Solubilization of Azelnidipine in TPGS Micelles: Structural Insights, Micellar Stability, and Sustained Drug Release Behavior

Abstract

Polyethoxylated (PEO)-based nonionic surfactants, such as D-α-Tocopheryl polyethylene glycol succinate (TPGS), offer significant advantages in drug delivery due to their low toxicity, mild interaction with biological membranes, and ability to form stable micellar systems. This study investigates the solubilization and delivery of the poorly water-soluble drug AZP using TPGS micelles.

Highlights

• Low CMC (0.002 % w/v) of TPGS displayed monodisperse spherical morphology confirmed via DLS and TEM.
• High drug entrapment efficiency (86 %) was achieved for the poorly soluble drug AZP.
• Fluorescence studies confirmed AZP localization in the micelle core, ensuring protection from aqueous environments.
• Nanocarriers are used to enhance solubility, stability, and systemic delivery.

TPGS exhibited a low critical micelle concentration (0.002% w/v), forming stable, spherical, and monodisperse micelles (9.99–13.51 nm) with high drug-loading efficiency (86%). Fluorescence quenching studies confirmed the encapsulation of AZP in the hydrophobic micellar core, protecting it from aqueous degradation. In vitro release profiles showed sustained drug release from TPGS micelles, with less than 20% drug release in 6 hours compared to 90% from free AZP. Dilution studies showed micelle stability up to 30-fold dilution, with disassembly observed at higher dilutions.

These findings underscore the potential of TPGS micelles as effective nanocarriers to improve the solubility, stability, and bioavailability of hydrophobic drugs, while enabling controlled release for better therapeutic performance.

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Materials

Azelnidipine (99% pure) and D-α-Tocopheryl polyethylene glycol succinate (TPGS, ≥ 98%, MW 1513 Da) were generously provided by Pure Chem Pvt. Ltd., India. Pyrene was purchased from Sigma-Aldrich, USA. All reagents were of analytical grade. Deuterated water was procured from Tokyo Chemical Industries, Japan. Buffers were prepared according to the Indian Pharmacopoeia.

Solubilization of Azelnidipine in TPGS Micelles: Structural Insights, Micellar Stability, and Sustained Drug Release Behavior, Srushti Shah, Vandana Patel, Posted Date: July 25th, 2025, Research Square, DOI: https://doi.org/10.21203/rs.3.rs-7144838/v1

See also the interesting video on Vitamin E TPGS below and read more here