definiens: shall mean a compound or a pharma ceutically acceptable salt thereof comprising one constituent moiety covalently or ionically asso ciated with at least one other constituent moiety, wherein each moiety, in its separate form ( i.e., in the absence of the association ), is a therapeutically or pharma cologically active agent or a prodrug or pharmaceutically accep table salt of such an agent . The covalent associati on between said moieties can be either direct or indirect thro ugh a linker . Examples of covalent association incl ude without limitation ester, amide, carbamate, carbonate, cycl ic ketal, thioester, thioamide, thiocarbamate, thio carbonate, xanthate, and phosphate ester bonds . Each constitue nt moiety of a CODRUG ™ compound can be the same as or different from the other constituent moiety . Upon c leavage of the covalent or ionic association, the i ndividual constituent moieties are reconstituted as the thera peutically or pharmacologically active forms of the same moieties prior to conjugation