5-aminolevulinic acid prodrugs for use in photodynamic therapy and photodynamic diagnosis

There is provided a compound of Formula (I) and salts thereof, where R1 is an oxime or an alkylated oxime; the alkylated oxime comprises a linear or branched alkyl group of length C1 to C5; and R2 are each independently (a) an unsubstituted or substituted linear or branched alkyl group of chain length C1-7, (b) an aryl substituted alkyl group, where the aryl group is substituted, (c) an alkoxy substituted alkyl group, where the alkoxy group is substituted by a methoxy group or an alkoxy group substituted with an alkoxy group, or (d) an H atom, where the substituents in (a) and (b) are hydroxy, alkoxy, acyloxy, alkoxycarbonyloxy, amino, aryl, nitro, oxo or fluoro groups. The compounds may be used as a medicament.