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.

The characterization of Pluronic P123 micelles in the presence of sunscreen agents.

OBJECTIVES: The triblock copolymer Pluronic® is widely used in the personal care industry, including sun protection, for its film-forming and solubilization capabilities. In this study, the effect of three commonly used organic UV filters (ethylhexyl methoxycinnamate [EMC], ethylhexyl triazone [EHT], and avobenzone [AVB]) on the structure of Pluronic P123 micelles was investigated. METHODS: The Pluronic P123 micelle structure has been investigated using dynamic surface tension, nuclear magnetic resonance (NMR) and small-angle neutron scattering (SANS). RESULTS: Dynamic surface tension results show strong interactions between the UV filters and Pluronic® evident by sharp changes in the surface activity of the latter. The NMR results have revealed the creation of a hydrophobic microenvironment special to the Pluronic PPO core group in the presence of UV filters. Some interaction with the hydrophilic EO was also recorded, albeit weaker. This is further confirmed by SANS, where the Pluronic P123 micelles interacted with varying strengths with the UV filters, resulting in sharp changes in their size and shape. CONCLUSIONS: We have demonstrated the sensitivity of the Pluronic P123 micelles to the presence of various UVA/B filters. The micelles shape varied from spherical to cylindrical as the concentration and type of the UV filters were varied. These variations in the shape are expected to have a significant effect on the sun protection factor (SPF), as it affects the solubilization of the UV filters within a formulation in addition to the formulations' rheological profile and film-forming behaviour.

OBJECTIFS: le copolymère tribloc Pluronic® est largement utilisé dans le domaine des soins personnels, notamment la protection solaire, pour ses capacités de formation de film et de solubilisation. Cette étude a permis d'étudier l'effet de trois filtres UV organiques couramment utilisés (éthylhexyl méthoxycinnamate [EMC], éthylhexyl triazone [EHT] et avobenzone [AVB]) sur la structure des micelles P123 Pluronic. MÉTHODES: la structure de la micelle P123 Pluronic a été étudiée à l'aide d'une tension superficielle dynamique, d'une résonance magnétique nucléaire (RMN) et d'une diffusion de neutrons aux petits angles (DNPA). RÉSULTATS: les résultats de la tension superficielle dynamique montrent de fortes interactions entre les filtres UV et Pluronic®, ce qui se traduit par de fortes variations de l'activité superficielle de ce dernier. Les résultats de la RMN ont montré la création d'un micro-environnement hydrophobe spécifique au groupe principal de l'OPP pluronique en présence de filtres UV. Une certaine interaction avec l'OE hydrophile a également été enregistrée, quoique plus faible. Ceci est confirmé par la DNPA, où les micelles P123 Pluronic ont interagi avec des forces variables avec les filtres UV, entraînant des changements importants dans leur taille et leur forme. CONCLUSIONS: nous avons démontré la sensibilité des micelles P123 Pluronic à la présence de différents filtres UVA/B. La forme des micelles variait de sphérique à cylindrique en fonction de la concentration et du type de filtres UV. Ces variations de forme devraient avoir un effet significatif sur le facteur de protection solaire (SPF), car elles affectent la solubilisation des filtres UV dans une formulation, en plus du profil rhéologique et du comportement de formation de film des formulations.

Melanoma-targeted photodynamic therapy based on hypericin-loaded multifunctional P123-spermine/folate micelles.

