Micellar Formulation Research Articles

Reversibly disulfide cross-linked micelles improve the pharmacokinetics and facilitate the targeted, on-demand delivery of doxorubicin in the treatment of B-cell lymphoma.

Doxorubicin (DOX) is commonly used to treat human malignancies, and its efficacy can be maximized by limiting the cardiac toxicity when combined with nanoparticles. Here, we reported a unique type of reversibly disulfide cross-linked micellar formulation of DOX (DOX-DCMs) for the targeted therapy of B-cell lymphoma. DOX-DCMs exhibited high drug loading capacity, optimal particle sizes (15-20 nm), outstanding stability in human plasma, and stimuli-responsive drug release profile under reductive conditions. DOX-DCMs significantly improved the pharmacokinetics of DOX, and its elimination half-life (t1/2) and area under curve (AUC) were 5.5 and 12.4 times of that of free DOX, respectively. Biodistribution studies showed that DOX-DCMs were able to preferentially accumulate in the tumor site and significantly reduce the cardiac uptake of DOX. In a xenograft model of human B-cell lymphoma, compared with the equivalent dose of free DOX and non-crosslinked counterpart, DOX-DCMs not only significantly inhibited the tumor growth and prolonged the survival rate, but also remarkably reduced DOX-associated cardiotoxicity. Furthermore, the exogenous administration of N-acetylcysteine (NAC) at 24 h further improved the therapeutic efficacy of DOX-DCMs, which provides a "proof-of-concept" for precise drug delivery on-demand, and may have great translational potential as future cancer nano-therapeutics.

Improving the topical ocular pharmacokinetics of lyophilized cyclosporine A-loaded micelles: formulation, in vitro and in vivo studies

Dry eye syndrome (DES) is one of the most common disorders of the eye for which combined treatment includes modification of the ocular environment and pathogenic therapies. Cyclosporine A (CsA), a immunosuppressive agent, has been demonstrated to be effective for the treatment of DES but is limited clinically by its low ocular bioavailability due to poor water solubility. In this paper, methoxy poly (ethylene glycol)-poly (lactide) polymer (mPEG-PLA) micelles were investigated as alternative vehicles for the solubilization and delivery of CsA to the eye. The in vitro stability indicated that CsA-loaded micellar lyophilized powder was stable for at least 3 months and the release profile showed a sustained release manner of CsA from micelles physically. In vivo ocular distribution studies demonstrated that the micellar formulations exhibited a 4.5-fold increase in retention effect at eyes compared with 0.05% CsA emulsion. In addition, the in vivo pharmacokinetics profile showed that the CsA-loaded micelles could enhance the retention time, achieving longer effect toward the DES. These studies proposed an effective micelle formulation as a novel ocular drug delivery system to improve solubility and bioavailability of ophthalmic CsA-controlled delivery.

Micellar formulations of Crizotinib and Dasatinib in the management of glioblastoma multiforme

Glioblastoma multiforme (GBM) defies the currently practiced management of radiotherapy, chemotherapy and surgery and hence, it is associated with a high fatality rate with a median survival of 14.6 months. In our previous work investigating different tyrosine kinase inhibitors (TKIs), we established that a combination of Crizotinib and Dasatinib exerted the most potent effect on different GBM cell lines. In this work, to improve targeted therapy at the site of the tumour and avoid systemic toxicity, we exploited the enhanced permeability and retention effect by designing micellar formulations of these two TKIs. Crizotinib and Dasatinib were successfully encapsulated in poly(styrene-co-maleic acid) (SMA) micelles which were then evaluated for their physicochemical characteristics, anti-proliferative effect, mode of cell death, efficacy in spheroid models, effect on cell signalling, antiangiogenic potential and in vivo anticancer activity. Our results showed that this combination had induced a potent anti-proliferative effect in four GBM cell lines grown as a monolayer and as a spheroid. The combination was also efficacious in in vitro models of angiogenesis and vascular mimicry. In vivo data showed the enhanced activity of the micellar TKIs compared to free drugs. In conclusion, we proved that micellar formulations of Crizotinib and Dasatinib carry promising in vitro and in vivo efficacy that warrant further investigation.

