Effect of mucoadhesive polymers on the in vitro performance of insulin-loaded silica nanoparticles: Interactions with mucin and biomembrane models

Engineering resveratrol-loaded chitosan nanoparticles for potential use against Helicobacter pylori infection

Helicobacter pylori (H. pylori) is a microorganism directly linked to severe clinical conditions affecting the stomach. The virulence factors and its ability to form biofilms increase resistance to conventional antibiotics, growing the need for new substances and strategies for the treatment of H. pylori infection. The trans-resveratrol (RESV), a bioactive polyphenol from natural sources, has a potential activity against this gastric pathogen. Here, Chitosan nanoparticles (NP) containing RESV (RESV-NP) were developed for H. pylori management. The RESV-NP were prepared using the ionic gelation method and characterized by Dynamic Light Scattering (DLS), Nanoparticle Tracking Analysis (NTA) and, Cryogenic Transmission Electron Microscopy (Cryo - TEM). The encapsulation efficiency (EE) and in vitro release rate of RESV were quantified using high-performance liquid chromatography (HPLC). RESV-NP performance against H. pylori was evaluated by the quantification of the minimum inhibitory/bactericidal concentrations (MIC/MBC), time to kill, alterations in H. pylori morphology in its planktonic form, effects against H. pylori biofilm and in an in vitro infection model. RESV-NP cytotoxicity was evaluated against AGS and MKN-74 cell lines and by hemolysis assay. Acute toxicity was tested using Galleria mellonella model assays. RESV-NP showed a spherical shape, size of 145.3 ± 24.7 nm, polydispersity index (PDI) of 0.28 ± 0.008, and zeta potential (ZP) of + 16.9 ± 1.81 mV in DLS, while particle concentration was 3.12 x 1011 NP/mL (NTA). RESV-NP EE was 72 %, with full release within the first 5 min. In microbiological assays, RESV-NP presented a MIC/MBC of 3.9 µg/mL, a time to kill of 24 h for complete eradication of H. pylori. At a concentration of 2xMIC (7.8 µg/mL), RESV-NP completely eradicated the H. pylori biofilm, and in an in vitro infection model, RESV-NP (4xMIC - 15.6 µg/mL) showed a significant decrease in bacterial load (1 Log10CFU/mL) when compared to the H. pylori J99 control. In addition, they did not demonstrate a toxic character at MIC concentration for both cell lines. The use of the RESV-NP with mucoadhesion profile is an interesting strategy for oral administration of substances targeting gastric disorders, linked to H. pylori infections.

Chitosan surface modification modulates the mucoadhesive, permeation and anti-angiogenic properties of gellan gum/bevacizumab nanoparticles

Bevacizumab (BVZ) was the first monoclonal antibody approved by the FDA and has shown an essential advance in the antitumor therapy of colorectal cancer (CRC), however, the systemic action of BVZ administered intravenously can trigger several adverse effects. The working hypothesis of the study was to promote the modulation of the mucoadhesion properties and permeability of the BVZ through the formation of nanoparticles (NPs) with gellan gum (GG) with subsequent surface modification with chitosan (CS). NPs comprising BVZ and GG were synthesized through polyelectrolyte complexation, yielding spherical nanosized particles with an average diameter of 264.0 ± 2.75 nm and 314.0 ± 0.01 nm, polydispersity index of 0.182 ± 0.01 e 0.288 ± 0.01, and encapsulation efficiency of 29.36 ± 0.67 e 60.35 ± 0.27 mV, for NPs without (NP_BVZ) and with surface modification (NP_BVZ + CS). The results showed a good ability of nanoparticles with surface modification to modulate the NPs biological properties.

Surface functionalization affects the retention and bio-distribution of orally administered mesoporous silica nanoparticles in a colitis mouse model

Besides the many advantages of oral drug administration, challenges like premature drug degradation and limited bioavailability in the gastro-intestinal tract (GIT) remain. A prolonged residence time in the GIT is beneficial for enhancing the therapeutic outcome when treating diseases associated with an increased intestinal clearance rate, like inflammatory bowel disease (IBD). In this study, we synthesized rod-shaped mesoporous silica nanoparticles (MSNs) functionalized with polyethylene glycol (PEG) or hyaluronic acid (HA) and investigated their bio-distribution upon oral administration in vivo. The negatively charged, non-toxic particles showed different accumulation behavior over time in healthy mice and in mice with dextran sulfate sodium (DSS)-induced intestinal inflammation. PEGylated particles were shown to accumulate in the lower intestinal tract of healthy animals, whereas inflammation promoted retention of HA-functionalized particles in this area. Overall systemic absorption was low. However, some particles were detected in organs of mice with DSS-induced colitis, especially in the case of MSN-PEG. The in vivo findings were connected to surface chemistry-related differences in particle adhesion on Caco-2/Raji and mucus-producing Caco-2/Raji/HT29 cell co-culture epithelial models in vitro. While the particle adhesion behavior in vivo was mirrored in the in vitro results, this was not the case for the resorption results, suggesting that the in vitro model does not fully reflect the erosion of the inflamed epithelial tissue. Overall, our study demonstrates the possibility to modulate accumulation and retention of MSNs in the GIT of mice with and without inflammation through surface functionalization, which has important implications for the formulation of nanoparticle-based delivery systems for oral delivery applications.

Coating with tripolyphosphate-crosslinked chitosan as a novel approach for enhanced stability of emulsomes following oral administration: Rutin as a model drug with improved anti-hyperlipidemic effect in rats

The aim of the current study is to preserve the emulsomal vesicles against the harsh condition of gastrointestinal tract (GIT), after oral administration, employing tripolyphosphate (TPP)-crosslinked chitosan as a protective coating layer. Rutin was used as a model drug with evaluation of anti-hyperlipidemic activity in rats. The rutin loaded unmodified emulsomes were prepared using tripalmitin and soybean phosphatidylcholine (SPC), by thin film method. Drug loading for the prepared formulations ranged between 6.80 and 15.50 %. The selected formulation (RT-Emuls-6) comprised tripalmitin and SPC, molar ratio 1:1, and exhibited particle size (PS) and zeta potential (ZP) of 150.40 nm and -35.35 mV, respectively. RT-Emuls-6 was then modified by coating with either solely chitosan (RT-Emuls-6-Ch) or TPP-crosslinked chitosan (RT-Emuls-6-Ch-TPP-1). The latter exhibited PS and ZP values of 269.60 nm and 37.17 mV, respectively. Transmission electron microscopy of RT-Emuls-6-Ch-TPP-1 showed a dense pale greyish layer of a coating layer of chitosan crosslinked with TPP surrounding SPC bilayers. Fourier transform infrared spectroscopy analysis along with X-ray powder diffraction confirmed cross-linking between chitosan and TPP. Stability study in the simulated GIT fluids revealed that the order of rutin retained percentage was RT-Emuls-6-Ch-TPP-1 > RT-Emuls-6-Ch > RT-Emuls-6 (80.02, 50.66 and 44.41 %, respectively for simulated gastric fluid and 63.50, 55.66 and 24.00 %, respectively for simulated intestinal fluid, after 2 h incubation). Anti-hyperlipidemic activity of rutin loaded emulsomes was evaluated, after oral administration, in a high fat diet-induced hyperlipidemia in rats. The order of activity was as follows: RT-Emuls-6-Ch-TPP-1 > RT-Emuls-6-Ch > RT-Emuls-6 > free rutin. These findings revealed the potential of TPP-crosslinked chitosan as a protective coating layer for enhancing the stability of emulsomes against the harsh condition of GIT. RT-Emuls-6-Ch-TPP-1 had a potent anti-hyperlipidemic activity via regulation of lipids, oxidative stress, irisin and uncoupling protein 1.

