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.

Design, Development, and Evaluation of SA-F127:TPGS Polymeric Mixed Micelles for Improved Delivery of Glipizide Drug: In-vitro, Ex-vivo, and In-vivo Investigations.

The anti-diabetic glipizide (GLN) drug has notable pharmaceutical advantages, but poor aqueous solubility restricts its wide applications. The present work was to develop a mixed polymeric micelle system composed of SA-F127 and TPGS to improve the water solubility and effective delivery of the GLN. First, we synthesized SA-F127 and confirmed it through FTIR, NMR, and GPC techniques. The GLN-PMM were fabricated with the thin-film technique and optimized with CCD design. The developed GLN-PMM was characterized using DLS, Zeta, TEM, Rheology, FTIR, DSC, and XRD measurements. The GLN-PMM manifested a spherical morphology with 67.86 nm particle size, a -3.85 mV zeta potential, and a 0.582±0.06 PDI value. The polymeric mixed micelles showed excellent compatibility with GLN and were amorphous in nature. NMR studies confirmed the encapsulation of GLN in the core of the mixed micelle. In addition, the GLN-PMM micelles were tested in vitro for cumulative drug release, ex vivo for permeation, and in vivo for anti-diabetic investigations. The GLN-PMM release profile in the various pH environments showed over 90% after 24 h, clearly indicating sustained release. The GLN-PMM micelles gave higher 88.86±3.39% GLN permeation from the goat intestine compared with free GLN. In-vivo anti-diabetic investigation proves the powerful anti-diabetic properties of GLN-PMM in comparison to the marketed formulation. These findings demonstrated that the polymeric mixed micelles of SA-F127 and TPGS could be a promising, effective, and environment-friendly approach for oral delivery of the GLN.

Pluronic-Based Mixed Polymeric Micelles Enhance the Therapeutic Potential of Curcumin.

Curcumin is a naturally occurring constituent of turmeric that is a good substitute for synthetic medicines for the treatment of different diseases, due to its comparatively safer profile. However, there are certain shortcomings that limit its use as an ideal therapeutic agent. In order to overcome these drawbacks, we prepared novel curcumin-loaded mixed polymeric micelles using different biocompatible polymers by the thin-film hydration method. We investigated the critical micelle concentration and temperature, drug loading and encapsulation efficiency, and minimum inhibitory concentration by spectrophotometry. Surface morphology, stability, particle size, drug-polymer interaction, and physical state of the prepared formulations were investigated using scanning electron microscopy, zeta potential, particle size analyzer, Fourier-transform infrared spectroscopy, and X-ray diffraction, respectively. The drug loading and entrapment efficiency were significantly increased (P < 0.01) when curcumin was encapsulated with pluronic-based mixed polymeric micelles as compared to that of pluronic-based micelles alone. In vitro studies exhibited that pluronic-based mixed polymeric micelles significantly increased anticancer (P < 0.01), antimicrobial (P < 0.001), antioxidant (P < 0.001), and α-amylase inhibitory (P < 0.001) activities when compared to pure curcumin and/or pluronic-based micelles alone. These findings suggest that the formation of mixed polymeric micelles increases the stability and solubility of curcumin.

Folic acid grafted mixed polymeric micelles as a targeted delivery strategy for tamoxifen citrate in treatment of breast cancer.

The objective of this study was to develop folic acid (FA) grafted mixed polymeric micelles loaded with Tamoxifen citrate (TMXC) to enhance its antitumor activity in breast tissues. The conjugated folic acid Pluronic 123 (FA-P123) was prepared using carbonyl diimidazole cross-linker chemistry and confirmed using FTIR and 1HNMR. TMXC-loaded P123/P84 (unconjugated) and TMXC-loaded FA-P123/P84 (conjugated) micelles were examined for encapsulation efficiency, particle size, surface charge, in vitro drug release, cytotoxic effect, and cellular uptake by a breast cancer cell line. The conjugated TMXC-loaded micelle exhibited a nanoparticle size of 35.01 ± 1.20 nm, a surface charge of-20.50 ± 0.95 mV, entrapped 87.83 ± 5.10% and released 67.58 ± 2.47% of TMXC after 36 h. The conjugated micelles exhibited a significantly higher cellular uptake of TMXC by the MCF-7 cell line and improved in vitro cytotoxicity by 2.48 folds compared to the TMXC-loaded unconjugated micelles. The results of in vivo studies indicated that TMXC-loaded FA-P123/P84 has a potential antitumor activity, as revealed by a significant reduction of tumor volume in tumor-bearing mice compared to TMXC-loaded unconjugated micelles. In conclusion, the obtained results suggested that conjugated FA-P123/P84 micelles could be an encouraging carrier for the treatment of breast cancer with TMXC.

