A method of producing a rapamycin-containing composition for treating
skin disease, which comprises the steps of dissolving rapamycin in an
ethanol-containing
solvent, adding a gelling and / or
thickening agent to the resulting rapamycin-containing solution, and adjusting the pH of the resulting rapamycin-containing composition to 5.5 to 6.1 with
triethanolamine or
tris(
hydroxymethyl)aminomethane (
TRIS) is provided. A method of inhibiting degradation of rapamycin in a rapamycin-containing composition for treating
skin diseases, wherein the method comprises the step of adjusting the pH of the composition to 5.5 to 6.1 with
triethanolamine or
tris(
hydroxymethyl)aminomethane is also provided. A rapamycin-containing composition for treating
skin diseases comprising (i) rapamycin, (ii)
carboxylic acid-containing aqueous
polymer, and (iii) at least one pH adjuster selected from
triethanolamine and tri(
hydroxymethyl)aminomethane, having a pH of 5.5 to 6.1 is also provided. The
carboxylic acid-containing
polymer may be carboxy
vinyl polymer (carbomer),
carboxymethyl cellulose or carboxyethyl
cellulose. The skin
disease may be dermatitis,
contact dermatitis,
psoriasis,
atopic dermatitis,
seborrheic dermatitis, nummular eczema,
vitiligo, keloids, autosensitised dermatitis, stasis dermatitis, sebaceous deficiency eczema, skin tumours of
tuberous sclerosis, and skin tumours of Recklinghausen’s
disease. Preferred topical gels comprise rapamycin, carboxy
vinyl polymer (carbomer),
ethanol, water and either triethanolamine or
tris(hydroxymethyl)aminomethane.