Multifunctional P123 micelle linked covalently with spermine (SM) and folic acid (FA) was developed as a drug delivery system of hypericin (HYP). The chemical structures of the modified copolymers were confirmed by spectroscopy and spectrophotometric techniques (UV-vis, FTIR, and 1H NMR). The copolymeric micelles loading HYP were prepared by solid dispersion and characterized by UV-vis, fluorescence, dynamic light scattering (DLS), ζ potential, and transmission electron microscopy (TEM). The results provided a good level of stability for HYP-loaded P123-SM, P123-FA, and P123-SM/P123-FA in the aqueous medium. The morphology analysis showed that all copolymeric micelles are spherical. Well-defined regions of different contrast allow us to infer that SM and FA were localized on the surface of micelles, and the HYP molecules are located in the core region of micelles. The uptake potential of multifunctional P123 micelle was accessed by exposing the micellar systems loading HYP to two cell lines, B16-F10 and HaCaT. HYP-loaded P123 micelles reveal a low selectivity for melanoma cells, showing significant photodamage for HaCat cells. However, the exposition of B16-F10 cells to Hyp-loaded SM- and FA-functionalized P123 micelles under light irradiation revealed the lowest CC50 values. The interpretation of these results suggested that the combination of SM and FA on P123 micelles is the main factor in enhancing the HYP uptake by melanoma cells, consequently leading to its photoinactivation.

Hyaluronic acid coated Pluronic F127/Pluronic P123 mixed micelle for targeted delivery of Paclitaxel and Curcumin.

The hydrophobicity of most of the anticancer drugs offers a great challenge in selecting a system for their effective transport. Here comes the importance of micelles that offers a hydrophobic core for incorporating these drugs. In this study, Hyaluronic Acid coated Pluronic mixed micelle loaded with Paclitaxel and Curcumin was designed and evaluated its anticancer activity in MCF-7 cells. Pluronic F127 (PF127) and Pluronic P123 (PP123) were taken for preparing the mixed micelles. The targeting ligand folic acid (FA) was conjugated to one end of PP123 forming FA-PP. The end hydroxyl groups of PF127 were oxidized to aldehyde groups resulted in PF-CHO. Mixed micelles were prepared from PF-CHO and FA-PP and the end aldehyde groups were used for coating the micelles with hyaluronic acid. The material was characterized using FTIR, H1NMR, DLS, FE-SEM and TEM. The coated micelles showed spherical shape with drug loading efficiency of 50.15 and 65.05% for Paclitaxel and Curcumin, respectively. In vitro drug release was studied at pH 5.5 and 7.4. Dual drug-loaded material showed higher in-vitro anticancer activity than free Paclitaxel and Curcumin. The results suggested that synthesized mixed micelle with dual drugs showed great potential for targeted delivery to MCF-7 cells.

A Fluorescence Study of the Interaction of Anticancer Drug Molecule Doxorubicin Hydrochloride in Pluronic P123 and F127 Micelles.

Drug delivery systems for the sustained and target delivery of doxorubicin to tumor cells are a topic of interest due to the efficacy of the doxorubicin in cancer treatment. The use of polymers such as Pluronic is being studied widely for the formulation of doxorubicin hydrochloride. However, the basic understanding of the physicochemical properties of pluronic micelles in presence of doxorubicin hydrochloride is a very essential topic of study. Doxorubicin hydrochloride is fluorescent; this helped us to study its sensitivity towards the Pluronic microenvironment using the fluorescence technique. In this work, the interaction and place of location of doxorubicin hydrochloride in Pluronic F127 and P123 micelles has been studied extensively using steady-state fluorescence intensity, dynamic fluorescence lifetime, quenching studies, dynamic light scattering, and zeta potential measurements, at different Pluronic concentrations. Using a fluorescence quenching experiment, doxorubicin hydrochloride was found to reside near the hydrophilic PEO corona region of the Pluronic micelles. For both the Pluronic, in the concentration range of study, the micellar size was found to be below 30 nm; this may have a greater advantage for various applications.

Selective photodynamic effects on cervical cancer cells provided by P123 Pluronic®-based nanoparticles modulating hypericin delivery.

