Design of sustained-release nitrendipine microspheres having solid dispersion structure by quasi-emulsion solvent...

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Drug Delivery Systems

Background:

• Nitrendipine, a poorly water-soluble drug, exhibits low oral bioavailability.
• Developing effective drug delivery systems is crucial for improving therapeutic outcomes.
• Sustained-release formulations can enhance drug efficacy and patient compliance.

Purpose of the Study:

• To prepare and characterize one-step, sustained-release nitrendipine microspheres with a solid dispersion structure.
• To investigate the impact of formulation variables on microsphere properties and drug release.
• To evaluate the in vivo bioavailability of the developed nitrendipine microspheres.

Main Methods:

• Spherical crystallization technique (quasi-emulsion solvent diffusion method) using solid dispersing and sustained-release polymers.
• Micromeritic property and in vitro dissolution profile analysis.
• X-ray diffraction (XRD) and differential scanning calorimetry (DSC) for solid-state characterization.
• In vivo bioavailability study in healthy dogs.

Main Results:

• Particle size was primarily influenced by agitation speed.
• Dissolution rate was enhanced by dispersing agents and sustained by retarding agents.
• XRD and DSC confirmed nitrendipine's amorphous state within the microspheres, indicating effective dispersion.
• Microspheres demonstrated good stability under accelerated storage conditions.
• Relative bioavailability was significantly higher (107.78% vs. Baypress, 309.82% vs. conventional tablets).

Conclusions:

• The developed sustained-release nitrendipine microspheres with a solid dispersion structure effectively improve bioavailability.
• The formulation allows for controlled drug release, prolonging the Tmax value.
• This approach offers a viable strategy for enhancing the delivery of water-insoluble drugs.