Poloxamers, poloxamines and polymeric micelles: Definition, structure and therapeutic applications in cancer

Electrically conductive and antimicrobial Pluronic-based hydrogels

Electrically conductive hydrogels (ECHs) combine the electrical properties of conductive materials with the unique features of hydrogels. They are attractive for various biomedical applications due to their smart response to electrical fields. Owing to their distinctive properties, such as biocompatibility, thermosensitivity and self-assembling behaviour, Pluronics can be adopted for the generation of hydrogels for biomedical applications. Here, innovative self-assembling ECHs holding antimicrobial properties for biomedical applications are developed, providing a full characterization of their macroscopic and microscopic properties. The rheological, morphological, and structural properties of Pluronic F68 (PF68) in the presence of conductive poly(3,4-ethylenedioxythiophene):poly-(styrenesulfonate) (PEDOT:PSS) are studied to optimize the synthesis of novel biocompatible and electrically conductive hydrogels. The addition of silver (Ag) flakes to the aqueous samples of PF68/PEDOT:PSS is used to further enhance the systems electrical conductivity and antimicrobial potency. Aqueous optimal samples with 45 wt% PF68 and different PEDOT:PSS/silver contents are investigated by means of experimental rheology and small-angle X-ray scattering (SAXS), to unveil the influence of both PEDOT:PSS and silver on the phase diagram, macroscopic flow properties, and morphology of the Pluronic-based systems. The presence of PEDOT:PSS and silver flakes endows Pluronic systems with high conductive properties, while preserving the same self-assembly features of PF68 in water. Moreover, the functionalisation with silver flakes confers antimicrobial properties to the ECHs, as demonstrated by growth inhibition of the multi-drug resistant bacterium Staphylococcus aureus. The use of PF68 in this work provides a novel route for the synthesis of innovative ECHs, whose functionalities such as self-assembling behaviour, biocompatibility, conductivity, and bioactivity may inspire future avenues in the biomedical field.

Glycyrrhizic Acid Formulated in Hydrotalcite Nanocarriers Intended to Act as a Hepatoprotective Agent

The article focuses on preparing a nanoformulation based on hydrotalcite and glycyrrhizic acid (GA), seeking a hepatoprotective effect. For this purpose, hydrotalcite-GA formulations were prepared by varying the following conditions to obtain optimal systems in terms of size and PDI (the lowest values), and Z potential (the highest values): (i) type of hydrotalcite (obtained by co-precipitation or calcined hydrotalcite); method used (ultrasound or high shear stirring), and (iii) type of stabilizer (Tween®80 or Pluronic® F-127). The best results were obtained using hydrotalcite obtained by co-precipitation, with high shear stirring and adding a stabilizer, either Tween®80 (HT-T80-GA: mean particle size = 315 nm, PDI = 0.18, Z potential = -20.93) or Pluronic® F-127 (HT-PF127-GA: mean particle size = 307 nm; PDI = 0.27, Z potential = -21.03). After stability studies, the HT-T80-GA formulation was chosen to study antioxidant activity, cytotoxicity, and intracellular penetration capacity. Although the hepatoprotective effect of GA in solution allowed a high viability and antioxidant activity, the fact of including GA in the HT-T80-GA formulation favored its penetration into hepatocytes, with a decrease in Caspase-3/7 expression of C-9 hepatocyte cells treated with H2O2, suggesting the capacity to inhibit apoptosis.

Lyso-phosphatidylcholine as an interfacial stabilizer for parenteral monoclonal antibody formulations

Therapeutic proteins suffer from physical and chemical instability in aqueous solution. Polysorbates and poloxamers are often added for protection against interfacial stress to prevent protein aggregation and particle formation. Previous studies have revealed that the hydrolysis and oxidation of polysorbates in parenteral formulations can lead to the formation of free fatty acid particles, insufficient long-term stabilization, and protein oxidation. Poloxamers, on the other hand, are considered to be less effective against protein aggregation. Here we investigated two lyso-phosphatidylcholines (LPCs) as potential alternative surfactants for protein formulations, focusing on their physicochemical behavior and their ability to protect against the formation of monoclonal antibody particles during mechanical stress. The hemolytic activity of LPC was tested in varying ratios of plasma and buffer mixtures. LPC effectively stabilized mAb formulations when shaken at concentrations several orders of magnitude below the onset of hemolysis, indicating that the potential for erythrocyte damage by LPC is non-critical. LPC formulations subjected to mechanical stress through peristaltic pumping exhibited comparable protein particle formation to those containing polysorbate 80 or poloxamer 188. Profile analysis tensiometry and dilatational rheology indicated that the stabilizing effect likely arises from the formation of a viscoelastic film at approximately the CMC. Data gathered from concentration-gradient multi-angle light scattering and isothermal titration calorimetry support this finding. Surfactant desorption was evaluated through sub-phase exchange experiments. While LPCs readily desorbed from the interface, resorption occurred rapidly enough in the bulk solution to prevent protein adsorption. Overall, LPCs behave similarly to polysorbate with respect to interfacial stabilization and show promise as a potential substitute for polysorbate in parenteral protein formulations.

Self-assembly of Pluronics: A critical review and relevant applications

Pluronics, alias poloxamers, are synthetic amphiphilic copolymers owning a triblock structure with a central hydrophobic poly(propylene oxide) (PPO) segment linked to two lateral hydrophilic poly(ethylene oxide) (PEO) chains. Commercially, Pluronics exist in numerous types according to the length of PPO and PEO chains, exhibiting different behavior and phase diagrams in solution. Concentrated aqueous solutions of Pluronics form thermoreversible gel-like systems. Properties, such as versatility, biocompatibility, nontoxicity, thermosensitivity and self-assembling behavior, make them extremely attractive for numerous applications. This review paper provides an overview on Pluronics, with a focus on their properties and phase behaviors, and on the effect of the presence of salts and additives. Different strategies to endow Pluronics with improved and extra properties, such as their chemical modification and mixed micelles, are briefly illustrated. Furthermore, a synopsis of useful experimental methodologies for understanding the flow properties of Pluronic-based systems is presented, providing a practical guide to their experimental characterization. Eventually, significant advances of Pluronic-based materials are briefly reviewed to elucidate their role in diverse applications, ranging from drug delivery and tissue engineering to bioprinting, cell cultures, personal care industry, conductive hydrogels, and electrocatalytic science. The current article is a critical review of Pluronic block copolymers, not intended as just inert materials but also as systems with functional properties able to revolutionize the paradigm of many technological fields.

