Patent ID: 8431612

Claim:
A compound according to structural formula (I) R—X—O—C(O)—R′ (I) including salts and hydrates thereof, wherein: R is a residue of a phorbol ester, wherein the phorbol ester is ingenol-3-acetate, ingenol-3-propionate, ingenol-3-palmitate, ingenol-3-angelate or ingenol-3-benzoate; X is an alkylene chain containing from 1 to 12 carbon atoms; R′ is a moiety that is ionizable at a pH in the range of about 2.0-8.0, wherein R′ comprises a carboxyl group of the formula —(CH 2 ) m —C(O)OM, m being an integer ranging from 1 to 4, or wherein R′ comprises an amino acid selected from —(CH 2 ) n —CH[(CH 2 ) n —NH 2 ]—(CH 2 ) n —C(O)OM and —(CH 2 ) n CH(NH 2 )—(CH 2 ) n —C(O)OM, each n being, independently of the others, an integer ranging from 0 to 4, and M is hydrogen or a counter ion; the illustrated —X—O—C(O)—R′ group is linked to the 6-carbon of R; and the illustrated —X—O—C(O)—R′ group hydrolyzes under biological conditions to yield a group of the formula —X—OH.