POLYETHYLENE GLYCOL DERIVATISED DIHYDRO OR TETRAHYDRO PORPHYRINS, THEIR PREPARATION AND THEIR USE AS TUMOUR LOCALISING, PHOTOSENSITISING COMPOUNDS

摘要

Compounds being polyethylene glycol derivatised, pharmacologically acceptable, tumour locating dihydro or tetrahydro porphyrins of formulae (4, 5 and 6), wherein R1n may be -OH but in at least two instances is a chain of formula (-O-Xp-¢CH2CH2O!m-Y)n wherein n = 1 to 3, m = 5 to 250 and p = 0 to 1; the group Y may be a C1-C12 alkyl or acyl group but preferably a methyl group; the linking group X may be present or absent, but if present may be of the following alternative forms: R2 = -(C=O)-(CH2)q-O- where q = 1 to 5; R3 = -CH2-CH(OH)- (CH2)s-O- where s = 1 to 4; R4 = -(C=O)-(CH2)t-(C=O)-O- where t = 1 to 4. Improved tumour localisation of polyether-substituted photosensitising compounds is given leading to their more efficient uptake into tumour cells. Lower overall doses of drug give an improved side-effect profile of the treatment especially with regard to skin photosensitisation.