Development of a Quantitative Method for Formulation Microenvironmental pH Assessment

Area of Science:

• Pharmaceutical Sciences
• Analytical Chemistry
• Materials Science

Background:

• Pharmaceutical formulations often contain pH modifiers to enhance drug dissolution and stability.
• Ionizable drugs exhibit pH-dependent solubility, necessitating precise control of the microenvironmental pH.
• Current methods for assessing microenvironmental pH in complex formulations can be limited.

Purpose of the Study:

• To develop a quantitative method for assessing the microenvironmental pH of pharmaceutical formulations.
• To enable spatial pH mapping within dissolving drug compacts.
• To provide a tool for optimizing oral pharmaceutical formulations.

Main Methods:

• Utilized dual-emission pH-sensitive fluorescent dyes for imaging.
• Employed confocal laser scanning microscopy to visualize dissolving formulation compacts.
• Analyzed images using Python code to generate quantitative pH maps.

Main Results:

• Successfully mapped spatial pH changes across distinct layers of dissolving compacts.
• Demonstrated pH mapping over a broad pH range using two different fluorescent dyes.
• Validated a robust technique for microenvironmental pH assessment.

Conclusions:

• The developed technique offers a reliable method for assessing microenvironmental pH in pharmaceutical formulations.
• This approach can optimize formulation performance and stability, reducing reformulation needs.
• The technique has the potential to expedite the development of new pharmaceutical products.