Mixed Polymeric Micelles for Rapamycin Skin Delivery.

Facial angiofibromas (FA) are one of the most obvious cutaneous manifestations of tuberous sclerosis complex. Topical rapamycin for angiofibromas has been reported as a promising treatment. Several types of vehicles have been used hitherto, but polymeric micelles and especially those made of d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) seem to have shown better skin bioavailability of rapamycin than the so far commonly used ointments. To better understand the influence of polymeric micelles on the behavior of rapamycin, we explored it through mixed polymeric micelles combining TPGS and poloxamer, evaluating stability and skin bioavailability to define an optimized formulation to effectively treat FA. Our studies have shown that TPGS improves the physicochemical behavior of rapamycin, i.e., its solubility and stability, due to a strong inclusion in micelles, while poloxamer P123 has a more significant influence on skin bioavailability. Accordingly, we formulated mixed-micelle hydrogels containing 0.1% rapamycin, and the optimized formulation was found to be stable for up to 3 months at 2-8 °C. In addition, compared to hydroalcoholic gel formulations, the studied system allows for better biodistribution on human skin.

Microemulsions as Lipid Nanosystems Loaded into Thermoresponsive In Situ Microgels for Local Ocular Delivery of Prednisolone.

This study aimed to develop and evaluate thermoresponsive in situ microgels for the local ocular delivery of prednisolone (PRD) (PRD microgels) to improve drug bioavailability and prolong ocular drug residence time. Lipid nanosystems of PRD microemulsions (PRD-MEs) were prepared and evaluated at a drug concentration of 0.25-0.75%. PRD microgels were prepared by incorporating PRD-MEs into 10 and 12% Pluronic® F127 (F127) or combinations of 12% F127 and 1-10% Kolliphor®P188 (F68). PRD microgels were characterized for physicochemical, rheological, and mucoadhesive properties, eye irritation, and stability. Results showed that PRD-MEs were clear, miscible, thermodynamically stable, and spherical with droplet size (16.4 ± 2.2 nm), polydispersity index (0.24 ± 0.01), and zeta potential (-21.03 ± 1.24 mV). The PRD microgels were clear with pH (5.37-5.81), surface tension (30.96-38.90 mN/m), size, and zeta potential of mixed polymeric micelles (20.1-23.9 nm and -1.34 to -10.25 mV, respectively), phase transition temperature (25.3-36 °C), and gelation time (1.44-2.47 min). The FTIR spectra revealed chemical compatibility between PRD and microgel components. PRD microgels showed pseudoplastic flow, viscoelastic and mucoadhesive properties, absence of eye irritation, and drug content (99.3 to 106.3%) with a sustained drug release for 16-24 h. Microgels were physicochemically and rheologically stable for three to six months. Therefore, PRD microgels possess potential vehicles for local ocular delivery.

Efavirenz Loaded Mixed Polymeric Micelles: Formulation, Optimization, and In Vitro Characterization.

Efavirenz (EFZ) is a biopharmaceutics classification system (BCS) Class-II, first-line antiretroviral (ARV) drug. However, its utility through the oral route is restricted by its poor solubility. The objective of this study was to formulate EFZ-loaded binary-mixed micelles as a potential carrier for oral administration of EFZ. Rubingh's regular solution theory was used to determine the interaction behavior of the two components (Cremophor RH 40 and Phospholipon 80H) and of the mixed micelles and synergistic behavior was confirmed. The mixed miceller system was formulated using solvent evaporation method and a 32 factorial design was used for the optimization of selected independent variables. Miceller systems were further characterized in terms of morphology, particle size, zeta potential, percent entrapment efficiency, and drug loading. Fourier transform infrared and differential scanning calorimetry measurements confirmed the entrapment of EFZ in the micelles. The optimized formulation presented desirable qualities viz., nanometric size (17.27 ± 0.079), high entrapment efficiency, and good colloidal stability. The prepared optimized micelles can be potential carriers for EFZ in ARV therapies.

Honokiol/Magnolol-Loaded Self-Assembling Lecithin-Based Mixed Polymeric Micelles (lbMPMs) for Improving Solubility to Enhance Oral Bioavailability.

