Dapsone

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Cat Number

API0231521

CAS Number

80-08-0

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Product Detail Description Scientific Support Customer Q&A

CAS Number

80-08-0

EINECS

201-248-4

Storage

Store at room temperature

Synonyms

4,4'-Sulfonyldianiline; Diaphenylsulfone; 4,4'-Diaminodiphenyl sulfone; Dapson; 4,4'-Diaminodiphenylsulfone; DADPS; Diphenasone; Novophone; Disulone; Sulfona

Molecular Formula

C12H12N2O2S

Molecular Weight

248.3

Smiles

C1=CC(=CC=C1N)S(=O)(=O)C2=CC=C(C=C2)N

Appearance

White to off-white powder

Melting Point

175-177℃

Boiling Point

511.7℃

General Description

Dapsone is a sulfone antibiotic with both antimicrobial and anti-inflammatory properties, synthesized as a synthetic derivative of the sulfonamide class. It is available in oral formulation and has been a cornerstone of therapy for certain infectious and inflammatory dermatologic conditions for decades. The agent is characterized by its slow acetylation metabolism and prolonged half-life.

Mechanism of Action

As an antimicrobial, dapsone inhibits bacterial synthesis of dihydrofolic acid by competing with para-aminobenzoic acid for the enzyme dihydropteroate synthase, exerting a bacteriostatic effect against Mycobacterium leprae. Its anti-inflammatory mechanism involves the inhibition of neutrophil chemotaxis, suppression of lysosomal enzyme release, and antagonism of the myeloperoxidase-halide system, which reduces tissue damage in neutrophilic dermatoses.

Application

It is a first-line agent for the treatment of leprosy in combination with rifampin and clofazimine as part of multidrug therapy. In dermatology, it is indicated for dermatitis herpetiformis, an intensely pruritic cutaneous manifestation of gluten sensitivity, where it provides rapid symptom control. Additional applications include the management of linear IgA disease, bullous pemphigoid, and other inflammatory dermatoses unresponsive to conventional therapy.

Dapsone for adult primary immune thrombocytopenia was evaluated in a multicenter RCT and a real‑world cohort. In the RCT (93 patients), 78.3% of dapsone‑treated patients discontinued after a median 4.6 weeks due to adverse events (66.7%) or lack of efficacy (33.3%). Response rates at week 52 were 21.7% with dapsone plus prednisone versus 8.5% with prednisone alone (P=0.17). In the observational cohort (46 patients), 30.4% experienced adverse events, leading to discontinuation in 23.9%, with a response rate of 13.6%.

Fig. 1 Probability of dapsone discontinuation over time. (Larue M, et al., 2025)

References

Larue M, et al. Efficacy and safety of dapsone in adult primary immune thrombocytopenia. Blood Adv. 2025; 9(8):1976-1983.

Does Dapsone require protection from light during storage?

Yes, it is photosensitive. Prolonged exposure to light can cause discoloration and degradation. Store in light-resistant containers in a cool, dry place.

What is the recommended storage temperature for Dapsone?

Store at controlled room temperature, between 15°C and 25°C. Avoid excessive heat, which can accelerate oxidative degradation.

Is Dapsone susceptible to oxidation, and how is this prevented?

Yes, the aromatic amine moiety is prone to oxidation. Our packaging minimizes headspace, and we recommend storing the material in its original container until use.

How is the impurity profile of Dapsone monitored for dermatological formulations?

We use a validated HPLC method to monitor related substances, including the known impurity monoacetyldapsone, ensuring compliance with pharmacopoeial limits.