Bepotastine Besylate

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Cat Number

API0232146

CAS Number

190786-44-8

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Product Detail Description Scientific Support Customer Q&A

CAS Number

190786-44-8

EINECS

878-395-1

Storage

Store at room temperature

Synonyms

Bepotastine besylate; Bepreve; Talion; Bepotastine benzenesulfonate; 6W18MO1QR3

Molecular Formula

C27H31ClN2O6S

Molecular Weight

547.1

Smiles

C1CN(CCC1O[C@@H](C2=CC=C(C=C2)Cl)C3=CC=CC=N3)CCCC(=O)O.C1=CC=C(C=C1)S(=O)(=O)O

Appearance

White to pale yellowish-white crystalline powder

Melting Point

138-141°C

Boiling Point

546.8±50.0°C at 760 mmHg (Predicted)

Relative Density

1.3±0.1

General Description

Bepotastine besylate is a second‑generation, peripherally selective antihistamine with a piperidine core, structurally similar to cetirizine. The besylate salt (benzenesulfonate) enhances solubility and stability. The molecule contains a carboxylic acid group that limits blood‑brain barrier penetration, reducing sedative effects. It exists as a racemate, with both enantiomers exhibiting H1 antagonism.

Mechanism of Action

Bepotastine competitively antagonizes histamine at H1 receptors, blocking histamine‑induced vasodilation, vascular permeability, and sensory nerve stimulation. Additionally, it stabilizes mast cells by inhibiting the release of histamine, leukotrienes, and other inflammatory mediators. This dual action suppresses both early and late phases of the allergic response.

Application

Bepotastine is indicated for the treatment of itching associated with allergic conjunctivitis when administered topically. It also has oral formulations for allergic rhinitis and urticaria in certain countries. The besylate salt provides rapid onset (within 3‑5 minutes) and sustained duration of action.

Integrated analysis of two phase III conjunctival allergen challenge (CAC) trials and one phase IV environmental study examined bepotastine besilate ophthalmic solution 1.5% (BBOS) for ocular itching and associated nasal symptoms. In CAC studies, BBOS reduced nasal congestion, pruritus, rhinorrhea, and a non‑ocular composite symptom score at 15 min and 8 h (P≤0.01 vs. placebo). In the environmental study, BBOS reduced sneezing, nasal pruritus, and total nasal symptom score over 2 weeks, and more patients had investigator‑reported improvement in overall nasal symptoms (P≤0.04). Topical ocular BBOS alleviates rhinitis symptoms associated with allergic conjunctivitis.

Fig. 1 Phase III conjunctival allergen challenge (CAC) study design. (Cavet ME, et al., 2018)

References

Cavet ME, et al. Bepotastine besilate ophthalmic solution 1.5% for alleviating nasal symptoms in patients with allergic conjunctivitis. J Asthma Allergy. 2018;11:29-39.

Does Bepotastine Besylate require protection from light during storage?

Yes, it is moderately photosensitive. Light exposure can cause discoloration and degradation. Store in light-resistant containers, preferably amber glass.

What is the recommended storage temperature for Bepotastine Besylate?

Store at controlled room temperature (15-25°C). Avoid excessive heat above 30°C, which can accelerate oxidation of the piperidine ring.

Is Bepotastine Besylate stable in ophthalmic solution formulations?

Yes, when preserved with benzalkonium chloride and protected from light.

How is the impurity bepotastine N-oxide (an oxidative degradation product) monitored?

This degradation product is quantified using a stability-indicating HPLC method, ensuring it remains below pharmacopoeial limits.