A Pharmacokinetic Model for Quantifying the Effect of Vascular Permeability on the Choice of Drug Carrier: A Framework for Personalized Nanomedicine

Tumor Supplying Artery Injection of Liposome@Sunitinib Could Effectively Inhibit the Progression of Kidney Tumor

Renal cell carcinoma (RCC) is one of the most common malignancies in the urinary system and is not sensitive to chemotherapy or radiotherapy in its advanced stages. Sunitinib is recommended as a first-line target drug for unresectable and metastatic RCC by targeting tyrosine kinase-related signaling pathways, but its therapeutic effect is unsatisfactory. Recently, nanomaterials have shown great prospects in the medical field because of their unique physicochemical properties. Particularly, liposomes are considered as ideal drug delivery systems due to their biodegradability, biocompatibility, and ideal drug-loading efficiency. Considering that tumor supplying artery injection can directly distribute drugs into tumor tissues, in this study, liposomes were employed to encapsulate water-insoluble sunitinib to construct the liposome@sunitinib (Lipo@Suni) complex, so that the drug could directly target and distribute into tumor tissue, and effectively trapped in tumor tissues after tumor supplying artery injection for the advantage of the physicochemical properties of liposomes, thereby achieving a better therapeutic effect on advanced RCC. Here, we found that compared with the peripheral intravenous administration, trans-renal arterial administration increases the content and prolongs the retention time of liposomes in tumor tissues; accordingly, more sunitinib is dispersed and retained in tumor tissues. Ultimately, trans-renal arterial administration of Lipo@Suni exerts a better suppressive effect on RCC progression than peripheral intravenous administration, even better than the conventional oral administration of sunitinib.

Strategies to improve the EPR effect: A mechanistic perspective and clinical translation

Many efforts have been made to achieve targeted delivery of anticancer drugs to enhance their efficacy and to reduce their adverse effects. These efforts include the development of nanomedicines as they can selectively penetrate through tumor blood vessels through the enhanced permeability and retention (EPR) effect. The EPR effect was first proposed by Maeda and co-workers in 1986, and since then various types of nanoparticles have been developed to take advantage of the phenomenon with regards to drug delivery. However, the EPR effect has been found to be highly variable and thus unreliable due to the complex tumor microenvironment. Various physical and pharmacological strategies have been explored to overcome this challenge. Here, we review key advances and emerging concepts of such EPR-enhancing strategies. Furthermore, we analyze 723 clinical trials of nanoparticles with EPR enhancers and discuss their clinical translation.

Computational model of silica nanoparticle penetration into tumor spheroids: Effects of methoxy and carboxy PEG surface functionalization and hyperthermia

Drug delivery to tumors suffers from poor solubility, specificity, diffusion through the tumor micro-environment and nonoptimal interactions with components of the extracellular matrix and cell surface receptors. Nanoparticles and drug-polymer complexes address many of these problems. However, large size exasperates the problem of slow diffusion through the tumor. Three-dimensional tumor spheroids are good models to evaluate approaches to mitigate these difficulties and aid in design strategies to improve the delivery of drugs to treat cancer effectively. Diffusion of drug carriers is highly dependent on cell uptake rate parameters (association/dissociation) and temperature. Hyperthermia increases molecular transport and is known to act synergistically with chemotherapy to improve treatment. This study presents a new inverse estimation approach based on Bayesian probability for estimating nanoparticle cell uptake rates from experiments. The parameters were combined with a finite element computational model of nanoparticle transport under hyperthermia conditions to explore its effect on tumor porosity, diffusion and particle binding (association and dissociation) at cell surfaces. Carboxy-PEG-silane (cPEGSi) nanoparticles showed higher cell uptake compared to methoxy-PEG-silane (mPEGSi) nanoparticles. Simulations were consistent with experimental results from Skov-3 ovarian cancer spheroids. Amorphous silica (cPEGSi) nanoparticles (58 nm) concentrated at the periphery of the tumor spheroids at 37°C but mild hyperthermia (43°C) increased nanoparticle penetration. Thus, hyperthermia may enhance cancer treatment by improving blood delivery to tumors, enhancing extravasation and penetration into tumors, trigger release of drug from the carrier at the tumor site and possibly lead to synergistic anti-cancer activity with the drug.

