Topical compositions and methods for treating psoriasis

A pharmaceutical composition comprising:

• tazarotene, 0.045% w/w,
• diethyl sebacate, 2.97% w/w,
• light mineral oil, 8.03% w/w,
• sorbitan monooleate, 0.1% w/w,
• sorbitol solution (70%), 10.7% w/w,
• methyl paraben, 0.17% w/w,
• propyl paraben, 0.03% w/w,
• edetate disodium dihydrate, 0.05% w/w,
• carbomer copolymer type B, 0.4% w/w,
• carbomer homopolymer type A, 0.6% w/w,
• sodium hydroxide, q.s. to pH of 5.5±0.5, and
• purified water, q.s. to 100% w/w.