At present, cervical cancer is the fourth leading cause of cancer among women worldwide with no effective treatment options. In this study we aimed to evaluate the efficacy of hypericin (HYP) encapsulated on Pluronic® P123 (HYP/P123) photodynamic therapy (PDT) in a comprehensive panel of human cervical cancer-derived cell lines, including HeLa (HPV 18-positive), SiHa (HPV 16-positive), CaSki (HPV 16 and 18-positive), and C33A (HPV-negative), compared to a nontumorigenic human epithelial cell line (HaCaT). Were investigated: (i) cell cytotoxicity and phototoxicity, cellular uptake and subcellular distribution; (ii) cell death pathway and cellular oxidative stress; (iii) migration and invasion. Our results showed that HYP/P123 micelles had effective and selective time- and dose-dependent phototoxic effects on cervical cancer cells but not in HaCaT. Moreover, HYP/P123 micelles accumulated in endoplasmic reticulum, mitochondria and lysosomes, resulting in photodynamic cell death mainly by necrosis. HYP/P123 induced cellular oxidative stress mainly via type II mechanism of PDT and inhibited cancer cell migration and invasion mainly via MMP-2 inhibition. Taken together, our results indicate a potentially useful role of HYP/P123 micelles as a platform for HYP delivery to more specifically and effectively treat cervical cancers through PDT, suggesting they are worthy for in vivo preclinical evaluations.

pH-sensitive pluronic micelles combined with oxidative stress amplification for enhancing multidrug resistance breast cancer therapy.

Multidrug resistance (MDR) is one of the major obstacles to clinical cancer chemotherapy. Herein, we designed new pH-sensitive pluronic micelles with the synergistic effects of oxidative therapy and MDR reversal. Pluronic (P123) was modified with α-tocopheryl succinate (α-TOS) via an acid-labile ortho ester (OE) linkage to give a pH-sensitive copolymer (POT). Self-assembled POT micelles exhibited desirable size (~80 nm), excellent anti-dilution ability, high drug loading (~85%), acid-triggered degradation and drug release behaviours. In vitro cell experiments verified that POT micelles could significantly reverse MDR through suppressing the function of drug effluxs mediated by P123 and induce more reactive oxygen species (ROS) generation mediated by α-TOS, resulting in enhanced cytotoxicity and apoptosis in MDR cells. In vivo studies further revealed that DOX-loaded POT micelles (POT-DOX) possessed the highest drug accumulation (3.03% ID/g at 24 h) and the strongest tumour growth inhibition (TGI 83.48%). Pathological analysis also indicated that POT-DOX could induce more apoptosis or necrosis at the site of tumour without distinct damage to normal tissues. Overall, these smart POT micelles have great potential as promising nano-carriers for MDR reversal and cancer treatment.

Selective Photodynamic Effects on Breast Cancer Cells Provided by p123 Pluronic®- Based Nanoparticles Modulating Hypericin Delivery.

BACKGROUND: Breast cancer is the most relevant type of cancer and the second cause of cancer- related deaths among women in general. Currently, there is no effective treatment for breast cancer although advances in its initial diagnosis and treatment are available. Therefore, the value of novel anti-tumor therapeutic modalities remains an immediate unmet need in clinical practice. Following our previous work regarding the properties of the Pluronics with different photosensitizers (PS) for photodynamic therapy (PDT), in this study we aimed to evaluate the efficacy of supersaturated hypericin (HYP) encapsulated on Pluronic® P123 (HYP/P123) against breast cancer cells (MCF-7) and non-tumorigenic breast cells (MCF-10A). METHODS: Cell internalization and subcellular distribution of HYP/P123 was confirmed by fluorescence microscopy. The phototoxicity and citototoxicity of HYP/P123 was assessed by trypan blue exclusion assay in the presence and absence of light. Long-term cytotoxicity was performed by clonogenic assay. Cell migration was determined by the wound-healing assay. Apoptosis and necrosis assays were performed by annexin VFITC/ propidium Iodide (PI) by fluorescence microscopy. RESULTS: Our results showed that HYP/P123 micelles had high stability and high rates of binding to cells, which resulted in the selective internalization in MCF-7, indicating their potential to permeate the membrane of these cells. Moreover, HYP/P123 micelles accumulated in mitochondria and endoplasmic reticulum organelles, resulting in the photodynamic cell death by necrosis. Additionally, HYP/P123 micelles showed effective and selective time- and dose dependent phototoxic effects on MCF-7 cells but little damage to MCF-10A cells. HYP/P123 micelles inhibited the generation of cellular colonies, indicating a possible capability to prevent the recurrence of breast cancer. We also demonstrated that HYP/P123 micelles inhibit the migration of tumor cells, possibly by decreasing their ability to form metastases. CONCLUSION: Taken together, the results presented here indicate a potentially useful role of HYP/P123 micelles as a platform for HYP delivery to more specifically and effectively treat human breast cancers through photodynamic therapy, suggesting they are worthy for in vivo preclinical evaluations.

