The invention relates to a class of molecules obtained for conjugating a species or substrate to Bortezomib by means of bonds of the boronic diester type which are stable in a neutral environment but which are capable of being degraded in a slightly acid environment (pH=4.5-5.0) releasing the drug Bortezomib and which can also be conjugated on the surface of a cro-nanosystem (a type of substrate) for the delivery of drugs in such a way as to become a constituent thereof. They represent a class of Bortezomib prodrugs with respect to hydrolysis of the boronic ester. They may be used in the transport and release of Bortezomib when it is necessary to diffuse it in slightly acid pH environments after passing through neutral pH environments in which the drug remains stably conjugated in the form of a non-biologically-active boronic ester. In practice the invention may be used for the intracellular release of Bortezomib where the latter will permit the drug to be transported in a biologically inactive form through the blood flow while undergoing pH-induced chemical degradation once introduced into the intracellular environment, inducing diffusion of the therapeutically effective form of Bortezomib. In the situation where this is used as a constituent of a drug delivery system, it will be anchored thereto and being provided with a delivery function it will be capable of reaching the intracellular environment at pH 4.5 where degradation of the prodrug to which the invention relates will take place, inducing diffusion of the Bortezomib.