Multilayered polymer coating modulates mucoadhesive and biological properties of camptothecin-loaded lipid nanocapsules

Lipid core nanocapsules (NCs) coated with multiple polymer layers were rationally designed as a potential approach for the colonic delivery of camptothecin (CPT). Chitosan (CS), hyaluronic acid (HA) and hypromellose phthalate (HP) were selected as coating materials, to modulate the mucoadhesive and permeability properties of CPT regarding the improvement of local and targeted action in the colon cancer cells. NCs were prepared by emulsification/solvent evaporation method and coated with multiple polymer layers by polyelectrolyte complexation technique. NCs exhibited spherical shape, negative zeta potential, and size ranged from 184 to 252 nm. The high efficiency of CPT incorporation (>94%) was evidenced. The ex vivo permeation assay showed that nanoencapsulation reduced the permeation rate of CPT through the intestinal mucosa by up to 3.5 times, and coating with HA and HP reduced the permeation percentage by 2 times when compared to NCs coated only with CS. The mucoadhesive capacity of NCs was demonstrated in gastric and enteric pH. Nanoencapsulation did not reduce the antiangiogenic activity of CPT and, additionally, it was observed that nanoencapsulation resulted in localized antiangiogenic action of CPT.

Aloe vera and copaiba oleoresin-loaded chitosan films for wound dressings: microbial permeation, cytotoxicity, and in vivo proof of concept

Chitosan films are commonly used for wound dressing, provided that this polymer has healing, mucoadhesiveness and antimicrobial properties. These properties can be further reinforced by the combination of chitosan with polysaccharides and glycoproteins present in aloe vera, together with copaiba oleoresin's pharmacological activity attributed to sesquiterpenes. In this work, we developed chitosan films containing either aloe vera, copaiba oil or both, by casting technique, and evaluated their microbial permeation, antimicrobial activity, cytotoxicity, and in vivo healing potential in female adult rats. None of the developed chitosan films promoted microbial permeation, while the cytotoxicity in Balb/c 3 T3 clone A31 cell line revealed no toxicity of films produced with 2 % of chitosan and up to 1 % of aloe vera and copaiba oleoresin. Films obtained with either 0.5 % chitosan or 0.5 % copaiba oleoresin induced cell proliferation which anticipate their potential for closure of wound and for the healing process. The in vivo results confirmed that tested films (0.5 % copaiba-loaded chitosan film and 0.5 % aloe vera-loaded chitosan film) were superior to a commercial dressing film. For all tested groups, a fully formed epithelium was seen, while neoformation of vessels seemed to be greater in formulations-treated groups than those treated with the control. Our work confirms the added value of combining chitosan with aloe vera and copaiba oil in the healing process of wounds.

pH-Responsive and Mucoadhesive Nanoparticles for Enhanced Oral Insulin Delivery: The Effect of Hyaluronic Acid with Different Molecular Weights

Drug degradation at low pH and rapid clearance from intestinal absorption sites are the main factors limiting the development of oral macromolecular delivery systems. Based on the pH responsiveness and mucosal adhesion of hyaluronic acid (HA) and poly[2-(dimethylamino)ethyl methacrylate] (PDM), we prepared three HA–PDM nano-delivery systems loaded with insulin (INS) using three different molecular weights (MW) of HA (L, M, H), respectively. The three types of nanoparticles (L/H/M-HA–PDM–INS) had uniform particle sizes and negatively charged surfaces. The optimal drug loadings of the L-HA–PDM–INS, M-HA–PDM–INS, H-HA–PDM–INS were 8.69 ± 0.94%, 9.11 ± 1.03%, and 10.61 ± 1.16% (w/w), respectively. The structural characteristics of HA–PDM–INS were determined using FT-IR, and the effect of the MW of HA on the properties of HA–PDM–INS was investigated. The release of INS from H-HA–PDM–INS was 22.01 ± 3.84% at pH 1.2 and 63.23 ± 4.10% at pH 7.4. The protective ability of HA–PDM–INS with different MW against INS was verified by circular dichroism spectroscopy and protease resistance experiments. H-HA–PDM–INS retained 45.67 ± 5.03% INS at pH 1.2 at 2 h. The biocompatibility of HA–PDM–INS, regardless of the MW of HA, was demonstrated using CCK-8 and live–dead cell staining. Compared with the INS solution, the transport efficiencies of L-HA–PDM–INS, M-HA–PDM–INS, and H-HA–PDM–INS increased 4.16, 3.81, and 3.10 times, respectively. In vivo pharmacodynamic and pharmacokinetic studies were performed in diabetic rats following oral administration. H-HA–PDM–INS exhibited an effective hypoglycemic effect over a long period, with relative bioavailability of 14.62%. In conclusion, these simple, environmentally friendly, pH-responsive, and mucoadhesive nanoparticles have the potential for industrial development. This study provides preliminary data support for oral INS delivery.

Assessment of Efficacy and Safety Using PPAR-γ Agonist-Loaded Nanocarriers for Inflammatory Eye Diseases

Drug-loaded nanocarriers (NCs) are new systems that can greatly improve the delivery and targeting of drugs to specific tissues and organs. In our work, a PPAR-γ agonist loaded into polymeric NCs was prepared, stabilized by spray-drying, and tested in vitro, ex vivo, and in vivo (animal models) to provide a safe formulation for optical anti-inflammatory treatments. The NCs were shown to be well tolerated, and no signs of irritancy or alterations of the eye properties were detected by the in vitro HET-CAM test and in vivo Draize test. Furthermore, no signs of cytotoxicity were found in the NC formulations on retinoblastoma cells (Y-79) analyzed using the alamarBlue assay, and the transmittance experiments evidenced good corneal transparency with the formulations tested. The ocular anti-inflammatory study confirmed the significant prevention efficacy using the NCs, and these systems did not affect the corneal tissue structure. Moreover, the animal corneal structure treated with the NCs was analyzed using X-ray diffraction using synchrotron light. Small-angle X-ray scattering (SAXS) analysis did not show a significant difference in corneal collagen interfibrillar spacing after the treatment with freshly prepared NCs or NCs after the drying process compared to the corresponding negative control when inflammation was induced. Considering these results, the PPAR-γ agonist NCs could be a safe and effective alternative for the treatment of inflammatory ocular processes.