Pharmacokinetics and Pharmacodynamics Modeling and Simulation Systems to Support the Development and Regulation of Liposomal Drugs

Liposomal formulations have been developed to improve the therapeutic index of encapsulated drugs by altering the balance of on- and off-targeted distribution. The improved therapeutic efficacy of liposomal drugs is primarily attributed to enhanced distribution at the sites of action. The targeted distribution of liposomal drugs depends not only on the physicochemical properties of the liposomes, but also on multiple components of the biological system. Pharmacokinetic⁻pharmacodynamic (PK⁻PD) modeling has recently emerged as a useful tool with which to assess the impact of formulation- and system-specific factors on the targeted disposition and therapeutic efficacy of liposomal drugs. The use of PK⁻PD modeling to facilitate the development and regulatory reviews of generic versions of liposomal drugs recently drew the attention of the U.S. Food and Drug Administration. The present review summarizes the physiological factors that affect the targeted delivery of liposomal drugs, challenges that influence the development and regulation of liposomal drugs, and the application of PK⁻PD modeling and simulation systems to address these challenges.

Flexible Nanoparticles Reach Sterically Obscured Endothelial Targets Inaccessible to Rigid Nanoparticles

Molecular targeting of nanoparticle drug carriers promises maximized therapeutic impact to sites of disease or injury with minimized systemic effects. Precise targeting demands addressing to subcellular features. Caveolae, invaginations in cell membranes implicated in transcytosis and inflammatory signaling, are appealing subcellular targets. Caveolar geometry has been reported to impose a ≈50 nm size cutoff on nanocarrier access to plasmalemma vesicle associated protein (PLVAP), a marker found in caveolae in the lungs. The use of deformable nanocarriers to overcome that size cutoff is explored in this study. Lysozyme-dextran nanogels (NGs) are synthesized with ≈150 or ≈300 nm mean diameter. Atomic force microscopy indicates the NGs deform on complementary surfaces. Quartz crystal microbalance data indicate that NGs form softer monolayers (≈60 kPa) than polystyrene particles (≈8 MPa). NGs deform during flow through microfluidic channels, and modeling of NG extrusion through porous filters yields sieving diameters less than 25 nm for NGs with 150 and 300 nm hydrodynamic diameters. NGs of 150 and 300 nm diameter target PLVAP in mouse lungs while counterpart rigid polystyrene particles do not. The data in this study indicate a role for mechanical deformability in targeting large high-payload drug-delivery vehicles to sterically obscured targets like PLVAP.

Nanoformulated paclitaxel and AZD9291 synergistically eradicate non-small-cell lung cancers in vivo

AIM

This study aims to develop new nanoformulations of EGFR T790M targeted inhibitor AZD9291 and paclitaxel (PTX) for combination therapy of lung cancer.

MATERIALS & METHODS

We prepared and characterized PTX- and AZD9291-loaded disulfide cross-linking micelles (DCMs), and evaluate their combination effect and toxicity in vitro and in lung cancer-bearing mice.

RESULTS

Drug-loaded DCMs were relatively small in size, and possessed glutathione-responsive drug release. The combination of PTX-DCMs and AZD92921-DCMs exhibited strong synergistic effects in both cell line and in vivo without additional toxicity. Molecular studies demonstrated the synergistic modification in both IKB-α/NF-κB/Bcl-2 and EGFR/Akt pathways.

CONCLUSION

The combination of DCM-loaded AZD9291 and PTX could potentially offer more effective and less toxicity treatment options for lung cancer patients.

