Page 54 - Practical DF2 Corrected (2)

Pharm D Clinical Pharmacy program 2024-2025 Level 2, Semester 2 Pharmaceutical Dosage Forms II (PT 405)

Sunscreen Cream

• Solar light is composed of visible, infrared, and ultraviolet radiations.
• Of these radiations, UV rays are responsible for the therapeutic and noxious

effects on the skin.

• UV radiation may penetrate the skin inducing degeneration of the prickle layer.

→ where histidine is transferred to histamine → released histamine dilates

blood vessels, induces irritation, itching, etc.

• Thus, excessive exposure to UV may lead to burning (degeneration of the

prickle layer) and histaminic syndromes.

• They by their turn, leads to the excessive biosynthesis of melanin bodies in the

skin to act as protector from UV burning action → tanning of the skin.

• Moreover, the excessive exposure to UV may induce transient paralysis in heat

regulating center with the subsequent increase in body temperature, headache,

nausea, .... etc. i.e., symptoms of sun-strock.

• Sunscreen preparations are presented to prevent noxious effect of UV.

• These contain either a UV scattering agent e.g., calamine (calazol lotion) or

UV absorbing drugs (e.g., Salicylamide, aminobenzoates, dioxyacetone).

o These drugs are formulated as creams, lotion or spray.

o The creams are usually of o/w type.

o The medicament is usually oil soluble and has no ability to be absorbed i.e.,

of superficial activity.

The formula for preparation of sunscreen cream is the following:

Rx/

Stearic acid 15 g

Cetyl alcohol 0.5 g

Lanolin 2g

Glycerin 5g

Sodium hydroxide 0.18 g

Potassium hydroxide 0.5 g

Calamine 5g

Distilled water 75 g

Fiat cream. Mitte 15 g

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