Mucoadhesive Marine Polysaccharides

Mucoadhesive polymers are of growing interest in the field of drug delivery due to their ability to interact with the body’s mucosa and increase the effectiveness of the drug. Excellent mucoadhesive performance is typically observed for polymers possessing charged groups or non-ionic functional groups capable of forming hydrogen bonds and electrostatic interactions with mucosal surfaces. Among mucoadhesive polymers, marine carbohydrate biopolymers have been attracting attention due to their biocompatibility and biodegradability, sample functional groups, strong water absorption and favorable physiochemical properties. Despite the large number of works devoted to mucoadhesive polymers, there are very few systematic studies on the influence of structural features of marine polysaccharides on mucoadhesive interactions. The purpose of this review is to characterize the mucoadhesive properties of marine carbohydrates with a focus on chitosan, carrageenan, alginate and their use in designing drug delivery systems. A wide variety of methods which have been used to characterize mucoadhesive properties of marine polysaccharides are presented in this review. Mucoadhesive drug delivery systems based on such polysaccharides are characterized by simplicity and ease of use in the form of tablets, gels and films through oral, buccal, transbuccal and local routes of administration.

Development of Peptide Targeted PLGA-PEGylated Nanoparticles Loading Licochalcone-A for Ocular Inflammation

Licochalcone-A is a natural compound with anti-inflammatory properties. However, it possesses low water solubility, making its application for the treatment of ocular inflammation difficult. To overcome this drawback, biodegradable nanoparticles incorporating Licochalcone-A have been developed. Additionally, to avoid fast clearance and increase cellular internalization into the ocular tissues, PLGA nanoparticles have been functionalized using PEG and cell penetrating peptides (Tet-1 and B6). To optimize the formulations, a factorial design was carried out and short-term stability of the nanoparticles was studied. Moreover, morphology was also observed by transmission electron microcopy and in vitro drug release was carried out. Ocular tolerance of the formulations was ensured in vitro and in vivo and anti-inflammatory therapeutic efficacy was also assessed. Surface functionalized nanoparticles loading Licochalcone-A were developed with an average size below 200 nm, a positive surface charge, and a monodisperse population. The formulations were non-irritant and showed a prolonged Licochalcone-A release. Despite the fact that both Licochalcone-A Tet-1 and B6 functionalized nanoparticles demonstrated to be suitable for the treatment of ocular inflammation, B6 targeted nanoparticles provided greater therapeutic efficacy in in vivo assays.

Comparative Study of Chitosan and Oligochitosan Coatings on Mucoadhesion of Curcumin Nanosuspensions

Curcumin nanosuspensions (Cur-NSs), chitosan-coated Cur-NSs (CS-Cur-NSs), and oligochitosan-coated Cur-NSs (OCS-Cur-NSs) were prepared by using an ultrasonic homogenization technique. The mean particle size of Cur-NSs was 210.9 nm and significantly (p < 0.05) increased to 368.8 nm by CS coating and decreased to 172.8 nm by OCS coating. Encapsulation efficiencies of Cur-NSs, CS-Cur-NSs, and OCS-Cur-NSs were 80.6%, 91.4%, and 88.5%, respectively. The mucin adsorption of Cur-NSs was steeply increased about 3–4 times by CS and OCS coating. Morphological changes of these NSs were studied using circular dichroism spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and transmission electron microscopy (TEM). Thus, CS-Cur-NSs and OCS-Cur-NSs showed great potential as mucoadhesive nano-carriers for the efficient delivery of water insoluble compounds like curcumin to the gastrointestinal system.

A novel versatile flow-donor chamber as biorelevant ex-vivo test assessing oral mucoadhesive formulations

Oral transmucosal drug delivery is a non-invasive administration route for rapid therapeutic onset and greater bioavailability avoiding the first-pass metabolism. Mucoadhesive formulations are advantageous as they may retain the drug at the administration site. Proper equipment to assess mucoadhesive properties and corresponding drug absorption is fundamental for the development of novel drug delivery systems. Here we developed a new flow-through donor chamber for well-established diffusion cells, and we tested the effects on drug and formulation retention in situ of adding mucoadhesive polymers or mesoporous silica particles to a reference formulation. Mesoporous silica particles are of particular interest as they may be used to encapsulate and retain drug molecules. Compared to other ex-vivo methods described in literature for assessing mucoadhesive performance and transmucosal drug delivery, this new donor chamber provides several advantages: i) it reflects physiological conditions better as a realistic saliva flow can be provided over the administration site, ii) it is versatile since it can be mounted on any kind of vertical diffusion cell allowing simultaneous detection of drug retention at the administration site and drug permeation through the tissue, and iii) it enables optical quantification of formulations residence time aided by image processing. This new flow-through donor diffusion cell set-up proved sensitive to differentiate a reference formulation from one where 20 %(w/w) Carbomer was added (to further improve the mucoadhesive properties), with respect to both drug and formulation residence times. We also found that mesoporous silica particles, investigated as particles only and mixed together with the reference formulation, gave very similar drug and formulation retention to what we observed with the mucoadhesive Carbomer. However, after some time (>30 min) it became obvious that the tablet excipients in the reference formulation promote particle retention on the mucosa. This work provides a new simple and versatile biorelevant test for the evaluation of oral mucoadhesive formulations and paves the way for further studies on mesoporous silica particles as valuable excipients for enhancing oral mucoadhesion.

Optimization of Nanoparticles for Smart Drug Delivery: A Review

Nanoparticle delivery systems have good application prospects in the treatment of various diseases, especially in cancer treatment. The effect of drug delivery is regulated by the properties of nanoparticles. There have been many studies focusing on optimizing the structure of nanoparticles in recent years, and a series of achievements have been made. This review summarizes the optimization strategies of nanoparticles from three aspects-improving biocompatibility, increasing the targeting efficiency of nanoparticles, and improving the drug loading rate of nanoparticles-aiming to provide some theoretical reference for the subsequent drug delivery of nanoparticles.

Calcium hydroxide-loaded PLGA biodegradable nanoparticles as an intracanal medicament

AIM

To develop a formulation in which calcium hydroxide (Ca(OH)₂) was successfully loaded into poly(lactic-co-glycolic acid) (PLGA) biodegradable nanoparticles (NPs) to be used in the field of endodontics as an intracanal medicament, including NP optimization and characterization, plus drug release profile of the NPs compared with free Ca(OH)₂. Additionally, the depth and area of penetration of the NPs inside the dentinal tubules of extracted teeth were compared with those of the free Ca(OH)₂.

