Development and characterization of lipid-polymeric nanoparticles for oral insulin delivery

Engineered nanoparticles in non-invasive insulin delivery for precision therapeutics of diabetes

Diabetes mellitus is a chronic disease leading to the death of millions a year across the world. Insulin is required for Type 1, Type 2, and gestational diabetic patients, however, there are various modes of insulin delivery out of which oral delivery is noninvasive and convenient. Moreover, factors like insulin degradation and poor intestinal absorption play a crucial role in its bioavailability and effectiveness. This review discusses various types of engineered nanoparticles used in-vitro, in-vivo, and ex-vivo insulin delivery along with their administration routes and physicochemical properties. Injectable insulin formulations, currently in use have certain limitations, leading to invasiveness, low patient compliance, causing inflammation, and side effects. Based on these drawbacks, this review emphasizes more on the non-invasive route, particularly oral delivery. The article is important because it focuses on how engineered nanoparticles can overcome the limitations of free therapeutics (drugs alone), navigate the barriers, and accomplish precision therapeutics in diabetes. In future, more drugs could be delivered with a similar strategy to cure various diseases and resolve challenges in drug delivery. This review significantly describes the role of various engineered nanoparticles in improving the bioavailability of insulin by protecting it from various barriers during non-invasive routes of delivery.

Oral Insulin Delivery: A Review on Recent Advancements and Novel Strategies

BACKGROUND

Due to the lifestyle of people in the community in recent years, the prevalence of diabetes mellitus has increased, so New drugs and related treatments are also being developed.

INTRODUCTION

One of the essential treatments for diabetes today is injectable insulin forms, which have their problems and limitations, such as invasive and less admission of patients and high cost of production. According to the mentioned issues, Theoretically, Oral insulin forms can solve many problems of injectable forms.

METHODS

Many efforts have been made to design and introduce Oral delivery systems of insulin, such as lipid-based, synthetic polymer-based, and polysaccharide-based nano/microparticle formulations. The present study reviewed these novel formulations and strategies in the past five years and checked their properties and results.

RESULTS

According to peer-reviewed research, insulin-transporting particles may preserve insulin in the acidic and enzymatic medium and decrease peptide degradation; in fact, they could deliver appropriate insulin levels to the intestinal environment and then to blood. Some of the studied systems increase the permeability of insulin to the absorption membrane in cellular models. In most investigations, in vivo results revealed a lower ability of formulations to reduce BGL than subcutaneous form, despite promising results in in vitro and stability testing.

CONCLUSION

Although taking insulin orally currently seems unfeasible, future systems may be able to overcome mentioned obstacles, making oral insulin delivery feasible and producing acceptable bioavailability and treatment effects in comparison to injection forms.

Enhancement of Oral Bioavailability of Protein and Peptide by Polysaccharide-based Nanoparticles

Oral drug delivery is a prevalent and cost-effective method due to its advantages, such as increased drug absorption surface area and improved patient compliance. However, delivering proteins and peptides orally remains a challenge due to their vulnerability to degradation by digestive enzymes, stomach acids, and limited intestinal membrane permeability, resulting in poor bioavailability. The use of nanotechnology has emerged as a promising solution to enhance the bioavailability of these vital therapeutic agents. Polymeric NPs, made from natural or synthetic polymers, are commonly used. Natural polysaccharides, such as alginate, chitosan, dextran, starch, pectin, etc., have gained preference due to their biodegradability, biocompatibility, and versatility in encapsulating various drug types. Their hydrophobic-hydrophilic properties can be tailored to suit different drug molecules.

