Water-soluble paclitaxel derivates and pharmaceutical composition and medicinal application thereof

The invention provides water-soluble derivates of paclitaxel antitumor drugs paclitaxel and docetaxel shown by Ia and Ib and nontoxic pharmaceutically-acceptable salts thereof, wherein in the formulae Ia and Ib, n is an integer selected from 1 to 4; R is natural or non-natural L or D type amino acid side chain, including H, -CH3, -CH(CH3)2, -CH2CH(CH3)2, -CH(CH3)(CH2CH3), -CH2OH, -CH(OH)(CH3), -CH2SH, -CH2CH2SCH3, -CH2COOH, -CH2CONH2, -CH2CH2COOH, -CH2CH2CONH2, -(CH2)3NHC(NH)(NH2), and -(CH2)4NH2.