METHODOLOGY

Ca(OH)₂ NPs were prepared using the solvent displacement method. NPs was optimized with a central composite design to obtain a final optimized formulation. The morphology of the NPs was examined under transmission electron microscopy (TEM), and characterization was carried out using X-ray diffraction (XRD), Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC). The drug release profile of the Ca(OH)₂ NPs and free Ca(OH)₂ was evaluated up to 48 h. Finally, the depth and area of penetration inside the dentinal tubules of extracted teeth were examined for both the Ca(OH)₂ NPs and free Ca(OH)₂ using the Mann-Whitney U test to determine any significant differences.

RESULTS

Utilizing the optimized formulation, the Ca(OH)₂ NPs had an average size below 200 nm and polydispersity index lower than 0.2, along with a highly negative zeta potential and suitable entrapment efficiency percentage. The spherical morphology of the Ca(OH)₂ NPs was confirmed using TEM. The results of the XRD, FTIR and DSC revealed no interactions and confirmed that the drug was encapsulated inside the NPs. The drug release profile of the Ca(OH)₂ NPs exhibited a prolonged steady release that remained stable up to 48 h with higher concentrations than the free Ca(OH)₂. After examination by confocal laser scanning microscopy, Ca(OH)₂ NPs had a significantly greater depth and area of penetration inside dentinal tubules compared with the free drug.

CONCLUSIONS

Ca(OH)₂-loaded PLGA NPs were successfully optimized and characterized. The NPs exhibited a prolonged drug release profile and superior penetration inside dentinal tubules of extracted teeth when compared to Ca(OH)₂ .

Berberine Encapsulated Lecithin-Chitosan Nanoparticles as Innovative Wound Healing Agent in Type II Diabetes

The aim of this research is to formulate a lecithin–chitosan based nanoparticulate system loaded with berberine (BER-LC-CTS-NPs) that could be integrated into a topically applied formulation and assessed for healing wounds in a diabetic animal model. In order to formulate BER-LC-CTS-NPs, soybean lecithin, isopropyl myristate, and berberine dispersed in ethanolic solution were added into an aqueous solution of chitosan dropwise with sonication. We assessed the influence of lecithin amount, chitosan amount, and isopropyl myristate concentration on particle diameter, zeta potential, and entrapment and employed a Box–Behnken statistical design. The resulting optimized BER-LC-CTS-NPs had a mean size of 168.4 nm, a surface charge of 33.1 mV, and entrapment of 82.3%. The optimized BER-LC-CTS-NPs showed a sustained in vitro release profile. Furthermore, the potential of the optimized BER-LC-CTS-NPs integrated into a topical gel formulation for wound healing in streptozocin-induced diabetic rats was assessed. Our findings show that combining chitosan and berberine in the nanoparticles produces a synergistic effect when it comes to wound healing. The optimized nanoparticulate system works by reducing inflammation, inducing blood vessels and fibroblast proliferation, and promoting mature collagen fibers deposition. Based on the experimental results, lecithin–chitosan nanoparticles loaded with berberine have evolved as a promising strategy for accelerating wound the healing process in diabetic patients. However, the clinical merits of the developed system need to be investigated in diabetic patients.

Molecular prospect of type-2 diabetes: Nanotechnology based diagnostics and therapeutic intervention

About ninety percent of all diabetic conditions account for T2D caused due to abnormal insulin secretion/ action or increased hepatic glucose production. Factors that contribute towards the aetiology of T2D could be well explained through biochemical, molecular, and cellular aspects. In this review, we attempt to explain the recent evolving molecular and cellular advancement associated with T2D pathophysiology. Current progress fabricated in T2D research concerning intracellular signaling cascade, inflammasome, autophagy, genetic and epigenetics changes is discretely explained in simple terms. Present available anti-diabetic therapeutic strategies commercialized and their limitations which are needed to be acknowledged are addressed in the current review. In particular, the pre-eminence of nanotechnology-based approaches to nullify the inadequacy of conventional anti-diabetic therapeutics and heterogeneous nanoparticulated systems exploited in diabetic researches are also discretely mentioned and are also listed in a tabular format in the review. Additionally, as a future prospect of nanotechnology, the review presents several strategic hypotheses to ameliorate the austerity of T2D by an engineered smart targeted nano-delivery system. In detail, an effort has been made to hypothesize novel nanotechnological based therapeutic strategies, which exploits previously described inflammasome, autophagic target points. Utilizing graphical description it is explained how a smart targeted nano-delivery system could promote β-cell growth and development by inducing the Wnt signaling pathway (inhibiting Gsk3β), inhibiting inflammasome (inhibiting NLRP3), and activating autophagic target points (protecting Atg3/Atg7 complex from oxidative stress) thereby might ameliorate the severity of T2D. Additionally, several targeting molecules associated with autophagic and epigenetic factors are also highlighted, which can be exploited in future diabetic research.

Fabrication of All-Trans Retinoic Acid loaded Chitosan/Tripolyphosphate Lipid Hybrid Nanoparticles as a Novel Oral Delivery Approach for Management of Diabetic Nephropathy in Rats

The present study aims to formulate all-trans retinoic acid (ATRA) loaded chitosan/tripolyphosphate lipid hybrid nanoparticles (CTLHNs) for enhancing its solubility and oral delivery. This is to improve ATRA therapeutic effect on diabetic nephropathy (DN). CTLHNs were prepared by o/w homogenization, employing stearic acid, to form lipid nanoparticles coated with chitosan that is stabilized against acidic pH via sodium tripolyphosphate crosslinking. Chitosan coated (F7) and naked lipid nanoparticles (F6) were also prepared for comparison with CTLHNs. In vitro characterization for the prepared formulations was performed comprising entrapment efficiency, particle size, zeta potential, transmission electron microscopy, FT-IR spectroscopy and x-ray diffraction. Stability of chitosan coat in GI fluid revealed that CTLHNs were more stable than F7. In vitro release indicated an enhanced release of ATRA from the developed formulations. In vitro mucoadhesion study proved a notable mucoadhesive property for CTLHNs. In DN rat model, serum levels of creatinine and urea were elevated, over expression of tumor necrosis factor alpha (TNF-α), granulocyte macrophage colony-stimulating factor (GM-CSF), vascular endothelial growth factor (VEGF) and intercellular adhesion molecule-1 (ICAM-1) were observed. In addition, adenosine monophosphate activated protein kinase (AMPK) and liver kinase B1 (LKB1) expressions were decreased in DN rats. Treatment with free ATRA and the selected formulations led to a significant amelioration of DN by reducing of creatinine, urea, TNF-α, ICAM-1, GM-CSF, VEGF levels as well as elevating AMPK and LKB1 levels. The order of activity was: CTLHNs > F7 > F6 > free ATRA, as proved by histopathological examination.

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.