Solid Lipid Nanoparticles vs. Nanostructured Lipid Carriers: A Comparative Review

Solid-lipid nanoparticles and nanostructured lipid carriers are delivery systems for the delivery of drugs and other bioactives used in diagnosis, therapy, and treatment procedures. These nanocarriers may enhance the solubility and permeability of drugs, increase their bioavailability, and extend the residence time in the body, combining low toxicity with a targeted delivery. Nanostructured lipid carriers are the second generation of lipid nanoparticles differing from solid lipid nanoparticles in their composition matrix. The use of a liquid lipid together with a solid lipid in nanostructured lipid carrier allows it to load a higher amount of drug, enhance drug release properties, and increase its stability. Therefore, a direct comparison between solid lipid nanoparticles and nanostructured lipid carriers is needed. This review aims to describe solid lipid nanoparticles and nanostructured lipid carriers as drug delivery systems, comparing both, while systematically elucidating their production methodologies, physicochemical characterization, and in vitro and in vivo performance. In addition, the toxicity concerns of these systems are focused on.

Solid lipid nanoparticles: a promising tool for insulin delivery

INTRODUCTION

Insulin plays a critical role in metabolism modulation including carbohydrate, lipid, and protein metabolism. There is room to improve insulin delivery but optimizing the best carrier remains challenging. Traditional and conventional approaches for insulin delivery do not emulate the normal fate of insulin release in the body. Despite extensive research attempts to overcome this and other challenges, the goal of achieving optimal insulin delivery that emulates the natural system remains unresolved.

AREAS COVERED

Solid Lipid Nanoparticles (SLNs) may provide a solution, because they are nontoxic, biocompatible, and straightforward to formulate thus providing a promising platform for achieving targeted and controlled delivery of various therapeutic agents. This review aims to provide an overview on the suitability and application of SLNs for insulin delivery. A special emphasis is placed on the biopharmaceutical aspects of insulin loaded SLNs which have not been explored in detail to date.

EXPERT OPINION

SLNs have proven to be safe and versatile drug delivery systems suitable for insulin delivery and capable of improving the efficacy and pharmacokinetic profile of encapsulated insulin. There is still some work to be done to fully explore SLNs' true potential as drug delivery and specifically insulin delivery vehicles suitable for clinical use.

Strategies to improve insulin delivery through oral route: A review

Diabetes mellitus is found to be among the most suffered and lethal diseases for mankind. Diabetes mellitus type-1 is caused by the demolition of pancreatic islets responsible for the secretion of insulin. Insulin is the peptide hormone (anabolic] that regulates the metabolism of carbohydrates, fats, and proteins. Upon the breakdown of the natural process of metabolism, the condition leads to hyperglycemia (increased blood glucose levels]. Hyperglycemia demands outsourcing of insulin. The subcutaneous route was found to be the most stable route of insulin administration but faces patient compliance problems. Oral Insulin delivery systems are the patient-centered and innovative novel drug delivery system, eliminating the pain caused by the subcutaneous route of administration. Insulin comes in contact across various barriers in the gastrointestinal tract, which has been discussed in detail in this review. The review describes about the different bioengineered formulations, including microcarriers, nanocarriers, Self-Microemulsifying drug delivery systems (SMEDDs), Self-Nanoemulsifying drug delivery systems (SNEDDs), polymeric micelles, cochleates, etc. Surface modification of the carriers is also possible by developing ligand anchored bioconjugates. A study on evaluation has shown that the carrier systems facilitate drug encapsulation without tampering the properties of insulin. Carrier-mediated transport by the use of natural, semi-synthetic, and synthetic polymers have shown efficient results in drug delivery by protecting insulin from harmful environment. This makes the formulation readily acceptable for a variety of populations. The present review focuses on the properties, barriers present in the GI tract, overcome the barriers, strategies to formulate oral insulin formulation by enhancing the stability and bioavailability of insulin.

