Advantageous delivery of nifedipine from inorganic materials showing increased solubility and biocompatibility

• Nifedipine was intercalated in mont-K10 clay and loaded inside channels of MCM-41.
• MCM-41 holds higher drug loadings than K10 clay.
• Drug release from MCM-41 is fast, showing a concentration peak reached shortly.
• K10 clay shows biocompatibility by incorporating Ca2+ ions after drug release.
• Drug inside host materials is more resistant to photodegradation than in neat form.

Nifedipine, a potent calcium-channel blocking agent, widely used for treating hypertension has been immobilized inside inorganic matrix materials. The drug was intercalated in Montmorillonite K10 clay by cation exchange, and loaded by an adsorption method inside the channels of mesoporous MCM-41. Spectroscopic evidence (FTIR, powder X-ray diffraction (XRD)) as well as elemental analysis thermal analysis and electron microscopy revealed the preparation of the drug-loaded materials. Release profiling in a simulated body fluid from MCM-41 is fast, indicating that a concentration peak is reached in a short period of time, while the release profile from K10 is much slower. The release profile from MCM-41 leads to higher drug solubility compared even with neat drug solubility, which is advantageous in a drug known for its low solubility (ca. 20 μg mL–1). The same is true for K10 clay although its slow release kinetics leave it behind. Spectroscopic data supports this fact by showing that intermolecular host–guest interactions occur thus leading to the observed kinetic effects in the release experiments. In addition it is found that nifedipine inside the host materials is more resistant to photodegradation than in its pure form thus showing another important feature of the hybrid organic/inorganic formulation, as evidenced by GC data.

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