Formulation and Characterization of Magnetic Polyglutaraldehyde Nanoparticles as Carriers for Poly-l-Lysine-Methotrexate

Using the statistically optimised method, submicron magnetic polyglutaraldehyde nanoparticles (Fe-PGNP) with free surface carboxylic groups have been synthesized. A model anticancer agent methotrexate (MTX) has been chemically bonded onto the surface of these particles using poly-l-Lysine (PL) as a spacer. The drug release characteristics of the final delivery device, i.e. Fe-PGNP]-PL-MTX, has been elucidated at 37?C in a medium containing a proteolytic enzyme. Results demonstrate that using particles containing about 8% w/w of Fe₃O₄, and PL-MTX conjugate constituting 256 μg MTX per mg of PL, almost 50% of the conjugate can be covalently linked onto the carrier surface. Release studies failed to demonstrate the presence of free drug. However it appears that MTX-oligopeptides are released from the carrier as a result of the enzymatic hydrolysis of biodegradable bonds. It is suggested that Fe-PGNP]-PL-MTX may be useful in the intracellular active targeting of bonded drug(s).