Alcaftadine

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Cat Number

API0232141

CAS Number

147084-10-4

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Product Detail Description Scientific Support Customer Q&A

CAS Number

147084-10-4

EINECS

899-976-6

Storage

Store at room temperature

Synonyms

Lastacaft; alcaftadina; R-89674; alcaftadinum; DTXSID80598455; 11-(1-methylpiperidin-4-ylidene)-6,11-dihydro-5H-imidazo[2,1-b][3]benzazepine-3-carbaldehyde

Molecular Formula

C19H21N3O

Molecular Weight

307.4

Smiles

CN1CCC(=C2C3=CC=CC=C3CCN4C2=NC=C4C=O)CC1

Appearance

White to yellow powder

Melting Point

167°C

Boiling Point

556.2±60.0°C at 760 mmHg (Predicted)

Relative Density

1.2±0.1

General Description

Alcaftadine is a novel dibenzazepine derivative with potent dual‑action antihistaminic and anti‑inflammatory properties. The molecule does not contain a carboxylic acid group, distinguishing it from classical antihistamines. Alcaftadine is a small lipophilic compound designed for topical ophthalmic use.

Mechanism of Action

Alcaftadine acts as a high‑affinity, competitive H1 histamine receptor antagonist, blocking histamine‑induced vasodilation and pruritus. Additionally, it prevents the release of histamine from mast cells and inhibits eosinophil chemotaxis. This dual mechanism suppresses both the early and late phases of allergic response.

Application

Alcaftadine is indicated for the prevention of itching associated with allergic conjunctivitis. Its onset of action is rapid, and a single dose provides protection for up to 16 hours. Unlike older antihistamine eye drops, alcaftadine has mast cell stabilizing activity, making it effective for both acute symptoms and prophylactic use.

In a prospective, observer‑masked study of 180 patients with mild‑to‑moderate allergic conjunctivitis, alcaftadine 0.25%, olopatadine 0.2%, and bepotastine 1.5% all effectively reduced Total Ocular Scoring System (TOSS) scores over 14 days. However, bepotastine and alcaftadine produced significantly greater symptom resolution than olopatadine (P=0.008). All three were safe. Bepotastine and alcaftadine appear superior to olopatadine for treating allergic conjunctivitis.

Fig. 1 Flowchart of recruitment, randomization and follow up. (Ayyappanavar S, et al., 2021)

References

Ayyappanavar S, et al. Comparative analysis of safety and efficacy of Alcaftadine 0.25%, Olopatadine hydrochloride 0.2% and Bepotastine besilate 1.5% in allergic conjunctivitis. Indian J Ophthalmol. 2021;69(2):257-261.

Does Alcaftadine require protection from light during long-term storage?

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

What is the recommended storage temperature for Alcaftadine?

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

Is Alcaftadine stable in ophthalmic solution formulations with preservatives?

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

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

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