Tailoring lipid-polymer hybrid nanoparticles as smart nanocarriers for entacapone delivery for managing Parkinson’s disease

Abstract

Entacapone is a catechol-O-methyltransferase (COMT) inhibitor, widely used for the symptomatic treatment of Parkinson’s disease. However, it presents setbacks associated with a short half-life and a poor blood-brain barrier permeability. In order to surpass these limitations, entacapone was encapsulated in lipid-polymer hybrid nanoparticles (LPHNPs) functionalized with vitamin E (TPGS), using different liquid lipids as olive oil and coconut oil, and the co-surfactant and penetration enhancer Transcutol® HP. Depending on the system chosen, the nanoformulations presented differences in the hydrodynamic sizes (D_DLS) after synthesis, and an increasing particle size in the following order: Transcutol® HP< olive oil < coconut oil. The nanoformulations presented interaction with mucins and serum proteins, which anticipates a good permeability for oral and intranasal administration. No cytotoxic effects were observed in human neuroblastoma (SH-SY5Y), human hepatocellular carcinoma (HepG2), or squamous cell carcinoma (RPMI 2650) cell lines for concentrations below 10 µM. Furthermore, olive oil and Transcutol® HP nanoformulations maintained the COMT inhibition effect in HepG2 cells and presented antioxidant and iron chelation properties in SH-SY5Y cells. An increase in entacapone permeability was observed for Transcutol® HP nanoformulations using in vitro RPMI cells. In vivo study using Caenorhabditis elegans as a model demonstrated survival percentages > 80% after acute exposure to the nanoformulations in concentrations up to 40 μM in both wild-type (N2) and parkinson’s disease model (WLZ3) strain, and antioxidant activity for HTT@Ent (40 μM) formulation in wlz3 strain. Overall, this work shows that the encapsulation of entacapone could be an interesting alternative in solving the drug performance by improving its physicochemical properties and permeability.

Introduction

Parkinson’s disease (PD) is a complex and multifactorial disorder, characterized by the progressive degeneration of a specific neural population responsible for locomotor functions and a widespread depletion of the neurotransmitter dopamine. At pathophysiological level, PD is linked to a complex array of interlinked mechanisms that involve protein aggregation, abnormal vesicular trafficking, oxidative stress (ROS), iron overload and mitochondrial dysfunction [1]. As a result, PD significantly hinder life’s quality, with symptoms that include movement-related symptoms, such as tremors, bradykinesia and postural instability, together with non-motor ones such as depression, mood alteration and sleep disturbances [2], [3], [4]. Due the complex nature and pathophysiological complexity, finding effective therapeutic solutions has become a struggle for the scientific community as no disease-modifying therapies have been found so far. The currently available therapies are palliative, meant to manage the associated symptoms and give patients some relief.

Since PD motor symptoms are a result of dopaminergic neuronal death and dopamine depletion, therapies currently available focus on improving this neurotransmitter levels in the CNS. The “gold standard” treatment is the administration of Levodopa, a drug that acts as a dopamine precursor, together with adjunctive therapies used to improve its half-life in the blood such as Aromatic L-amino acid decarboxylase inhibitors or Catechol-O-methyltransferase inhibitors (iCOMT) [5]. Entacapone is an effective and safe reversible iCOMT, however it has poor oral bioavailability (≈ 35%) and is quickly eliminated after oral administration, whereas around 90% of entacapone is eliminated in the first 30–40 min due to extensive first-pass metabolism, thus requiring frequent administrations (up to 10 daily dosages) [6]. Plus, entacapone only has peripheral activity since it is not capable to cross the blood-brain barrier (BBB) and inhibit COMT in the CNS [7].

The BBB is the main limiting factor for drug delivery to the CNS, as nearly 98% of small molecules cannot cross or bypass it [8]. Intranasal drug delivery is one of the most promising administration routes to overcome the problem. It is a non-invasive route that offers a high surface area for drug absorption and a direct route to deliver drugs to the CNS, thus bypassing the BBB and avoiding first-pass metabolism [8], [9].

In recent years, nanotechnology has been recognized as a promising approach for effective drug delivery. Nanocarriers, such as polymeric and lipidic nanoparticles (NPs), allow the targeted and controlled drug release, via oral and intranasal delivery, overcoming drugs’ permeability issues, minimizing toxicity, and improving its pharmacodynamics and ADMET properties [10], [11]. Lipid-based NPs have proven to be a stimulating alternative to solve entacapone setbacks by improving permeability in a co-culture model of Caco-2/HT29-MTX cell lines while still maintaining the COMT inhibitory activity [12]. Also, polylactic co-glycolic acid (PLGA)-based polymeric NPs showed an enhancement of cell membrane permeation but a low entacapone entrapment capacity [12]. In this context, lipid-polymer hybrid nanoparticles (LPHNPs) can be also looked as promising as they can present the advantages of both components. They are considered to be advanced core–shell nanoconstructs and present higher cellular delivery efficiency in vivo when compared to both polymeric and lipidic NPs [10]. LPHNPs have been designed to present increased biocompatibility, controlled drug release, and improving drugs’ half-lives, while minimizing side-effects [13].

