In silico analytico-mathematical interpretation of biopolymeric assemblies: Quantification of energy surfaces and molecular attributes via atomistic simulations

Ellagic acid-loaded, tween 80-coated, chitosan nanoparticles as a promising therapeutic approach against breast cancer: In-vitro and in-vivo study

AIMS

Among polyphenolic phytoconstituents with anticancer properties, Ellagic acid (EA) is widely reported for its translational potential in vitro but efficient in vivo delivery of EA has been a challenge. We, for the first time, used a tween 80 coated nano delivery of Ellagic acid to evaluate its preclinical efficacy in vitro and in vivo for breast cancer.

MAIN METHODS

To overcome the challenges of in vivo delivery, two batches of chitosan-based nanoformulations of EA (with and without tween 80 coating) were prepared by the ionotropic gelation method. The nanoformulations were characterized and further evaluated in vitro against breast cancer cells (MCF7) and in vivo with EAC tumor-bearing mice for establishing their anticancer efficacy compared to Ellagic acid alone. A quantitative simulation study was undertaken to understand if the observed antitumor efficacy is due to the synergistic efficacy of the Chitosan-Ellagic acid combination.

KEY FINDINGS

Results revealed that nanoformulations consist of good nano-sized encapsulation of EA and showed good drug entrapment-release capacity. Nano-encapsulated EA is biocompatible and exhibited higher cytotoxicity in vitro compared to EA alone. Similarly, significantly higher tumor regression was observed in nano-EA treated mice compared to EA alone, and best efficacy was observed with the nanoformulation with tween 80 coating. Furthermore, nanoformulations showed higher apoptosis in tumor tissues with no significant tissue toxicity in vital organs.

SIGNIFICANCE

We report synergism of Chitosan-Ellagic acid combination in the tween 80 coated nanoparticles of Ellagic acid resulting in enhanced anti-breast tumor efficacy that may be of translational value for other tumor types, too.

A Newfangled Collagenase Inhibitor Topical Formulation Based on Ethosomes with Sambucus nigra L. Extract

Sambucus nigra L. (S. nigra) is a shrub widespread in Europe and western Asia, traditionally used in medicine, that has become popular in recent years as a potential source of a wide range of interesting bioactive compounds. The aim of the present work was to develop a topical S. nigra extract formulation based on ethosomes and thus to support its health claims with scientific evidence. S. nigra extract was prepared by an ultrasound-assisted method and then included in ethosomes. The ethosomes were analyzed in terms of their size, stability over time, morphology, entrapment capacity (EC), extract release profile, stability over time and several biological activities. The prepared ethosomes were indicated to be well defined, presenting sizes around 600 nm. The extract entrapment capacity in ethosomes was 73.9 ± 24.8%, with an interesting slow extract release profile over 24 h. The extract-loaded ethosomes presented collagenase inhibition activity and a very good skin compatibility after human application. This study demonstrates the potential use of S. nigra extract incorporated in ethosomes as a potential cosmeceutical ingredient and on further studies should be performed to better understand the impact of S. nigra compounds on skin care over the time.

Synthesis and characterization of Chitosan-Catechol conjugates: Development and in vitro, in silico and in vivo evaluation of mucoadhesive pellets of lafutidine

Present study was aimed to synthesize and characterize Chitosan-Catechol conjugates and to design and develop mucoadhesive pellets loaded with lafutidine. SEM images indicated the presence of fibrous structures responsible for enhanced mucoadhesive potential of Chitosan-Catechol conjugates. Thermodynamic stability and amorphous nature of conjugates was confirmed by DSC and XRD studies respectively. Rheological studies were used to evaluate polymer mucin interactions wherein strong interactions between Chitosan-Catechol conjugate and mucin was observed in comparison to pristine chitosan and mucin. The mucoadhesion potential of Chitosan-Catechol (Cht-C) versus Chitosan (Cht) was assessed in silico using molecular mechanics simulations and the results obtained were compared with the in vitro and ex vivo results. Cht-C/mucin demonstrated much higher energy stabilization (∆E ≈ −65 kcal/mol) as compared to Cht/mucin molecular complex. Lafutidine-loaded pellets were prepared from Chitosan (LPC) and Chitosan-Catechol conjugates (LPCC) and were evaluated for various physical properties viz. flow, circularity, roundness, friability, drug content, particle size and percent mucoadhesion. In vitro drug release studies on LPC and LPCC pellets were performed for computing t50%, t90% and mean dissolution time. The values of release exponent from Korsmeyer-Peppas model was reported to be 0.443 and 0.759 for LPC and LPCC pellets suggesting Fickian and non-Fickian mechanism representing drug release, respectively. In vivo results depicted significant controlled release and enhanced residence of the drug after being released from the chitosan-catechol coated pellets. Chitosan-Catechol conjugates were found to be a promising biooadhesive polymer for the development of various mucoadhesive formulations.