Characterization and optimization of de-esterified Tragacanth-chitosan nanocomposite as a potential carrier for oral delivery of insulin: In vitro and ex vivo studies

Oral administration of insulin is one of the most challenging topics within this area, because insulin is degraded in stomach before it enters the bloodstream. In this study, for the first time, a nano-carrier for controlled and targeted oral delivery of insulin was developed using de-esterified Tragacanth and chitosan. The fabricated nanoparticles were synthesized using coacervation technique and their properties were optimized using response surface methodology. The effect of experimental variables on the particle size and loading efficiency was examined. In addition, the interactions between components were analyzed using Fourier transform infrared. The thermal stability of nanoparticles was studied by thermal gravimetric analysis. The insulin loading efficiency was measured and in vitro release profile and ex vivo insulin permeability was determined. Optimized nanoparticles showed spherical shape with a size less than 200 nm and zeta potential of +17 mV. Owing to their nanoscale dimensions and mucoadhesiveness, nanoparticles were synthesized using medium molecular weight of Chitosan. The insulin loading efficacy for the system was 6.4%, released under simulated gastrointestinal conditions in a pH-dependent manner. Based on all of the obtained results, it can be concluded that these nanoparticles can potentially be utilized as a carrier for the oral insulin delivery.

The effect of hypergravity in intestinal permeability of nanoformulations and molecules

The oral administration of drugs remains a challenge due to rapid enzymatic degradation and minimal absorption in the gastrointestinal tract. Mechanical forces, namely hypergravity, can interfere with cellular integrity and drug absorption, and there is no study describing its influence in the intestinal permeability. In this work, it was studied the effect of hypergravity on intestinal Caco-2 cells and its influence in the intestinal permeability of different nanoformulations and molecules. It was shown that the cellular metabolic activity and integrity were maintained after exposure to different gravity-levels (g-levels). Expression of important drug transporters and tight junctions' proteins was evaluated and, most proteins demonstrated a switch of behavior in their expression. Furthermore, paracellular transport of FITC-Dextran showed to significantly increase with hypergravity, which agrees with the decrease of transepithelial electrical resistance and the increase of claudin-2 at higher g-levels. The diffusion of camptothecin released from polymeric micelles revealed a significant decrease, which agrees with the increased expression of the P-gp observed with the increase in g-levels, responsible for pumping this drug out. The neonatal Fc receptor-mediated transport of albumin-functionalized nanoparticles loaded with insulin showed no significant changes when increasing the g-levels. Thus, this study supports the effect of hypergravity on intestinal permeability is dependent on the molecule studied and the mechanism by which it is absorbed in the intestine.

β-Cyclodextrin-containing chitosan-oligonucleotide nanoparticles improve insulin bioactivity, gut cellular permeation and glucose consumption

OBJECTIVES

The main objective of the present study was to develop a nanoparticulate drug delivery system that can protect insulin against harsh conditions in the gastrointestinal (GI) tract. The effects of the following employed techniques, including lyophilisation, cross-linking and nanoencapsulation, on the physicochemical properties of the formulation were investigated.

METHODS

We herein developed a nanocarrier via ionotropic gelation by using positively charged chitosan and negatively charged Dz13Scr. The lyophilised nanoparticles with optimal concentrations of tripolyphosphate (cross-linking agent) and β-cyclodextrin (stabilising agent) were characterised by using physical and cellular assays.

KEY FINDINGS

The addition of cryoprotectants (1% sucrose) in lyophilisation improved the stability of nanoparticles, enhanced the encapsulation efficiency, and ameliorated the pre-mature release of insulin at acidic pH. The developed lyophilised nanoparticles did not display any cytotoxic effects in C2C12 and HT-29 cells. Glucose consumption assays showed that the bioactivity of entrapped insulin was maintained post-incubation in the enzymatic medium.

CONCLUSIONS

Freeze-drying with appropriate cryoprotectant could conserve the physiochemical properties of the nanoparticles. The bioactivity of the entrapped insulin was maintained. The prepared nanoparticles could facilitate the permeation of insulin across the GI cell line.

