چکیده (انگلیسی):

The purpose of this research was to explore theapplication of ionic interactions between
naproxen sodium (NS) and chitosan (CH) in complexes (NSC) prepared by tray drying (TD) and spray
drying (SD) methods. Drug–polymer ratio (1:1) in the NSC was optimized on the basis of dialysis studies.
The particulate systems of NSC were prepared by tray drying (TD) and spray drying (SD) methods.
Release retarding polymers were added to the NSC and to the physical mixtures containing NS–CH and
their effects on water uptake, matrix erosion and drug release at different pH were compared. Spray
dried complexes (SDC) were spherical, free flowing, light and fine amorphous particles in contrast to the
crystalline, hard, tenacious, irregularly shaped, denser tray dried complexes (TDC) with poor flowability.
Differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and Fourier transform
infrared (FTIR) patterns confirm the conversion of crystalline to high energy amorphous phase suitable
for ionic interactions in NSC. Presence of release retarding polymers, kappa carrageenan and
hydroxypropylmethylcellulose (HPMC) in the NSC compacts retarded the drug release and improved
the matrix integrity. Carrageenan matrices exhibited more retardation than HPMC tablets. FTIR
patterns, erosion, swelling and drug release from matrices support ionic interactions between NS and CH
in NSC. The reasons for retarded drug release from the chitosan matrices at acidic pH include poor
solubility of drug at acidic pH, formation of a rate limiting polymer gel barrier along the periphery of
matrices and the ionic interactions between oppositely charged moieties.