Macroporous chitosan/methoxypoly(ethylene glycol) based cryosponges with unique morphology for tissue engineering applications

Three-dimensional porous scaffolds are widely employed in tissue engineering and regenerative medicine for their ability to carry bioactives and cells; and for their platform properties to allow for bridging-the-gap within an injured tissue. This study describes the effect of various methoxypolyethylene glycol (mPEG) derivatives (mPEG (-OCH₃ functionality), mPEG-aldehyde (mPEG-CHO) and mPEG-acetic acid (mPEG-COOH)) on the morphology and physical properties of chemically crosslinked, semi-interpenetrating polymer network (IPN), chitosan (CHT)/mPEG blend cryosponges. Physicochemical and molecular characterization revealed that the –CHO and –COOH functional groups in mPEG derivatives interacted with the –NH₂ functionality of the chitosan chain. The distinguishing feature of the cryosponges was their unique morphological features such as fringe thread-, pebble-, curved quartz crystal-, crystal flower-; and canyon-like structures. The morphological data was well corroborated by the image processing data and physisorption curves corresponding to Type II isotherm with open hysteresis loops. Functionalization of mPEG had no evident influence on the macro-mechanical properties of the cryosponges but increased the matrix strength as determined by the rheomechanical analyses. The cryosponges were able to deliver bioactives (dexamethasone and curcumin) over 10 days, showed varied matrix degradation profiles, and supported neuronal cells on the matrix surface. In addition, in silico simulations confirmed the compatibility and molecular stability of the CHT/mPEG blend compositions. In conclusion, the study confirmed that significant morphological variations may be induced by minimal functionalization and crosslinking of biomaterials.

Further Evidence of Possible Therapeutic Uses of Sambucus nigra L. Extracts by the Assessment of the In Vitro and In Vivo Anti-Inflammatory Properties of Its PLGA and PCL-Based Nanoformulations

Sambucus nigra L. is widely used in traditional medicine with different applications. However, confirmative studies are strongly required. This study aimed to assess the biological activities of the S. nigra flower's extract encapsulated into two different types of nanoparticles for optimizing its properties and producing further evidence of its potential therapeutic uses. Different nanoparticles (poly(lactide-co-glycolide, PLGA) and poly-Ɛ-caprolactone (PCL), both with oleic acid, were prepared by emulsification/solvent diffusion and solvent-displacement methods, respectively. Oleic acid was used as a capping agent. After the nanoparticles' preparation, they were characterized and the biological activities were studied in terms of collagenase, in vitro and in vivo anti-inflammatory, and in vitro cell viability. Rutin and naringenin were found to be the major phenolic compounds in the studied extract. The encapsulation efficiency was higher than 76% and revealed to have an impact on the release of the extract, mainly for the PLGA. Moreover, biochemical and histopathological analyses confirmed that the extract-loaded PLGA-based nanoparticles displayed the highest anti-inflammatory activity. In addition to supporting the previously reported evidence of potential therapeutic uses of S. nigra, these results could draw the pharmaceutical industry's interest to the novelty of the nanoproducts.