N-(2-hydroxy)-propyl-3-trimethylammonium, O-palmitoyl chitosan: Synthesis, physicochemical and biological properties

Two samples of N-(2-hydroxy)-propyl-3-trimethylammonium, O-palmitoyl chitosan (DPCat) with different average degrees of quaternization named as DPCat35 (DQ¯ = 35%) and DPCat80 (DQ¯ = 80%), were successfully synthesized by reacting glycidyltrimethylammonium chloride (GTMAC) with O-palmitoyl chitosan (DPCh) derivative (DS¯ = 12%). Such amphiphilic derivatives of chitosan were fully water-soluble at 1.0 < pH < 12.0 and showed significant electrostatic stability enhancement of a self-assembly micellar nanostructure (100-320 nm) due to its positively-charged out-layer. In vitro mucoadhesive and cytotoxicity essays toward healthy fibroblast cells (Balb/C 3T3 clone A31 cell), human prostate cancer (DU145) and liver cancer (HepG2/C3A) cell lines revealed that the biological properties of DPCat derivatives were strongly dependent on DQ¯. Additionally, DPCat35 had better interactions with the biological tissue and with mucin glycoproteins at pH 7.4 as well as exhibited potential to be used on the development of drug delivery systems for prostate and liver cancer treatment.

Antibacterial coating of tooth surface with ion-releasing pre-reacted glass-ionomer (S-PRG) nanofillers

OBJECTIVES

Surface pre-reacted glass-ionomer (S-PRG) fillers release antibacterial borate and fluoride ions. We fabricated nanoscale S-PRG fillers (S-PRG nanofillers) for antibacterial coating of tooth surfaces and assessed the antibacterial effects of this coating in vitro. In addition, we creating a canine model of periodontitis to evaluate the effectiveness of S-PRG nanofiller application on tooth roots and improvement of periodontal parameters.

METHODS

Human dentin blocks were coated with S-PRG nanofiller (average particle size: 0.48 μm) and then characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDX), and ion-releasing test. Antibacterial effects of dentin blocks coated with S-PRG nanofiller were examined using bacterial strains, Streptococcus mutans and Actinomyces naeslundii. Next, we created an experimental model of periodontitis in furcation of premolars of beagle dogs. Then, S-PRG nanofiller coating was applied onto exposed tooth root surfaces. Periodontal parameters, gingival index (GI), bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment level (CAL), were measured from baseline until 4 weeks. In addition, bone healing was radiographically and histologically examined.

RESULTS

SEM and EDX revealed that S-PRG nanofillers uniformly covered the dentin surface after coating. Dentin blocks coated with S-PRG nanofiller showed ion-releasing property, bacterial growth inhibition, and sterilization effects. In the experimental periodontitis model, S-PRG nanofiller coating significantly reduced clinical inflammatory parameters, such as GI (P < 0.01) and BOP (P < 0.05), compared to uncoated samples. In addition, PPD and CAL significantly decreased by S-PRG nanofiller coating (2 weeks: P < 0.05; 3 and 4 weeks: P < 0.01), suggesting the improvement of periodontitis. Micro-CT and histology revealed that bone healing of furcation defects was enhanced by S-PRG nanofiller coating.

CONCLUSION

S-PRG nanofiller coating provides antibacterial effects to tooth surfaces and improves clinical parameters of periodontitis.

Oral peptide delivery: challenges and the way ahead

Peptides and proteins have emerged as potential therapeutic agents and, in the search for the best treatment regimen, the oral route has been extensively evaluated because of its non-invasive and safe nature. The physicochemical properties of peptides and proteins along with the hurdles in the gastrointestinal tract (GIT), such as degrading enzymes and permeation barriers, are challenges to their delivery. To address these challenges, several conventional and novel approaches, such as nanocarriers, site-specific and stimuli specific delivery, are being used. In this review, we discuss the challenges to the oral delivery of peptides and the approaches used to tackle these challenges.

Nanoparticles integrating natural and synthetic polymers for in vivo insulin delivery

The aims of the current study were to develop insulin-loaded nanoparticles comprised of various polymers at different compositions, and to evaluate their ability to lower blood glucose levels in diabetic rats following subcutaneous and oral administrations. Several combinations of natural and synthetic polymers have been utilized for preparation of nanoparticles including, chitosan, alginate, albumin and Pluronic. Nanosized (170 nm-800 nm) spherical particles of high encapsulation efficiency (15-52%) have been prepared. Composition and ratios between the integrated polymers played a pivotal role in determining size, zeta potential, and in vivo hypoglycemic activity of particles. After subcutaneous and oral administration in diabetic rats, some of the insulin-loaded nanoparticles were able to induce much higher hypoglycemic effect as compared to the unloaded free insulin. For instance, subcutaneous injection of nanoparticles comprised of chitosan combined with sodium tripolyphosphate, Pluronic or alginate/calcium chloride, resulted in comparable hypoglycemic effects to free insulin, at two-fold lower dose. Nanoparticles were well-tolerated after oral administration in rats, as evidenced by by measuring levels of alanine aminotransferase, aspartate aminotransferases, albumin, creatinine and urea. This study indicates that characteristics and delivery efficiency of nanomaterials can be controlled via utilizing several natural/synthetic polymers and by fine-tuning of combination ratio between polymers.

Silica Nanoparticles in Transmucosal Drug Delivery

Transmucosal drug delivery includes the administration of drugs via various mucous membranes, such as gastrointestinal, nasal, ocular, and vaginal mucosa. The use of nanoparticles in transmucosal drug delivery has several advantages, including the protection of drugs against the harsh environment of the mucosal lumens and surfaces, increased drug residence time, and enhanced drug absorption. Due to their relatively simple synthetic methods for preparation, safety profile, and possibilities of surface functionalisation, silica nanoparticles are highly promising for transmucosal drug delivery. This review provides a description of silica nanoparticles and outlines the preparation methods for various core and surface-functionalised silica nanoparticles. The relationship between the functionalities of silica nanoparticles and their interactions with various mucous membranes are critically analysed. Applications of silica nanoparticles in transmucosal drug delivery are also discussed.

Melatonin loaded lecithin-chitosan nanoparticles improved the wound healing in diabetic rats

Wound healing in diabetic patients remains a worldwide problem that can cause amputations and even lead to death. This work aimed to produce lecithin-chitosan nanoparticles loaded with melatonin (MEL-NP) incorporated in a topical formulation to be evaluated for healing in the in vivo animal model for diabetes. To produce nanoparticles, an ethanolic solution containing soybean lecithin and melatonin was added dropwise to an aqueous solution of chitosan under sonication. The nanoparticles were physicochemical characterized and evaluated in vivo for toxicity using the Galleria mellonella model and its potential for wound healing in diabetic rats. The MEL-NPs presented a particle size of 160 nm and a zeta potential of 25 mV. The melatonin entrapment efficiency was 27%. Our results indicated that treatment with MEL-NP improved wound healing demonstrated by wound closure earlier than the other treatments evaluated. A desired therapeutic effect was achieved by MEL-NP in the induction of fibroblast and angiogenic proliferation. In addition, it was accompanied by an expressive collagen deposition. Considering the observed data, the MEL-NP developed could be used as a proof of concept to develop a promising strategy for the healing of diabetic wound.

