based on customer request.

Specifications

Specifications & Purity

MW 5000 Da

Storage

Room temperature

Shipped In

Normal

Chemical and Physical Properties

• Solubility: Yellow solid or viscous liquid depends on molecule weight;Soluble in regular aqeous solution as well as most organic solvents

Application Protocols

Item-specific protocols

• Not specified for this item; refer to the CoA/Spec Sheet and SDS for any available guidance.

General handling guidance (for research use only; literature-based)

• Stock preparation: Dissolve the conjugate in a minimal volume of DMSO to make a concentrated stock (e.g., 50–200 mg/mL as solubility allows), then dilute into PBS or culture media immediately before use. Record final DMSO percentage.
• Sterile work: If required, filter-sterilize through a 0.22 μm PES filter after complete dissolution. Verify recovery to rule out filter adsorption.
• Release assay setup: Incubate defined concentrations in buffered media at 37 °C; sample at scheduled intervals; quench aliquots on ice; analyze free MTX by HPLC.
• Controls: Include free MTX, unconjugated PEG (same Mn), and buffer-only blanks.

Critical notes

• Exact concentrations, incubation times, and analytical methods must be optimized for your system. The above are general starting points and not item-specific recommendations.

Biological Roles

Scope note

• No item-specific biological data are provided. The following summarizes general, literature-based roles of the MTX moiety and the impact of PEGylation; this is for research context only and not a clinical claim.

General biology (literature)

• Methotrexate (MTX) is an antifolate that inhibits enzymes in folate metabolism, notably dihydrofolate reductase (DHFR), thereby modulating nucleotide biosynthesis in cell systems. This underpins its frequent use as a tool compound in biochemical assays and cell culture studies.
• PEGylation typically increases apparent hydrodynamic radius, reduces non-specific protein binding, and can attenuate cell uptake relative to the parent small molecule. Conjugation may also alter recognition by folate transporters depending on the attachment site and steric context.
• Linker-dependent release: Ester/carbonate linkages may hydrolyze under physiological or lysosomal conditions to regenerate MTX over time; amide linkages are generally more stable. The actual biological activity of a conjugate therefore depends on release kinetics, substitution site(s), and loading.

Research implications

• mPEG–MTX is useful for probing: (a) how macromolecular size and hydrophilicity affect interaction with cells and proteins, (b) the relationship between conjugate stability and observed cellular responses, and (c) assay interferences due to PEG.

Caveats

• Activity, uptake, and toxicity of any specific mPEG–MTX lot are experiment- and linkage-dependent; verify experimentally in your system.

Buffer Applications

Relevance

• mPEG Methotrexate is not a buffering agent and is not typically used to establish or maintain pH in solutions.

Practical guidance (general)

• When formulating aqueous solutions or conducting release/transport assays, select buffers that balance solubility and stability:
  • Near-neutral buffers (e.g., PBS, HEPES, pH 7.2–7.5) are commonly used to minimize base- or acid-catalyzed hydrolysis.
  • Acetate/citrate buffers (pH 4–6) or phosphate (pH ~6–8) may be chosen for mimicking endosomal vs. extracellular environments in release studies.
• Ionic strength and divalent cations can modulate aggregation and adsorption; include consistent salt conditions across experiments.

Item-specific buffer recommendations

• Not specified for this item; refer to CoA/Spec Sheet and validate buffer compatibility empirically.

Green Alternatives

Context

• This product is a polymer–drug conjugate rather than a commodity solvent or reagent. “Greenness” considerations focus on solvent choice, purification, and waste minimization during handling and study.

Greener handling suggestions (general guidance)

• Prefer water or buffered saline as primary media whenever possible; reserve DMSO/DMF for concentrated stocks only.
• Conduct release studies in minimal volumes and design sampling schedules that reduce replicate waste.
• For purification, use aqueous SEC or dialysis instead of large-volume organic precipitations when feasible.