A doxorubicin loaded chitosan-poloxamer in situ implant for the treatment of breast cancer

Breast cancer is a serious concern for many women worldwide. Drug-loaded implants have shown several benefits over systemic administrations. To provide anti-cancer drugs with controlled release and reduced systemic toxicity, biodegradable in situ implants have attracted a lot of attention. In the present study, we aimed to design and optimize a doxorubicin-loaded chitosan-poloxamer in situ implant for breast cancer treatment. Utilizing Box-Behnken Design and a Quality-by-Design (QbD) methodology, the in situ implant was prepared with chitosan (X1), poloxamer 407 concentration (X2), and stirring time (X3) as the independent variables. It was characterized for its in vitro gelation time, pH, rheology, and morphology, and evaluated based on drug release profile, in vitro cytotoxicity activities, in vitro anti-inflammatory potential, in vitro cellular uptake, and in vivo anti-inflammatory and pharmacokinetics to ensure their therapeutic outcomes. The results revealed that the prepared formulation showed a gelation time of 26 ± 0.2 s with a viscosity of 8312.6 ± 114.2 cPs at 37 °C. The developed formulation showed better cytotoxic activity in MCF-7 cell lines compared to the free drug solution. It demonstrated reduced levels of pro-inflammatory cytokines in RAW 264.7 macrophages. Further, the prepared in situ implant increases the intracellular accumulation of DOX in the MCF-7 cells. The in vivo pharmacokinetic investigations depicted an increase in t 1/2 and a decrease in AUC of the developed formulation resulting in prolonged drug release and there could be a lower drug concentration in the bloodstream than for the free drug. Therefore, the developed in situ implant may offer a viable option for breast cancer treatment.

Formulation of Thermo-Sensitive In Situ Gels Loaded with Dual Spectrum Antibiotics of Azithromycin and Ofloxacin

In situ gels have been developed as an innovative strategy to prolong corneal residence time and enhance drug absorption compared to traditional eye drops. Our study aimed to formulate an ophthalmic in situ gel with a combination of two thermosensitive poloxamers, P407 and P188, in an optimal ratio not only to increase the time of action but also to increase the solubility of selected antibiotics for the treatment of ophthalmic infections. Two BSC II class substances, Azithromycin and Ofloxacin, with different mechanisms of action, have been incorporated into the in situ gel system after determining their solubility. The antibiotics-loaded in situ gel formulation was evaluated for its clarity, pH, rheological properties, and gel characteristics of gelling time, temperature, and capacity. The formulation demonstrated satisfactory clarity, appropriate pH, effective gelation properties in simulated tear fluid, and suitable rheological characteristics. In addition, APIs release insight has been studied through a dissolution test, and the effectivity against sensitive and resistant bacterial strains has been proved through the antimicrobial study. Therefore, our in situ gel system based on thermosensitive poloxamers, with two hydrophobic antibiotics, AZM and OFX, can be considered a valuable approach for ophthalmic drug delivery with an enhancement of the antibiotics bioavailability through increasing the contact time with the ocular surface and enhancing patient compliance.

In vivo evaluation of a Nano-enabled therapeutic vitreous substitute for the precise delivery of triamcinolone to the posterior segment of the eye

This study focused on the design of a thermoresponsive, nano-enabled vitreous substitute for the treatment of retinal diseases. Synthesis of a hydrogel composed of hyaluronic acid and a poloxamer blend was undertaken. Poly(D,L-lactide-co-glycolide) acid nanoparticles encapsulating triamcinolone acetonide (TA) were synthesised with a spherical morphology and mean diameter of ~ 153 nm. Hydrogel fabrication and nanoparticle loading within the hydrogel was confirmed via physicochemical analysis. Gelation studies indicated that hydrogels formed in nine minutes and 10 min for the unloaded and nanoparticle-loaded hydrogels, respectively. The hydrogels displayed in situ gel formation properties, and rheometric viscoelastic studies indicated the unloaded and loaded hydrogels to have modulus values similar to those of the natural vitreous at 37 °C. Administration of the hydrogels was possible via 26G needles allowing for clinical application and drug release of triamcinolone acetonide from the nanoparticle-loaded hydrogel, which provided sustained in vitro drug release over nine weeks. The hydrogels displayed minimal swelling, reaching equilibrium swelling within 12 h for the unloaded hydrogel, and eight hours for the nanoparticle-loaded hydrogel. Biodegradation in simulated vitreous humour with lysozyme showed < 20% degradation within nine weeks. Biocompatibility of both unloaded and loaded hydrogels was shown with mouse fibroblast and human retinal pigment epithelium cell lines. Lastly, a pilot in vivo study in a New Zealand White rabbit model displayed minimal toxicity with precise, localised drug release behaviour, and ocular TA levels maintained within the therapeutic window for the 28-day investigation period, which supports the potential applicability of the unloaded and nanoparticle-loaded hydrogels as vitreous substitutes that function as drug delivery systems following vitrectomy surgery.

Local Drug Delivery Systems as Novel Approach for Controlling NETosis in Periodontitis

Periodontitis is a chronic inflammation caused by periodontopathogenic bacteria in the dental biofilm, and also involves the inflammatory-immune response of the host. Polymorphonuclear neutrophils (PMNs) play essential roles in bacterial clearance by multiple mechanisms, including the formation of neutrophil extracellular traps (NETs) that retain and destroy pathogens. During PD progression, the interaction between PMNs, NETs, and bacteria leads to an exaggerated immune response and a prolonged inflammatory state. As a lesion matures, PMNs accumulate in the periodontal tissues and die via NETosis, ultimately resulting in tissue injury. A better understanding of the role of NETs, the associated molecules, and the pathogenic pathways of NET formation in periodontitis, could provide markers of NETosis as reliable diagnostic and prognostic tools. Moreover, an assessment of NET biomarker levels in biofluids, particularly in saliva or gingival crevicular fluid, could be useful for monitoring periodontitis progression and treatment efficacy. Preventing excessive NET accumulation in periodontal tissues, by both controlling NETs' formation and their appropriate removal, could be a key for further development of more efficient therapeutic approaches. In periodontal therapy, local drug delivery (LDD) systems are more targeted, enhancing the bioavailability of active pharmacological agents in the periodontal pocket and surrounding tissues for prolonged time to ensure an optimal therapeutic outcome.

Cytotoxicity of Doxorubicin-Curcumin Nanoparticles Conjugated with Two Different Peptides (CKR and EVQ) against FLT3 Protein in Leukemic Stem Cells

A targeted micellar formation of doxorubicin (Dox) and curcumin (Cur) was evaluated to enhance the efficacy and reduce the toxicity of these drugs in KG1a leukemic stem cells (LSCs) compared to EoL-1 leukemic cells. Dox-Cur-micelle (DCM) was developed to improve the cell uptake of both compounds in LSCs. Cur-micelle (CM) was produced to compare with DCM. DCM and CM were conjugated with two FLT3 (FMS-like tyrosine kinase)-specific peptides (CKR; C and EVQ; E) to increase drug delivery to KG1a via the FLT3 receptor (AML marker). They were formulated using a film-hydration technique together with a pH-induced self-assembly method. The optimal drug-to-polymer weight ratios for the DCM and CM formulations were 1:40. The weight ratio of Dox and Cur in DCM was 1:9. DCM and CM exhibited a particle size of 20-25 nm with neutral charge and a high %EE. Each micelle exhibited colloidal stability and prolonged drug release. Poloxamer 407 (P407) was modified with terminal azides and conjugated to FLT3-targeting peptides with terminal alkynes. DCM and CM coupled with peptides C, E, and C + E exhibited a higher particle size. Moreover, DCM-C + E and CM-C + E showed the highest toxicity in KG-1a and EoL-1 cells. Using two peptides likely improves the probability of micelles binding to the FLT3 receptor and induces cytotoxicity in leukemic stem cells.