Sodium cholate-enhanced polymeric micelle system for tumor-targeting delivery of paclitaxel.

PurposePolymeric micelles are attractive nanocarriers for tumor-targeted delivery of paclitaxel (PTX). High antitumor efficacy and low toxicity require that PTX mainly accumulated in tumors with little drug exposure to normal tissues. However, many PTX-loaded micelle formulations suffer from low stability, fast drug release, and lack of tumor-targeting capability in the circulation. To overcome these challenges, we developed a micellar formulation that consists of sodium cholate (NaC) and monomethoxy poly (ethylene glycol)-block-poly (d,l-lactide) (mPEG-PDLLA).MethodsPTX-loaded NaC-mPEG-PDLLA micelles (PTX-CMs) and PTX-loaded mPEG-PDLLA micelles (PTX-Ms) were formulated, and their characteristics, particle size, surface morphology, release behavior in vitro, pharmacokinetics and in vivo biodistributions were researched. In vitro and in vivo tumor inhibition effects were systematically investigated. Furthermore, the hemolysis and acute toxicity of PTX-CMs were also evaluated.ResultsThe size of PTX-CMs was 53.61±0.75 nm and the ζ-potential was −19.73±0.68 mV. PTX was released much slower from PTX-CMs than PTX-Ms in vitro. Compared with PTX-Ms, the cellular uptake of PTX-CMs was significantly reduced in macrophages and significantly increased in human cancer cells, and therefore, PTX-CMs showed strong growth inhibitory effects on human cancer cells. In vivo, the plasma AUC0−t of PTX-CMs was 1.8-fold higher than that of PTX-Ms, and 5.2-fold higher than that of Taxol. The biodistribution study indicated that more PTX-CMs were accumulated in tumor than PTX-Ms and Taxol. Furthermore, the significant antitumor efficacy of PTX-CMs was observed in mice bearing BEL-7402 hepatocellular carcinoma and A549 lung carcinoma. Results from drug safety assessment studies including acute toxicity and hemolysis test revealed that the PTX-CMs were safe for in vivo applications.ConclusionThese results strongly revealed that NaC-mPEG-PDLLA micelles can tumor-target delivery of PTX and enhance drug penetration in tumor, suggesting that NaC-mPEG-PDLLA micelles are promising nanocarrier systems for anticancer drugs delivery.

Pluronic-SAILs (surface active ionic liquids) mixed micelles as efficient hydrophobic quercetin drug carriers

The present manuscript reports a systematic investigation on the solubilization of hydrophobic drug Quercetin (QCT) in pluronic F108 and its mixed micelles with surface active ionic liquids (SAILs) having same alkyl chain length but different hydrophobic head groups viz. 1-dodecyl-3-methylimidazolium bromide [Mim]; N-dodecyl-Nmethylpiperidinium bromide, [Pip]; N-dodecyl-Nmethylpyrrolidinium bromide, [Pyr]. Employing UV–visible spectroscopy, we have determined the solubility, loading efficiency and partition coefficient of QCT in the pluronic F108 and F108-SAILs mixed micelles. The F108-SAIL mixed micellar system possessed higher solubilization capacity for QCT. Further, the effect of varying composition of mixed micelles on the solubilization of QCT has also been evaluated and discussed in detail. A significant difference between the hydrodynamic diameter (Dh) of loaded and unloaded F108 as well as F108-SAILs mixed micelles confirmed that QCT has been solubilized in these micelles. Differential pulse voltammetry (DPV) measurements have been successfully employed to determine the possible location of the QCT in the both pluronic F108 and pluronic F108-SAILs mixed micelles. These measurements indicated that most of QCT is solubilized in the core of the F108 and F108-SAILs mixed micelles. In vitro drug release study of three different F108-SAILs mixed micellar formulations show sustained release behavior according to their interaction with the QCT. Higher anticancer effects were observed in the case of micellar QCT than the free QCT confirm the efficiency of the prepared formulations. The results demonstrated that the composition of mixed micelles had a profound effect on solubilization capacity and the drug release behavior from the F108-SAILs mixed micelles can be easily tuned by changing the head group of SAILs.

Preparation, Characterization and In Vivo Antitumor Evaluation of a Micellar Formulation of Camptothecin Prodrug

Preparation, Characterization and <i>In</i><i> Vivo</i> Antitumor Evaluation of a Micellar Formulation of Camptothecin Prodrug

Sodium deoxycholate mediated enhanced solubilization and stability of hydrophobic drug Clozapine in pluronic micelles

In this report, the solubilization behaviour of a hydrophobic drug Clozapine (CLZ) in micellar suspensions of pluronics having different hydrophilic lipophilic balance (HLB) ratios viz. P84, F127 and F108 in the absence and presence of bile salt sodium deoxycholate (SDC) has been studied. UV–Vis spectroscopy has been exploited to determine the solubilization capacity of the investigated micellar systems in terms of drug loading efficiency, average number of drug molecules solubilized per micelle (ns), partition coefficient (P) and standard free energy of solubilization (∆G°). The morphological and structural changes taking place in pluronics in different concentration regimes of SDC and with the addition of drug CLZ has been explored using dynamic light scattering (DLS) and small angle neutron scattering (SANS) measurements. The SANS results revealed that aggregation behaviour of pluronic-SDC mixed micelles gets improved in the presence of drug. The micropolarity measurements have been performed to shed light on the locus of solubilization of the drug in pure and mixed micellar systems. The compatibility between CLZ and drug carriers (pluronics and SDC) was confirmed using powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FTIR) techniques. Among the investigated systems, P84-SDC mixed system was found to be highly efficient for CLZ loading. The long term stability data indicated that CLZ loaded P84-SDC mixed micellar formulation remained stable for 3months at room temperature. Further, it was revealed that the CLZ loaded P84-SDC mixed micelles are converted into CLZ loaded pure P84 micelles at 30-fold dilutions which remain stable up to 48-fold dilutions. The results from the present studies suggest that P84-SDC mixed micelles can serve as suitable delivery vehicles for hydrophobic drug CLZ.

Mixed micelles for encapsulation of doxorubicin with enhanced in vitro cytotoxicity on breast and ovarian cancer cell lines versus Doxil®

Doxorubicin (DOX) is used as a “first-line” antineoplastic drug in ovarian and metastatic breast cancer. However, serious side effects, such as cardiotoxicity have been reported after DOX intravenous administration. Hence, we investigated different micelle-former biomaterials, as Soluplus®, Pluronic F127, Tetronic T1107 and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) to develop a potential mixed micellar nanocarrier for DOX delivery. Since DOX hydrochloride is a poor candidate to be encapsulated inside the hydrophobic core of the mixed micelles, we assayed a hydrophobic complex between DOX and sodium deoxycholate (NaDC) as an excellent candidate to be encapsulated within polymeric micelles. The combination of T1107:TPGS (1:3, weight ratio) demonstrated the best physicochemical properties together with a high DL capacity (6.43% w/v). Particularly, DOX in vitro release was higher at acidic tumour microenvironment pH value (5.5) than at physiological counterpart (7.4). The hydrodynamic diameter of the DOX/NaDC-loaded mixed micellar system was 10.7nm (PDI=0.239). The in vitro cytotoxicity of the mixed micellar formulation resulted significantly (p<0.05) higher than Doxil® against ovarian (SKOV-3) and triple-negative breast cancer cells (MDA-MB- 231). Further, the in vitro cellular uptake assays demonstrated a significant increment (p<0.05) of the DOX intracellular content for the mixed micelles versus Doxil® for both, SKOV-3 (at 2, 4 and 6h of incubation) and MDA-MB-231 (at 4h of incubation) cells. These findings suggest that T1107:TPGS (1:3) mixed micelles could be employed as a potential nanotechnological platform for drug delivery of DOX.

Biodistribution and In Vivo Antileishmanial Activity of 1,2-Distigmasterylhemisuccinoyl-sn-Glycero-3-Phosphocholine Liposome-Intercalated Amphotericin B.

1,2-Distigmasterylhemisuccinoyl-sn-glycero-3-phosphocholine (DSHemsPC) is a new lipid in which two molecules of stigmasterol (an inexpensive plant sterol) are covalently linked via a succinic acid to glycerophosphocholine. Our previous study revealed that liposome (Lip)-intercalated amphotericin B (AMB) prepared from DSHemsPC (DSHemsPC-AMB-Lip) possesses excellent colloidal properties and in vitro antifungal and antileishmanial activities similar to those of the liposomal AMB preparation AmBisome. The aim of this study was to determine the biodistribution and evaluate the antileishmanial effects of DSHemsPC-AMB-Lip in Leishmania major-infected BALB/c mice. The serum profile and tissue concentrations of AMB were similar in DSHemsPC-AMB-Lip- and AmBisome-treated mice after intravenous (i.v.) injection. Multiple i.v. doses of the micellar formulation of AMB (Fungizone; 1 mg/kg of body weight), DSHemsPC-AMB-Lip (5 mg/kg), and AmBisome (5 mg/kg) were used in L. major-infected BALB/c mouse models of early and established lesions. In a model of the early lesions of cutaneous leishmaniasis (CL), the results indicated that the level of footpad inflammation was significantly (P < 0.001) lower in mice treated with DSHemsPC-AMB-Lip and AmBisome than mice treated with empty liposomes or 5% dextrose. The splenic and footpad parasite load was also significantly (P < 0.001) lower in these groups of mice than in control mice that received 5% DW or free liposome. The in vivo activity of DSHemsPC-AMB-Lip was comparable to that of AmBisome, and both provided improved results compared to those achieved with Fungizone at the designated doses. The results suggest that systemic DSHemsPC-AMB-Lip administration may be useful for the treatment of leishmaniasis, and because it costs less to produce DSHemsPC-AMB-Lip than AmBisome, DSHemsPC-AMB-Lip merits further investigation.

Styrene maleic acid encapsulated raloxifene micelles for management of inflammatory bowel disease

BackgroundInflammatory bowel disease (IBD) comprises a group of disorders that manifest through chronic inflammation of the colon and small intestine. Although the exact cause of IBD is still unclear, dysfunctional immunoregulation involving overproduction of inflammatory cytokines such as TNF-α, and IL-6 have been implicated in pathogenesis. Current therapy relies on immunosuppression, cytotoxic drugs, and monoclonal antibodies against TNF-α. These classes of drugs have severe side-effects, especially when used for long duration. Our previous work with raloxifene, a selective estrogen receptor modulator, has shown that the drug, and to a greater extent its micellar formulation, has a significant suppressive effect on NF-κB, an essential immune-regulator. This finding directed the current work towards testing the anti-inflammatory and immunomodulatory effects of raloxifene using cell lines, as well as testing the potential use of the styrene maleic acid (SMA) micelles loaded with raloxifene (SMA-Ral) against dextran sulfate sodium (DSS) induced colitis in an in vivo model of IBD.ResultsTreatment of MCF-7 cells with TNF-α was shown to protect the cells from the cytotoxic effect of raloxifene (42 vs. 10% cell death, with TNF-α. Treating CaCo-2 cells with both free and SMA-Ral improved cell survival after exposure to 2% DDS with significantly higher protection with SMA-Ral. Treatment of U-937 with SMA-Ral and free-Ral resulted in down-regulation of TNF-α, IL-1β, IL-6, and MIP1α, with greater inhibition of the SMA-Ral, compared to free Ral. Balb/c mice treated with raloxifene and SMA-Ral showed weight gain at 14 days, compared to the control group (122, and 115% respectively). Treatment with raloxifene prevented DSS-induced diarrhea in 6/6 of free raloxifene treated mice and in 5/6 mice treated with SMA-Ral. Control group of DSS-treated mice showed average colon length of 7.4 cm compared to 13 cm in the control group. The average colon length was 12.3 and 11.5 cm for raloxifene and SMA-Ral treated groups, respectively. Furthermore, inflammatory cytokines such as IL-6 and TNF-α were reduced in serum of animals treated with free-Ral and SMA-Ral.ConclusionsRaloxifene and its micellar formulation warrants further studies to understand their effect on the treatment of colitis.Graphical abstractSMA-Raloxifene preparation and its in vivo and in vitro effect on colitis

Chitosan coated PluronicF127 micelles for effective delivery of Amphotericin B in experimental visceral leishmaniasis

The goal of study was to develop micellar formulation of Amphotericin B (AmB) to improve its antileishmanial efficacy. AmB loaded pluronic F127 (PF 127) micelles were developed and coated with chitosan (Cs-PF-AmB-M) to accord immunoadjuvant and macrophage targeting properties. Hemolysis and cytotoxicity studies demonstrated that Cs-PF-AmB-M was 7.93 fold (at 20μg/ml AmB concentration) and 9.35 fold less hemolytic and cytotoxic, respectively in comparison to AmB suspension. Flow cytometry studies indicated that Cs-PF-FITC-M was 21.97 fold higher internalized byJ774A.1 macrophage in comparison to PF-FITC-M.Cs-PF-AmB-M showed excellent in-vitro (1.82 fold in compared to AmB suspension) and in-vivo (75.84±7.91% parasitic inhibition) antileishmanial activity against macrophage resident intracellular promastigotes and Leishmania donovani infected Syrian hamsters, respectively. Chitosan coating stimulated a Th1 immune response mediating auxiliary immunotherapeutic action as judged by in-vitro and in-vivo cytokine and mRNA expression. Toxicity studies demonstrated normal blood urea nitrogen (BUN) and plasma creatinine (PC) level and no sign of abnormal histopathology upon intravenous administration of micellar formulations. Pharmacokinetic profiling and tissue distribution studies indicated that AmB was preferentially localized in macrophage harboring tissue instead of kidney, thereby circumventing the characteristic nephrotoxicity. Conclusively, Cs-PF-AmB-M could be a viable alternative for the current immuno and chemotherapy of visceral leishmaniasis (VL).

Corrigendum to ''A glucose-targeted mixed micellar formulation outperforms Genexol in breast cancer cells'' [Euro. J. Pharmaceut. Biopharmaceut. 114 (2017) 305-316

Corrigendum to ''A glucose-targeted mixed micellar formulation outperforms Genexol in breast cancer cells'' [Euro. J. Pharmaceut. Biopharmaceut. 114 (2017) 305-316

In vitro and in vivo delivery of artemisinin loaded PCL–PEG–PCL micelles and its pharmacokinetic study

Artemisinin (ART) is a natural anti-malarial sesquiterpene lactone with anticancer properties, but its application is limited because of its low water solubility. To increase the bioavailability and water solubility of ART, we synthesized three series of poly (ɛ-caprolactone)–poly (ethylene glycol)–poly (ɛ-caprolactone) (PCL–PEG–PCL) tri-block copolymers. The structure of the copolymers was characterized by HNMR, FTIR, DSC and GPC techniques. ART was encapsulated inside micelles by a nanoprecipitation method which leading to the formation of ART/PCL–PEG–PCL micelles. The obtained micelles were characterized by DLS and AFM technique. The results showed that the average size of micelles was about 83.22 nm. ART was encapsulated into PCL–PEG–PCL micelles with encapsulation efficacy of 89.23 ± 1.41%. In vivo results demonstrated that this formulation significantly increased drug accumulation in tumours. Pharmacokinetic study in rats revealed that in vivo drug exposure of ART was significantly increased and prolonged by intravenously administering ART-loaded micelles when compared with the same dose of free ART. The MTT assay showed that bare PCL–PEG–PCL micelles is non-toxic to MCF7 and 4T1 cancer cell lines whereas the ART/PCL–PEG–PCL micelles showed a specific toxicity to both cancer cell lines. Therefore, the polymeric micellar formulation of ART based copolymer could provide a desirable process for ART delivery.