Chitosan Film Containing Mansoa hirsuta Fraction for Wound Healing

Chitosan films entrapped with the Mansoa hirsuta fraction (CMHF) was developed as a new dressing for wound care. The chromatographic profile of the M. hirsuta fraction (MHF) was evaluated by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and the results showed that MHF is rich in acid triterpenes. Physicochemical characterization of the films prepared using the solvent casting method was performed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry (TGA), differential scanning calorimetry (DCS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and mechanical properties. CMHF exhibited characteristic bands of both chitosan and MHF, revealing a physical mixture of both. CMHF presented an amorphous nature, thermostability, and dispersion of MHF in the chitosan matrix, resulting in a rough structure. Incorporation of M. hirsuta fraction into chitosan matrix favorably enhanced the mechanical performance and films thickness. The in vivo wound treatment with CMHF for seven days showed a characteristic area of advanced healing, re-epithelization, cell proliferation, and collagen formation. Furthermore, wound closure reached 100% contraction after 10 days of treatment with modulation of interleukins. The incorporation of M. hirsuta fraction into chitosan films was advantageous and showed great potential for stimulating wound repair and regeneration.

Smart Protein-Based Formulation of Dendritic Mesoporous Silica Nanoparticles: Toward Oral Delivery of Insulin

Oral insulin administration still represents a paramount quest that almost a century of continuous research attempts did not suffice to fulfill. Before pre-clinical development, oral insulin products have first to be optimized in terms of encapsulation efficiency, protection against proteolysis, and intestinal permeation ability. With the use of dendritic mesoporous silica nanoparticles (DMSNs) as an insulin host and together with a protein-based excipient, succinylated β-lactoglobulin (BL), pH-responsive tablets permitted the shielding of insulin from early release/degradation in the stomach and mediated insulin permeation across the intestinal cellular membrane. Following an original in vitro cellular assay based on insulin starvation, direct cellular fluorescent visualization has evidenced how DMSNs could ensure the intestinal cellular transport of insulin.

Surface Modification of Mobile Composition of Matter (MCM)-41 Type Silica Nanoparticles for Potential Oral Mucosa Vaccine Delivery

Development of mobile composition of matter (MCM)-41 silica nanoparticles faces challenges, e.g. surface charge properties, antigen loading efficiency, protecting from enzymes and harsh GIT environment and effective release at target mucosal site. We report the production and characterization of polymer and amine modified MCM-41 type silica nanoparticles for oral antigen delivery using ovalbumin (OVA) as model antigen. Nanoparticles were characterized by dynamic light scattering (DLS), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, circular dichroism (CD), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), mucin binding, stability in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) and in vitro OVA release in SGF and SIF. Unmodified nanoparticles size of 146 nm increased to 175-321 nm after modification while modified particles remained intact for more than 3 h in SGF and 96 h in SIF (DLS and SEM). Mucin binding proved polyethylene glycol (PEG) and chitosan modified nanoparticles as potential candidates for oral mucosa delivery. Both showed highest OVA encapsulation at 67% and 73%, and sustained OVA release in SIF (96 h) at 65% and 64% respectively. BET results showed that nanopores were not blocked during surface modification. CD and SDS-PAGE showed that OVA conformational structure did not change after release from the nanoparticles.

In Vitro Characterization, Modelling, and Antioxidant Properties of Polyphenon-60 from Green Tea in Eudragit S100-2 Chitosan Microspheres

Eudragit S100-coated chitosan microspheres (S100Ch) are proposed as a new oral delivery system for green tea polyphenon-60 (PP60). PP60 is a mixture of polyphenolic compounds, known for its active role in decreasing oxidative stress and metabolic risk factors involved in diabetes and in other chronic diseases. Chitosan-PP60 microspheres prepared by an emulsion cross-linking method were coated with Eudragit S100 to ensure the release of PP60 in the terminal ileum. Different core–coat ratios of Eudragit and chitosan were tested. Optimized chitosan microspheres were obtained with a chitosan:PP60 ratio of 8:1 (Ch-PP60_8:1), rotation speed of 1500 rpm, and surfactant concentration of 1.0% (m/v) achieving a mean size of 7.16 µm. Their coating with the enteric polymer (S100Ch-PP60) increased the mean size significantly (51.4 µm). The in vitro modified-release of PP60 from S100Ch-PP60 was confirmed in simulated gastrointestinal conditions. Mathematical fitting models were used to characterize the release mechanism showing that both Ch-PP60_8:1 and S100Ch-PP60 fitted the Korsmeyers–Peppas model. The antioxidant activity of PP60 was kept in glutaraldehyde-crosslinked chitosan microspheres before and after their coating, showing an IC₅₀ of 212.3 µg/mL and 154.4 µg/mL, respectively. The potential of chitosan microspheres for the delivery of catechins was illustrated, with limited risk of cytotoxicity as shown in Caco-2 cell lines using the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The beneficial effects of green tea and its derivatives in the management of metabolic disorders can be exploited using mucoadhesive chitosan microspheres coated with enteric polymers for colonic delivery.

Synergistic Release of Crop Nutrients and Stimulants from Hydroxyapatite Nanoparticles Functionalized with Humic Substances: Toward a Multifunctional Nanofertilizer

The use of salt- or macro-sized NPK fertilizers is typically associated with low nutrient use efficiency and water eutrophication. Nanotechnology can overcome such drawbacks, but its practical application on a large scale is limited by (i) high costs and difficult scale-up of nanoparticle synthesis, (ii) questionable advantages over traditional methods, and (iii) health hazards related to nanomaterial introduction in the food stream and the environment. Here, we report on a novel biocompatible and multifunctional P nanofertilizer obtained by self-assembling natural or synthetic humic substances and hydroxyapatite nanoparticles using a simple and straightforward dipping process, exploiting the interaction between the polyphenolic groups of humic substances and the surface of nanohydroxyapatite. Pot tests using the as-prepared materials were performed on Zea mays as a model crop, and the results were compared to those obtained using commercial fused superphosphate and bare nanohydroxyapatites. A significant improvement, in terms of early plant growth, corn productivity, rhizosphere bacteria, and the resistance to NaCl-induced abiotic stresses, was achieved using hydroxyapatite nanoparticles assembled with humic substances. These effects were ascribed to the synergistic co-release of phosphate ions and humic substances, which are two types of plant-beneficial agents for crop nutrition and stimulation, respectively. The release patterns were proven to be tunable with the amount of humic substances adsorbed on the nanoparticles, inducing competition between humic-substance-driven phosphorous dissolution and block of water contact. Such positive effects on plant growth in association with its intrinsic biocompatibility, simple synthesis, and multifunctionality qualify this novel nanofertilizer as a promising material for large-scale use in the agronomic field.

