Related Experiment Videos
Nifedipine loaded chitosan microspheres: characterization of internal structure
A K Singla1, M L Sharma, S Dhawan
1Department of Pharmaceutics, University Institute of Pharmaceutical Sciences Chandigarh, Panjab University, India. singlaak2000@yahoo.com
Summary
Researchers visualized nifedipine-loaded chitosan microspheres using scanning electron microscopy. Drug crystallization was observed, but at 2% loading, nifedipine appeared molecularly dispersed within the chitosan matrix.
Area of Science:
- Materials Science
- Pharmaceutical Sciences
- Polymer Chemistry
Background:
- Chitosan microspheres are widely investigated for drug delivery applications.
- Understanding the internal structure and drug distribution within microspheres is crucial for optimizing drug release profiles.
- Nifedipine, a calcium channel blocker, is frequently formulated into oral dosage forms.
Purpose of the Study:
- To investigate the internal structure and nifedipine distribution within chitosan microspheres using advanced imaging techniques.
- To determine the effect of drug loading concentration on nifedipine's physical state within the microspheres.
- To evaluate the impact of preparation parameters on microsphere morphology and drug entrapment.
Main Methods:
- Preparation of unloaded and nifedipine-loaded chitosan microspheres.
- Sectioning of microspheres using ultramicrotomy after embedding in a polymerized resin.
- Microscopic analysis using scanning electron microscopy (SEM) to visualize internal structures.
- Powder X-ray diffractometry (PXRD) to assess the crystalline state of nifedipine within the microspheres.
Main Results:
- SEM revealed a dense matrix in unloaded microspheres and visible nifedipine crystals in drug-loaded microspheres.
- At 2% nifedipine loading, no crystalline drug was observed via SEM or PXRD, suggesting molecular dispersion or dissolution.
- High surfactant (Span 85) concentration led to microsphere surface collapse but maintained internal density.
- Stirring during preparation improved drug entrapment and altered crystal morphology.
- Dissolution studies indicated the formation of pores within the microsphere internal structure.
Conclusions:
- Chitosan microspheres can effectively encapsulate nifedipine, with the drug's physical state dependent on loading concentration.
- Molecular dispersion of nifedipine at 2% loading may enhance its dissolution rate and bioavailability.
- Preparation methods significantly influence microsphere morphology, drug distribution, and entrapment efficiency.
- The observed pore formation after dissolution suggests potential mechanisms for controlled drug release.