Detailed Study on the Interfacial Interaction between Different Polyoxometalates and Tetronic Block Copolymers Exploring the Langmuir-Blodgett Technique

Polyoxometalates (POMs) interact with various biologically relevant entities. A basic understanding of this interaction is very important for various applications in the biological field. In this work, the focus is on the study of the interaction between tetronics and Keggin POMs. T701 and T90R4 are the two tetronics considered here; they have different solubilities in water due to different PPO/PEO ratios. The arrangement of PPO and PEO is also different with respect to the central ethylenediamine groups. Three different Keggin-type POMs, phosphomolybdic acid (PMA), phosphotungstic acid (PTA), and silicotungstic acid (STA), with different charge densities are chosen for an elaborate investigation using Langmuir-Blodgett technique. The observation is analyzed thoroughly, which shows both electrostatic interaction and adsorption of POMs on the PPO blocks of the tetronics due to the chaotropic effect, which is responsible for the binding of POMs (in subphase) with the tetronic monolayer. This interaction results in an expanded yet rigid monolayer for POM-tetronic association on the surface. Surface pressure vs mean molecular area isotherm is the key characterization to reach the conclusion. UV-vis spectroscopy, NMR, ITC, ellipsometric studies, FTIR, and SEM also serve as supportive characterization techniques.

Cellulose- and Saccharide-Based Orally Dispersible Thin Films Transform the Solid States and Dissolution Characteristics of Poorly Soluble Curcumin

This study aimed at developing and optimizing the orally dispersible thin film (ODTF) containing a plant-derived drug-curcumin (CUR). CUR belongs to a biopharmaceutical classification system (BCS) class IV compound that requires improving its water solubility and tissue permeability preceding formulation. An ODTF was applied to produce a solid dispersion matrix for CUR to resolve such solubility and permeability problems. The film-forming polymers used in the study were cellulose-based (hydroxypropyl methylcellulose/HPMC and carboxymethylcellulose/CMC) and saccharide-based maltodextrin (MDX). Poloxamer (POL) was also employed as surfactant and solubilizer. The solvent casting technique was applied to produce the films. The ethanolic solution of CUR was mixed with an aqueous solution of POLs and then incorporated into different film-forming polymers prior to casting. The processing of the CUR with POL solution was intended to aid in the even dispersion of the drug in the polymeric matrices and enhance the wettability of the films. The physical state and properties of the films were characterized in terms of their morphology, crystallinity of the drug, and phase miscibility of the mixtures. The dissolution profile of the films was also evaluated in terms of dissolution rate and dissolution efficiency. The obtained ODTF products were smooth and flat-surfaced. Physical characterization also indicated that the CUR was homogeneously dispersed in the ODTFs and no longer existed as crystalline material as revealed by X-ray diffraction (XRD). The CUR was also not phase-separated from the films as disclosed by differential scanning calorimetry (DSC). Such dispersion was achieved through the solubilizing effect of POLs and compact polymeric film matrices that prevented the CUR from recrystallization. Furthermore, the ODTFs also improved the dissolution of CUR by 3.2-fold higher than the raw CUR. Overall, cellulose-based films had favorable physical properties compared with saccharide-based films.

Development and Characterization of Gelatin-Based Hydrogels Containing Triblock Copolymer and Phytic Acid

In recent research, significant interest has been directed towards gelatin-based hydrogels due to their affordable price, extensive availability, and biocompatibility, making them promising candidates for various biomedical applications. The development and characterization of novel hydrogels formed from varying ratios of gelatin, triblock copolymer Pluronic F-127, and phytic acid have been presented. Swelling properties were examined at different pH levels. The morphology of hydrogels and their thermal properties were analyzed using scanning electron microscopy (SEM), thermogravimetric analysis (TG), and differential scanning calorimetry (DSC). Fourier-transform infrared (FTIR) analysis of the hydrogels was also performed. The introduction of phytic acid in the hydrogel plays a crucial role in enhancing the intermolecular interactions within gelatin-based hydrogels, contributing to a more stable, elastic, and robust network structure.

Variations in the inner core affect the pharmacokinetics of indomethacin-encapsulated polymeric micelles

Hydrophobic ion pairing (HIP) is a drug encapsulation technology that uses electrostatic interactions between a drug and an additive. However, although polymeric micelles can encapsulate hydrophobic drugs in the core, the encapsulated drug often leaks. Therefore, we designed polymeric micelles with HIP functionalized in a hydrophobic inner core using three diblock copolymers comprising polypeptides with different ratios of polar and hydrophobic amino acids and polyethylene glycol (PEG) to encapsulate indomethacin (IND). The three IND-encapsulated HIP micelles showed different area under the curve (AUC) values as an index of blood retention after intravenous injection in mice. Despite having the same PEG shell, IND-PEG-poly(H/F)n showed a 1.56-fold higher AUC than IND-PEG-poly(D/F)n. PEG interface morphologies were evaluated to determine the differences in pharmacokinetic parameters caused by changes in inner core HIP patterns. The micellarized diblock copolymer was desorbed from IND-PEG-poly(D/F)n due to electrostatic repulsion between IND and the diblock copolymer comprising aspartic acid. Our results suggest that changes in the HIP patterns of the micelle inner core affected the PEG interface morphologies, such as PEG density and diblock copolymer desorption from micelles. These phenomena might lead to changes in the interaction of plasma proteins and drug dispositions.

Quantitative Analysis of Poloxamer 188 in Biotherapeutic Process Streams Using Liquid Chromatography-Triple-Quadrupole Mass Spectrometry

Poloxamer 188, also known as Pluronic F-68, is an excipient added to the biotherapeutic protein-manufacturing process. Poloxamer 188 (P188) is a nonionic triblock copolymer surfactant that can be used as a shear protective excipient in bioreactors. In the current study, a method for the process clearance monitoring of poloxamer 188 during downstream processing of biotherapeutics using liquid chromatography-triple-quadrupole mass spectrometry was developed and validated. Chromatographic separation of P188 was achieved using a Phenomenex, Luna 3 μm phenyl-hexyl, 150 × 2 mm column, and quantitation was achieved using a triple-quadrupole mass spectrometer operated in selected reaction monitoring mode. Linearity was assessed over a working range of 250-10,000 ng/mL. Precision and accuracy were within 15% of the theoretical spike levels assessed across the three different concentration levels. For this study, two different IgG1 antibodies were used for the method validation activities. Analyte specificity and selectivity were deemed acceptable based on no extraneous peaks present. System suitability was evaluated throughout this study in anticipation of the introduction of this method into the quality control environment. This method was successfully validated and used to monitor the clearance of poloxamer 188 in a tangential flow filtration purification step during biotherapeutic downstream processing. In addition, the capability of the method to successfully support poloxamer 188 mixing studies is presented in this work.

