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Development of a Novel Alginate-Based Amlodipine Nanoplex for the Formulation of an Oral Film in Antihypertensive Therapy

Year: 2026

Type: article

Abstract: Background/Objectives: Amlodipine is an antihypertensive agent characterized by low aqueous solubility and variable oral bioavailability. This study aimed to formulate and characterize amlodipine–alginate nanoplexes and to incorporate the optimized system into an oral film dosage form. Methods: Nanoplexes were prepared via ionic complexation employing alginates (ALG) with diverse physicochemical properties, including low (LV) and medium (MV)-viscosity grades, as well as alginates with varying M/G ratios. The nanoplexes were thoroughly characterized employing a comprehensive set of analytical techniques. In addition, intermolecular interactions were examined using computational simulation studies. Results: The nanoplexes demonstrated high encapsulation efficiencies (>80%), with MV alginate yielding particles with greater drug loading but larger mean diameters compared with that prepared using LV alginate. Computational simulation studies revealed favorable interaction energies between the drug and the polyelectrolyte, particularly within microenvironments enriched in guluronic acid–rich repeat regions. These interactions were corroborated by infrared spectroscopy, while differential scanning calorimetry and X-ray diffraction analysis confirmed the amorphous solid state of amlodipine within the nanoplexes. Dissolution studies demonstrated an inverse relationship between alginate viscosity and drug release rate, with formulations based on LV alginate exhibiting rapid drug release. The final hydroxypropylmethylcellulose film incorporating ALG-MV nanoplexes exhibited adequate mechanical integrity and achieved approximately 95% drug release within 30 min. Conclusions: The developed film presenting a viable approach to enhance the delivery of amlodipine. Overall, this approach constitutes a significant advancement in the delivery of poorly soluble drugs through the integration of nanostructured systems with flexible oral film platforms.

Source: Pharmaceutics

DOI: 10.3390/pharmaceutics18060653