Diphenhydramine hydrochloride

Diphenhydramine hydrochloride (CAS 147-24-0), commonly referenced as diphenhydramine HCl, is an antihistamine active pharmaceutical ingredient used across prescription and OTC drug manufacturing.

It functions as an H1-receptor antagonist, making it a core API in formulations targeting allergy relief, sleep aid, and motion sickness indications. In OTC pharmaceutical manufacturing, it is the active ingredient in oral tablets.

It is also used in capsules and liquid formulations for allergy and nighttime sleep products. Topical drug products including creams, gels, and sprays incorporate it as an antipruritic agent to address skin irritation.

These topical applications are frequently used for insect bite reactions. Injectable formulations for hospital and clinical use also rely on this API, requiring tightly controlled purity specifications for safety.

In personal care, it appears in select cosmetic formulations where antipruritic or soothing claims are supported by regulatory frameworks. Diphenhydramine HCl is supplied as a white crystalline powder.

It is available in USP, BP, and Ph. Eur. grades to meet the documentation requirements of regulated pharmaceutical markets. This ensures compliance with international quality standards.

Technical-grade material is also available for non-pharmaceutical industrial applications where compendial certification is not required. This provides flexibility for various manufacturing needs and budgets.