Nanopharmaceutics: Part I-Clinical Trials Legislation and Good Manufacturing Practices (GMP) of Nanotherapeutics in the EU

The latest advances in pharmaceutical technology are leading to the development of cutting edged approaches to produce what is now known as the “Holy Grail” of medicine—nanopharmaceutics. Over the latest decade, the pharmaceutical industry has made important contributions to the scale up of these new products. To ensure their quality, efficacy, and safety for human use, clinical trials are mandatory. Yet, regulation regarding nanopharmaceuticals is still limited with a set of guidelines being recently released with respect to compliance with quality and safety. For the coming years, updates on regulatory issues about nanopharmaceuticals and their use in clinical settings are expected. The use of nanopharmaceuticals in clinical trials depends on the approval of the production methods and assurance of the quality of the final product by implementation and verification of the good manufacturing practices (GMP). This review addresses the available legislation on nanopharmaceuticals within the European Union (EU), the GMP that should be followed for their production, and the current challenges encountered in clinical trials of these new formulations. The singular properties of nanopharmaceuticals over their bulk counterparts are associated with their size, matrix composition, and surface properties. To understand their relevance, four main clinical trial guidelines, namely, for intravenous iron-based nanopharmaceuticals, liposomal-based nanopharmaceuticals, block copolymer micelle-based nanopharmaceuticals, and related to surface coating requirements, are described here.

Oral nanoparticles based on gellan gum/pectin for colon-targeted delivery of resveratrol

Nanoparticles based on gellan gum/pectin blends were designed for colon-targeted release of resveratrol (RES). Their impact on drug release rates and permeability were evaluated using Caco-2 cell model and mucus secreting triple co-culture model. Polymeric nanoparticles (PNP) were successfully prepared by nebulization/ionotropic gelation, achieving high drug loading (>80%). PNP were spherical with a low positive charge density (+5mV) and exhibited diameters of around 330 nm. Developed PNP were able to promote effective modulation of drug release rates, so that only 3% of RES was released in acidic media over 2 h, and, in pH 6.8, the drug was released in a sustained manner, reaching 85% in 30 h. The permeability of RES-loaded PNP in the Caco-2 model was 0.15%, while in the triple co-culture model, in the presence of mucus, it reached 5.5%. The everted gut sac experiment corroborated the low permeability of RES-loaded PNP in the presence or absence of mucus and highlighted their high ability to interact with the intestinal tissue. Results indicate that the novel PNP developed in this work are safe and promising carriers for controlled delivery of RES at the colon.

Silica-Coated Nanoparticles with a Core of Zinc, l-Arginine, and a Peptide Designed for Oral Delivery

Nanoparticle constructs for oral peptide delivery at a minimum must protect and present the peptide at the small intestinal epithelium in order to achieve oral bioavailability. In a reproducible, scalable, surfactant-free process, a core was formed with insulin in ratios with two established excipients and stabilizers, zinc chloride and l-arginine. Cross-linking was achieved with silica, which formed an outer shell. The process was reproducible across several batches, and physicochemical characterization of a single batch was confirmed in two independent laboratories. The silica-coated nanoparticles (SiNPs) entrapped insulin with high entrapment efficiency, preserved its structure, and released it at a pH value present in the small intestine. The SiNP delivered insulin to the circulation and reduced plasma glucose in a rat jejunal instillation model. The delivery mechanism required residual l-arginine in the particle to act as a permeation enhancer for SiNP-released insulin in the jejunum. The synthetic process was varied in terms of ratios of zinc chloride and l-arginine in the core to entrap the glucagon-like peptide 1 analogue, exenatide, and bovine serum albumin. SiNP-delivered exenatide was also bioactive in mice to some extent following oral gavage. The process is the basis for a platform for oral peptide and protein delivery.

Micro and nanoscale technologies in oral drug delivery

Oral administration is a pillar of the pharmaceutical industry and yet it remains challenging to administer hydrophilic therapeutics by the oral route. Smart and controlled oral drug delivery could bypass the physiological barriers that limit the oral delivery of these therapeutics. Micro- and nanoscale technologies, with an unprecedented ability to create, control, and measure micro- or nanoenvironments, have found tremendous applications in biology and medicine. In particular, significant advances have been made in using these technologies for oral drug delivery. In this review, we briefly describe biological barriers to oral drug delivery and micro and nanoscale fabrication technologies. Micro and nanoscale drug carriers fabricated using these technologies, including bioadhesives, microparticles, micropatches, and nanoparticles, are described. Other applications of micro and nanoscale technologies are discussed, including fabrication of devices and tissue engineering models to precisely control or assess oral drug delivery in vivo and in vitro, respectively. Strategies to advance translation of micro and nanotechnologies into clinical trials for oral drug delivery are mentioned. Finally, challenges and future prospects on further integration of micro and nanoscale technologies with oral drug delivery systems are highlighted.

Nanoparticle Delivery Systems in the Treatment of Diabetes Complications

Diabetes mellitus, an incurable metabolic disease, is characterized by changes in the homeostasis of blood sugar levels, being the subcutaneous injection of insulin the first line treatment. This administration route is however associated with limited patient's compliance, due to the risk of pain, discomfort and local infection. Nanoparticles have been proposed as insulin carriers to make possible the administration of the peptide via friendlier pathways without the need of injection, i.e., via oral or nasal routes. Nanoparticles stand for particles in the nanometer range that can be obtained from different materials (e.g., polysaccharides, synthetic polymers, lipid) and are commonly used with the aim to improve the physicochemical stability of the loaded drug and thereby its bioavailability. This review discusses the use of different types of nanoparticles (e.g., polymeric and lipid nanoparticles, liposomes, dendrimers, niosomes, micelles, nanoemulsions and also drug nanosuspensions) for improved delivery of different oral hypoglycemic agents in comparison to conventional therapies.

Mucoadhesive improvement of alginate microspheres as potential gastroretentive delivery carrier by blending with Bletilla striata polysaccharide

As polysaccharide from Bletilla striata (BSP) was anticipated with mucoadhesive improvement in sodium alginate (SA) microspheres, BSP was mixed with SA to construct a composite microsphere to retain in the gastrointestinal tract for a long time. The morphological properties, particle size and thermodynamic properties of the microspheres in combination with comprehensive evaluations in the swelling properties, mucin adsorption, ex vivo and in vivo gastric retention were determined to characterize the mucoadhesion of SA-BSP blend microspheres. Results showed that the prepared microspheres were discrete and spherical. The addition of BSP increased flexibility and reduced rigidity of SA microsphere. Furthermore, the swelling property, mucin adsorption ability and the retention rate on the gastric mucosa of SA matrix were increased after blending with BSP. Mucoadhesion tests showed the SA-BSP microspheres stayed much longer in rats' stomach than the SA microsphere did. Above all, the SA-BSP microspheres with the enhanced mucoadhesion suggested being a potential drug carrier in developing the gastroretentive drug delivery system.

