Factors Affecting the Dissolution of Indomethacin Solid Dispersions

Area of Science:

• Pharmaceutical Sciences
• Materials Science

Background:

• Indomethacin (IM) is an insoluble drug with poor bioavailability.
• Supersaturation techniques are crucial for enhancing the dissolution of poorly soluble drugs.
• Solid dispersions (SDs) offer a promising approach to improve drug solubility and dissolution.

Purpose of the Study:

• To investigate the impact of carrier type, drug/carrier ratio, binary carriers, and preparation method on indomethacin dissolution under supersaturation.
• To evaluate the influence of solvent evaporation (SE) and hot melt extrusion (HME) on indomethacin solid dispersions.
• To determine the relationship between drug crystallinity/amorphous state and dissolution rate in solid dispersions.

Main Methods:

• Preparation of indomethacin solid dispersions using poloxamer 188, PVP K30, and binary carriers.
• Utilized solvent evaporation (SE) and hot melt extrusion (HME) as preparation techniques.
• Analyzed drug dissolution profiles, crystal form (X-ray diffraction), and amorphous content (using techniques not specified but implied).

Main Results:

• Poloxamer 188 and PVP K30 showed better dissolution with SE; increasing drug/carrier ratio enhanced dissolution for poloxamer 188 SDs but decreased it for PVP K30 SDs.
• HME resulted in lower dissolution for poloxamer 188 and PVP K30 SDs compared to SE, but binary carrier SDs prepared by HME showed the best dissolution.
• SE induced a crystal form change in poloxamer 188 SDs, while HME did not; IM was amorphous in PVP K30 SDs prepared by both methods.
• SE resulted in coexisting amorphous and crystalline drugs in binary carrier systems, whereas HME yielded negligible amorphous IM.
• Higher amorphous proportion did not consistently correlate with higher dissolution rates.

Conclusions:

• Carrier type, drug/carrier ratio, and preparation method significantly influence indomethacin dissolution from solid dispersions.
• Solvent evaporation and hot melt extrusion yield different solid-state properties and dissolution behaviors.
• Factors beyond amorphous content, including carrier properties and particle characteristics, are critical for optimizing drug dissolution in solid dispersions.