Pegylated lysine based copolymeric dendritic micelles for solubilization and delivery of artemether

A newer polymeric amphiphilic micellar system was developed in the present study for solubilization and controlled delivery of an antimalarial drug, Artemether (ART). Methoxy polyethylene glycol (MPEG) 2000 and 5000 were used as hydrophilic terminal.

The hydrophobic di-Fluorene methoxycarbonyl-l-lysine (di-FMOC-L-lysine) was linked initially to the single reactive end of MPEG, and to the two amino groups of l-lysine by consecutive peptide linkages and deprotection upto 2.5 generations (G). Half-generations are diFMOC-lysine terminated systems and full-generations are deprotected l-lysine terminated systems. The half-generation (0.5 G, 1.5 G and 2.5 G) dendritic micelles of MPEG 2000 and 5000 were used to solubilize artemether. IR, NMR and Mass spectroscopy characterized the synthesis of these micellar systems. The CMC of the systems was determined. Then formulations made were characterized for solubility enhancement (i.e. drug loading) and drug-release profile.

There is considerable solubility enhancement of artemether upto three to fifteen times depending on concentration, generation and type of dendritic micelles used. The size and shape were studied using transmission electron microscopy. The stability of the micellar formulation was also determined by storing the micelles at various temperatures for a definite period of time followed by its successive dilutions. The dendritic carriers were found to form stable micelles at 10-30 microg/ml (lower CMCs) depending on generation and type of MPEG used. The formulations increased the stability of the drug and also prolonged the release of artemether upto 1-2 days in vitro.

From all the studies performed, it can be concluded that these micellar systems can be used for the safe and effective delivery of insoluble bioactive.