Synthesis of amphiphilic Janus dendrimer and its application in improvement of hydrophobic drugs solubility in aqueous media

Abstract

Classic dendrimers are not used in many specific applications such as simultaneous loading of different drugs due to the existence of identical end groups. The possibility of designing the structure in dendrimers paves the way to synthesize more complicated dendrimers. This includes the creation of various types of peripheral groups on the surface of dendrimers to synthesize for example Janus dendrimers. Nowadays, three main methods are proposed for the synthesis of Janus dendrimers in which the high amount of conventional dendrimers is produced. The goal of this work is to develop a new method for synthesis of Janus dendrimers without production of conventional dendrimers. The present method has three main stages for the synthesis of Janus dendrimers including synthesis of 5th generation PPI dendrimer with cystamine core and hydrophobic surface, conversion of disulfide bonds to thiol group using a structure scission approach, and the formation of PAMAM hydrophilic dendrons with amine end groups. Different analyses including FT-IR, NMR, DLS, and GPC are used to prove the success of the synthesis route. Also, due to application of dendrimers in drug delivery including solubility improvement of hydrophobic drugs, Janus dendrimers are used to improve solubility of tetracycline and dexamethasone in presence of different generations of Janus dendrimers. Since the Janus dendrimers have both hydrophilic and hydrophobic ends, as well as having numerous terminal groups and numerous internal cavities, they have resulted in significant improvements in drug solubility. Also, solubility of the two hydrophobic drugs in water was increased by increasing concentration and generation of dendrimer.