Role of lipid nanocarriers for enhancing oral absorption and bioavailability of insulin and GLP-1 receptor agonists

Growing demand for insulin and glucagon-like peptide-1 receptor agonists (GLP-1 RA) is observed, considering the progressive nature of diabetes and the potential therapeutic role of peptides in its treatment. However, chronic parenteral administration is responsible for pain and rashes at the site of injection. Oral delivery of insulin and GLP-1 RA promises better patient compliance owing to their ease of administration and reduction in chances of peripheral hypoglycaemia and weight gain. The review article discusses the potential of lipid carriers in combination with different strategies such as absorption enhancers, PEGylation, lipidisation, etc. The lipid nanocarriers improve the membrane permeability and oral bioavailability of high molecular weight peptides. Additionally, the clinical status of different nanocarriers for anti-diabetic peptides is discussed. Previous research on nanocarriers showed significant hypoglycaemic activity and safety in animal studies; however, extrapolation of the same in human subjects is not validated. With the rising global burden of diabetes, the lipid nanocarriers show the potential to revolutionise treatment with oral delivery of insulin and GLP-1 RA.

Fabrication techniques for the preparation of orally administered insulin nanoparticles

The development of orally administered protein drugs is challenging due to their intrinsic unfavourable features, including large molecular size and poor chemical stability, both of which limit gastrointestinal (GI) absorption efficiency. Nanoparticles can overcome the GI barriers effectively and improve the oral bioavailability of proteins in the GI tract. They possess large surface area to volume ratio, and can facilitate the GI absorption of nanoparticles via the paracellular and transcellular routes. Nanoparticles can be prepared by various fabrication techniques that can encapsulate the fragile therapeutic proteins via hydrophobic bonding and electrostatic interaction. A desirable technique should involve minimal harsh conditions and encapsulate therapeutic proteins with preserved functionalities. The current review examines the characteristics of each preparation technique, and illustrates the examples of insulin-loaded nanoparticles that have been developed in each fabrication method. The following techniques, which include nanoprecipitation, hydrophobic conjugation, flash nanocomplexation, double emulsion, ionotropic gelation, and layer-by-layer adsorption, have been used to formulate ligand-modified nanoparticles for targeted delivery of insulin. Other techniques, including reduction, complex coacervation (polyelectrolyte complexation), hydrophobic ion pairing and emulsion solvent diffusion method, and sol-gel technology, were also discussed in the latter part of the review due to their extensive use in fabrication of insulin nanoparticles. This review also discusses the strategies that have been utilised during the formulation process to improve the stability and bioactivity of therapeutic proteins.

Oral delivery of liraglutide-loaded Poly-N-(2-hydroxypropyl) methacrylamide/chitosan nanoparticles: Preparation, characterization, and pharmacokinetics

The delivery of peptides or protein drugs via the oral route has always presented a significant challenge. Here, nanoparticles for the oral delivery of liraglutide are prepared. The nanoparticles are composed of the biodegradable carrier materials chitosan and poly-N-(2-hydroxypropyl) methacrylamide (pHPMA). In addition, CSKSSDYQC (CSK) and hemagglutinin-2 (HA₂) are introduced into the particles to improve the in vivo bioavailability of liraglutide. The size of the nanoparticles is less than 200 nm, and the encapsulation efficiency is approximately 80%. Compared with the subcutaneously injected liraglutide solution group (100%), the relative bioavailability of the nanoparticle group modified with CSK and HA₂ reached 10.12%, which is 2.53 times that of the oral liraglutide solution group. In vivo imaging results showed that pHPMA/HA₂-CSK chitosan nanoparticles (pHPMA/HA-CCNPs) are retained in the gastrointestinal tract for up to 12 h, which is beneficial for oral absorption. CSK and HA₂ modified pHPMA/chitosan nanoparticles significantly improved liraglutide oral bioavailability and therefore have the potential to be applied for oral administration of peptides and proteins.

Development of orally administered insulin-loaded polymeric-oligonucleotide nanoparticles: statistical optimization and physicochemical characterization

INTRODUCTION

Therapeutic peptides are administered via parenteral route due to poor absorption in the gastrointestinal (GI) tract, instability in gastric acid, and GI enzymes. Polymeric drug delivery systems have achieved significant interest in pharmaceutical research due to its feasibility in protecting proteins, tissue targeting, and controlled drug release pattern.

