In Vitro: Clobetasol propionate has an IC50 of 15.6 μM for CYP3A4. Clobetasol propionate (1 μM; 24 hours) selectively inhibits CYP3A5 and does not increase the protein level of CYP3A4. Clobetasol propionate does not affect cell growth in any cell line (AsPC-1 wild-type (WT), AsPC-1CYP3A5–/– cells with CYP3A5 overexpression (“3A5–/– + 3A5OE” cells), and AsPC-1CYP3A5–/– cells with CYP3A4 overexpression (“3A5–/– + 3A4OE” cells)).
In Vivo: Clobetasol propionate (applied topically; daily for 14 days) reduces the epidermal thickness of both normal and psoriatic skin in human psoriatic skin-SCID mouse transplant model topical application.