Curcumin-loaded, alginate-gelatin composite fibers for wound healing applications

The wound healing process is characterized by varied biological and molecular cascades including inflammation, tissue proliferation, and remodeling phase. To augment and maintain these cascades, an all-natural matrix system is proposed. Biocompatible biopolymers, sodium alginate and gelatin, were employed to prepare microfibers via extrusion-gelation into a physical crosslinking solution. Curcumin, an anti-inflammatory, anti-oxidant and wound healing agent, was loaded into the fibers as a natural bioactive compound. Curcumin-loaded composite microfibers and blank microfibers were fabricated using biopolymers such as sodium alginate and gelatin. The formulation batches were coded as A1G9-A10G0 according to the varied concentrations of sodium alginate and gelatin. The molecular transitions within the composite microfibers were characterized using FTIR and were further corroborated using molecular mechanics analysis. In mechanical properties tensile strength and elongation-at-break (extensibility) were ranging between 1.08 ± 0.01 to 3.53 ± 0.41 N/mm² and 3.89 ± 0.18 to 0.61 ± 0.03%. The morphological analysis confirmed the formation and fabrication of the microfibers. In addition, physical evaluation including matrix degradation and entrapment efficiency was performed to give a comparative account of various formulations. The water uptake capacity of the blank and curcumin-loaded composite fibers was found to be in the range of 30.77 ± 2.17 to 100.00 ± 5.99 and 22.34 ± 1.11 to 56.34 ± 4.68, respectively. Composite microfibers presented a cumulative release of 85% in 72 h, confirming the prolonged release potential of the composite fibers. The drug release followed an anomalous (non-Fickian) release behavior asserting the role of degradation and diffusion. In an in vivo full-thickness cutaneous wound model, the composite microfibers provided higher degree of contraction 96.89 ± 3.76% as compared to the marketed formulation (Vicco turmeric cream). In conclusion, this all-natural, alginate-gelatin-curcumin composite has the potential to be explored as a cost-effective wound healing platform.

Folate-induced nanostructural changes of oligochitosan nanoparticles and their fate of cellular internalization by melanoma

This study examined the effects of folate environment of oligochitosan nanoparticles on their cellular internalization profiles in human melanoma cells. The conjugates and nanoparticles of oligochitosan-folate, oligochitosan-carboxymethyl-5-fluorouracil, and oligochitosan-folate-carboxymethyl-5-fluorouracil were synthesized by carbodiimide chemistry and prepared by nanospray drying technique respectively. The cellular internalization profiles of oligochitosan-folate nanoparticles against the human malignant melanoma cell line (SKMEL-28) were evaluated using confocal scanning electron microscopy technique through fluorescence labelling and endocytic inhibition, as a function of nanoparticulate folate content, size, polydispersity index, zeta potential, shape, surface roughness and folate population density. The cytotoxicity and cell cycle arrest characteristics of oligochitosan-folate-carboxymethyl-5-fluorouracil nanoparticles, prepared with an optimal folate content that promoted cellular internalization, were evaluated against the oligochitosan-folate and oligochitosan-carboxymethyl-5-fluorouracil conjugate nanoparticles. The oligochitosan-folate conjugate nanoparticles were endocytosed by melanoma cells via caveolae- and lipid raft-mediated endocytic pathways following them binding to the cell surface folate receptor. Nanoparticles that were larger and with higher folic acid contents and zeta potentials exhibited a higher degree of cellular internalization. Excessive conjugation of nanoparticles with folate resulted in a high nanoparticulate density of folate which hindered nanoparticles-cell interaction via folate receptor binding and reduced cellular internalization of nanoparticles. Conjugating oligochitosan with 20 %w/w folate was favorable for cellular uptake as supported by in silico models. Conjugating of oligochitosan nanoparticles with carboxymethyl-5-fluorouracil and 20 %w/w of folate promoted nanoparticles-folate receptor binding, cellular internalization and cancer cell death via cell cycle arrest at S phase at a lower drug dose than oligochitosan-carboxymethyl-5-fluorouracil conjugate nanoparticles and neat carboxymethyl-5-fluorouracil.