OBJECTIVE: This study was intended to utilize lecithin-based mixed polymeric micelles (lbMPMs) for enhancing the solubility and bioavailability of honokiol and magnolol to resolve the hindrance of their extreme hydrophobicity on the clinical applications. METHODS: Lecithin was selected to increase the volume of the core of lbMPMs, thereby providing a greater solubilization capacity. A series of amphiphilic polymers (sodium deoxycholate [NaDOC], Cremophor®, and Pluronic® series) were included with lecithin for screening and optimization. RESULTS: After preliminary evaluation and subsequentially optimization, two lbMPMs formulations composed of honokiol/magnolol:lecithin:NaDOC (lbMPMs[NaDOC]) and honokiol/magnolol:lecithin:PP123 (lbMPMs[PP123]) in respective ratios of 6:2:5 and 1:1:10 were optimally obtained with the mean particle sizes of 80-150 nm, encapsulation efficacy (EEs) of >90%, and drug loading (DL) of >9.0%. These lbMPMs efficiently stabilized honokiol/magnolol in phosphate-buffered saline (PBS) at room temperature or 4 °C and in fetal bovine serum or PBS at 37 °C. PK study demonstrated that lbMPMs[NaDOC] showed much improvement in enhancing bioavailability than that by lbMPMs[PP123] for both honokiol and magnolol. The absolute bioavailability for honokiol and magnolol after intravenous administration of lbMPMs[NaDOC] exhibited 0.93- and 3.4-fold increases, respectively, compared to that of free honokiol and magnolol. For oral administration with lbMPMs[NaDOC], the absolute bioavailability of honokiol was 4.8%, and the absolute and relative bioavailability of magnolol were 20.1% and 2.9-fold increase, respectively. CONCLUSION: Overall, honokiol/magnolol loaded in lbMPMs[NaDOC] showed an improvement of solubility with suitable physical characteristics leading to enhance honokiol and magnolol bioavailability and facilitating their wider application as therapeutic agents for treating human disorders.

Mixed Pluronic-Cremophor Polymeric Micelles as Nanocarriers for Poorly Soluble Antibiotics-The Influence on the Antibacterial Activity.

In this work, novel polymeric mixed micelles from Pluronic F127 and Cremophor EL were investigated as drug delivery systems for Norfloxacin as model antibiotic drug. The optimal molar ratio of surfactants was determined, in order to decrease critical micellar concentration (CMC) and prepare carriers with minimal surfactant concentrations. The particle size, zeta potential, and encapsulation efficiency were determined for both pure and mixed micelles with selected composition. In vitro release kinetics of Norfloxacin from micelles show that the composition of surfactant mixture generates tunable extended release. The mixed micelles exhibit good biocompatibility against normal fibroblasts MRC-5 cells, while some cytotoxicity was found in all micellar systems at high concentrations. The influence of the surfactant components in the carrier on the antibacterial properties of Norfloxacin was investigated. The drug loaded mixed micellar formulation exhibit good activity against clinical isolated strains, compared with the CLSI recommended standard strains (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29213, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922). P. aeruginosa 5399 clinical strain shows low sensitivity to Norfloxacin in all tested micelle systems. The results suggest that Cremophor EL-Pluronic F127 mixed micelles can be considered as novel controlled release delivery systems for hydrophobic antimicrobial drugs.

Multifunctional silica-coated mixed polymeric micelles for integrin-targeted therapy of pediatric patient-derived glioblastoma.

Glioblastoma multiforme (GBM) remains a major cause of mortality because treatments are precluded by to the limited transport and penetration of chemotherapeutics across the blood-brain barrier. Pitavastatin (PTV) is a hydrophobic Food and Drug Administration (FDA)-approved anticholesterolemic agent with reported anti-GBM activity. In the present study, we encapsulate PTV in silica-coated polymeric micelles (SiO2 PMs) surface-modified with the cyclic peptide Arg-Gly-Asp-Phe-Val (cRGDfV) that actively targets the αvß3 integrin overexpressed in the BBB endothelium and GBM. A central composite design is utilized to optimize the preparation process and improve the drug encapsulation ratio from 131 to 780 µg/mL. The silica shell provides full colloidal stability upon extreme dilution and enables a better control of the release kinetics in vitro with 28% of the cargo released after 12 h. Furthermore, SiO2 PMs show excellent compatibility and are internalized by human BBB endothelial cells, astrocytes and pericytes, as shown by confocal laser scanning fluorescence microscopy and flow cytometry. Finally, the anticancer efficacy is assessed in a pediatric patient-derived glioma cell line expressing high levels of the integrin subunits αv, ß3 and ß5. This PTV-loaded nanocarrier triggers apoptosis by reducing the mRNA level of anti-apoptotic genes NF-kß, IL-6, BIRC1 and BIRC5 by 89%, 33%, 81% and 63%, respectively, and the cell viability by >60%. Overall, our results suggest the potential of these hybrid nanocarriers for the targeted therapy of GBM and other tumors overexpressing integrin receptors.

