PEGylation of coenzyme Q 10 and in vitro release studies.

Methoxy polyethylene glycol conjugated with coenzyme Q10 (mPEG)-CoQ10 and analog adducts with amino acids as spacers were synthesized as a new drug delivery systems for CoQ10. Alanine and branched chain amino acids (valine, leucine and isoleucine) were conjugated to mPEG by an amide linkage and to CoQ10 by an ester bond. Recently, branched chain amino acids (BCAAs), which are released along with CoQ10, have received increasing attention as 'anti-fatigue' elements. FT-IR and 1H NMR spectroscopic analysis were useful to characterize the synthesized conjugates. Studies in vitro, in buffer solutions at different pH and in the presence of esterase were conducted. The hydrolysis studies showed a specific cleavage dependent on the pH of the medium and by the presence of proteolytic enzymes. The results showed the improvement of the pharmacokinetic properties of CoQ10. The antioxidant activity of the synthesized conjugates was also evaluated by DPPH assay.