1. Membrane Transporter/Ion Channel
  2. P-glycoprotein
  3. Valspodar

Valspodar (Synonyms: PSC 833)

Cat. No.: HY-17384 Purity: ≥98.0%
Handling Instructions

Valspodar (PSC 833) is a selective P-glycoprotein inhibitor that has been used as an experimental cancer treatment and chemosensitizer.

For research use only. We do not sell to patients.

Valspodar Chemical Structure

Valspodar Chemical Structure

CAS No. : 121584-18-7

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1 mg USD 200 In-stock
Estimated Time of Arrival: December 31
5 mg USD 550 In-stock
Estimated Time of Arrival: December 31
10 mg USD 920 In-stock
Estimated Time of Arrival: December 31
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Customer Review

Based on 13 publication(s) in Google Scholar

Top Publications Citing Use of Products

    Valspodar purchased from MCE. Usage Cited in: J Drug Target. 2016;24(5):441-9.

    Cells are co-treated with 5 μM of free LY156758 or an equivalent dose of SMA-LY156758 and either vehicle control (0.01% DMSO), Elacridar (1 μM), KO143 (5 μM), Valspodar (1 μM) or a combination of efflux inhibitors for 6 h.

    Valspodar purchased from MCE. Usage Cited in: Oncotarget. 2016 Oct 18;7(42):68623-68637.

    The effect of MDR1 on drug sensitivity to 5-FU in BGC-823 cells is tested by using MDR1 specific inhibitor PSC833. Cells are exposed to 2 μM 5-FU combined with PSC833 (0, 1, 3, 9 μM) for 72 h. Cell viability is detected by CCK-8 assay.
    • Biological Activity

    • Protocol

    • Purity & Documentation

    • References

    • Customer Review


    Valspodar (PSC 833) is a selective P-glycoprotein inhibitor that has been used as an experimental cancer treatment and chemosensitizer.

    In Vitro

    Valspodar (PSC 833) has no cytotoxicity effects at up to the concentration of 0.75 μg/mL. Valspodar (0.25, 0.5 and 0.75 μg/mL) and DOX-L are added to the DOX resistant cells, and cell kill efficacy of MDR cell type increases significantly when valspodar is administered alongside DOX-L. Valspodar (0.5 and 0.75 μg/mL), in combination with all concentrations of DOX, are most toxic and kill more than 70% of the resistant cells[1]. Pretreatment with PSC833 decreases the IC50 value of NSC 279836 in MDA-MB-435mdr cells to 0.4±0.02 μM in MDR cells and almost completely reverses the resistance of MDR cells to NSC 279836[3].

    MCE has not independently confirmed the accuracy of these methods. They are for reference only.

    In Vivo

    valspodar (10 mg/kg, o.p.) exhibits minimal blood-cell partitioning as reflected in its low mean blood-to-plasma ratio of approximately 0.52. Valspodar displays properties of slow clearance and a large volume of distribution. Valspodar shows properties of low hepatic extraction and wide distribution, similar to that of its structural analogue CsA[2]. Preadministration of PSC833 to mice increases NSC 279836 fluorescent intensity in MDR tumor to 94% of that in the wild-type tumors[3].

    MCE has not independently confirmed the accuracy of these methods. They are for reference only.

    Clinical Trial
    Molecular Weight




    CAS No.

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    Room temperature in continental US; may vary elsewhere.

    Powder -20°C 3 years
    In solvent -80°C 6 months
    -20°C 1 month
    Solvent & Solubility
    In Vitro: 

    DMSO : 12 mg/mL (9.88 mM; Need ultrasonic and warming)

    Stock Solutions
    Concentration Solvent Mass 1 mg 5 mg 10 mg
    1 mM 0.8233 mL 4.1165 mL 8.2330 mL
    5 mM 0.1647 mL 0.8233 mL 1.6466 mL
    10 mM --- --- ---
    *Please refer to the solubility information to select the appropriate solvent.
    In Vivo:
    • 1.

      Add each solvent one by one:  10% DMSO    90% corn oil

      Solubility: ≥ 2.5 mg/mL (2.06 mM); Clear solution

    *All of the co-solvents are provided by MCE.
    Cell Assay

    The in vitro cytotoxicity of various formulations against T47D/TAMR-6 cells is investigated by MTT assay. A 104 T47D/TAMR-6 cells are cultured in 96-well plate containing RPMI medium and incubated overnight to allow cell attachment. After 48 hours incubation, fresh medium containing serial concentration of various drug formulations, including free DOX, DOX-L, mixture of DOX-L and free Valspodar (PSC 833), mixture of DOX-L and PSC-L and DOX/PSC-L are added. The plates are then incubated for an additional 48 hours before washing with normal saline followed by adding MTT solution (0.5 mg/mL) to each well, and incubated for 4 h at 37°C. Then, the medium is removed, and DMSO is added to dissolve the formazan crystals. The plates are mildly shaken for 10 min to ensure the dissolution of formazan. The formazan dye is measured spectrophotometrically using microplate reader at 570 nm with reference standard of 690 nm as described before.

    MCE has not independently confirmed the accuracy of these methods. They are for reference only.

    Animal Administration

    Male Sprague–Dawley rats (250-350 g) are housed in temperature-controlled rooms with 12 h of light per day. The animals had free access to food and water prior to experimentation. Rats are divided into two groups: one group (n=6) receives intravenous dose (5 mg/kg) of valspodar and the other group administered valspodar orally (10 mg/kg). Stereoselective pharmacokinetics of desbutylhalofantrine, a metabolite of halofantrine, in the rat after administration of the racemic metabolite or parent drug. After surgery, the rats are transferred to their regular holding cages and allowed free access to water, but food is withheld overnight. The next morning, rats are transferred to the metabolic cages and dosed with valspodar.

    MCE has not independently confirmed the accuracy of these methods. They are for reference only.


    Purity: 99.27%

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    ValspodarPSC 833PSC833PSC-833P-glycoproteinP-gpPgpMultidrug resistance protein 1MDR1ATP-binding cassette sub-family B member 1ABCB1Cluster of differentiation 243CD243Inhibitorinhibitorinhibit

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