MATERIALS AND METHODS

In this study, the size, polydispersity index, and zeta potential of insulin-loaded nanoparticles were characterized by dynamic light scattering and laser Doppler micro-electrophoresis. The main and interaction effects of chitosan concentration and Dz13Scr concentration on the physicochemical properties of the prepared insulin-loaded nanoparticles (size, polydispersity index, and zeta potential) were evaluated statistically using analysis of variance. A robust procedure of reversed-phase high-performance liquid chromatography was developed to quantify insulin release in simulated GI buffer. Results and discussion: We reported on the effect of two independent parameters, including polymer concentration and oligonucleotide concentration, on the physical characteristics of particles. Chitosan concentration was significant in predicting the size of insulin-loaded CS-Dz13Scr particles. In terms of zeta potential, both chitosan concentration and squared term of chitosan were significant factors that affect the surface charge of particles, which was attributed to the availability of positively-charged amino groups during interaction with negatively-charged Dz13Scr. The excipients used in this study could fabricate nanoparticles with negligible toxicity in GI cells and skeletal muscle cells. The developed formulation could conserve the physicochemical properties after being stored for 1 month at 4 °C.

CONCLUSION

The obtained results revealed satisfactory results for insulin-loaded CS-Dz13Scr nanoparticles (159.3 nm, pdi 0.331, -1.08 mV). No such similar study has been reported to date to identify the main and interactive significance of the above parameters for the characterization of insulin-loaded polymeric-oligonucleotide nanoparticles. This research is of importance for the understanding and development of protein-loaded nanoparticles for oral delivery.

Hypromellose - A traditional pharmaceutical excipient with modern applications in oral and oromucosal drug delivery

Hydroxypropylmethylcellulose (HPMC), also known as Hypromellose, is a traditional pharmaceutical excipient widely exploited in oral sustained drug release matrix systems. The choice of numerous viscosity grades and molecular weights available from different manufacturers provides a great variability in its physical-chemical properties and is a basis for its broad successful application in pharmaceutical research, development, and manufacturing. The excellent mucoadhesive properties of HPMC predetermine its use in oromucosal delivery systems including mucoadhesive tablets and films. HPMC also possesses desirable properties for formulating amorphous solid dispersions increasing the oral bioavailability of poorly soluble drugs. Printability and electrospinnability of HPMC are promising features for its application in 3D printed drug products and nanofiber-based drug delivery systems. Nanoparticle-based formulations are extensively explored as antigen and protein carriers for the formulation of oral vaccines, and oral delivery of biologicals including insulin, respectively. HPMC, being a traditional pharmaceutical excipient, has an irreplaceable role in the development of new pharmaceutical technologies, and new drug products leading to continuous manufacturing processes, and personalized medicine. This review firstly provides information on the physical-chemical properties of HPMC and a comprehensive overview of its application in traditional oral drug formulations. Secondly, this review focuses on the application of HPMC in modern pharmaceutical technologies including spray drying, hot-melt extrusion, 3D printing, nanoprecipitation and electrospinning leading to the formulation of printlets, nanoparticle-, microparticle-, and nanofiber-based delivery systems for oral and oromucosal application. Hypromellose is an excellent excipient for formulation of classical dosage forms and advanced drug delivery systems. New methods of hypromellose processing include spray draying, hot-melt extrusion, 3D printing, and electrospinning.

