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Partic. vol. 40 pp. 169-176 (October 2018)
doi: 10.1016/j.partic.2017.10.002

Fabrication of core–shell PLGA/PLA–pNIPAM nanocomposites for improved entrapment and release kinetics of antihypertensive drugs

Tanushree Basu, Bonamali Pal, Satnam Singh*

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ssingh@thapar.edu

Highlights

    • Core–shell PLA/PLGA–pNIPAM nanoparticles were synthesized as a biocompatible drug carrier. • Ramipril-loaded PLGA–pNIPAM core–shell NPs exhibited higher entrapment efficiency (78%) than PLA. • Up to 96% sustained release over 24 h in PBS medium was achieved for PLGA–pNIPAM NPs. • Ramipril release from PLGA–pNIPAM core–shell NPs was diffusion controlled.

Abstract

Polylactic acid (PLA) and poly(lactic-co-glycolic) acid (PLGA) are two commonly applied biodegradable polymers for the preparation of nanocomposites used in drug-delivery systems. However, these polymers lack desirable attributes such as resistance to aggregation during long-term storage due to lyophilisation. To improve their efficacy, in this work, PLA and PLGA were encapsulated within a shell of poly(N-isopropylacrylamide) (pNIPAM) using a single emulsion technique followed by an aqueous free radical precipitation polymerisation process, yielding core–shell PLA/PLGA–pNIPAM nanocomposites. The nanocomposites were characterised using zeta potential, dynamic light scattering, and transmission electron microscopy analyses and were further applied as a delivery system for ramipril, an antihypertensive drug. The drug-loaded PLGA–pNIPAM core–shell nanoparticles exhibited a higher drug content (91%) and entrapment efficiency (78%) than their PLA counterparts. An in vitro release study of the formulations at pH 7.3 in phosphate-buffered saline indicated that PLGA was more efficient than PLA with a sustained release of 86% of ramipril from the polymer matrix within 24 h. Furthermore, to determine the release kinetics, the data were fitted to Korsmeyer–Peppas and Higuchi models; the release of ramipril from the polymer matrix followed zero-order rate kinetics and an anomalous (non-Fickian) diffusion mechanism.

Graphical abstract

Keywords

Poly(lactic-co-glycolic) acid; Polylactic acid; Poly(N-isopropylacrylamide); Antihypertensive drug; Entrapment efficiency; Drug release