Lauric acid-based thermosensitive delivery system for the treatment of head and neck squamous cell carcinoma

Traditional treatments for head and neck squamous cell carcinoma (HNSCC) such as surgery, radiation therapy, and chemotherapy, often have severe side effects. Local delivery of chemotherapeutic agents can be a promising approach to minimise systemic toxicity and improve efficacy. Lauric acid (LA), was explored as a novel injectable thermosensitive drug reservoir as a depot for sustained release of anticancer drugs to treat HNSCC. LA was characterised in terms of melting temperature and gelation time. The efficacy of LA-based drug formulations was tested in vitro in a HNSCC cell line and in vivo in a mouse model of HNSCC. LA was modified to have a melting point of 38.5 °C and a gelation time of 40 s at 37.5 °C, rendering it suitable for injection at body temperature. LA- based doxorubicin (DOXO) formulation showed slow release with a maximum of 18% release after 3 days. The in vitro study showed that LA enhanced the cytotoxic effect of DOXO. LA combined with DOXO prevented tumour progression and LA alone significantly reduced the original tumour volume compared to the untreated control group. These findings confirmed that LA can function as practical carrier for the local delivery of chemotherapeutics and provides a safe and simple strategy for the delivery of hydrophobic anticancer drugs and warrant further testing in clinical trials.

Transparent silk fibroin film-facilitated infected-wound healing through antibacterial, improved fibroblast adhesion and immune modulation

The clinical application of regenerated silk fibroin (RSF) films for wound treatment is restricted by its undesirable mechanical properties and lack of antibacterial activity. Herein, different pluronic polymers were introduced to optimize their mechanical properties and the RSF film with 2.5% pluronic F127 (RSFPF127) stood out to address the above issues owing to its satisfactory mechanical properties, hydrophilicity, and transmittance. Diverse antibacterial agents (curcumin, Ag nanoparticles, and antimicrobial peptide KR-12) were separately encapsulated in RSFPF127 to endow it with antibacterial activity. In vitro experiments revealed that the medicated RSFPF127 could persistently release drugs and had desirable bioactivities toward killing bacteria, promoting fibroblast adhesion, and modulating macrophage polarization. In vivo experiments revealed that medicated RSFPF127 not only eradicated methicillin-resistant Staphylococcus aureus in the wound area and inhibited inflammatory responses, but also facilitated angiogenesis and re-epithelialization, regardless of the types of antibacterial agents, thus accelerating the recovery of infected wounds. These results demonstrate that RSFPF127 is an ideal matrix platform to load different types of drugs for application as wound dressings.

Mixed Pluronic/lecithin micelles formulation for oral bioavailability of candesartan cilexetil drug: in vitro characterization and in vivo pharmacokinetic investigations

OBJECTIVE

This study aimed to develop a mixed polymeric micelle formulation incorporating candesartan cilexetil (CAND) drug to enhance its oral bioavailability for the better treatment of hypertension.

METHODS

A Box-Behnken design was utilized to optimize the CAND-incorporated mixed polymeric micelles formulation (CAND-PFLC) consisting of Pluronics (P123 and F68) and lecithin (LC). The optimized CAND-PFLC micelles formulation was characterized for size, shape, zeta potential, polydispersity index (PDI), and entrapment efficiency (%EE). An in vitro release study, ex vivo permeability investigation, and an in vivo pharmacokinetic analysis were carried out to evaluate the performance of the formulation.

RESULTS

The optimized CAND-PFLC micelles formulation demonstrated a spherical shape, a particle size of 44 ± 2.03 nm, a zeta potential of -7.07 ± 1.39 mV, a PDI of 0.326 ± 0.06, and an entrapment efficiency of 87 ± 3.12%. The formulation exhibited excellent compatibility, better stability, and a noncrystalline nature. An in vitro release study revealed a faster drug release of 7.98% at gastric pH in 2 hrs and 94.45% at intestinal pH within 24 hrs. The ex vivo investigation demonstrated a significantly enhanced permeability of CAND, with 94.86% in the micelle formulation compared to 9.03% of the pure drug. In vivo pharmacokinetic analysis showed a 4.11-fold increase in oral bioavailability of CAND compared to the marketed formulation.

CONCLUSION

The CAND-PFLC mixed micelle formulation demonstrated improved performance compared to pure CAND, indicating its potential as a promising oral drug delivery system for the effective treatment of hypertension.

Development of Statistically Optimized Piperine-Loaded Polymeric Nanoparticles for Breast Cancer: In Vitro Evaluation and Cell Culture Studies

Piperine (PPN) is a natural alkaloid derived from black pepper (Piper nigrum L.) and has garnered substantial attention for its potential in breast cancer therapy due to its diverse pharmacological properties. However, its highly lipophilic characteristics and poor dissolution in biological fluids limit its clinical application. Therefore, to overcome this limitation, we formulate and evaluate PPN-encapsulated polycaprolactone (PCL) nanoparticles (PPN-PCL-NPs). The nanoparticles were prepared by a single-step nanoprecipitation method and further optimized by a formulation design approach. The influence of selected independent variables PCL (X1), poloxamer 188 (P-188; X2), and stirring speed (SS; X3) were investigated on the particle size (PS), polydispersity index (PDI), and % encapsulation efficiency (EE). The selected optimized nanoparticles were further assessed for stability, in vitro release, and in vitro antibreast cancer activity in the MCF-7 cancer cell line. The PS, PDI, zeta potential, and % EE of the optimized PPN-PCL-NPs were observed to be 107.61 ± 5.28 nm, 0.136 ± 0.011, -20.42 ± 1.82 mV, and 79.53 ± 5.22%, respectively. The developed PPN-PCL-NPs were stable under different temperature conditions with insignificant changes in their pharmaceutical attributes. The optimized PPN-PCL-NPs showed a burst release for the first 6 h and later showed sustained release for 48 h. The PPN-PCL-NPs exhibit exceptional cytotoxic effects in MCF-7 breast tumor cells in comparison with the native PPN. Thus, the formulation of PPN-loaded PCL-NPs can be a promising approach for better therapeutic efficacy against breast cancer.