Lyophilisation Improves Bioactivity and Stability of Insulin-Loaded Polymeric-Oligonucleotide Nanoparticles for Diabetes Treatment

The oral bioavailability of therapeutic proteins is limited by the gastrointestinal barriers. Encapsulation of labile proteins into nanoparticles is a promising strategy. In order to improve the stability of nanoparticles, lyophilisation has been used to remove water molecules from the suspension. Although various cryoprotections were employed in the preparation of lyophilised nanoparticles, the selection of cryoprotectant type and concentration in majority of the developed formulation was not justified. In this study, nanoparticles were fabricated by cationic chitosan and anionic Dz13Scr using complex coacervation. The effect of cryoprotectant types (mannitol, sorbitol, sucrose and trehalose) and their concentrations (1, 3, 5, 7, 10% w/v) on physiochemical properties of nanoparticles were measured. Cellular assays were performed to investigate the impact of selected cryoprotectant on cytotoxicity, glucose consumption, oral absorption mechanism and gastrointestinal permeability. The obtained results revealed that mannitol (7% w/v) could produce nanoparticles with small size (313.2 nm), slight positive charge and uniform size distribution. The addition of cryoprotectant could preserve the bioactivity of entrapped insulin and improve the stability of nanoparticles against mechanical stress during lyophilisation. The gastrointestinal absorption of nanoparticles is associated with both endocytic and paracellular pathways. With the use of 7% mannitol, lyophilised nanoparticles induced a significant glucose uptake in C2C12 cells. This work illustrated the importance of appropriate cryoprotectant in conservation of particle physiochemical properties, structural integrity and bioactivity. An incompatible cryoprotectant and inappropriate concentration could lead to cake collapse and formation of heterogeneous particle size populations.

Bio-nanotechnological advancement of orally administered insulin nanoparticles: Comprehensive review of experimental design for physicochemical characterization

Therapeutic proteins are labile macromolecules that are prone to degradation during production, freeze-drying and storage. Recent studies showed that nanoparticles can enhance the stability and oral bioavailability of encapsulated proteins. Several conventional approaches (enzyme inhibitors, mucoadhesive polymers) and novel strategies (surface modification, ligand conjugation, flash nano-complexation, stimuli-responsive drug delivery systems) have been employed to improve the physiochemical properties of nanoparticles such as size, zeta potential, morphology, polydispersity index, drug release kinetics and cell-targeting capacity. However, clinical translation of protein-based nanoparticle is limited due to poor experimental design, protocol non-compliance and instrumentation set-up that do not reflect the physiological conditions, resulting in difficulties in mass production of nanoparticles and waste in research funding. In order to address the above concerns, we conducted a comprehensive review to examine the experimental designs and conditions for physical characterization of protein-based nanoparticles. Reliable and robust characterization is essential to verify the cellular interactions and therapeutic potential of protein-based nanoparticles. Importantly, there are a number of crucial factors, which include sample treatment, analytical method, dispersants, sampling grid, staining, quantification parameters, temperature, drug concentration and research materials, should be taken into careful consideration. Variations in research protocol and unreasonable conditions that are used in optimization of pharmaceutical formulations can have great impact in result interpretation. Last but not least, we reviewed all novel instrumentations and assays that are available to examine mucus diffusion capacity, stability and bioactivity of protein-based nanoparticles. These include circular dichroism, fourier transform infrared spectroscopy, X-ray diffractogram, UV spectroscopy, differential scanning calorimetry, fluorescence spectrum, Förster resonance energy transfer, NMR spectroscopy, Raman spectroscopy, cellular assays and animal models.

Nanotechnology Advanced Strategies for the Management of Diabetes Mellitus

Background:

Medications currently available for the management of diabetes mellitus are inconvenient and have some limitations. Thus, investigations for novel approaches are needed to deliver and target antidiabetics safely to the site of action.

Objective:

The present review emphasizes the limitations of conventional antidiabetics and provides the recent progresses of nanotechnology in the treatment of diabetes mellitus with a special highlight on the novel nanocarriers methodologies employed as antidiabetic drug delivery systems.

Methods:

The potential nanocarriers employed for the treatment of diabetes comprise liposomes, niosomes, self-nanoemulsifying drug delivery systems, polymeric nanoparticles, gold nanoparticles, dendrimers and micelles. Herbal nanomedicine has also emerged to be a promising way for adequate delivery of herbal compounds. Other nanotechnology approaches involve the usage of oral insulin, inhalable insulin, artificial pancreas, and nanopump.