Colon targeting of celecoxib nanomixed micelles using pulsatile drug delivery systems for the prevention of inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a debilitating condition characterized by chronic inflammation of the colon which can increase the risk of colon cancer. Celecoxib (CXB), a cyclooxygenase-2 inhibitor, showed potential for the prophylaxis against IBD. However, it suffers from poor aqueous solubility and cardiovascular toxicity on prolonged use. Here, CXB solubility was enhanced using nanomixed micelles (NMMs) and then colon targeted in a pulsatile system to minimize systemic side effects. Pluronic P123 NMMs with bile salts or hydrophilic Pluronics were prepared using the thin film hydration technique. NMMs were characterized for particle size, size distribution and zeta potential before and after freeze drying and for solubility enhancement. The freeze dried NMMs were then loaded in pulsatile systems with varying tablet plugs containing time-dependent polymers at different concentrations. The optimum NMM consisted of Pluronic P123 and sodium taurocholate (1:1) and CXB:surfactant mixture ratio of 1:30. The pulsatile capsules, containing a tablet plug made of 75% Carbopol®, achieved the target release profile with 88.35% of the dose released after an 8 hrs lag period. Finally, the optimum NMM/pulsatile system showed protective effect against experimentally-induced colitis compared to conventional capsules and pulsatile capsules filled with pure CXB.

Effect of cosurfactant addition on phase behavior and microstructure of a water dilutable microemulsion.

This study reports a detailed characterization of a nonionic microemulsion (µE) composed of n-butylacetate/α-tocopheryl polyethylene glycol succinate (TPGS)/alcohol/water. Two approaches of expanding the monophasic area were explored; (i) addition of Pluronic® 123 (P123) in aqueous phase, and (ii) use of short chain alcohol (CnHn+1OH; n = 2-4) as cosurfactant. Pseudo-ternary phase diagrams were constructed using water titration method. Characterizations were performed using dynamic light scattering (DLS), differential scanning calorimetry (DSC), small angle neutron scattering (SANS) and electron microscopic techniques. DSC and SANS results showed gradual structural transformation from water-in-oil to oil-in-water system. The optimized formulation (oil/Smix/water - 19/40/41) showed average hydrodynamic diameter of 22 nm, consistent with electron microscopic observations. Ethanol (EtOH), with its high fluidity and smaller headgroup area, offered maximum expansion in the phase boundary. Surfactant unimers, derived from EtOH-driven de-micellization, reinforced the interface and solubilized the incoming oil molecules. Oil incorporation was accompanied with improved loading of carbamazepine, a hydrophobic drug. Except marginal swelling, no significant microstructural changes were noticed during water dilution (≈90%) and salt addition (0.9% NaCl) in the optimized µE formulation. A linear increase in oil incorporation was noticed upon adding propylene glycol as a cosolvent.

Role of molecular weight and hydrophobicity of amphiphilic tri-block copolymers in temperature-dependent co-micellization process and drug solubility.

