Controlled release of linear-dendritic hybrids of carbosiloxane dendrimer: the effect of hybrid's amphiphilicity on drug-incorporation; hybrid-drug interactions and hydrolytic behavior of nanocarriers.

Dendritic micelles formed from amphiphilic dendritic ABA triblock copolymers based on organic linear poly(ethylene oxide) and inorganic dendritic block containing silicon atoms (OSC-D(Gn)-PEO-D(Gn)-CSO, n=1-3)(1) were evaluated as drug delivery vehicles for a drug in both lipophilic and hydrophilic forms. The physical parameters of the drug-incorporated carriers including the influences of drug:carrier ratio, the release kinetics of the drugs from the micellar solution were measured. The apparent partition constant of drug between the carriers and the external medium was studied as well. It was observed that the loading efficiency and hydrolytic behavior of the hybrids depend on several factors, such as type of interaction between host and guest molecules, generation of the dendritic copolymers and pH. The release profiles of the drugs from the micelle solution were found to be a slow steady release at pH 1, 7.4 and 10. Investigation of the drug release dynamics in buffered media at pH 7.4 showed that the drug released through the carriers with slight deviation follow Fickian and Case II diffusion mechanisms for drugs in lipophilic and hydrophilic forms, respectively.