A cross-sectional study of the availability and pharmacist's knowledge of nano-pharmaceutical drugs in Palestinian hospitals

BACKGROUND

Nanomedicine is the medical application of nanomaterials that may have an infinite size with the range less than 100 nm. This science has provided solutions to many of the current limitations in the diagnosis and treatment of diseases. Therefore, the pharmacist's knowledge and awareness of nano-pharmaceutical drugs will increase their availability in the market, and will improve the patient's compliance to their drug therapy. This study aimed to determine the availability of nano-pharmaceutical drugs in Palestinian hospitals and evaluate the extent of pharmacist's knowledge about them.

METHODS

A cross-sectional study design questionnaire was used to determine the availability of nano-pharmaceutical drugs based on the database of the ministry of health in the Palestinian hospitals (governmental, private and non- governmental organizations). Moreover, the knowledge of these nano-pharmaceutical drugs among pharmacists working in Palestinian hospitals was assessed based on developed questionnaire from the literature of the pharmaceutical formulations and nano-formulations. The variables were analyzed using Statistical Package for Social Sciences (SPSS 22).

RESULT

Fifty six pharmacists from 27 hospitals in the West bank completed the survey. The results regarding the availability of nano-pharmaceutical drugs indicated only eight available in hospitals with a frequency range 0-39.3%. Moreover, pharmacist's knowledge in the pharmaceutical formulations was better than that in nano-formulations.

CONCLUSIONS

The availability of nano-pharmaceutical drugs in Palestinian hospitals was not adequate due to the lack of various nano-pharmaceutical drugs. The knowledge among pharmacists regarding nano-pharmaceutical drugs should be improved by providing courses in nanomedicine during the undergraduate pharmacy programs.

Challenges and strategies in anti-cancer nanomedicine development: An industry perspective

Successfully translating anti-cancer nanomedicines from pre-clinical proof of concept to demonstration of therapeutic value in the clinic is challenging. Having made significant advances with drug delivery technologies, we must learn from other areas of oncology drug development, where patient stratification and target-driven design have improved patient outcomes. We should evolve our nanomedicine development strategies to build the patient and disease into the line of sight from the outset. The success of small molecule targeted therapies has been significantly improved by employing a specific decision-making framework, such as AstraZeneca's 5R principle: right target/efficacy, right tissue/exposure, right safety, right patient, and right commercial potential. With appropriate investment and collaboration to generate a platform of evidence supporting the end clinical application, a similar framework can be established for enhancing nanomedicine translation and performance. Building informative data packages to answer these questions requires the following: (I) an improved understanding of the heterogeneity of clinical cancers and of the biological factors influencing the behaviour of nanomedicines in patient tumours; (II) a transition from formulation-driven research to disease-driven development; (III) the implementation of more relevant animal models and testing protocols; and (IV) the pre-selection of the patients most likely to respond to nanomedicine therapies. These challenges must be overcome to improve (the cost-effectiveness of) nanomedicine development and translation, and they are key to establishing superior therapies for patients.

Assessing the Benefits of Drug Delivery by Nanocarriers: A Partico/Pharmacokinetic Framework

OBJECTIVE

An in vivo kinetic framework is introduced to analyze and predict the quantitative advantage of using nanocarriers to deliver drugs, especially anticancer agents, compared to administering the same drugs in their free form.

METHODS

This framework recognizes three levels of kinetics. First is the particokinetics associated with deposition of nanocarriers into tissues associated with drug effect and toxicity, their residence inside those tissues, and elimination of the nanocarriers from the body. Second is the release pattern in time of free drug from the nanocarriers. Third is the pharmacokinetics of free drug, as it relates to deposition and elimination processes in the target and toxicity associated tissues, and total body clearance. A figure of merit, the drug targeting index (DTI), is used to quantitate the benefit of nanocarrier-based drug delivery by considering the effects of preferential deposition of nanoparticles into target tissues and relative avoidance of tissues associated with drug toxicity, compared to drug that is administered in its free form.

RESULTS

General methods are derived for calculating DTI when appropriate particokinetic, pharmacokinetic, and drug release rate information is available, and it is shown that relatively simple algebraic forms result when some common assumptions are made.