The binary P123 + F108, + F98, + F88, + F68, + F87 and + P84 systems were used to systematically explore the effect of molecular weight and hydrophobicity of Pluronic on the tendency of cooperative binding between parent copolymers and solubility of drug (ibuprofen) in these mixed Pluronic systems. Temperature-dependent co-micellization process in these systems was carefully investigated by using high sensitivity differential scanning calorimeter (HSDSC), dynamic light scattering (DLS) and small angle X-ray scattering (SAXS). All the HSDSC thermograms for these systems consistently exhibit two endothermic (micellization) peaks apart by at least 13.3 °C. It was evidenced that micelles are mainly formed by P123, the copolymer with a lower critical micelle temperature (CMT), at low temperatures. Raising temperature would dehydrate the other Pluronic with a higher CMT to be integrated into the neat P123 micelles developed at low temperatures. When the temperature is further increased beyond the second endothermic peak, the mixed micelles with a two-shell structure and characteristic corona lengths of their parent copolymers are observed to prove the existence of cooperative binding between parent copolymers. All the binary mixed Pluronic systems used in this study exhibit cooperative binding to form unimodal distribution of mixed micelles, except the P123 + F68 system. The SAXS results show that P123 + F68 system at 65 °C exhibits bimodal distribution of aggregates with coexisting of neat F68 micelles (65% in number) and P123 + F68 mixed micelles (35% in number). It is interesting to find out that P123 and F68 with distinct polypropylene oxide (PPO) moieties (i.e., a difference of 37 PO units) would exhibit very weak cooperative binding to partially form mixed micelles. Addition of ibuprofen in the P123 + F68 system would substantially enhance the cooperative binding between P123 and F68 to form bimodal distribution of aggregates with coexisting of neat F68 micelles (drops down to 30% in number) and P123 + F68 mixed micelles (increases up to 70% in number). For the systems with ibuprofen incorporated, SAXS results demonstrate that the drug is mainly encapsulated in the core of neat micelles developed at low temperatures. The solubility of ibuprofen in the 0.5 wt% P123 + 0.368 wt% P84 system is as high as 2.62 mg/ml, which is 114 times more than that in pure water at 37 °C.

Improving Product Specificity of Whole-Cell Alkane Oxidation in Nonconventional Media: A Multivariate Analysis Approach.

Two-liquid-phase reaction media have long been used in bioconversions to supply or remove hydrophobic organic reaction substrates and products to reduce inhibitory and toxic effects on biocatalysts. In case of the terminal oxyfunctionalization of linear alkanes by the AlkBGT monooxygenase the excess alkane substrate is often used as a second phase to extract the alcohol, aldehyde, and acid products. However, the selection of other carrier phases or surfactants is complex due to a large number of parameters that are involved, such as biocompatibility, substrate bioavailability, and product extraction selectivity. This study combines systematic high-throughput screening with chemometrics to correlate physicochemical parameters of a range of cosolvents to product specificity and yield using a multivariate regression model. Partial least-squares regression shows that the defining factor for product specificity is the solubility properties of the reaction substrate and product in the cosolvent, as measured by Hansen solubility parameters. Thus the polarity of cosolvents determines the accumulation of either alcohol or acid products. Whereas usually the acid product accumulates during the reaction, by choosing a more polar cosolvent the 1-alcohol product can be accumulated. Especially with Tergitol as a cosolvent, a 3.2-fold improvement in the 1-octanol yield to 18.3 mmol L-1 is achieved relative to the control reaction without cosolvents.

Temperature Evaluation of Curcumin Keto-Enolic Kinetics and Its Interaction with Two Pluronic Copolymers.

Curcumin (CUR), a natural hydrophobic polyphenol isolated from Curcuma longa, has been reported to possess two main equilibria in aqueous solutions, diketo/keto-enolic tautomerism and self-aggregation. The thermodynamics of tautomeric equilibrium is well established; however, its kinetic parameters have been sparsely studied. Various efforts have been made to improve CUR solubility in aqueous media. We evaluated how the kinetics of tautomerism and the interaction of CUR with pluronic P123 and F127 copolymers in solution were affected by temperature, using UV-vis and fluorescence spectroscopies. Pluronic particle sizes with and without CUR were acquired by dynamic light scattering. The interaction in the solid state was verified by differential scanning calorimetry (DSC). The equilibrium rate that displaces to the diketo form increased fivefold when the temperature rose from 294 to 314 K with an activation energy of 61.2 kJ mol-1. The CUR solubility increased from 2.58 to 6.77 mg g-1 when incorporated in P123 and from 0.05 to 3.54 mg g-1 when incorporated in F127 with a change in the temperature from 298 to 314 K. This process had a Gibbs free energy of around -1 and -13 kJ mol-1 because of CUR solubilization into the inner core of pluronic micelles. Particle sizes of about 11 nm were obtained for both copolymers containing CUR in an aqueous solution above the critical micelle temperature. DSC measurements showed melting point depression of both CUR and F127. P123 presented no significant variation in the melting point because of its low melting enthalpy. The results indicate that temperature significantly influences CUR kinetic tautomerism and its interaction with both P123 and F127 copolymers. P123 presents a higher interaction in aqueous solution with CUR than F127. Both pluronics could contribute to a safer and more efficient CUR administration in the bloodstream.

Rapid formation of Small Unilamellar Vesicles (SUV) through low-frequency sonication: An innovative approach.

Liposomes are membrane models and excellent Drug Delivery Systems. However, their preparation is expensive, labor intensive, time consuming, and sometimes toxic. Recently, we published an innovative methodology for the production of homogeneous Small Unilamellar Vesicles (SUV) through a simple, fast, relatively low cost, and reproducible process that resulted in very stable vesicles. The methodology involves a small amount of F127 triblock Pluronic® copolymer (0.02% m/V) to a phospholipid (DPPC, DOPC, and DSPC), followed by the solid dispersion methodology. After that, during the thin-film hydration process (of lipids and F127), SUVs are quickly formed after 30 s of sonication using bath equipment at a low frequency of 42 kHz. The resultant colloidal solution was homogeneous with liposomes lower than ˜100 nm of hydrodynamic diameter. The SUV formation is highly temperature dependent. However, it functions independently from the lipid´s phase (gel or liquid-crystal phases). A preparation with Pluronic P123 did not lead to homogeneous SUV. We found that the conditions for SUV formation feature a mixture of F127 and lipids at above a critical temperature. This temperature is not the copolymer´s CMT (micelle is not required). Interestingly, the long PEO groups of F127 play an essential role in this SUV formation, which is proposed to be governed by the "Budding Off" model. The findings show a complex combination of factors: a sum of the sonoporation, the oscillation effects of the compressed/dilated regions, the frequency of oscillation, and the temperature-dependence on long PEO groups. Also, the outer lipid monolayer interaction might by responsible for generating "daughter" vesicles from "mother" vesicles in the mechanism.

Leukocyte-mimicking Pluronic-lipid nanovesicle hybrids inhibit the growth and metastasis of breast cancer.

Breast cancer is a severe threat to the health of women, and the metastasis of tumor cells leads to high mortality in female patients. Evidence shows that leukocytes are recruited by breast tumors through adhesion to inflammatory endothelial cells as well as tumor cells. Moreover, it is known that Pluronic P123 is effective in the reduction of matrix metalloproteinases (MMPs), which play a key role in the degradation of the extracellular matrix (ECM), therefore helping tumor cells to escape from the primary site. Inspired by these mechanisms, we established a leukocyte-mimicking Pluronic-lipid nanovesicle hybrid (LPL) through integrating the membrane proteins extracted from leukocytes with membrane-like vesicles, with Pluronic P123 hybridized in the lipid bilayer, while paclitaxel (PTX) was selected as the model drug. The hybrid vesicles were perfectly incorporated with the leukocyte membrane proteins, and no disruption to the lipid membrane was caused by P123, with the bio-targeting ability of leukocytes and the MMP-9-downregulation effect of P123 fully preserved in LPL. LPL exhibited enhanced cellular uptake and anti-metastasis efficacy in in vitro assays, while significant tumor targeting capabilities were also found through biodistribution assays. Moreover, the in vivo therapeutic effects of PTX-loaded LPL (PTX-LPL) were observed, with an 80.84% inhibition rate of tumor growth and a 10.62% metastatic rate of tumor foci in lung tissue. Furthermore, the amounts of MMP-9 and neutrophils in the tumor as well as in the lung were greatly reduced with PTX-LPL. In summary, LPL may have potential applications in metastatic breast cancer therapy.