Moreover, LPHNPs can be easily up-scaled and functionalized with different ligands, namely with D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) which presents an amphiphilic nature and is used as emulsifier, gelling agent, solubilizer and dispersant agent [10], [14]. TPGS also contains polyethylene glycol, which is often used for nanocarriers’ optimization, reducing NP’s opsonization and adding a stealth effect, avoiding their clearance through the mononuclear phagocyte system [7]. Also, TPGS has been used for PD therapy, acting as a trap for free radicals and interrupting damaging cell chain reactions [15]. LPHNPs can be prepared by using natural oils, such as coconut and olive oils, which are known by their beneficial antioxidant properties, improving the protection against ROS overproduction, and related oxidative stress effects, like inflammation [10]. Coconut oil contains polyphenols, important antioxidants that could reduce lipid peroxidation, and olive oil contains oleuropein, which can act as free radical scavengers and reduce or minimize peroxidation-related events [16].

To the best of the authors’ knowledge, no study has explored the use of LPHNPs to encapsulate entacapone in order to improve its physicochemical properties. Moreover, understanding how entacapone behaves in different NPs with different lipids could bring valuable insights in designing new nanomedicine-based therapeutics for complex diseases. Hence, under this work, it was envisaged to create non-toxic entacapone-loaded LPHNPs, capable to exert both antioxidant and COMT inhibition, being also capable to surpass the nasal epithelial cell monolayer. Different natural liquid lipids (olive and coconut oils) as well as Transcutol® HP were used to improve the encapsulation of entacapone and potentiate the antioxidant activity. The functionalization of LPHNPs with TPGS was also performed in order to improve antioxidant activity. Moreover, the nanoformulations were tested in in vivo model, Caenorhabditis elegans (C. elegans) are a relatively new in vivo method that allows for the study of genetics and different diseases [17], [18]. This model is also very interesting for studying diseases that affect the nervous system, such as PD since it is very well characterized and presents some identifiable responses that can be extrapolated into human responses [19], [20], [21].

Download the full article as PDF here Tailoring lipid-polymer hybrid nanoparticles as smart nanocarriers for entacapone delivery for managing Parkinson’s disease

or continue reading here

Materials

Poly(lactic-co-glycolic acid) (PLGA) (Mw∼44 kDa; LA:GA 50:50) with terminal carboxylic acid was kindly offered by Corbion Purac and used without further purification. Transcutol® HP was kindly offered by Gattefossé (Lyon, France). Bleach, olive and coconut oils were purchased in the market. Entacapone was acquired from Amadis Chemicals, China. Dulbecco’s PBS (10x) was purchased BioConcept, Amimed. Phosphate-buffered saline solution (PBS 10 ×), heat-inactivated bovine serum (FBS), antibiotic (10,000 U/mL penicillin, 10,000 μg/mL streptomycin), and Hank’s balanced salt solution without and with calcium and magnesium [HBSS (−/−) and HBSS (+/+)] were purchased from PanBiotech. Trypsin (0.25% and 0.05%) was acquired from Merck. Mucins type II, Kolliphor® P188, hydroxypropyl-β-cyclodextrin (HPβCD), Minimum essential medium (MEM 0643), Dulbecco’s modified eagle’s medium (DMEM D7777) with 4.5 g/L glucose, neutral red, sulforhodamine B sodium salt and sodium bicarbonate were acquired from Sigma-Aldrich Química SA (Sintra, Portugal). Resazurin sodium salt was purchased from TCI Chemicals. Acetonitrile and acetone were acquired from Carlo Erba. Trifluoroacetic acid (TFA) were purchased from Honeywell. NaOH and NaCl were purchased from Thermo Fisher Scientific. The water used was ultrapure filtered (Millipore, Burlington, MA, USA).

Cláudia Sofia Machado, Joana Moreira, Isadora Silva, Ana Rita Alfenim, Vinicius de Monte Vidal, Victoria Díaz-Tomé, Francisco J. Otero Espinar, Miguel Pinto, Carlos Fernandes, Tailoring lipid-polymer hybrid nanoparticles as smart nanocarriers for entacapone delivery for managing Parkinson’s disease, Biomedicine & Pharmacotherapy, Volume 200, 2026, 119536, ISSN 0753-3322, https://doi.org/10.1016/j.biopha.2026.119536.

See also the interesting video on Vitamin E TPGS: