Mixed micelles of TPGS and Soluplus® for co-delivery of paclitaxel and fenretinide: in vitro and in vivo anticancer study

Cancer cell membrane-modified Soluplus® micelles for gemcitabine delivery to pancreatic cancer using a prodrug approach

Pancreatic cancer (PC) is one of the most lethal malignancies worldwide and its incidence is increasing. Chemotherapy is often associated to limited efficacy, poor targeting and systemic toxicity. In this work, the hydrophilic gemcitabine (GEM), widely used in PC treatment alone or in combination, was conjugated with vitamin E succinate (VES) and encapsulated in Soluplus® micelles. This prodrug approach facilitated encapsulation of the anticancer drug into the self-assembled copolymer micelles. Soluplus®/VES-GEM micelles were optimized regarding the ratio of the components and the preparation process. The micelles were small-sized (<80 nm), monodisperse, and highly stable, efficiently retaining the conjugate drug and showing significant antiproliferative activity against BxPC3 cell line. To improve biofunctionalization and targeting properties of prepared Soluplus®/VES-GEM micelles, biomimetic modification with PC cell membrane was further attempted by co-extruding PC cell membrane (BxPC3) nanovesicles with Soluplus®/VES-GEM micelles. Several protocols were attempted to prepare the BxPC3-modified Soluplus®/VES-GEM micelles and the outcomes were analyzed in detail. Overall, the results pave the way to innovative PC-targeted nanotherapies by maximizing GEM encapsulation in hydrophobic compartments with high stability and affinity. The results also highlight the need of higher resolution techniques to characterize cell membrane coating of nanocarriers bearing highly hydrophilic shells.

Evaluation of Anticancer Efficacy of D-α-Tocopheryl Polyethylene-Glycol Succinate and Soluplus® Mixed Micelles Loaded with Olaparib and Rapamycin Against Ovarian Cancer

Purpose

Ovarian cancer has the highest mortality rate and lowest survival rate among female reproductive system malignancies. There are treatment options of surgery and chemotherapy, but both are limited. In this study, we developed and evaluated micelles composed of D-α-tocopheryl polyethylene-glycol (PEG) 1000 succinate (TPGS) and Soluplus® (SOL) loaded with olaparib (OLA), a poly(ADP-ribose)polymerase (PARP) inhibitor, and rapamycin (RAPA), a mammalian target of rapamycin (mTOR) inhibitor in ovarian cancer.

Methods

We prepared micelles containing different molar ratios of OLA and RAPA embedded in different weight ratios of TPGS and SOL (OLA/RAPA-TPGS/SOL) were prepared and physicochemical characterized. Furthermore, we performed in vitro cytotoxicity experiments of OLA, RAPA, and OLA/RAPA-TPGS/SOL. In vivo toxicity and antitumor efficacy assays were also performed to assess the efficacy of the mixed micellar system.

Results

OLA/RAPA-TPGS/SOL containing a 4:1 TPGS:SOL weight ratio and a 2:3 OLA:RAPA molar ratio showed synergistic effects and were optimized. The drug encapsulation efficiency of this formulation was >65%, and the physicochemical properties were sustained for 180 days. Moreover, the formulation had a high cell uptake rate and significantly inhibited cell migration (**p < 0.01). In the in vivo toxicity test, no toxicity was observed, with the exception of the high dose group. Furthermore, OLA/RAPA-TPGS/SOL markedly inhibited tumor spheroid and tumor growth in vivo.

Conclusion

Compared to the control, OLA/RAPA-TPGS/SOL showed significant tumor inhibition. These findings lay a foundation for the use of TPGS/SOL mixed micelles loaded with OLA and RAPA in the treatment of ovarian cancer.

Better together: nanoscale co-delivery systems of therapeutic agents for high-performance cancer therapy

Combination therapies can enhance the sensitivity of cancer to drugs, lower drug doses, and reduce side effects in cancer treatment. However, differences in the physicochemical properties and pharmacokinetics of different therapeutic agents limit their application. To avoid the above dilemma and achieve accurate control of the synergetic ratio, a nanoscale co-delivery system (NCDS) has emerged as a prospective tool for combined therapy in cancer treatment, which is increasingly being used to co-load different therapeutic agents. In this study, we have summarized the mechanisms of therapeutic agents in combination for cancer therapy, nanoscale carriers for co-delivery, drug-loading strategies, and controlled/targeted co-delivery systems, aiming to give a general picture of these powerful approaches for future NCDS research studies.