How Can Biomolecules Improve Mucoadhesion of Oral Insulin? A Comprehensive Insight using Ex-Vivo, In Silico, and In Vivo Models

Currently, insulin can only be administered through the subcutaneous route. Due to the flaws associated with this route, it is of interest to orally deliver this drug. However, insulin delivered orally has several barriers to overcome as it is degraded by the stomach’s low pH, enzymatic content, and poor absorption in the gastrointestinal tract. Polymers with marine source like chitosan are commonly used in nanotechnology and drug delivery due to their biocompatibility and special features. This work focuses on the preparation and characterization of mucoadhesive insulin-loaded polymeric nanoparticles. Results showed a suitable mean size for oral administration (<600 nm by dynamic laser scattering), spherical shape, encapsulation efficiency (59.8%), and high recovery yield (80.6%). Circular dichroism spectroscopy demonstrated that protein retained its secondary structure after encapsulation. Moreover, the mucoadhesive potential of the nanoparticles was assessed in silico and the results, corroborated with ex-vivo experiments, showed that using chitosan strongly increases mucoadhesion. Besides, in vitro and in vivo safety assessment of the final formulation were performed, showing no toxicity. Lastly, the insulin-loaded nanoparticles were effective in reducing diabetic rats’ glycemia. Overall, the coating of insulin-loaded nanoparticles with chitosan represents a potentially safe and promising approach to protect insulin and enhance peroral delivery.

Development and Mechanistic Insight into the Enhanced Cytotoxic Potential of Parvifloron D Albumin Nanoparticles in EGFR-Overexpressing Pancreatic Cancer Cells

Pancreatic cancer is one of the most lethal cancers, with an extremely poor prognosis. The development of more effective therapies is thus imperative. Natural origin compounds isolated from Plectranthus genus, such as parvifloron D (PvD), have cytotoxic and antiproliferative activity against human tumour cells. However, PvD is a very low water-soluble compound, being nanotechnology a promising alternative strategy to solve this problem. Therefore, the aim of this study was to optimize a nanosystem for preferential delivery of PvD to pancreatic tumour cells. Albumin nanoparticles (BSA NPs) were produced through a desolvation method. Glucose cross-linking and bioactive functionalization profiles of BSA platform were elucidated and analysed using static lattice atomistic simulations in vacuum. Using the optimized methodology, PvD was encapsulated (yield higher than 80%) while NPs were characterized in terms of size (100–400 nm) and morphology. Importantly, to achieve a preferential targeting to pancreatic cancer cells, erlotinib and cetuximab were attached to the PvD-loaded nanoparticle surface, and their antiproliferative effects were evaluated in BxPC3 and Panc-1 cell lines. Erlotinib conjugated NPs presented the highest antiproliferative effect toward pancreatic tumour cells. Accordingly, cell cycle analysis of the BxPC3 cell line showed marked accumulation of tumour cells in G1-phase and cell cycle arrest promoted by NPs. As a result, erlotinib conjugated PvD-loaded BSA NPs must be considered a suitable and promising carrier to deliver PvD at the tumour site, improving the treatment of pancreatic cancer.

In Vitro and In Silico Analyses of Nicotine Release from a Gelisphere-Loaded Compressed Polymeric Matrix for Potential Parkinson's Disease Interventions

This study aimed to develop a prolonged-release device for the potential site-specific delivery of a neuroprotective agent (nicotine). The device was formulated as a novel reinforced crosslinked composite polymeric system with the potential for intrastriatal implantation in Parkinson's disease interventions. Polymers with biocompatible and bioerodible characteristics were selected to incorporate nicotine within electrolyte-crosslinked alginate-hydroxyethylcellulose gelispheres compressed within a release rate-modulating external polymeric matrix, comprising either hydroxypropylmethylcellulose (HPMC), polyethylene oxide (PEO), or poly(lactic-co-glycolic) acid (PLGA) to prolong nicotine release. The degradation and erosion studies showed that the produced device had desirable robustness with the essential attributes for entrapping drug molecules and retarding their release. Zero-order drug release was observed over 50 days from the device comprising PLGA as the external matrix. Furthermore, the alginate-nicotine interaction, the effects of crosslinking on the alginate-hydroxyethycellulose (HEC) blend, and the effects of blending PLGA, HPMC, and PEO on device performance were mechanistically elucidated using molecular modelling simulations of the 3D structure of the respective molecular complexes to predict the molecular interactions and possible geometrical orientation of the polymer morphologies affecting the geometrical preferences. The compressed polymeric matrices successfully retarded the release of nicotine over several days. PLGA matrices offered minimal rates of matrix degradation and successfully retarded nicotine release, leading to the achieved zero-order release for 50 days following exposure to simulated cerebrospinal fluid (CSF).