Macrophage selective photodynamic therapy by meta-tetra(hydroxyphenyl)chlorin loaded polymeric micelles: A possible treatment for cardiovascular diseases

Selective elimination of macrophages by photodynamic therapy (PDT) is a new and promising therapeutic modality for the reduction of atherosclerotic plaques. m-Tetra(hydroxyphenyl)chlorin (mTHPC, or Temoporfin) may be suitable as photosensitizer for this application, as it is currently used in the clinic for cancer PDT. In the present study, mTHPC was encapsulated in polymeric micelles based on benzyl-poly(ε-caprolactone)-b-methoxy poly(ethylene glycol) (Ben-PCL-mPEG) using a film hydration method, with loading capacity of 17%. Because of higher lipase activity in RAW264.7 macrophages than in C166 endothelial cells, the former cells degraded the polymers faster, resulting in faster photosensitizer release and higher in vitro photocytotoxicity of mTHPC-loaded micelles in those macrophages. However, we observed release of mTHPC from the micelles in 30min in blood plasma in vitro which explains the observed similar in vivo pharmacokinetics of the mTHPC micellar formulation and free mTHPC. Therefore, we could not translate the beneficial macrophage selectivity from in vitro to in vivo. Nevertheless, we observed accumulation of mTHPC in atherosclerotic lesions of mice aorta's which is probably the result of binding to lipoproteins upon release from the micelles. Therefore, future experiments will be dedicated to increase the stability and thus allow accumulation of intact mTHPC-loaded Ben-PCL-mPEG micelles to macrophages of atherosclerotic lesions.

Abstract 4012: Visualization of EPR effect and active targeting by using microscopic mass spectrometry

Abstract Microscopic mass spectrometry (MMS), in which a microscope is coupled with an atmospheric pressure matrix-assisted laser desorption/ionization (MALDI) and quadruple ion trap time-of-flight (TOF) analyzer has been developed for the investigation of the distribution of various molecules including drugs. The matrix-coated drug sample is ionized and then separated on the basis of its mass-to-charge ratio (m/z). Images were acquired from imaging mass spectrometry (IMS) or tandem mass spectrometry (MS/MS) data. Recently, pharmacokinetic (PK) and pharmacodynamic (PD) studies have become important to evaluate the efficacy and toxicity of the drugs. In these analyses, tissue homogenates are generally used for the quantification by high-performance liquid chromatography (HPLC) or liquid chromatography mass spectrometry (LC-MS). However, they lack the information regarding the drug distribution in a specific anatomical area. The information of the drug distribution would allow us to optimize the drug design enabling more efficient drug delivery. (1) We studied the tissue distribution of paclitaxel (PTX) and its micellar formulation (NK105) using a MMS. NK105 showed much stronger antitumor effects on a human pancreatic cancer BxPC3 xenograft than PTX. In the drug imaging, we demonstrated that NK105 delivered more PTX to the whole tumor tissue. In the mouse model, PTX caused the peripheral neurotoxicity but NK105 did not. Multiple high drug-signal areas surrounding and inside the caudal nerve were observed in the case of PTX, whereas the signals after NK105 administration were quite low. (2) The tissue distribution and controlled drug release of ADC (antibody-drug conjugate) consisting of a tissue factor specific antibody (TF) linked to the anticancer agent monomethyl auristatin E (MMAE) was evaluated in comparison with control-ADC (control antibody-MMAE conjugation). TF-ADC showed stronger antitumor effect on BxPC3 xenograft than control-ADC. We then established the selective detection method of MMAE for distinguishing free MMAE and its conjugated form. The released MMAE signal detected following the accumulation of TF-ADC was greatest 24 h after the administration, compared with the control-ADC at the same time (P&amp;lt;0.01). In summary, we succeeded in visualizing (1) the EPR (Enhanced permeability and retention) effect and (2) active targeting using MMS. The data obtained will facilitate more efficient drug development in the preclinical setting. Citation Format: Masahiro Yasunaga, Masaru Furuta, Koretsugu Ogata, Yuki Fujiwara, Yoshikatsu Koga, Yasuhiro Matsumura. Visualization of EPR effect and active targeting by using microscopic mass spectrometry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4012. doi:10.1158/1538-7445.AM2017-4012

Design and evaluation of mPEG-PLA micelles functionalized with drug-interactive domains as improved drug carriers for docetaxel delivery