Comparison of common media (general)

• Water/PBS: Highest EHS profile; minimal VOCs; compatible with most bioassays. Tradeoff: potential hydrolysis for base-labile linkages at elevated pH.
• Ethanol (if soluble): Lower toxicity than many aprotic solvents; flammable. Tradeoff: limited solvency for higher-MW conjugates.
• DMSO: High solvency, low volatility (reduced inhalation risk). Tradeoff: Operator dermal exposure risk; ensure glove compatibility and keep final assay % low.

Process considerations

• Replace halogenated solvents in analytics where practical (e.g., acetonitrile/water gradients in HPLC rather than CH2Cl2).
• Use room-temperature operations (as allowed by stability) to reduce energy inputs.
• Consolidate cleaning with water-based detergents that efficiently remove PEG residues, minimizing repeat washes.

Note

• No item-specific green certifications or metrics are provided; consult institutional sustainability frameworks for further guidance.

Pharmaceutical Uses

Scope

• No pharmacopeial status or item-specific formulation role is provided. The following discusses general, research-oriented formulation contexts; no therapeutic claims are made.

General formulation roles (literature/general knowledge)

• Model prodrug: mPEG–MTX conjugates are used in R&D to study how PEGylation impacts solubility, stability, and release of MTX in simulated physiological media.
• Carrier interactions: The conjugate can be co-formulated with surfactants, lipids, or block copolymers to form mixed micelles or nanoparticles for in vitro evaluation of loading and release behavior.
• Excipients/vehicles: Aqueous buffers (PBS, HEPES) or isotonic saline are typical vehicles for biological testing; DMSO stocks may be prepared for later dilution.

Manufacturing/analytical considerations (general)

• Quality attributes: drug loading (wt%), residual free MTX, average MW and dispersity (SEC), and stability under ICH-like conditions (temperature/light/humidity) are key parameters in preformulation studies.
• Sterility: For cell-based work, 0.22 μm filtration is common if the conjugate dissolves fully; confirm no filter adsorption.

Item-specific pharmacopeial or regulatory notes

• Not specified for this item; consult the CoA/SDS for any additional guidance.

Physical Properties

Item-specific specifications

• Appearance, exact MW, MF, pKa/logP, melting/boiling points, density, refractive index, UV cutoff: Not specified for this item; refer to CoA/Spec Sheet.

General properties of mPEG–MTX conjugates (literature/general knowledge)

• Physical form: Typically an amorphous solid or viscous gum depending on PEG MW and loading; hygroscopic tendencies may increase with lower MW PEGs.
• Solubility: Enhanced aqueous solubility versus free MTX. Commonly soluble in water, saline, and biological buffers; readily soluble in polar organics (DMSO, DMF). Solubility increases with higher PEG MW and ionization of MTX carboxylates (basic pH). Poorly soluble in nonpolar solvents (hexanes, toluene).
• Ionization: MTX contains multiple acidic functions (two carboxylates; literature pKa values for MTX are ~3–5 for carboxyls and higher for the p-amine), which influence conjugate charge state; actual pKa of the conjugate depends on linkage and microenvironment.
• Aggregation: PEG–drug conjugates may self-assemble into micellar aggregates above a critical aggregation concentration (CAC), modulated by solvent ionic strength and temperature.
• Viscosity: Concentrated aqueous solutions can be moderately viscous, scaling with PEG MW and concentration.

Practical notes

• To characterize a specific lot, determine: aqueous solubility at experimental pH, GPC/SEC for Mn/Mw/Ð, and 1H/13C NMR to confirm degree and site of substitution. If UV–Vis is used, MTX chromophores typically absorb near 302–305 nm (literature), but verify for the conjugate.

Quality and Grades

Item-specific quality

• Grade/purity: Not specified for this item; refer to CoA/Spec Sheet.

