Related Experiment Videos
Simultaneous effect of cyclodextrin complexation, pH, and hydrophilic polymers on naproxen solubilization
M Cirri1, F Maestrelli, G Corti
1Dipart. di Scienze Farmaceutiche, Università di Firenze, Polo Scientifico di Sesto Fiorentino, Via U. Schiff 50019 Sesto Fiorentino, Firenze, Italy.
Journal of Pharmaceutical and Biomedical Analysis
|January 13, 2006
Summary
The study shows that pH control and adding polymers like PVP can significantly improve naproxen solubility using cyclodextrins (CyDs). This combined approach enhances complex stability and reduces the amount of CyD required for effective drug solubilization.
Area of Science:
- Pharmaceutical Sciences
- Physical Chemistry
- Drug Delivery Systems
Background:
- Naproxen, an ionizable drug, exhibits pH-dependent solubility.
- Cyclodextrins (CyDs) are known to enhance drug solubility through complexation.
- Understanding the interplay of pH, CyD derivatives, and polymers is crucial for optimizing drug formulation.
Purpose of the Study:
- To investigate the effect of pH on naproxen complexation and solubilization with various cyclodextrins (beta-cyclodextrin and its derivatives).
- To evaluate the combined impact of pH variation and hydrophilic polymer addition on cyclodextrin efficacy.
- To determine the optimal conditions for enhancing naproxen solubility and complex stability.
Main Methods:
- Phase-solubility analysis was conducted in buffered aqueous solutions across a pH range of 1.1 to 6.5.
- The interaction between naproxen and different cyclodextrin derivatives (neutral, cationic, anionic) was studied.
- The influence of hydrophilic polymers, specifically polyvinylpyrrolidone (PVP), on complexation and solubility was assessed.
Main Results:
- The type of cyclodextrin substituent significantly affected solubilizing efficiency, with methyl derivatives being most effective.
- Unexpectedly, the charge of the cyclodextrin derivative did not influence its interaction with the ionizable naproxen.
- While drug solubility increased with pH, cyclodextrin complexation efficiency and stability decreased at higher pH due to the charged drug.
- Hydrophilic polymer addition, particularly PVP, counteracted the pH-induced destabilization, enhancing complex stability (e.g., up to 60% increase for hydroxypropyl beta-cyclodextrin).
Conclusions:
- A combined strategy of pH control and hydrophilic polymer addition effectively enhances naproxen solubilization and cyclodextrin complexation.
- This approach improves the stability of naproxen-cyclodextrin complexes and reduces the required cyclodextrin concentration.
- Theoretical modeling of drug solubility curves can guide the selection of optimal experimental conditions for desired naproxen solubility.