Nifedipine loaded chitosan microspheres prepared by emulsification phase-separation

Area of Science:

• Materials Science
• Pharmaceutical Sciences
• Polymer Chemistry

Background:

• Nifedipine is a crucial calcium channel blocker for treating cardiovascular diseases.
• Chitosan microspheres offer a promising biodegradable drug delivery system.
• Optimizing nifedipine encapsulation and release from chitosan matrices is essential for effective therapy.

Purpose of the Study:

• To develop and characterize nifedipine-chitosan microspheres using an emulsification phase-separation method.
• To investigate the effect of nifedipine loading on microsphere properties and drug release kinetics.
• To confirm the molecular dispersion of nifedipine within the chitosan matrix.

Main Methods:

• Emulsification phase-separation technique for microsphere preparation.
• Differential scanning calorimetry (DSC) for thermal analysis.
• X-ray diffractometry (XRD) for structural elucidation.
• Scanning electron microscopy (SEM) for morphological examination.
• Drug release studies fitting to coupled Fickian/Case II transport models.

Main Results:

• High yield and entrapment efficiency of nifedipine were achieved.
• Excellent swelling properties of the nifedipine-chitosan microspheres were observed.
• Molecular dispersion of nifedipine at 1.84% loading was confirmed by DSC, XRD, and SEM.
• Drug release was faster at lower nifedipine loadings.
• Zero-order release kinetics were approached at higher polymer content, indicated by a diffusional exponent (n) close to one.

Conclusions:

• The emulsification phase-separation method is effective for producing nifedipine-chitosan microspheres with high yield and drug entrapment.
• Nifedipine-chitosan microspheres demonstrate tunable release characteristics influenced by drug loading.
• The observed release kinetics suggest potential for controlled drug delivery applications.