Synthesis and characterization of pH-responsive N-naphthyl-N,O-succinyl chitosan micelles for oral meloxicam delivery

• Novel pH-responsive N-naphthyl-N,O-succinyl chitosan (NSCS) was synthesized.
• Meloxicam (MX) was loaded into NSCS micelles by physical entrapment methods.
• Drug-loaded methods affect loading efficiency, particle size and micelle stability.
• The MX release behaviors from MX-loaded micelles were adjusted by pH.
• NSCS micelles are less toxic on Caco-2 cells.

The aim of this study was to synthesize pH responsive chitosan and to evaluate the influence of drug-loaded micelle methods on loading efficiency, particle size and micelle stability. N-naphthyl-N,O-succinyl chitosan (NSCS) was successfully synthesized and meloxicam (MX) was loaded into the inner core of the NSCS micelles by physical entrapment methods (dialysis, O/W emulsion, dropping and evaporation) with a regular spherical shape (particle size 84–382 nm). MX-loaded micelles by evaporation method showed the highest entrapment efficiency. The stability of the drug-loaded micelles depended on not only the methods but also the initial of drug. NSCS micelles are less toxic on Caco-2 cells. In acidic medium at 0–2 h, percentage cumulative release of MX from MX-loaded micelles was similar to free drug. When the pH was adjusted to pH 6.8, the MX release was increased significantly. Therefore, this NSCS micelle would be desirable to develop MX carrier for oral drug delivery.