How PEG–drug conjugate quality is typically defined (general guidance)

• Identity/structure: Verified by 1H/13C NMR (PEG backbone, aromatic MTX resonances), FT-IR (C=O, C–O–C), and, where feasible, MALDI-TOF/ESI to estimate average mass.
• Molecular weight distribution: Report Mn, Mw, and dispersity (Ð) by GPC/SEC with appropriate calibration (PEG or universal calibration with dn/dc correction).
• Drug loading: Quantify MTX content by UV–Vis (ε near 302–305 nm, literature) or HPLC after controlled hydrolysis; report as wt% or mol% substitution.
• Residuals/impurities: Assess residual solvents (GC), free MTX (HPLC), and unreacted PEG (SEC/HPLC). Heavy metals and water content are application-dependent; if required, request specific limits from CoA.
• Functional integrity: For ester/carbonate linkages, assess stability (pH 7.4 and pH 5.5, 37 °C) and report half-life where applicable.

Interpreting common grade terms (general)

• Research grade: Suitable for exploratory R&D; may not include pharmacopeial testing.
• HPLC grade (solvent context) or “low UV” is not applicable to this solid; however, “HPLC-verified” may indicate chromatographic purity assessment for free MTX.

Notes

• If this item includes a specified average PEG MW or linkage type, those parameters dominate performance; obtain and review the item-specific CoA for batch-critical details.

Reaction and Applications

Item-specific applications

• Manufacturer application text: Not provided for this item.

General research applications for mPEG–MTX (literature/general knowledge; no clinical claims)

• Prodrug and delivery studies: Model system to investigate PEGylation effects on antifolate transport, release kinetics (hydrolysis/enzymatic cleavage), and biodistribution proxies in vitro.
• Nanostructure formation: Amphiphilic conjugates may self-assemble into micelles or participate in co-assembly with amphiphiles/polymers for carrier development; useful for studying critical aggregation concentration and cargo co-loading.
• Surface conjugation: When prepared with latent reactive handles (not specified here), PEG–MTX can be immobilized on nanoparticles or surfaces to study ligand-density and binding phenomena. For this mPEG-capped variant, the PEG terminus is methoxy (nonreactive), so further covalent modification typically proceeds via MTX side groups only if available after conjugation (linkage-dependent).
• Analytical method development: Calibration and validation of release assays (HPLC/LC–MS) under physiologically relevant conditions; UV–Vis methods leveraging MTX chromophores.

Practical considerations

• Verify linkage chemistry (ester/carbonate/amide) for appropriate stability testing.
• Establish mass balance between free MTX, conjugated MTX, and PEG during hydrolysis studies.
• Use controls: free MTX, unconjugated PEG of matching Mn, and, where relevant, a noncleavable analogue for mechanistic comparison.

Reaction Conditions

Applicability

• This product is not a classical reagent for stoichiometric or catalytic reactions. The most relevant “conditions” are those governing stability and release of MTX from the conjugate.

General conditions for stability/release studies (literature/general guidance)

• Hydrolytic stability: Assess in phosphate-buffered saline (PBS, pH 7.4) and acetate/citrate buffer (pH 5–6) at 37 °C to emulate extracellular and endosomal/lysosomal environments. Sample over hours to days depending on linkage.
• Enzymatic conditions: Where applicable, include esterases or lysosomal mimic cocktails to probe enzyme-accelerated release (if the conjugate bears hydrolyzable linkages). Maintain enzyme controls and temperature (37 °C).
• Organic cosolvent effects: DMSO can suppress aggregation but may also alter hydrolysis kinetics; keep ≤1–2% v/v in aqueous assays when possible.
• Light and oxidation: Protect from intense light; PEG backbones are generally robust but aromatic MTX chromophores can undergo photochemical changes in some media.

Analytical readouts

• HPLC/LC–MS for free MTX quantitation; SEC for intact conjugate size; UV–Vis at ~302–305 nm (MTX chromophore, literature) for rapid screening with appropriate calibration.

Item-specific parameters (temperatures, half-lives, kinetic constants)

• Not specified for this item; determine empirically for each batch and linkage.