Results:

Nanocarriers have proved to lead a successful delivery of antidiabetic medications, aiming at drug targeting for enhanced efficacy and safety.

Conclusion:

These innovative generations of drug delivery systems have important benefits over conventionally existing ones. The future of nanotechnology in the management of diabetes is still open with several prospects and will be of pronounced significance.

Lipid-polymer hybrid nanoparticles for controlled delivery of hydrophilic and lipophilic doxorubicin for breast cancer therapy

Background: Lipid polymer hybrid nanoparticles (LPHNPs) for the controlled delivery of hydrophilic doxorubicin hydrochloride (DOX.HCl) and lipophilic DOX base have been fabricated by the single step modified nanoprecipitation method.

Materials and methods: Poly (D, L-lactide-co-glicolide) (PLGA), lecithin, and 1,2-distearoyl-Sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000 (DSPE-PEG 2000) were selected as structural components.

Results: The mean particle size was 173–208 nm, with an encapsulation efficiency of 17.8±1.9 to 43.8±4.4% and 40.3±0.6 to 59. 8±1.4% for DOX.HCl and DOX base, respectively. The drug release profile was in the range 33–57% in 24 hours and followed the Higuchi model (R²=0.9867–0.9450) and Fickian diffusion (n<0.5). However, the release of DOX base was slower than DOX.HCl. The in vitro cytotoxicity studies and confocal imaging showed safety, good biocompatibility, and a higher degree of particle internalization. The higher internalization of DOX base was attributed to higher permeability of lipophilic component and better hydrophobic interaction of particles with cell membranes. Compared to the free DOX, the DOX.HCl and DOX base loaded LPHNPs showed higher antiproliferation effects in MDA-MB231 and PC3 cells.

Conclusion: Therefore, LPHNPs have provided a potential drug delivery strategy for safe, controlled delivery of both hydrophilic and lipophilic form of DOX in cancer cells.

Cherry Extract from Prunus avium L. to Improve the Resistance of Endothelial Cells to Oxidative Stress: Mucoadhesive Chitosan vs. Poly(lactic-co-glycolic acid) Nanoparticles

Polyphenolic compounds contained in cherry extract (CE) are well known for their antioxidant and anti-inflammatory properties. Unfortunately, most of these natural compounds have low oral bioavailability, reducing their widespread use. Here, different concentrations of polyphenol-rich CE from Tuscany (Italy), encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), were compared with those encapsulated in two NP types, different from each other in terms of mucoadhesivity, obtained with chitosan derivatives (Ch-der), regarding CE gastrointestinal (GI) permeability and protective effect on oxidative stress. Different NP systems were physico-chemically characterized, and the antioxidant GI permeability was evaluated in a triple-cell co-culture model (Caco-2/HT29-MTX/Raji B), resembling the intestine. PLGA NPs efficiently entrapped CE (up to 840 µg gallic acid equivalent (GAE)/mL) without altering size (210 nm), polydispersity index (0.05), or zeta potential (−10.7 mV). Such NPs promoted permeation of encapsulated CE at a CE polyphenolic concentration of at least 2 µg GAE/mL. More mucoadhesive NPs from Ch-der, coded quaternary ammonium S-protected thiolated chitosan (QA-Ch-S-pro) NP, promoted CE GI permeation of 0.5 µg GAE/mL. At higher concentrations of Ch-der polymers, the resulting NPs containing CE were toxic toward Caco-2 and HT29-MTX cells. CE protected human umbilical vein endothelial cells (HUVECs) from oxidative stress and maintained its activity when entrapped in PLGA NPs. CE encapsulated in QA-Ch-S-pro NP protected HUVECs from oxidative stress, even more effectively than non-encapsulated CE. Furthermore, mucoadhesive NPs from Ch-der were more effective antioxidant protectors than PLGA NPs, but less cytotoxic PLGA NPs could be more useful when comparatively high therapeutic antioxidant doses are needed.