Interaction of methylparaben and propylparaben with P123/F127 mixed polymeric micelles.

This paper reports the interaction between Pluronic F127, P123 and their mixed micelles with methylparaben and propylparaben. The UV studies revealed that, the spectral behavior of mixed micelle of F127 and P123 with parabens lay between their individual micellar behaviors. The cloud point studies have shown similar results. It was observed that the intensity of fluorescence spectra, compared with the single micelle-drug combinations was much higher with the mixed micelle-methylparaben combinations and lower with the mixed micelle-propylparaben combinations. The number of binding sites was calculated. Static nature of quenching was observed. The dissociation constant KD for methylparaben - mixed pluronic and propylparaben - mixed pluronic combinations were 21.18 × 10-3 L mol-1 and 32.57 × 10-3 L mol-1 respectively. This suggests that there was stronger binding between methylparaben and mixed micelle compared to propylparaben and mixed micelle. Dynamic light scattering studies indicated that the addition of NaCl to the mixed micelle and parabens facilitated the micellar aggregation and better encapsulation efficiency for the drug. Scanning electron microscope images showed the incorporation of methylparaben and propylparaben molecules into the surface cavities of mixed micelle, pointing towards the change in morphology. This is probably the first report on interaction study of parabens with mixed micelles.

Targeted and Synergic Glioblastoma Treatment: Multifunctional Nanoparticles Delivering Verteporfin as Adjuvant Therapy for Temozolomide Chemotherapy.

Despite advances in cancer therapies, glioblastoma multiforme treatment remains inefficient due to the brain-blood barrier (BBB) inhibitory activity and to the low temozolomide (TMZ) chemotherapeutic selectivity. To improve therapeutic outcomes, in this work we propose two strategies, (i) photodynamic therapy (PDT) as adjuvant treatment and (ii) engineering of multifunctional theranostic/targeted nanoparticles ( m-NPs) that integrate biotin as a targeting moiety with rhodamine-B as a theranostic agent in pluronic P85/F127 copolymers. These smart m-NPs can surmount the BBB and coencapsulate multiple cargoes under optimized conditions. Overall, the present study conducts a rational m-NP design, characterization, and optimizes the formulation conditions. Confocal microscopy studies on T98-G, U87-MG, and U343 glioblastoma cells and on NIH-3T3 normal fibroblast cells show that the m-NPs and the encapsulated drugs are selectively taken up by tumor cells presenting a broad intracellular distribution. The formulations display no toxicity in the absence of light and are not toxic to healthy cells, but they exert a robust synergic action in cancer cells in the case of concomitant PDT/TMZ treatment, especially at low TMZ concentrations and higher light doses, as demonstrated by nonlinear dose-effect curves based on the Chou-Talalay method. The results evidenced different mechanisms of action related to the disjoint cell cycle phases at the optimal PDT/TMZ ratio. This effect favors synergism between the PDT and the chemotherapy with TMZ, enhances the antiproliferative effect, and overcomes cross-resistance mechanisms. These results point out that m-NP-based PDT adjuvant therapy is a promising strategy to improve TMZ-based glioblastoma multiforme treatments.

Dexamethasone loaded multi-layer poly-l-lactic acid/pluronic P123 composite electrospun nanofiber scaffolds for bone tissue engineering and drug delivery.