Polymeric micelles are very attractive drug delivery systems for hydrophobic agents, owing to their readily tailorable chemical structure and ease for scale-up preparation. However, the intrinsic poor stability of drug-loaded micelles presents one of the major challenges for most micellar systems in the translation to clinical applications. In this study, a simple, well-defined, and easy-to-scale up 9-Fluorenylmethoxycarbonyl (Fmoc) and tert-butoxycarbonyl (Boc) containing lysine dendronized mPEG-PLA (mPEG-PLA-Lys(FB)2) micellar formulation was designed and prepared for docetaxel (DTX) delivery, in an effort to improve the stability of the micelles, and its physicochemical properties, pharmacokinetics, and anti-tumor efficacy against SKOV-3 ovarian cancer were evaluated. MPEG-PLA-Lys(FB)2 was synthesized via a three-step synthetic route, and it actively interacted with DTX in aqueous media to form stable micelles with small particle sizes (~17–19 nm) and narrow size distribution (PI < 0.1), which can be lyophilized and easily reconstituted in saline without significant change in particle size distribution. In vitro drug-release study demonstrated that mPEG-PLA-Lys(FB)2 micelles achieved delayed and sustained release manner of DTX in comparison with mPEG-PLA micelles. Further in vivo xenograft tumor model in nude mice DTX/mPEG-PLA-Lys(FB)2 micelles demonstrated significantly higher inhibitory effect on tumor growth than the marketed formulation Taxotere. Thus, our system may hold promise as a simple and effective delivery system for DTX with a potential for translation into clinical study.

Doxorubicin delivered by a redox-responsive dasatinib-containing polymeric prodrug carrier for combination therapy

Two novel prodrug polymers POEG-b-PSSDas (redox-sensitive) and POEG-b-PCCDas (redox-insensitive), which consist of poly(oligo(ethylene glycol) methacrylate) (POEG) hydrophilic blocks and dasatinib (DAS, an oncogenic tyrosine kinases inhibitor) conjugated hydrophobic blocks, were designed as dual-functional carriers for codelivery with doxorubicin (DOX). Both carriers retained antitumor activity of DAS and could form mixed micelles with DOX. Compared to POEG-b-PCCDas micelles, incorporation of disulfide linkage into POEG-b-PSSDas micelles facilitated efficient cleavage of DAS from prodrug micelles in tumor cells/tissues, leading to a higher level of anti-tumor activity in vitro and in vivo. In addition, DOX-loaded POEG-b-PSSDas micelles exhibited triggered DOX release under a redox environment (10mM glutathione, GSH), and demonstrated enhanced cytotoxicity against 4T1.2 and PC3 cell lines compared to DOX and DOX-loaded POEG-b-PCCDas micelles. More importantly, DOX-loaded POEG-b-PSSDas micelles were more effective in inhibiting the tumor growth and prolonging the survival rate in an aggressive murine breast cancer model (4T1.2) compared to DOX-loaded POEG-b-PCCDas micelles and a micellar formulation co-loaded with DOX and DAS. This redox-responsive prodrug micellar system provides an attractive strategy for effective combination of tumor targeted therapy and traditional chemotherapy, which warrants further investigation.

Novel carvedilol paediatric nanomicelle formulation: in-vitro characterization and in-vivo evaluation.

Carvedilol (CAR) is a poorly water-soluble beta-blocker. Its encapsulation within nanomicelles (NMs) could improve drug solubility and its oral bioavailability, allowing the development of a paediatric liquid CAR formulation with commercially available copolymers: D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and poly(vinyl caprolactam)-poly(vinyl acetate)-poly(ethylene glycol) (Soluplus® ). Drug-loaded NMs were prepared by copolymer and CAR dispersion in distilled water. Micellar size and morphology were characterized by dynamic light scattering and transmission electron microscopy, respectively. In-vitro drug permeation studies were evaluated by conventional gut sac method. In-vivo CAR oral bioavailability from NMs dispersions and drug control solution was evaluated in Wistar rats. Carvedilol apparent aqueous solubility was increased (up to 60.4-folds) after its encapsulation within NMs. The micellar size was ranged between 10.9 and 81.9 nm with a monomodal size distribution. There was a significant enhancement of CAR relative oral bioavailability for both copolymers vs a micelle-free drug solution (P < 0.05). This improvement was higher for TPGS-based micelles (4.95-fold) in accordance with the in-vitro CAR permeation results. The present investigation demonstrates the development of highly concentrated CAR liquid micellar formulation. The improvement on drug oral bioavailability contributes to the potential of this NMs formulation to enhance CAR paediatric treatment.