Synthesis and Optimization of Next-Generation Low-Molecular-Weight Pentablock Copolymer Nanoadjuvants

Polymeric nanomaterials such as Pluronic®-based pentablock copolymers offer important advantages over traditional vaccine adjuvants and have been increasingly investigated in an effort to develop more efficacious vaccines. Previous work with Pluronic® F127-based pentablock copolymers, functionalized with poly(diethyl aminoethyl methacrylate) (PDEAEM) blocks, demonstrated adjuvant capabilities through the antigen presentation and crosslinking of B cell receptors. In this work, we describe the synthesis and optimization of a new family of low-molecular-weight Pluronic®-based pentablock copolymer nanoadjuvants with high biocompatibility and improved adjuvanticity at low doses. We synthesized low-molecular-weight Pluronic® P123-based pentablock copolymers with PDEAEM blocks and investigated the relationship between polymer concentration, micellar size, and zeta potential, and measured the release kinetics of a model antigen, ovalbumin, from these nanomaterials. The Pluronic® P123-based pentablock copolymer nanoadjuvants showed higher biocompatibility than the first-generation Pluronic® F127-based pentablock copolymer nanoadjuvants. We assessed the adjuvant capabilities of the ovalbumin-containing Pluronic® P123-based pentablock copolymer-based nanovaccines in mice, and showed that animals immunized with these nanovaccines elicited high antibody titers, even when used at significantly reduced doses compared to Pluronic® F127-based pentablock copolymers. Collectively, these studies demonstrate the synthesis, self-assembly, biocompatibility, and adjuvant properties of a new family of low-molecular-weight Pluronic® P123-based pentablock copolymer nanomaterials, with the added benefits of more efficient renal clearance, high biocompatibility, and enhanced adjuvanticity at low polymer concentrations.

Molecular insights into the aggregation and solubilizing behavior of biocompatible amphiphiles Gelucire® 48/16 and Tetronics® 1304 in aqueous media

A comparative analysis of the micellar and solubilizing properties of two polyethylene glycol (PEG)-based amphiphilic biocompatible excipients: Gelucire® 48/16 (Ge 48/16) and Tetronics® 1304 (T1304), in the presence and absence of salt, was conducted. As there is a dearth of research in this area, the study aims to shed light on the behavior of these two nonionic surfactants and their potential as nanocarriers for solubilizing pharmaceuticals. Various techniques such as cloud point (CP), dynamic light scattering (DLS), small-angle neutron scattering (SANS), Fourier transform infrared spectroscopy (FT-IR), UV spectrophotometry, and high-performance liquid chromatography (HPLC) were employed. The solubility of quercetin (QCT), a flavonoid with anti-inflammatory, antioxidant, and anti-cancer properties, was evaluated and the interaction between QCT and the micellar system was examined. The analysis revealed the occurrence of strong interactions between QCT and surfactant molecules, resulting in enhanced solubility. It was observed that the micellar size and solubilizing ability were significantly improved in the presence of salt, while the CP decreased. Ge 48/16 exhibited superior performance, with a remarkable increase in the solubility of QCT in the presence of salt, suggesting its potential as an effective nanocarrier for a range of pharmaceutics, and yielding better therapeutic outcomes.

Priming of Pisum sativum seeds with stabilized Pluronic P85 nanomicelles: effects on seedling development and photosynthetic function

Natural and synthetic polymers are widely explored for improving seed germination and plant resistance to environmental constraints. Here, for the first time, we explore stabilized nanomicelles composed of the biocompatible triblock co-polymer Pluronic P85 (SPM) as a priming agent for Pisum sativum (var. RAN-1) seeds. We tested a wide concentration range of 0.04-30 g(SPM) L-1. Applying several structural and functional methods we revealed that the utilized nanomicelles can positively affect root length, without any negative effects on leaf anatomy and photosynthetic efficiency at 0.2 g L-1, while strong negative effects were recorded for 10 and 30 g(SPM) L-1 concerning root length, leaf histology, and photoprotection capability. Our data strongly suggest that SPM can safely be utilized for seed priming at specific concentrations and are suitable objects for further loading with plant growth regulators.

Effect of 3-Carene and the Micellar Formulation on Leishmania (Leishmania) amazonensis

Leishmaniases are neglected tropical diseases caused by obligate intracellular protozoa of the genus Leishmania. The drugs used in treatment have a high financial cost, a long treatment time, high toxicity, and variable efficacy. 3-Carene (3CR) is a hydrocarbon monoterpene that has shown in vitro activity against some Leishmania species; however, it has low water solubility and high volatility. This study aimed to develop Poloxamer 407 micelles capable of delivering 3CR (P407-3CR) to improve antileishmanial activity. The micelles formulated presented nanometric size, medium or low polydispersity, and Newtonian fluid rheological behavior. 3CR and P407-3CR inhibited the growth of L. (L.) amazonensis promastigote with IC₅₀/48h of 488.1 ± 3.7 and 419.9 ±1.5 mM, respectively. Transmission electron microscopy analysis showed that 3CR induces multiple nuclei and kinetoplast phenotypes and the formation of numerous cytosolic invaginations. Additionally, the micelles were not cytotoxic to L929 cells or murine peritoneal macrophages, presenting activity on intracellular amastigotes. P407-3CR micelles (IC₅₀/72 h = 0.7 ± 0.1 mM) increased the monoterpene activity by at least twice (3CR: IC₅₀/72 h >1.5 mM). These results showed that P407 micelles are an effective nanosystem for delivering 3CR and potentiating antileishmanial activity. More studies are needed to evaluate this system as a potential therapeutic option for leishmaniases.

Ionic Liquids Mediated Micellization of Pluronic Copolymers: Aggregation Behavior of Amphiphilic Triblock Copolymers

Understanding the micellization of amphiphilic triblock copolymers, especially Pluronics can play a persuasive role in engineering "smart" formulations for drug delivery applications. Their underlying self-assembly in the presence of designer solvents such as ionic liquids (ILs) provides combinatorial benefits of unique munificent properties of ILs and copolymers. The complex molecular interactions in the Pluronic copolymers/ILs mixed system influence the aggregation mechanism of copolymers depending on various aspects with no standardized factors to govern the structure-property relationship, which led to the practical applications. Here, we summarized recent progress in understanding the micellization process of IL-Pluronic mixed systems. Special emphasis was given to pure Pluronic systems (i.e., PEO-PPO-PEO) without any structural modifications, such as copolymerization with other functional groups, and ILs having cholinium and imidazolium groups. We expect that the correlation between existing/developing experimental and theoretical studies will provide the necessary basis and impetus for successful utilization in drug delivery applications.

Development and applications of mRNA treatment based on lipid nanoparticles

Nucleic acid-based therapies such as messenger RNA have the potential to revolutionize modern medicine and enhance the performance of existing pharmaceuticals. The key challenges of mRNA-based therapies are delivering the mRNA safely and effectively to the target tissues and cells and controlling its release from the delivery vehicle. Lipid nanoparticles (LNPs) have been widely studied as drug carriers and are considered to be state-of-the-art technology for nucleic acid delivery. In this review, we begin by presenting the advantages and mechanisms of action of mRNA therapeutics. Then we discuss the design of LNP platforms based on ionizable lipids and the applications of mRNA-LNP vaccines for prevention of infectious diseases and for treatment of cancer and various genetic diseases. Finally, we describe the challenges and future prospects of mRNA-LNP therapeutics.

