Calamine lotion & Difference between IP, USP & BP Calamine lotion

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Calamine lotion contains an equal quantity of calamine & zinc oxide suspended with the aid of Bentonite Magma in a solution of Calcium Hydroxide.

Difference between Calamine lotion BP & Calamine lotion USP/IP

Formula: ZaCO₃. Zn(OH)₂. xFe₂O₃ (BP) or Zn0. xFe₂O₃ (USP/IP)

Calamine USP

Calamine is Zinc Oxide with a small proportion of ferric oxide.
Calamine contains not less than 98.0 % and not more than 100.5 % of ZnO, calculated on the ignited basis.
Zn0. xFe₂O₃

Calamine BP

As per British Pharmacopoeia (BP), Calamine is basic zinc carbonate with a small proportion of ferric oxide.
Calamine contains not less than 98.0 % and not more than 100.5 % of ZnO, calculated on the ignited basis.
ZaCO₃. Zn(OH)₂. xFe₂O₃

Calamine IP

Calamine is Zinc Oxide with a small proportion of ferric oxide.
Calamine contains not less than 98.0 % and not more than 100.5 % of ZnO, calculated on the ignited basis.
Zn0. xFe₂O₃

Calamine BP is a basic zinc carbonate (ZaCO₃. Zn(OH)₂. xFe₂O₃) coloured with ferric oxide (Fe₂O₃) i.e. whereas calamine USP/IP is Zinc oxide (ZnO) with a small proportion of ferric oxide (Fe₂O₃).

The presence of ferric oxide gives a pink colour for cosmetic reasons.

The tern calamine besides being applied to the official product is also used to describe the impure native zinc carbonate.

Aqueous Calamine Cream

Aq. Calamine cream contains not less than 6.30 and not more than 7.67 per cent w/w of ZnO.

Calamine Lotion

Calamine lotion contains an equal quantity of calamine & zinc oxide suspended with the aid of Bentonite Magma in a solution of Calcium Hydroxide. Calamine lotion contains 1 % liquified phenol which provides a local anaesthetic, antiseptic & antipruritic (anti-itching) action apart from antiseptic action.

Use/Therapeutic Indications

Calamine Lotion is a mild astringent lotion recommended for the topical treatment of mild skin irritation and inflammation, including mild sunburn.

How to apply/administration calamine lotion?

Calamine Lotion is applied topically to the affected area with cotton wool and allowed to dry. Shake the bottle well before using.

Pharmacodynamic properties of calamine lotion

Zinc oxide and calamine have similar properties. Calamine has mild astringent, antipruritic and soothing actions. Zinc oxide is mildly astringent has covering, protective and cooling properties.
Calamine and zinc oxide produce astringent effects in the skin or mucous membranes by coagulating protein. The protein precipitates which forms serve as a protective coat, allowing new tissue to regenerate underneath. They are commonly used to reduce the extent of weeping in dermatitis and to check oozing and discharge in other mild disorders.
Phenol functions as a preservative in Calamine Lotion.
Bentonite is used as a stabilising and suspending agent in Calamine Lotion.

Pharmacokinetic properties

Zinc oxide or calamine are unlikely to be absorbed through the skin. Zinc salts are poorly absorbed from the gastrointestinal tract. Only a small proportion of dietary zinc is absorbed. Zinc is widely distributed throughout the body and is excreted in the faeces with only traces appearing in the urine.

Phenol is absorbed through the skin and mucous membrane. It is metabolised to phenylglucuronide and phenyl sulphate and small amounts are oxidised to catechol and quinol, which are mainly conjugated. The metabolites are excreted in the urine which may tint the urine green.

Calamine lotion FAQ

Q. 1. What is the difference between calamine lotion IP and calamine lotion USP?

Answer:- Calamine BP is a basic zinc carbonate (ZaCO₃. Zn(OH)₂. xFe₂O₃) coloured with ferric oxide (Fe₂O₃) i.e. whereas calamine USP/IP is Zinc oxide (ZnO) with a small proportion of ferric oxide (Fe₂O₃).

Q.2. What is the function of Phenol in calamine lotion?

Phenol provides a local anaesthetic, antiseptic & antipruritic (anti-itching) action apart from antiseptic action. Phenol functions as a preservative in Calamine Lotion.

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