Design of Silk-Elastin-Like Protein Nanoparticle Systems with Mucoadhesive Properties

Transmucosal drug delivery is a promising avenue to improve therapeutic efficacy through localized therapeutic administration. Drug delivery systems that increase retention in the mucosal layer are needed to improve efficiency of such transmucosal platforms. However, the applicability of such systems is often limited by the range of chemistries and properties that can be achieved. Here we present the design and implementation of silk-elastin-like proteins (SELPs) with mucoadhesive properties. SELP-based micellar-like nanoparticles provide a system to tailor chemical and physical properties through genetic engineering of the SELP sequence, which enables the fabrication of nanoparticles with specific chemical and physical features. Analysis of the adhesion of four different SELP-based nanoparticle systems in an artificial mucus system, as well as in in vitro cellular assays indicates that addition of mucoadhesive chemical features on the SELP systems increases retention of the particles in mucosal environments. The results indicated that SELP-based nanoparticles provide a useful approach to study and develop transmucosal protein drug delivery system with unique mucoadhesive properties. Future studies will serve to further expand the range of achievable properties, as well as the utilization of SELPs to fabricate mucoadhesive materials for in vivo testing.

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.

Sugar-Lowering Drugs for Type 2 Diabetes Mellitus and Metabolic Syndrome-Review of Classical and New Compounds: Part-I

Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia together with disturbances in the metabolism of carbohydrates, proteins and fat, which in general results from an insulin availability and need imbalance. In a great number of patients, marketed anti-glycemic agents have shown poor effectiveness in maintaining a long-term glycemic control, thus being associated with severe adverse effects and leading to an emerging interest in natural compounds (e.g., essential oils and other secondary plant metabolites, namely, flavonoid-rich compounds) as a novel approach for prevention, management and/or treatment of either non-insulin-dependent diabetes mellitus (T2DM, type 2 DM) and/or Metabolic Syndrome (MS). In this review, some of these promising glucose-lowering agents will be comprehensively discussed.

Association of Platelet-Rich Plasma and Auto-Crosslinked Hyaluronic Acid Microparticles: Approach for Orthopedic Application

Platelet-rich plasma (PRP) associated with high molecular weight hyaluronic acid (HA) has been clinically used for tissue regeneration in orthopedics. Despite the recognized beneficial clinical outcomes (e.g., early pain control, improvement of patients' functional limitation and longer-term effectiveness compared to PRP and HA alone in mild and moderate osteoarthritis treatments), its use is still challenging and controversial due to lack of standardization of association practical protocols. Moreover, most studies neglect the matrix structure, that generates the ultimate properties of the association among platelets, fibrin network and the microparticles. In the present work, we aimed to analyze the influence of the PRP/HA association with a controlled matrix structure on the stability, rheological behavior, release of growth factors and in vitro proliferation of human adipose-derived mesenchymal cells (h-AdMSCs). The attenuation of the negative charge of HA was also evaluated. Pure PRP (P-PRP) (i.e., plasma enriched with platelets and poor in leukocytes) was prepared by centrifugation and activated with serum and calcium chloride (_AP-PRP). Autocrosslinked hyaluronic acid (AHA) was prepared by organocatalyzed auto-esterification and structured in microparticles (_MPAHA) by shearing. The attenuation of the negative charge of _MPAHA was performed with chitosan (CHT) by polyelectrolyte complexation yielding _MPAHA-CHT. The results showed that microparticles (MPs) have viscoelastic properties, extrusion force and swelling ratio appropriate for injectable applications. The association of _AP-PRP with the controlled structure of _MPAHA and _MPAHA-CHT formed a matrix composed of platelets and of a fibrin network with fibers around 160 nm located preferably on the surface of the MPs with an average diameter of 250 μm. Moreover, _AP-PRP/_MPAHA and _AP-PRP/_MPAHA-CHT associations were non-toxic and supported controlled growth factor (PDGF-AB and TGF-β1) release and in vitro proliferation of h-AdMSC with a similar pattern to that of _AP-PRP alone. The best h-AdMSC proliferation was obtained with the _AP-PRP/_MPAHA-CHT_75:25 indicating that the charge attenuation improved the cell proliferation. Thus, the association of _AP-PRP with the controlled structure of HA can be a valuable approach for orthopedic applications.

Multifunctional oral delivery systems for enhanced bioavailability of therapeutic peptides/proteins

In last few years, therapeutic peptides/proteins are rapidly growing in drug market considering their higher efficiency and lower toxicity than chemical drugs. However, the administration of therapeutic peptides/proteins is mainly limited in parenteral approach. Oral therapy which was hampered by harsh gastrointestinal environment and poorly penetrating epithelial barriers often results in low bioavailability (less than 1%-2%). Therefore, delivery systems that are rationally designed to overcome these challenges in gastrointestinal tract and ameliorate the oral bioavailability of therapeutic peptides/proteins are seriously promising. In this review, we summarized various multifunctional delivery systems, including lipid-based particles, polysaccharide-based particles, inorganic particles, and synthetic multifunctional particles that achieved effective oral delivery of therapeutic peptides/proteins.

The Influence of Polysaccharide Coating on the Physicochemical Parameters and Cytotoxicity of Silica Nanoparticles for Hydrophilic Biomolecules Delivery

The present work reports the effect of polysaccharides (chitosan and sodium alginate) on silica nanoparticles (SiNP) for hydrophilic molecules delivery taking insulin as model drug. The influence of tetraethyl orthosilicate (TEOS) and homogenization speed on SiNP properties was assessed by a 22 factorial design achieving as optimal parameters: 0.43 mol/L of TEOS and homogenization speed of 5000 rpm. SiNP mean particle size (Z-Ave) was of 256.6 nm and polydispersity index (PI) of 0.218. SiNP coated with chitosan (SiNP-CH) or sodium alginate (SiNP-SA) increased insulin association efficacy; reaching 84.6% (SiNP-SA) and 90.8% (SiNP-CH). However, coated SiNP released 50%-60% of the peptide during the first 45 min at acidic environment, while uncoated SiNP only released 30%. Similar results were obtained at pH 6.8. The low Akaike's (AIC) values indicated that drug release followed Peppas model for SiNP-SA and second order for uncoated SiNP and SiNP-CH (pH 2.0). At pH 6.8, the best fitting was Boltzmann for Ins-SiNP. However, SiNP-CH and SiNP-SA showed a first-order behavior. Cytotoxicity of nanoparticles, assessed in Caco-2 and HepG2 cells, showed that 100 to 500 µg/mL SiNP-CH and SiNP-SA slightly decreased cell viability, comparing with SiNP. In conclusion, coating SiNP with selected polysaccharides influenced the nanoparticles physicochemical properties, the insulin release, and the effect of these nanoparticles on cell viability.