Carbamazepine/betaCD/HPMC solid dispersions. II. Physical characterization

Area of Science:

• Pharmaceutical Technology
• Materials Science

Background:

• Carbamazepine (CBZ) is an important antiepileptic drug with poor aqueous solubility.
• Solid dispersions are a promising approach to enhance the solubility and bioavailability of poorly soluble drugs like CBZ.
• Beta-cyclodextrin (betaCD) and hydroxypropyl methylcellulose (HPMC) are commonly used excipients in solid dispersion formulations.

Purpose of the Study:

• To prepare and characterize solid dispersions of carbamazepine (CBZ) using beta-cyclodextrin (betaCD) and/or hydroxypropyl methylcellulose (HPMC).
• To compare the effects of spray-drying versus physical mixing on the properties of CBZ solid dispersions.
• To investigate the interactions between CBZ and the chosen excipients.

Main Methods:

• Solid dispersions were prepared using spray-drying and physical mixing techniques.
• Characterization involved scanning electron microscopy (SEM), differential scanning calorimetry (DSC), infrared (IR) spectroscopy, and X-ray powder diffraction (XRPD).

Main Results:

• Spray-drying yielded homogeneous, spherical microparticles, indicating successful solid dispersion formation.
• Physical mixtures resulted in heterogeneous systems where individual components were identifiable.
• Thermal and IR analyses suggested strong interactions between CBZ and excipients in spray-dried samples.
• No polymorphic transitions of CBZ were observed after spray-drying, as confirmed by IR and XRPD.

Conclusions:

• Spray-drying is an effective method for creating homogeneous carbamazepine solid dispersions with significant drug-excipient interactions.
• The spray-drying process enhances the physical state of carbamazepine without inducing polymorphic changes.
• Solid dispersions prepared by spray-drying show potential for improving carbamazepine's pharmaceutical properties.