WARNING: This product is for research use only, not for human or veterinary use.

MedKoo CAT#: 100620

CAS#: 298-81-7

Description: Methoxsalen is a naturally occurring substance isolated from the seeds of the plant Ammi majus with photoactivating properties. As a member of the family of compounds known as psoralens or furocoumarins, methoxsalen's exact mechanism of action is unknown; upon photoactivation, methoxsalen has been observed to bind covalently to and crosslink DNA. Check for active clinical trials or closed clinical trials using this agent. (NCI Thesaurus).

Chemical Structure

CAS# 298-81-7

Theoretical Analysis

MedKoo Cat#: 100620
Name: Methoxsalen
CAS#: 298-81-7
Chemical Formula: C12H8O4
Exact Mass: 216.04226
Molecular Weight: 216.19
Elemental Analysis: C, 66.67; H, 3.73; O, 29.60

Price and Availability

Size Price Availability Quantity
100.0mg USD 170.0 2 Weeks
1.0g USD 320.0 2 Weeks
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Synonym: 8methoxypsoralen; Methoxypsoralen. US brand names: Ammoidin; Oxsorale

IUPAC/Chemical Name: 9-methoxy-7H-furo[3,2-g]chromen-7-one


InChi Code: InChI=1S/C12H8O4/c1-14-12-10-8(4-5-15-10)6-7-2-3-9(13)16-11(7)12/h2-6H,1H3


Appearance: Solid powder

Purity: >98% (or refer to the Certificate of Analysis)

Shipping Condition: Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition: Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Solubility: Soluble in DMSO, not in water

Shelf Life: >2 years if stored properly

Drug Formulation: This drug may be formulated in DMSO

Stock Solution Storage: 0 - 4 C for short term (days to weeks), or -20 C for long term (months).

HS Tariff Code: 2934.99.9001

Preparing Stock Solutions

The following data is based on the product molecular weight 216.19 Batch specific molecular weights may vary from batch to batch due to the degree of hydration, which will affect the solvent volumes required to prepare stock solutions.

Recalculate based on batch purity %
Concentration / Solvent Volume / Mass 1 mg 5 mg 10 mg
1 mM 1.15 mL 5.76 mL 11.51 mL
5 mM 0.23 mL 1.15 mL 2.3 mL
10 mM 0.12 mL 0.58 mL 1.15 mL
50 mM 0.02 mL 0.12 mL 0.23 mL

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 1: Zavigel'skii GB, Kotova VY. [SOS repair of 8-methoxypsoralene monoadducts in
DNA of lambda bacteriophage and plasmids is mediated by MucA'2B, but not UmuD'2c
(PolV) polymerase]. Genetika. 2013 Dec;49(12):1370-5. Russian. PubMed PMID:

2: Li J, Ma B, Zhang Q, Yang X, Sun J, Tang B, Cui G, Yao D, Liu L, Gu G, Zhu J,
Wei P, Ouyang P. Simultaneous determination of osthole, bergapten and
isopimpinellin in rat plasma and tissues by liquid chromatography-tandem mass
spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci. 2014 Nov
1;970:77-85. doi: 10.1016/j.jchromb.2014.06.014. Epub 2014 Jun 21. PubMed PMID:

Additional Information

Methoxsalen is a naturally occurring photoactive substance found in the seeds of the Ammi majus (Umbelliferae) plant. It belongs to a group of compounds known as psoralens or furocoumarins. The chemical name of methoxsalen is 9-methoxy-7H-furo[3,2-g][1]-benzopyran-7-one. Each mL of UVAOEX® (methoxsalen, 8-methoxypsoralen) Sterile Solution contains methoxsalen 20 mcg, propylene glycol 50 mg, sodium chloride 8 mg, sodium acetate 1.75 mg, ethanol 0.05 mL, glacial acetic acid 0.0012 mL, and Water for Injection 1.0 mL. UVAOEX® is used in combination with the UVAR® or UVAR® XTS™ Photopheresis System to extracorporeally treat leukocyte enriched buffy coat.
Mechanism of action
The exact mechanism of action of methoxsalen is not known.The best-known bio-chemical reaction of methoxsalen is wrth DNA. Methoxsalen,upon photoactivation,conjugates and forms covalent bonds with DNA which leads to the formation of both mono functional (addition to a single strand of DNA) and bifunctional adducts (cross linking of psoralen to both strands of DNA).  For the palliative treatment of Cutaneous T-Cell Lymphoma, Photopheresis consists of removing a portion of the patient's blood and separating the red blood cell from the white cell layer (buffy coat) by centrifugation. The red cells are returned to the patient and the UVADEX® Sterile Solutionis then injected into the instrument and mixed with the buffy coat. The instrument then irradiates this drug-cell mixture with ultra violet light (UVA light, 320-400 nm) and returns the treated cells to the patient. See the appropriate Operator's Manual for details of this process. Although extra corporeal phototherapy exposes less than 10% of the total body burden of malignant cells to methoxsalen plus light, some patients achieve a complete response. Animal studies suggest that the photopheresis may activate an immune-mediated response against the malignant T-cells.
Use of the UVAR® and UVAR® XTS™ Systems after oral administration of methoxsalen were previously approved for the treatment of Cutaneous T-Cell Lymphoma. Interpatient variability in peak plasma concentration after an oral dose of methoxsalen ranges from 6 to 15 fold. UVADEX® is injected directly into the separated buffy coat in the instrument in an attempt to diminish this interpatient variability and to improve the exposure of the cells to the drug. Methoxsalen is reversibly bound to serum albumin and is also preferentially taken up by epidermal cells. Methoxsalen is rapidly metabolized in humans, with approximately 95% of the drug excreted as metabolites in the urine within 24 hours. Systemic administration of methoxsalen followed by UVA exposure leads to cell injury. The most obvious manifestation of this injury after skin exposure is delayed erythema, which may not begin for several hours and peaks at 48-72 hours.The inflammation is followed over several days to weeks, by repair which is manifested by increased melanization of the epidermis and thickening of the stratum corneum. The total dose of methoxsalen delivered in UVADEX® is substantially lower (approximately 200 times) than that used with oral administration.