Safety and Handling

Item-specific hazard data

• Signal word, H-statements, GHS classification, pictograms: Not specified for this item; refer to the SDS.

General safety guidance (literature/general knowledge; not a substitute for SDS)

• Hazard considerations: Methotrexate is an antimetabolite; PEGylation may alter bioavailability but does not eliminate intrinsic hazards. Handle as potentially harmful by ingestion, inhalation, or skin/eye contact. Avoid aerosol/dust formation.
• PPE: Wear lab coat, safety glasses or face shield, and appropriate chemically resistant gloves (e.g., nitrile). Use in a chemical fume hood or ventilated enclosure to minimize exposure.
• Incompatibilities: Avoid strong oxidizers and strong acids/bases that may degrade ester/carbonate linkages. Aminolysis or hydrolysis may occur under strongly basic or nucleophilic conditions.
• First aid (overview): In case of skin contact, wash thoroughly with soap and water. For eye exposure, rinse cautiously with water for several minutes; remove contact lenses if present and easy. If inhaled, move person to fresh air. If ingested, rinse mouth; do not induce vomiting; seek medical attention. Always follow institutional protocols.
• Spill/accidental release: Absorb with inert material (e.g., vermiculite), avoid generating dust, and dispose according to local regulations for laboratory chemical waste.
• Waste: Collect solutions and solids in properly labeled hazardous waste containers; incineration via licensed contractor is typical for cytotoxic/antimetabolite-containing waste.

Authoritative source

• Always consult the product’s SDS and institutional EHS guidance for definitive hazard and handling requirements.

Solvent Selection

Item-specific directives

• No solvent recommendations are specified for this item; refer to CoA/Spec Sheet.

General solvent guidance for mPEG–MTX conjugates (literature/general knowledge)

• Polarity class: Amphiphilic macromolecular conjugate; hydrophilic behavior dominated by PEG segment; aromatic MTX moiety can drive limited hydrophobic interactions/aggregation.
• Likely good solvents: Water, PBS, saline, carbonate/bicarbonate buffers; DMSO, DMF. Ethanol and methanol may dissolve at modest concentrations depending on PEG MW and linkage.
• Poor solvents: Alkanes, ethers of low polarity (e.g., diethyl ether), and chlorinated nonpolar solvents (CH2Cl2) typically show low solubility.
• pH effects: Solubility increases as MTX carboxylates ionize (basic pH). Near-neutral buffers are generally suitable for handling; avoid strong base if ester linkages are present (risk of hydrolysis).

Small comparison (general)

• Water/PBS: Biocompatible, ideal for bioassays; may require gentle warming and time for full dissolution.
• DMSO: Excellent solvency; commonly used to prepare concentrated stocks for later dilution into buffers. Control final DMSO content in biological experiments.
• Carbonate buffer (pH ~9–10): Effective for rapid dissolution but may accelerate cleavage of base-labile linkages—use briefly and neutralize promptly if stability is a concern.

Practical tips

• Pre-wet with a small volume of DMSO, then bring to volume with buffer to minimize aggregation.
• Filter sterilize through 0.22 μm if sterile solutions are required; verify that no significant adsorption to filters occurs (PEG generally passes).

Storage and Reconstitution

Item-specific storage

• Storage conditions: Room temperature (per Product Data).
• Shipping: Shipped under normal conditions (per Product Data).

Stability notes

• Protect from moisture and prolonged exposure to strong light. If linkage is base-labile (not specified), avoid extended storage in basic environments.

General reconstitution guidance (literature/general knowledge)

• Aqueous use: Dissolve the required amount directly into water, PBS, or suitable buffer with gentle agitation; brief sonication or warming to 25–37 °C may assist dissolution. Adjust pH cautiously if necessary.
• Organic stocks: For maximal solubility, first dissolve in DMSO or DMF to prepare a concentrated stock; dilute into aqueous media immediately before use, keeping final organic content low.
• Sterile preparations: Filter through a 0.22 μm membrane after full dissolution, if sterility is required.

