Stable effervescent formulations using engineered citric acid composites

Overview

This technology addresses a long-standing stability challenge in effervescent tablet formulations. Citric acid, a key acid component that reacts with sodium hydrogen carbonate to release CO2, is prone to deliquescence under humid conditions. When citric acid absorbs moisture, it can prematurely react with hydrogen carbonate, causing product failure before use.

The solution involves loading citric acid into a mesoporous carrier to create a composite that remains physically stable even at relative humidity above 70%. The porous carrier physically separates citric acid from other tablet components during storage, preventing premature CO2 release. Upon contact with water, both components dissolve and react normally, delivering the intended effervescent function.

Technical specifications

• Mesoporous carrier encapsulation: Citric acid is loaded into a mesoporous carrier to form a stable composite, isolating it from sodium hydrogen carbonate and other reactive components during storage
• Humidity resistance: The composite remains physically stable at elevated humidity levels exceeding 70% RH, overcoming the deliquescence problem of free citric acid
• Functional release mechanism: Upon dissolution in water, both citric acid and sodium hydrogen carbonate dissolve and react to release CO2, preserving the intended effervescent performance
• Loading capacity: Planned evaluation of citric acid loading up to 40% (w/w) to identify optimal formulation parameters
• Formulation flexibility: Compatible with existing effervescent tablet manufacturing processes, requiring only substitution of standard citric acid with the engineered composite

Technology readiness level

This technology is at an early-to-mid stage of development. Planned validation activities include preparing citric acid-carrier composites across a range of loading levels, evaluating physical stability of composites at elevated humidities to identify the optimal carrier type and loading, and formulating complete effervescent tablets to test physical stability under stressed conditions such as 40°C and 75% relative humidity. These studies will establish the formulation parameters and performance benchmarks needed for commercial development and scale-up.