A Critical Sojourn of Polymeric Micelles: Technological Concepts, Recent Advances, and Future Prospects

Poorly soluble drug molecules/phytoconstituents are still a growing concern for biopharmaceutical delivery in the body. Polymeric micelles are the amphiphilic block copolymers and have been widely investigated as targeted nanocarriers for the treatment of various ailments. The versatility of nanocarriers is the self-assembling properties in the aqueous medium and forms a stable isotropic system in vivo. The hydrophobic core-hydrophilic shell configuration of the polymers used to the mixed micelles makes easy encapsulation of hydrophobic and hydrophilic drugs into the core. Polymeric micelles can also be combined with targeting ligands that increase their uptake by specific cells, decreasing off-target effects, and provide enhanced therapeutic effect. In the present review, we primarily focused on a critical appraisal of Polymeric micelles along with the method of preparation, mechanism of micelle formulation, and the ongoing formulations under clinical trials. In addition, the biological applications of this isotropic nanocarrier have been duly presented in each route of administration along with suitable case studies.

Effect of Contact Lens Solutions in Stabilizing the Activity of Tear Lysozyme

Purpose

Interactions between tear proteins and the interfaces of contact lenses can be complex and can influence contact lens wear success. Tear proteins, including lysozyme, function to maintain the balance of ocular surface homeostasis, as evidenced by the effects of its conformation relative to stabilizing the tear film and its potential impact on corneal epithelial cells. Contact lens manufacturers include components in lens care and blister package solutions to help stabilize the tear film and preserve homeostasis. This in vitro study was performed to evaluate the ability of daily disposable contact lens package solutions to stabilize lysozyme and preserve its native conformation under denaturing conditions.

Methods

Lysozyme was added to contact lens solutions sampled from kalifilcon A, etafilcon A, senofilcon A, narafilcon A, nelfilcon A, verofilcon A, delefilcon A, somofilcon A, and stenfilcon A blister packages, then mixed with the protein denaturant sodium lauryl sulfate. Lysozyme activity was evaluated by adding test solutions to a suspension of Micrococcus luteus. Native lysozyme lyses the Micrococcus luteus cell wall, which decreases suspension turbidity. Stabilization of lysozyme activity was determined by comparing suspension turbidity before and after exposure to test solutions.

Results

Lysozyme stabilization was 90.7% for kalifilcon A solution, a statistically significant improvement (p < 0.05) compared to phosphate buffered saline (PBS, negative control). No significant improvement was observed with any other contact lens solution (all lysozyme stabilization < 5.00%).

Conclusion

The representative tear protein lysozyme was significantly more stable in the novel kalifilcon A contact lens solution containing multiple moisturizers and osmoprotectants than in PBS or other daily disposable contact lens solutions. The lysozyme activity assay provides mechanistic evidence that the kalifilcon A contact lens solution can stabilize proteins under conditions that typically denature proteins, which may contribute to maintaining ocular surface homeostasis.

Phytochemical Characterization and Biological Evaluation of Origanum vulgare L. Essential Oil Formulated as Polymeric Micelles Drug Delivery Systems

This study presents phytochemical characterization and biological evaluation of Origanum vulgare L. essential oil (OEO) formulated as polymeric micelles drug delivery systems as a possible non-invasive approach for the management of skin tags. GC-MS analysis of Romanian OEO revealed the identification and quantification of 43 volatile compounds (thymol and carvacrol being the main ones). The antioxidant activity was shown by four consecrated methods: CUPRAC, ABTS, ORAC and DPPH. OEO was incorporated by micellar solubilization into a binary hydrogel based on a Pluronic F 127/L 31 block-copolymers mixture. The pH, consistency, spreadability, particle size, polydispersity index and zeta potential of the OEO-loaded poloxamer-based binary hydrogel (OEO-PbH) were investigated. OEO-PbH was skin compatible in terms of pH and exhibited adequate spreadability and consistency. The minimal inhibitory concentrations of the tested OEO were similar to those obtained for the formulation, lower (2.5 µg/mL) for yeast and higher (40-80 µg/mL) for Gram-negative bacilli. As keratinocytes are among main components of skin tags, an in vitro evaluation was conducted in order to see the effect of the formulation against HaCaT human keratinocytes. OEO-PbH decreased HaCaT cells migration and proliferation and elicited a cytotoxic and pro-apoptotic effect in a dose- and time-dependent manner. No harmful effect on the viability of dendritic cells (DCs) was detected following the incubation with different concentrations (0-200 µg/mL) of the 5% formulation. Treatment in inflammatory DCs (+LPS) indicated a decrease in cytokine production of IL-6, TNF-α and IL-23 but no significant effect on IL-10 in any of the tested concentrations.

New Advances in Biomedical Application of Polymeric Micelles

In the last decade, nanomedicine has arisen as an emergent area of medicine, which studies nanometric systems, namely polymeric micelles (PMs), that increase the solubility and the stability of the encapsulated drugs. Furthermore, their application in dermal drug delivery is also relevant. PMs present unique characteristics because of their unique core-shell architecture. They are colloidal dispersions of amphiphilic compounds, which self-assemble in an aqueous medium, giving a structure-type core-shell, with a hydrophobic core (that can encapsulate hydrophobic drugs), and a hydrophilic shell, which works as a stabilizing agent. These features offer PMs adequate steric protection and determine their hydrophilicity, charge, length, and surface density properties. Furthermore, due to their small size, PMs can be absorbed by the intestinal mucosa with the drug, and they transport the drug in the bloodstream until the therapeutic target. Moreover, PMs improve the pharmacokinetic profile of the encapsulated drug, present high load capacity, and are synthesized by a reproducible, easy, and low-cost method. In silico approaches have been explored to improve the physicochemical properties of PMs. Based on this, a computer-aided strategy was developed and validated to enable the delivery of poorly soluble drugs and established critical physicochemical parameters to maximize drug loading, formulation stability, and tumor exposure. Poly(2-oxazoline) (POx)-based PMs display unprecedented high loading concerning water-insoluble drugs and over 60 drugs have been incorporated in POx PMs. Among various stimuli, pH and temperature are the most widely studied for enhanced drug release at the site of action. Researchers are focusing on dual (pH and temperature) responsive PMs for controlled and improved drug release at the site of action. These dual responsive systems are mainly evaluated for cancer therapy as certain malignancies can cause a slight increase in temperature and a decrease in the extracellular pH around the tumor site. This review is a compilation of updated therapeutic applications of PMs, such as PMs that are based on Pluronics^®, micelleplexes and Pox-based PMs in several biomedical applications.