Aliquoting and shelf life

• Prepare single-use aliquots to minimize repeated opening. For aqueous solutions, short-term storage at 2–8 °C may be acceptable; for longer-term storage, freezing at −20 °C can be considered if the conjugate remains stable and solubility is retained after thawing. Specific shelf-life data are not specified for this item; validate empirically.

Research use note

• For research use only (per Product Data). Always consult the CoA and SDS for lot-specific instructions.

Structure and Identity

Item-specific facts (from Product Data)

• SKU: M163999
• Product name: mPEG Methotrexate (PEG methotrexate)
• Storage: Room temperature; shipped under normal conditions
• CAS, CID, InChIKey, SMILES, molecular formula, and average molecular weight: Not specified for this item; refer to CoA/Spec Sheet.

General structural description (literature/general knowledge)

• Composition: A covalent conjugate of methoxy-poly(ethylene glycol) (mPEG) and methotrexate (MTX, a folate analog with pteridine–p-aminobenzoate–glutamate motif).
• Architecture: mPEG is a linear, polydisperse polyether terminated by a nonreactive methoxy end; MTX provides aromatic heterocycles (pteridine), a para-aminobenzoate ring, and a glutamate tail with carboxylates.
• Linkage: mPEG–MTX conjugates are commonly assembled via ester, carbonate, or amide-type couplings between PEG hydroxyls/derivatives and MTX carboxyl(s). The specific linkage chemistry for this item is not specified; consult the CoA/SDS.
• 2D structural features: Expect a long, flexible –(CH2–CH2–O)n– chain (mPEG) appended to the MTX scaffold bearing multiple aromatic rings, heteroatoms (N, O), and ionizable carboxylate/aminobenzoate groups.
• Polydispersity: PEG chains exhibit a molecular weight distribution (Ð > 1); the stated average MW (not provided here) determines the conjugate’s hydrodynamic size and solubility.

Notes

• Without an InChIKey/SMILES or defined PEG chain length, a single, discrete molecular identity cannot be assigned; treat as a polymer–drug conjugate with an average composition.

Synthetic Utility

Item-specific note

• This product is a preformed PEG–drug conjugate; it is not primarily a synthetic building block. No reactive end-groups or linker details are provided for this item.

General utility in chemical biology/materials research (literature/general knowledge)

• Probe for conjugation strategies: Serves as a reference for studying the consequences of PEGylation site and linkage on small-molecule function and release.
• Supramolecular assembly: The amphiphilic nature can drive micellization or co-assembly with other macromolecules, enabling structure–property studies (CAC determination, size distribution by DLS/SEC-MALS).
• Method development: Useful for validating analytical workflows (controlled hydrolysis, HPLC/LC–MS quantitation of freed MTX, SEC profiling of conjugate vs. PEG).

Caveats and alternatives

• If further covalent functionalization is required, mPEG’s methoxy terminus is typically nonreactive; select PEG derivatives with activated or orthogonally protected termini (e.g., azide-, alkyne-, NHS-, maleimide-PEG) at the outset.
• For stable conjugates, amide/urea linkages are preferred; for releasable systems, carbonate/ester or enzymatically cleavable spacers are commonly employed (general guidance—linkage for this item is not specified).

Target Specificity

Item-specific data

• No target, epitope, clone, or species specificity information is provided for this item, and it is not an antibody/biologic.

Note

• While MTX as a small molecule interacts with folate pathway enzymes (e.g., DHFR) in general biochemical contexts, target engagement of any specific mPEG–MTX conjugate depends on release of MTX and is not specified for this item.

Frequently Asked Questions

How should this product be stored?

Store at room temperature.

How is this product shipped?

This product ships under standard ambient conditions. No temperature-controlled packaging is required.

What documentation is provided?

Available product documentation, including Certificates of Analysis (COA), Safety Data Sheets (SDS), and specification sheets, is shown in the product document area. Document availability and access follow the current site policy.