Gout therapeutics and drug delivery

Gout is a common inflammatory arthritis caused by persistently elevated uric acid levels. With the improvement of people's living standards, the consumption of processed food and the widespread use of drugs that induce elevated uric acid, gout rates are increasing, seriously affecting the human quality of life, and becoming a burden to health systems worldwide. Since the pathological mechanism of gout has been elucidated, there are relatively effective drug treatments in clinical practice. However, due to (bio)pharmaceutical shortcomings of these drugs, such as poor chemical stability and limited ability to target the pathophysiological pathways, traditional drug treatment strategies show low efficacy and safety. In this scenario, drug delivery systems (DDS) design that overcome these drawbacks is urgently called for. In this review, we initially describe the pathological features, the therapeutic targets, and the drugs currently in clinical use and under investigation to treat gout. We also comprehensively summarize recent research efforts utilizing lipid, polymeric and inorganic carriers to develop advanced DDS for improved gout management and therapy.

Soluplus®-based dissolving microarray patches loaded with colchicine: towards a minimally invasive treatment and management of gout

Considered as one of the most common inflammatory arthritis, gout is characterised by a sudden onset of severe joint pain. As the first-line drug of choice used in treating acute gout, colchicine (CLC) is hindered by poor gastrointestinal permeability as well as unfavourable gastrointestinal side effects. Herein, we present, for the first time, the preparation of microarray array patches (MAPs) made of a polymeric solubiliser, Soluplus®, loaded with CLC for its systemic delivery. The fabricated MAPs displayed acceptable mechanical properties and were capable of being inserted into the skin to a depth of ≈500 μm in full thickness ex vivo neonatal porcine skin, as evidenced by optical coherence tomography. In vitro dermatokinetic studies utilising full thickness neonatal porcine skin demonstrated that the CLC-loaded MAPs delivered CLC across all skin strata, resulting in a delivery efficiency of 73% after 24 hours. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and cell proliferation assays along with LIVE/DEAD™ staining on the 3T3-L1 cell line showed that the MAP formulation displayed minimal toxicity, with acceptable biocompatibility. Lastly, the anti-inflammatory properties of the formulation were evaluated using a THP-1 macrophage cell line. It was shown that treatment of THP-1 macrophages that are exposed to lipopolysaccharide (LPS) with CLC-loaded MAPs caused a significant (p < 0.05) reduction of TNF-α production, a pro-inflammatory cytokine typically associated with the early onset of acute gout. Accordingly, CLC-loaded MAPs could represent a new minimally-invasive alternative strategy for management of acute gout.

Anti-Proliferative Potential of Quercetin Loaded Polymeric Mixed Micelles on Rat C6 and Human U87MG Glioma Cells

Quercetin (Qu) is a natural flavonoid present in many commonly consumed food items and is also identified as a potential anticancer agent. The present study evaluates the Qu-loaded polymeric mixed micelles (Qu-PMMs) against C6 and U87MG glioma cell lines. The Box-Behnken Design (BBD) was employed to study the influence of independent variables such as Soluplus, Vitamin-E polyethyleneglycol-1000 succinate (E-TPGS), and poloxamer 407 concentrations on dependent variables including particle size (PS), polydispersity index (PDI), and percentage entrapment efficiency (%EE) of the prepared Qu-PMMs. The Qu-PMMs were further characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and were assessed for in vitro drug release, effect on cell viability, migration, cellular uptake, and apoptosis assays. The PS, PDI, and % EE of the optimized PMMs were 107.16 ± 1.06 nm, 0.236 ± 0.053, and 77.46 ± 1.94%, respectively. The FTIR and XRD revealed that the Qu was completely entrapped inside the PMMs. The SEM analysis confirmed the spherical shape of micelles. The in vitro cell viability study showed that the Qu-PMMs had 1.7 times higher cytotoxicity against C6 and U87MG cells than Qu pure drug (Qu-PD). Furthermore, Qu-PMMs demonstrated superior cellular uptake, inhibited migration, and induced apoptosis when tested against C6 and U87MG cells than pure Qu. Thus, the polymeric mixed micelle (PMMs) enhanced the therapeutic effect of Qu and can be considered an effective therapeutic strategy to treat Glioma.

Fast In Vitro Release and In Vivo Absorption of an Anti-Schizophrenic Drug Paliperidone from Its Soluplus®/TPGS Mixed Micelles

The purpose of this study was to develop a drug delivery system for paliperidone (PPD) in order to provide a more effective therapeutic strategy for patients with acute schizophrenia. PPD-loaded Soluplus®/TPGS mixed micelles (PPD-S/T-MM) were prepared using the thin-film hydration method. The critical micelle concentration (CMC) of blank S/T-MM was 4.77 × 10-2 mg/mL. PPD presented much higher solubility in PPD-S/T-MM formulation than that in pure water. The particle size of blank or drug loaded S/T-MM was around 60 nm. The polydispersity index (PDI) was less than 0.1. PPD-S/T-MM presented a nearly spherical shape under transmission electron microscopy. The encapsulation efficiency (EE%) of PPD-S/T-MM was higher than 94%. Based on the analysis of XRD and DSC, it was proved that PPD was incorporated in the core of the mixed micelles as amorphous dispersion or solid solution. PPD-S/T-MM were stable when they were undergoing dilution with water and the change of environmental pH. Although PPD-S/T-MM showed lower rates to release PPD than those from PPD raw material in acidic solution, they provided faster release rates in neutral conditions than those from PPD raw material who only showed modest dissolution in the same neutral condition. This proves that PPD-S/T-MM can release PPD in a more controlled manner. After oral administration of PPD-S/T-MM (dose of PPD, 6 mg/kg) in rats, the plasma concentration of PPD increased rapidly: Tmax was 0.83 ± 0.29 h, and Cmax was 844.33 ± 93.73 ng/mL. Oral administration of PPD suspension resulted in longer Tmax and lower Cmax. The relative oral bioavailability was about 158% for PPD-S/T-MM over PPD suspension. These findings confirm that PPD-S/T-MM can provide faster release in neutral conditions and better oral absorption in rats than those from PPD raw material, which should potentially benefit patients with acute schizophrenia.