Thermo-responsive nonionic amphiphilic copolymers as draw solutes in forward osmosis process for high-salinity water reclamation

Recently, thermo-responsive nonionic amphiphilic copolymers have shown a great potential as forward osmosis (FO) draw solutes for high-salinity water desalination and zero-liquid discharge (ZLD). However, the relationship between the copolymer structural properties and key characteristics as draw solutes, as well as copolymer's chemical stability after regeneration have not been much studied. In this work, we systematically investigated poly (ethylene oxide)-block-poly (propylene oxide)-block-poly (ethylene oxide) (PEO-PPO-PEO) copolymers as draw solute. The results showed that the PEO segments significantly influenced the viscosity, osmotic pressure and lowest phase separation temperature of the copolymer aqueous solutions. Among four commercial copolymers studied, Pluronic® L35 with moderate molecular weight (Mn 1,900 Da), 50% PEO, and relatively high hydrophilic-lipophilic balance (HLB) showed the best draw solution (DS) performance. It also showed great stability in physiochemical properties and draw capacity after more than ten cycles of regeneration. On the other hand, despite the fact that membrane fouling was observed due to the use of copolymer DS, the FO flux (∼1.2 L m^‒2 h^‒1, as similar with the virgin membrane) was not affected when high-salinity feedwater such as seawater RO brine was applied. Overall, our study has provided a more comprehensive understanding on the characteristics of nonionic amphiphilic copolymer DS and showcased the promise of copolymer-driven FO process in high-salinity water desalination and ZLD.

Long-acting injectable formulation technologies: Challenges and opportunities for the delivery of fragile molecules

INTRODUCTION

The development of long acting injectables (LAIs) for protein and peptide therapeutics has been a key challenge over the last 20 years. If these molecules offer advantages due to their high specificity and selectivity, their controlled release may confer several additional benefits in terms of extended half-life, local delivery, and patient compliance.

AREA COVERED

This manuscript aims to give an overview of peptide and protein based LAIs from an industrial perspective, describing both approved and promising technologies (with exceptions of protein engineering strategies and devices), their advantages and potential improvements to aid their access to the market.

EXPERT OPINION

Many LAIs have been developed for peptides, with formulations on the market for several decades. On the contrary, LAIs for proteins are still far from the market and issues related to manufacturing and sterilization of these products still need to be overcome. In situ forming depots (ISFDs), whose simple manufacturing conditions and easy administration procedures (without reconstitution) are strong advantages, appear as one of the most promising technologies for the delivery of these molecules. In this regard, the approval of ELIGARD® in the early 2000's (which still requires a complex reconstitution process), paved the way for the development of second-generation, ready-to-use ISFD technologies like BEPO® and FluidCrystal®.

Micelles as potential drug delivery systems for colorectal cancer treatment

Despite the significant progress in cancer therapy, colorectal cancer (CRC) remains one of the most fatal malignancies worldwide. Chemotherapy is currently the mainstay therapeutic modality adopted for CRC treatment. However, the long-term effectiveness of chemotherapeutic drugs has been hampered by their low bioavailability, non-selective tumor targeting mechanisms, non-specific biodistribution associated with low drug concentrations at the tumor site and undesirable side effects. Over the last decade, there has been increasing interest in using nanotechnology-based drug delivery systems to circumvent these limitations. Various nanoparticles have been developed for delivering chemotherapeutic drugs among which polymeric micelles are attractive candidates. Polymeric micelles are biocompatible nanocarriers that can bypass the biological barriers and preferentially accumulate in tumors via the enhanced permeability and retention effect. They can be easily engineered with stimuli-responsive and tumor targeting moieties to further ensure their selective uptake by cancer cells and controlled drug release at the desirable tumor site. They have been shown to effectively improve the pharmacokinetic properties of chemotherapeutic drugs and enhance their safety profile and anticancer efficacy in different types of cancer. Given that combination therapy is the new strategy implemented in cancer therapy, polymeric micelles are suitable for multidrug delivery and allow drugs to act concurrently at the action site to achieve synergistic therapeutic outcomes. They also allow the delivery of anticancer genetic material along with chemotherapy drugs offering a novel approach for CRC therapy. Here, we highlight the properties of polymeric micelles that make them promising drug delivery systems for CRC treatment. We also review their application in CRC chemotherapy and gene therapy as well as in combination cancer chemotherapy.

Poloxamer 188 as surfactant in biological formulations - An alternative for polysorbate 20/80?

Surfactants are used to stabilize biologics. Particularly, polysorbates (Tween® 20 and Tween® 80) dominate the group of surfactants in protein and especially antibody drug products. Since decades drug developers rely on the ethoxylated sorbitan fatty acid ester mixtures to stabilize sensitive molecules such as proteins. Reasons are (i) excellent stabilizing properties, and (ii) well recognized safety and tolerability profile of these polysorbates in humans, especially for parenteral applications. However, over the past decade concerns regarding the stability of these two polysorbates were raised. The search of alternatives with preferably less reservations concerning degradation and product quality reducing issues leads, among others, to poloxamer 188 (e.g. Kolliphor® P188), a nonionic triblock-copolymer surfactant. This review sums up our current knowledge related to the characterization and physico-chemical properties of poloxamer 188, its analytics and stability properties for biological formulations. Furthermore, the advantages and disadvantages as a suitable polysorbate-alternative for the stabilization of biologics are discussed.

Correia J, Moiseev RV, Cihova M, Gaboriau DCA, Krell J, Khutoryanskiy VV, Stevens MM, Georgiou TK. Investigation of the Thermogelation of a Promising Biocompatible ABC Triblock Terpolymer and Its Comparison with Pluronic F127

Thermoresponsive polymers with the appropriate structure form physical networks upon changes in temperature, and they find utility in formulation science, tissue engineering, and drug delivery. Here, we report a cost-effective biocompatible alternative, namely OEGMA300₁₅-b-BuMA₂₆-b-DEGMA₁₃, which forms gels at low concentrations (as low as 2% w/w); OEGMA300, BuMA, and DEGMA stand for oligo(ethylene glycol) methyl ether methacrylate (MM = 300 g mol^–1), n-butyl methacrylate, and di(ethylene glycol) methyl ether methacrylate, respectively. This polymer is investigated in depth and is compared to its commercially available counterpart, Poloxamer P407 (Pluronic F127). To elucidate the differences in their macroscale gelling behavior, we investigate their nanoscale self-assembly by means of small-angle neutron scattering and simultaneously recording their rheological properties. Two different gelation mechanisms are revealed. The triblock copolymer inherently forms elongated micelles, whose length increases by temperature to form worm-like micelles, thus promoting gelation. In contrast, Pluronic F127’s micellization is temperature-driven, and its gelation is attributed to the close packing of the micelles. The gel structure is analyzed through cryogenic scanning and transmission electron microscopy. Ex vivo gelation study upon intracameral injections demonstrates excellent potential for its application to improve drug residence in the eye.