Proteasome Inhibitor–Loaded Micelles Enhance Antitumor Activity Through Macrophage Reprogramming by NF-κB Inhibition

Macrophage reprogramming toward a tumor-attacking phenotype is a promising treatment strategy, yet such strategies are scarce and it is not clear how to combine them with cytotoxic therapies that are often used to treat solid tumors. Here, we evaluate whether a micelle-encapsulated proteasome inhibitor, that is, the peptide aldehyde drug MG132, which is cytotoxic to cancer cells, can reprogram macrophages to attack the tumor. Through in vitro studies, we demonstrated that the proteasome inhibition reduces nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling—a known promoter of tumor-supporting macrophages and chemoresistance—in both cancer cells and macrophages. In in vivo studies, we showed that, although free MG132 did not affect the macrophage phenotype in tumors even at its maximum tolerated dose, the micellar formulation of MG132 safely achieved simultaneous cancer cell killing and macrophage reprogramming, thereby enhancing the antitumor efficacy in a syngeneic, orthotopic breast cancer model.

Monitoring Organelle‐Specific Responses to Amphotericin B in Mammalian Cells and Candida albicans Biofilms

The use of indwelling medical devices such as catheters or dentures in combination with immunosuppressive therapies increase the body's susceptibility to fungal infections as a pathway to life threatening systemic infections. In particular, Candida albicans, an opportunistic pathogen existing in the normal microbial flora can produce serious systemic infections. This species is unique in its ability to exist in two phases: a yeast form and hyphal biofilm. Once it advances into its biofilm formation, Candida albicans is resistant towards drug treatment, making it immensely difficult to treat in clinical settings. Confocal laser microscopy using organelle‐specific fluorescent probes provides an internal view of Candida albicans along the stages of development and drug response. We have developed and deployed a series of our own naphthalimide‐based fluorescent probes targeted to mitochondria, lysosomes, and the Golgi apparatus to monitor organelle vitality in real time. The brightness, chemical and photo‐stability of our organelle probes allows us to image live cells in their appropriate culture media to observe cellular responses to drug treatments. The resistance to photobleaching makes them useful for longer periods of laser exposure as well as 3D imaging. We have investigated the various liposomal as well as micellar formulations of Amphotericin B including Fungizone, Abelcet, and Ambisome. All formulations of Amphotericin B display some level of toxicity, but lipid formulations such as Abelcet and Ambisome have shown a great reduction in human toxicity without significantly sacrificing their antifungal activity. Using our organelle probes in vitro, we are able to monitor the changes in specific organelles in both model human cells and Candida albicans yeast and hyphal cells to pinpoint the intracellular responses to Amphotericin B in both the target and host. Thus far we have found that Amphotericin B, especially Fungizone, leads to depolarization of mitochondria in some human cell lines while having little acute effect on mitochondria in Candida albicans biofilms. Comparable Amphotericin B doses in the forms of Abelcet and Ambisome, on the other hand, seem to allow for the maintenance of mitochondrial membrane potential in human cells as seen by persistent polarization following multiple hours of incubation. We are currently investigating the time‐dependent relationship between organelle vitality and the differing Amphotericin B formulations with all our probes and cell lines to provide insight as to how Amphotericin B affects mammalian, yeast and biofilm cells differently. Gaining this intracellular perspective of cell health will open doors for the optimization of antifungal drugs through pinpointing their effective mechanisms against fungi while minimizing cellular casualties resulting from organelle decline.Support or Funding InformationOffice of Research and Sponsored Programs‐UW‐Eau Claire