In tissue engineering, it is common to mix drugs that can control proliferation and differentiation of cells into polymeric solutions as part of composite to get bioactive scaffolds. However, direct incorporation of drugs might potentially result in undesired burst release. To overcome this problem, here we developed electrospun multilayer drug loaded poly-l-lactic acid/pluronic P123 (PLLA-P123) composite scaffolds. The drug was loaded into the middle layer. The surface, the mechanical and physiochemical properties of the scaffolds were evaluated. The drug release profiles were monitored. Finally, the osteogenic proliferation and differentiation potential were determined. The scaffolds fabricated here have appropriate surface properties, but with different mechanical strength and osteogenic proliferation and differentiation. Multi-layer scaffolds where the drug was in the middle layer and PLLA-plasma and PLLA-P123 with cover layer showed the best osteogenic proliferation and differentiation than the other groups of scaffolds. The drug release profiles of the scaffolds were completely different: single layer scaffolds showed burst release within the first day, while multilayer scaffolds showed controlled release. Therefore, the multilayer drug loaded scaffolds prepared have dual benefits can provide both better osteogenesis and controlled release of drugs and bioactive molecules at the implant site.

Cilostazol-loaded electrospun three-dimensional systems for potential cardiovascular application: Effect of fibers hydrophilization on drug release, and cytocompatibility.

Currently marketed drug-eluting stents are non-selective in their anti-restenotic action. New active substance introduction to polymeric stents and vascular grafts can promote early re-endothelialization, crucial in preventing implant restenosis. Additionally, managing material hydrophobicity by blending synthetic polymers limits adverse effects on bulk properties and controls active substance release. However, the influence of hydrophilic synthetic polymer on human cells in the cardiovascular system remains to be determined. In this report, effects of both poly(ε-caprolactone) (PCL) fibers hydrophilization with Pluronic P123 (P123) and cilostazol (CIL) loading were studied. Physicochemical and mechanical properties of electrospun tubular structures produced from PCL and PCL/P123 fibers with and without CIL were investigated and compared. Release profiles studies and in vitro cell proliferation assays of electrospun materials were conducted. It was found that P123 located near the surface of electrospun fibers increased the rate of CIL release. PCL formulation sustained human umbilical vein endothelial cells (HUVEC) growth for 48 h. Despite improved hydrophilicity, PCL/P123 formulations were found to reduce HUVEC viability. Both PCL and PCL/P123 materials reduced primary aortic smooth muscle cells (PASM) viability after 48 h. In PCL formulations containing CIL, drug release caused a decrease in PASM viability. P123 blending with PCL was found to be as a useful pre-fabrication technique for modulating surface hydrophobicity of electrospun materials and the release profile of incorporated active substance. The cytotoxicity of P123 was evaluated to improve the design of drug-loaded vascular grafts for cardiovascular applications.

Surfactant-assisted-water-exposed versus surfactant-aqueous-solution-exposed electrospinning of novel super hydrophilic polycaprolactone based fibers: Analysis of drug release behavior.

Surface hydrophilicity and scaffold integrity determine the drug release behavior of drug loaded electrospun fibrous mats. When mixture miscibility is acceptable, blend electrospinning of hydrophobic with hydrophilic polymers can improve scaffold hydrophilicity while the hydrophobic polymer maintains the mechanical strength of scaffold. Polycaprolactone (PCL) and Pluronic P123 (P123) blend electrospinning has been investigated. In routine blend electrospinning, surface enrichment of Pluronic sets a limit for P123 weight ratio in which exceeding from that limit causes the excess P123 to be accumulated within the electrospun fiber core. To overcome this setback, a method named surfactant assisted water exposed (SAWE) electrospinning was introduced which was proven to be effective for increasing the surface enrichment of Pluronic. In order to test the validity of this method, the electrospinning of solution containing PCL which is exposed to aqueous solution of P123 was investigated. This new method was named surfactant aqueous solution exposed (SASE) electrospinning. Myelin formation at the contact interface of aqueous solution and chloroform solution was studied and it was found that this layer can effectively barricade the migration of Pluronic chains between immiscible phases. For SASE, fiber surface coverage by P123 was uneven and loose. Electrospun scaffolds from SAWE and SASE were loaded with drug to investigate the effect of the exposure time during electrospinning on in vitro drug release. By increasing the exposure time, the abnormal two-stage phased release profile of SAWE became normal with moderate initial burst. Longer exposure time increased the initial burst of the drug loaded SASE fibers. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 597-609, 2019.