Polymeric Micelles: A Promising Pathway for Dermal Drug Delivery

Nanotechnology is an area in great development and with application in the most varied fields of science, including cosmetic and pharmaceutical industries. Because conventional formulations for topical application are not always able to effectively penetrate the physical barrier that human skin exerts against factors and compounds of the external environment, polymeric micelles appear as alternative carriers for drugs and active ingredients delivery, also allowing ingredients with lower solubility and higher lipophilicity to be delivered. In fact, the augmented bioavailability of drugs, greater efficacy even at a lower dose, and selective drug delivery in specific organelles are very interesting advantages of the polymeric micelles usage in cutaneous application. As a consequence, they show a reduction in many of the local and systemic adverse effects, which might lead to an increase in patient compliance to the therapeutics, constituting a promising alternative to conventional topical formulations.

A UHPLC-Q-TOF/MS method for the determination of poloxamer 124 and its application in a tissue distribution study in rats

Poloxamers are commonly used pharmaceutical excipients. They are high molecular weight polymers formed from polypropylene oxide (PPO) and polyethylene oxide (PEO). However, PL124, a low molecular weight example in the poloxamer family, has rarely been reported, and there is no research into its tissue distribution in the body after administration. In this study, rat tissue samples were quantitatively studied via UHPLC-Q-TOF/MS after the intravenous administration of 10 mg kg^-1 PL124. The quantitative method showed good sensitivity and selectivity. The linear range of PL124 was 0.1-5 μg mL^-1 and the LLOQ was 0.1 μg mL^-1. The relative error in terms of the accuracy was no higher than 13.9%, and the relative standard deviation in terms of the precision was no higher than 9.6%. The extraction recovery, matrix effect, and stability results of the established method were also satisfactory. The research showed that PL124 can be quickly distributed to large amounts of tissue, and tissue with higher levels of blood flow has higher concentrations. PL124 could be rapidly eliminated in 4 h from most organs, except the heart and liver. This study can be helpful for the further analysis of PL124.

Criteria Governing Rod Formation and Growth in Nonionic Polymer Micelles

Self-assembled wormlike micelles (WLMs) are widely studied in small-molecule surfactants due to their unique ability to break and recombine; however, less is known about the structure and dynamics of nonionic polymer WLMs. Here, solutions of seven triblock poloxamers, composed of poly(propylene oxide) (PPO) midblocks and poly(ethylene oxide) (PEO) end blocks, are comprehensively examined to determine the role of poloxamer composition, temperature, and inorganic salt type and concentration on rod formation and subsequent elongation into WLMs. Phase separation and sphere-to-rod transition temperatures were quantified via cloud point measurements and shear rheology, respectively, and corroborated with small-angle neutron scattering (SANS). The local microstructure of resulting rodlike micelles is remarkably similar across poloxamer type and sodium fluoride (NaF) or sodium chloride (NaCl) content. Salt addition reduces transition temperatures, with the most pronounced effects for poloxamers with high PEO molecular weights and PEO fractions. Between these two temperatures, several poloxamers elongate into WLMs, where shear rheology detects increases in viscosity up to 6 orders of magnitude. Despite similar local microstructures, poloxamer identity and salt content impact micelle growth substantially, where large poloxamers with lower PEO fractions exhibit the highest viscosities and longest relaxation times. While sodium fluoride has little impact on micelle growth, increasing NaCl concentration dramatically increases the WLM viscosity and relaxation time. This result is explained by different interactions of each salt with the micelle: whereas NaF interacts primarily with PEO chains, NaCl may also partition to the PPO/PEO interface in low levels, increasing micelle surface tension, scission energy, and contour length.

Formulation, Solubilization, and In Vitro Characterization of Quercetin-Incorporated Mixed Micelles of PEO-PPO-PEO Block Copolymers

Quercetin (QCN) is a plant polyphenol with a variety of medicinal effects. Poor water solubility, on the other hand, restricts its therapeutic effectiveness. The purpose of this study was to develop mixed micellar systems using two biocompatible amphiphilic PEO-PPO-PEO triblock copolymers, Pluronic P123 (EO₂₀-PO₇₀-EO₂₀) and Pluronic F88 (EO₁₀₄-PO₃₉-EO₁₀₄), in order to enhance the aqueous solubility and oral bioavailability of QCN drug. The critical micelle concentrations (CMCs) of mixed P123/F88 micellar solutions were investigated using UV-visible spectroscopy with pyrene as a probe. Mixed P123/F88 micelles have low CMCs, indicating that they have a stable micelle structure even when diluted. The solubility of QCN in aqueous mixed P123/F88 micellar solutions at different temperatures was investigated to better understand drug entrapment. The QCN solubility increased with increasing temperature in the mixed P123/F88 micellar system. The QCN-incorporated mixed P123/F88 micelles were prepared using the thin-film hydration method and were well characterized in terms of size and morphology, compatibility, in vitro release and antioxidant profile. In addition, the cell proliferation activity of the mixed micelles was evaluated in the MCF-7 cell line. The QCN-incorporated mixed P123/F88 micelles had a small particle size (< 25 nm) and a negative zeta potential with a spherical shape. The in vitro release behaviour of QCN from a mixed P123/F88 micellar system was slower and more sustained at physiological conditions. The oxidation resistance of QCN-incorporating mixed P123/F88 micelles was shown to be considerably higher than that of pure QCN. An in vitro cell proliferation study revealed that QCN-incorporated mixed micells were effective in inhibiting tumour cell growth. In conclusion, the QCN-incorporated mixed P123/F88 micelle may be a promising approach to increase QCN oral bioavailability, antioxidant activity, and cell viability.

mRNA-Based Cancer Vaccines: A Therapeutic Strategy for the Treatment of Melanoma Patients

Malignant melanoma is one of the most aggressive forms of cancer and the leading cause of death from skin tumors. Given the increased incidence of melanoma diagnoses in recent years, it is essential to develop effective treatments to control this disease. In this regard, the use of cancer vaccines to enhance cell-mediated immunity is considered to be one of the most modern immunotherapy options for cancer treatment. The most recent cancer vaccine options are mRNA vaccines, with a focus on their usage as modern treatments. Advantages of mRNA cancer vaccines include their rapid production and low manufacturing costs. mRNA-based vaccines are also able to induce both humoral and cellular immune responses. In addition to the many advantages of mRNA vaccines for the treatment of cancer, their use is associated with a number of challenges. For this reason, before mRNA vaccines can be used for the treatment of cancer, comprehensive information about them is required and a large number of trials need to be conducted. Here, we reviewed the general features of mRNA vaccines, including their basis, stabilization, and delivery methods. We also covered clinical trials involving the use of mRNA vaccines in melanoma cancer and the challenges involved with this type of treatment. This review also emphasized the combination of treatment with mRNA vaccines with the use of immune-checkpoint blockers to enhance cell-mediated immunity.