Dual pH/Redox-Responsive Mixed Polymeric Micelles for Anticancer Drug Delivery and Controlled Release.

Stimuli-responsive polymeric micelles (PMs) have shown great potential in drug delivery and controlled release in cancer chemotherapy. Herein, inspired by the features of the tumor microenvironment, we developed dual pH/redox-responsive mixed PMs which are self-assembled from two kinds of amphiphilic diblock copolymers (poly(ethylene glycol) methyl ether-b-poly(ß-amino esters) (mPEG-b-PAE) and poly(ethylene glycol) methyl ether-grafted disulfide-poly(ß-amino esters) (PAE-ss-mPEG)) for anticancer drug delivery and controlled release. The co-micellization of two copolymers is evaluated by measurement of critical micelle concentration (CMC) values at different ratios of the two copolymers. The pH/redox-responsiveness of PMs is thoroughly investigated by measurement of base dissociation constant (pKb) value, particle size, and zeta-potential in different conditions. The PMs can encapsulate doxorubicin (DOX) efficiently, with high drug-loading efficacy. The DOX was released due to the swelling and disassembly of nanoparticles triggered by low pH and high glutathione (GSH) concentrations in tumor cells. The in vitro results demonstrated that drug release rate and cumulative release are obviously dependent on pH values and reducing agents. Furthermore, the cytotoxicity test showed that the mixed PMs have negligible toxicity, whereas the DOX-loaded mixed PMs exhibit high cytotoxicity for HepG2 cells. Therefore, the results demonstrate that the dual pH/redox-responsive PMs self-assembled from PAE-based diblock copolymers could be potential anticancer drug delivery carriers with pH/redox-triggered drug release, and the fabrication of stimuli-responsive mixed PMs could be an efficient strategy for preparation of intelligent drug delivery platform for disease therapy.

A novel drug delivery system of mixed micelles based on poly(ethylene glycol)-poly(lactide) and poly(ethylene glycol)-poly(ɛ-caprolactone) for gambogenic acid.

In this study, a novel mixed polymeric micelles formed from biocompatible polymers, poly(ethylene glycol)-poly(lactide) (mPEG-PLA) and poly(ethylene glycol)-poly(ɛ-caprolactone) (mPEG-PCL), used as a novel nanocarrier to encapsulate gambogenic acid (GNA). GNA-loaded mixed polymeric micelles (GNA-MMs) was prepared by cosolvent evaporation method. The mean average size of GNA-MMs was (83.23 ± 1.06) nm (n = 3) and entrapment efficiency (EE%) of GNA-MMs was (90.18 ± 2.59) % (n = 3) as well as (12.36 ± 0.64) % (n = 3) for drug loading (DL%). Transmission electron microscopy revealed that the GNA-MMs were spherical with "core-shell" structures. Compared with free GNA solution, in vitro release of GNA from GNA-MMs showed a two-phase sustained release profile: an initial relatively fast phase and followed by a slower release phase. Pharmacokinetic results also indicated that the GNA-MMs have longer systemic circulation time and slower plasma elimination rate than free GNA solution. Moreover, the in vitro cytotoxicity assay showed that the IC50 values on HepG2 cells for GNA-MMs and free GNA were (5.67 ± 0.02) µM and (9.02 ± 0.03) µM, respectively. In addition, GNA-MMs significantly increased the HepG2 cellular apoptosis in a concentration-dependent manner. In conclusion, the results showed that mPEG-PLA/mPEG-PCL mixed micelles may serve as an ideal drug delivery system for GNA to prolong drug circulation time in body, enhance bioavailability and retained its potent antitumor effect.

Improved intestinal absorption of paclitaxel by mixed micelles self-assembled from vitamin E succinate-based amphiphilic polymers and their transcellular transport mechanism and intracellular trafficking routes.