Targeting Sphingolipids for Cancer Therapy

Sphingolipids are an extensive class of lipids with different functions in the cell, ranging from proliferation to cell death. Sphingolipids are modified in multiple cancers and are responsible for tumor proliferation, progression, and metastasis. Several inhibitors or activators of sphingolipid signaling, such as fenretinide, safingol, ABC294640, ceramide nanoliposomes (CNLs), SKI-II, α-galactosylceramide, fingolimod, and sonepcizumab, have been described. The objective of this review was to analyze the results from preclinical and clinical trials of these drugs for the treatment of cancer. Sphingolipid-targeting drugs have been tested alone or in combination with chemotherapy, exhibiting antitumor activity alone and in synergism with chemotherapy in vitro and in vivo. As a consequence of treatments, the most frequent mechanism of cell death is apoptosis, followed by autophagy. Aslthough all these drugs have produced good results in preclinical studies of multiple cancers, the outcomes of clinical trials have not been similar. The most effective drugs are fenretinide and α-galactosylceramide (α-GalCer). In contrast, minor adverse effects restricted to a few subjects and hepatic toxicity have been observed in clinical trials of ABC294640 and safingol, respectively. In the case of CNLs, SKI-II, fingolimod and sonepcizumab there are some limitations and absence of enough clinical studies to demonstrate a benefit. The effectiveness or lack of a major therapeutic effect of sphingolipid modulation by some drugs as a cancer therapy and other aspects related to their mechanism of action are discussed in this review.

Honokiol Prodrug Nanoparticles Based on In Situ Albumin Binding for Long Circulation and High Tumor Uptake

Honokiol (HK) has antiproliferation effects against numerous cancer cells, but its low solubility and bioavailability impede its application. In this study, a prodrug of HK (HP) featuring a maleimide group was synthesized and then mixed with tocopherol polyethylene glycol succinate to prepare prodrug nanoparticles (HP-NPs). In vitro albumin binding experiments showed that HP rapidly reacted with the cysteine thiols of albumin to form a covalent conjugate that released HK slowly in the LLC tumor cell line. In vitro cell apoptosis and uptake assays showed that the cellular uptake of the HK increased into the LLC cells as the albumin concentration increased. Strikingly, in vivo pharmacokinetics and pharmacodynamics measurements demonstrated that the HP-NPs significantly prolonged the circulation and increased tumor accumulation. Taken together, our study demonstrated, both in vitro and in vivo, that the albumin-based HP-NPs delivery system holds significant potential toward the treatment of lung cancer in clinical studies.

Does Oral Apigenin Have Real Potential for a Therapeutic Effect in the Context of Human Gastrointestinal and Other Cancers?

Apigenin (4′, 5, 7-trihydroxyflavone) is a plant flavone that has been found to have various actions against cancer cells. We evaluated available evidence to determine whether it is feasible for apigenin to have such effects in human patients.

Apigenin taken orally is systemically absorbed and recirculated by enterohepatic and local intestinal pathways. Its bioavailability is in the region of 30%. Once absorbed from the oral route it reaches maximal circulating concentration (C_max) after a time (T_max) of 0.5–2.5h, with an elimination half-life (T¹/₂) averaging 2.52 ± 0.56h.

Using a circulating concentration for efficacy of 1–5μmol/L as the target, we evaluated data from both human and rodent pharmacokinetic studies to determine if a therapeutic concentration would be feasible. We find that oral intake of dietary materials would require heroic ingestion amounts and is not feasible. However, use of supplements of semi-purified apigenin in capsule form could reach target blood levels using amounts that are within the range currently acceptable for other supplements and medications. Modified formulations or parenteral injection are suitable but may not be necessary.

Further work with direct studies of pharmacokinetics and clinical outcomes are necessary to fully evaluate whether apigenin will contribute to a useful clinical strategy, but given emerging evidence that it may interact beneficially with chemotherapeutic drugs, this is worthy of emphasis. In addition, more effective access to intestinal tissues from the oral route raises the possibility that apigenin may be of particular relevance to gastrointestinal disorders including colorectal cancer.