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

• Published in: Particuology 2018-10, Vol.40, p.169-176
• Main Authors: Basu, Tanushree, Pal, Bonamali, Singh, Satnam
• Format: Article
• Language: English
• Subjects: Antihypertensive drug; Drug release; Entrapment efficiency; Poly(lactic-co-glycolic) acid; Poly(N-isopropylacrylamide); Polylactic acid
• ISSN: 1674-2001; 2210-4291
• DOI: 10.1016/j.partic.2017.10.002

[Display omitted] •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 24h in PBS medium was achieved for PLGA–pNIPAM NPs.•Ramipril release from PLGA–pNIPAM core–shell NPs was diffusion controlled. 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 24h. 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.