To ensure that antitumor drugs can be effectively transported across intestinal barrier and then quickly released in tumor cells, mixed polymeric micelles (Mix-PMs) were designed and fabricated by combining poly(2-ethyl-2-oxazoline)-vitamin E succinate (PEOz-VES) with TPGS1000 for enhancing intestinal absorption of paclitaxel. PEOz-VES exhibited an extremely low critical micelle concentration and negligible cytotoxicity. The Mix-PMs were characterized to have about 20 nm in diameter, uniform spherical morphology, high drug-loading content and sustained drug release profile with a retained pH-sensitivity. The results of the transport through Caco-2 cell monolayers and intestinal absorption revealed that Mix-PMs displayed higher transcellular transport efficiency compared with PEOz-VES micelles and Taxol®. The possible mechanism of transcellular transport for Mix-PMs was elucidated to be mainly through clathrin- and caveolae/lipid rafts-mediated transcytosis. Confocal laser scanning micrographs revealed that late endosomes, lysosomes, endoplasmic reticulum, Golgi apparatus, and mitochondria were all involved in intracellular trafficking of Mix-PMs. The proteins involved in transcytosis of Mix-PMs and finally excreted were unraveled for the first time by the analysis of proteins in the basolateral media according to the proteomics method. Consequently, the fabricated mixed polymeric micelles may have great potential in enhancing intestinal absorption and accelerating drug release in tumor cells.

Curcumin-carboxymethyl chitosan (CNC) conjugate and CNC/LHR mixed polymeric micelles as new approaches to improve the oral absorption of P-gp substrate drugs.

The low oral bioavailability of numerous drugs has been mostly attributed to the significant effect of P-gp-mediated efflux on intestinal drug transport. Herein, we developed mixed polymeric micelles (MPMs) comprised of curcumin-carboxymethyl chitosan (CNC) conjugate, as a potential inhibitor of P-gp-mediated efflux and gastrointestinal absorption enhancer, and low-molecular-weight heparin-all-trans-retinoid acid (LHR) conjugate, as loading material, with the aim to improve the oral absorption of P-gp substrate drugs. CNC conjugate was synthesized by chemical bonding of curcumin (Cur) and carboxymethyl chitosan (CMCS) taking advantage of the inhibition of intestinal P-gp-mediated secretion by Cur and the intestinal absorption enhancement by CMCS. The chemical structure of CNC conjugate was characterized by 1H NMR with a degree of substitution of Cur of 4.52-10.20%. More importantly, CNC conjugate markedly improved the stability of Cur in physiological pH. Cyclosporine A-loaded CNC/LHR MPMs (CsA-CNC/LHR MPMs) were prepared by dialysis method, with high drug loading 25.45% and nanoscaled particle size (∼200 nm). In situ single-pass perfusion studies in rats showed that both CsA + CNC mixture and CsA-CNC/LHR MPMs achieved significantly higher Ka and Peff than CsA suspension in the duodenum and jejunum segments (p < 0.01), which was comparable to verapamil coperfusion effect. Similarly, CsA + CNC mixture and CsA-CNC/LHR MPMs significantly increased the oral bioavailability of CsA as compared to CsA suspension. These results suggest that CNC conjugate might be considered as a promising gastrointestinal absorption enhancer, while CNC/LHR MPMs had the potential to improve the oral absorption of P-gp substrate drugs.

Recent progress in biomedical applications of Pluronic (PF127): Pharmaceutical perspectives.

Most of the administered anti-cancer drugs are hydrophobic in nature and are known to have poor water solubility, short residence time, rapid clearance from the body and systemic side effects. Polymeric-based targeted particulate carrier system has shown to directly deliver the encapsulated anti-cancer drug to the desired site of action and prevent the interaction of encapsulated drug with the normal cells. Pluronic F127 (PF127) has been widely investigated for its broad-range of therodiagnostic applications in biomedical and pharmaceutical sciences, but rapid dissolution in the physiological fluids, short residence time, rapid clearance, and weak mechanical strength are the main shortcomings that are associated with PF127 and have recently been overcome by making various modifications in the structure of PF127 notably through preparation of PF127-based mixed polymeric micelles, PF127-conjugated nanoparticles and PF127-based hydrophobically modified thermogels. In this article, we have briefly discussed the recent studies that have been conducted on various anti-cancer drugs using PF127 as nano-carrier modified with other copolymers and/or conjugated with magnetic nanoparticles. The key findings of these studies demonstrated that the modified form of PF127 can significantly increase the stability of incorporated hydrophobic drugs with enhanced in vitro cytotoxicity and cellular uptake of anti-cancer drugs. Moreover, the modified form of PF127 has also shown its therapeutic potentials as therodiagnostics in various types of tumors and cancers. Hence, it can be concluded that the modified form of PF127 exhibits significant therodiagnostic effects with increased tumor-specific delivery of anti-cancer drugs having minimal toxic effects as compared to PF127 alone and/or other copolymers.