CONCLUSION

This approach may find use in developing and selecting nanocarrier formulations, either for populations or for individuals.

Computational and experimental approaches for investigating nanoparticle-based drug delivery systems

Most therapeutic agents suffer from poor solubility, rapid clearance from the blood stream, a lack of targeting, and often poor translocation ability across cell membranes. Drug/gene delivery systems (DDSs) are capable of overcoming some of these barriers to enhance delivery of drugs to their right place of action, e.g. inside cancer cells. In this review, we focus on nanoparticles as DDSs. Complementary experimental and computational studies have enhanced our understanding of the mechanism of action of nanocarriers and their underlying interactions with drugs, biomembranes and other biological molecules. We review key biophysical aspects of DDSs and discuss how computer modeling can assist in rational design of DDSs with improved and optimized properties. We summarize commonly used experimental techniques for the study of DDSs. Then we review computational studies for several major categories of nanocarriers, including dendrimers and dendrons, polymer-, peptide-, nucleic acid-, lipid-, and carbon-based DDSs, and gold nanoparticles. This article is part of a Special Issue entitled: Membrane Proteins edited by J.C. Gumbart and Sergei Noskov.

Enabling personalized cancer medicine decisions: The challenging pharmacological approach of PBPK models for nanomedicine and pharmacogenomics (Review)

The existing tumor heterogeneity and the complexity of cancer cell biology critically demand powerful translational tools with which to support interdisciplinary efforts aiming to advance personalized cancer medicine decisions in drug development and clinical practice. The development of physiologically based pharmacokinetic (PBPK) models to predict the effects of drugs in the body facilitates the clinical translation of genomic knowledge and the implementation of in vivo pharmacology experience with pharmacogenomics. Such a direction unequivocally empowers our capacity to also make personalized drug dosage scheme decisions for drugs, including molecularly targeted agents and innovative nanoformulations, i.e. in establishing pharmacotyping in prescription. In this way, the applicability of PBPK models to guide individualized cancer therapeutic decisions of broad clinical utility in nanomedicine in real-time and in a cost-affordable manner will be discussed. The latter will be presented by emphasizing the need for combined efforts within the scientific borderlines of genomics with nanotechnology to ensure major benefits and productivity for nanomedicine and personalized medicine interventions.

Nanoscale covalent organic frameworks as smart carriers for drug delivery

Two nanoscale covalent organic frameworks as drug carriers with good biocompatibility were developed, showing high drug loading capacity and sustained release in vitro.

Reformulating Tylocrebrine in Epidermal Growth Factor Receptor Targeted Polymeric Nanoparticles Improves Its Therapeutic Index

Several promising anticancer drug candidates have been sidelined owing to their poor physicochemical properties or unfavorable pharmacokinetics, resulting in high overall cost of drug discovery and development. Use of alternative formulation strategies that alleviate these issues can help advance new molecules to the clinic at a significantly lower cost. Tylocrebrine is a natural product with potent anticancer activity. Its clinical trial was discontinued following the discovery of severe central nervous system toxicities. To improve the safety and potency of tylocrebrine, we formulated the drug in polymeric nanoparticles targeted to the epidermal growth factor receptor (EGFR) overexpressed on several types of tumors. Through in vitro studies in different cancer cell lines, we found that EGFR targeted nanoparticles were significantly more effective in killing tumor cells than the free drug. In vivo pharmacokinetic studies revealed that encapsulation in nanoparticles resulted in lower brain penetration and enhanced tumor accumulation of the drug. Further, targeted nanoparticles were characterized by significantly enhanced tumor growth inhibitory activity in a mouse xenograft model of epidermoid cancer. These results suggest that the therapeutic index of drugs that were previously considered unusable could be significantly improved by reformulation. Application of novel formulation strategies to previously abandoned drugs provides an opportunity to advance new molecules to the clinic at a lower cost. This can significantly increase the repertoire of treatment options available to cancer patients.