Targeted delivery of albumin bound paclitaxel in the treatment of advanced breast cancer

Drug complexes: Perspective from Academic Research and Pharmaceutical Market

Despite numerous research efforts, drug delivery through the oral route remains a major challenge to formulation scientists. The oral delivery of drugs poses a significant challenge because more than 40% of new chemical entities are practically insoluble in water. Low aqueous solubility is the main problem encountered during the formulation development of new actives and for generic development. A complexation approach has been widely investigated to address this issue, which subsequently improves the bioavailability of these drugs. This review discusses the various types of complexes such as metal complex (drug-metal ion), organic molecules (drug-caffeine or drug-hydrophilic polymer), inclusion complex (drug-cyclodextrin), and pharmacosomes (drug-phospholipids) that improves the aqueous solubility, dissolution, and permeability of the drug along with the numerous case studies reported in the literature. Besides improving solubility, drug-complexation provides versatile functions like improving stability, reducing the toxicity of drugs, increasing or decreasing the dissolution rate, and enhancing bioavailability and biodistribution. Apart, various methods to predict the stoichiometric ratio of reactants and the stability of the developed complex are discussed.

Analysis of chemotherapy-induced peripheral neuropathy using the Japanese Adverse Drug Event Report database

Chemotherapy-induced peripheral neuropathy (CIPN) is a common adverse event associated with several antineoplastic drugs; however, the precise risks and time course of reactions of particular drugs are not clearly understood. The aim of this study was to evaluate the relationship between anticancer agents and CIPN development using data from the Japanese Adverse Drug Event Report (JADER) database and to characterize the time-to-onset and outcomes of CIPN. Chemotherapy-induced peripheral neuropathy was defined using the Medical Dictionary for Regulatory Activities preferred terms. Disproportionality analysis was performed by calculating the reporting odds ratio (ROR) with 95% confidence interval for signal detection. Data of nine Anatomical Therapeutic Chemical (ATC) drug categories correlated with CIPN development, in addition to the data of the time-to-onset and outcomes. Among 622,289 reports in the JADER database from April 2004 to March 2020, there were 1883 reports of adverse events corresponding to peripheral neuropathy. The ROR (95% confidence interval) for vinblastine, sorbent-based paclitaxel (sb-PTX), oxaliplatin, and bortezomib was 20.4 (12.5–33.4), 13.6 (11.9–15.7), 26.2 (23.6–29.1), and 30.8 (26.6–35.8), respectively. The median duration (interquartile range) to CIPN development after the administration of vinca alkaloids and analogues, taxanes, platinum compounds, and monoclonal antibodies was 11.0 (5.0–46.5), 22.5 (6.0–82.5), 22.0 (6.0–68.5), and 32.5 (11.3–73.8) days, respectively. The median duration (interquartile range) of sb-PTX and nanoparticle albumin-bound (nab)-PTX was 35.0 (7.0–94.0) and 5.5 (3.0–29.3) days, respectively. Our analysis of records in the JADER database revealed several drugs associated with a high risk for CIPN development. In particular, the development of CIPN after vinca alkaloid administration should be closely monitored for 2 weeks after administration. CIPN caused by nab-PTX showed significantly faster onset than that by sb-PTX. Patients who receive taxanes or monoclonal antibodies often do not show an improvement; accordingly, early treatment is required.

Quantitative systems pharmacology model predictions for efficacy of atezolizumab and nab-paclitaxel in triple-negative breast cancer

Background

Immune checkpoint blockade therapy has clearly shown clinical activity in patients with triple-negative breast cancer, but less than half of the patients benefit from the treatments. While a number of ongoing clinical trials are investigating different combinations of checkpoint inhibitors and chemotherapeutic agents, predictive biomarkers that identify patients most likely to benefit remains one of the major challenges. Here we present a modular quantitative systems pharmacology (QSP) platform for immuno-oncology that incorporates detailed mechanisms of immune–cancer cell interactions to make efficacy predictions and identify predictive biomarkers for treatments using atezolizumab and nab-paclitaxel.

Methods

A QSP model was developed based on published data of triple-negative breast cancer. With the model, we generated a virtual patient cohort to conduct in silico virtual clinical trials and make retrospective analyses of the pivotal IMpassion130 trial that led to the accelerated approval of atezolizumab and nab-paclitaxel for patients with programmed death-ligand 1 (PD-L1) positive triple-negative breast cancer. Available data from clinical trials were used for model calibration and validation.

Results

With the calibrated virtual patient cohort based on clinical data from the placebo comparator arm of the IMpassion130 trial, we made efficacy predictions and identified potential predictive biomarkers for the experimental arm of the trial using the proposed QSP model. The model predictions are consistent with clinically reported efficacy endpoints and correlated immune biomarkers. We further performed a series of virtual clinical trials to compare different doses and schedules of the two drugs for simulated therapeutic optimization.

Conclusions

This study provides a QSP platform, which can be used to generate virtual patient cohorts and conduct virtual clinical trials. Our findings demonstrate its potential for making efficacy predictions for immunotherapies and chemotherapies, identifying predictive biomarkers, and guiding future clinical trial designs.

Albumin-based lipoprotein nanoparticles for improved delivery and anticancer activity of curcumin for cancer treatment

Aim: To prepare curcumin (CUR)-loaded, dioleoyl phosphoethanolamine-conjugated human serum albumin nanoparticles (NPs) and to evaluate their effectiveness in breast cancer therapy. Materials & methods: The CUR-loaded NPs were physicochemically characterized and evaluated for their cytotoxicity in murine (4T1) and human breast cancer (MDA-MB-231) cell lines. The antitumor efficacy of the nanomedicine was evaluated in 4T1 tumor bearing mice. Results: The prepared NPs exhibited encapsulation and drug loading efficiencies of approximately 79 and 21%, respectively. The NPs were taken up efficiently and markedly hindered the proliferation of breast cancer cells compared with free drug. NPs exhibited greater suppression of tumor growth in 4T1 tumor bearing mice. Conclusion: CUR-human serum albumin-dioleoyl phosphoethanolamine NPs could be a potential treatment alternative for solid tumors, including breast cancer.

A Rationally Designed ICAM1 Antibody Drug Conjugate for Pancreatic Cancer

Outcomes for pancreatic cancer (PC) patients remain strikingly poor with a 5-year survival of less than 8% due to the lack of effective treatment modalities. Here, a novel precision medicine approach for PC treatment is developed, which is composed of a rationally designed tumor-targeting ICAM1 antibody-drug conjugate (ADC) with optimized chemical linker and cytotoxic payload, complemented with a magnetic resonance imaging (MRI)-based molecular imaging approach to noninvasively evaluate the efficiency of ICAM1 ADC therapy. It is shown that ICAM1 is differentially overexpressed on the surface of human PC cells with restricted expression in normal tissues, enabling ICAM1 antibody to selectively recognize and target PC tumors in vivo. It is further demonstrated that the developed ICAM1 ADC induces potent and durable tumor regression in an orthotopic PC mouse model. To build a precision medicine, an MRI-based molecular imaging approach is developed that noninvasively maps the tumoral ICAM1 expression that can be potentially used to identify ICAM1-overexpressing PC patients. Collectively, this study establishes a strong foundation for the development of a promising ADC to address the critical need in the PC patient care.

Carrier-free nanodrugs for safe and effective cancer treatment

Clinical applications of many anti-cancer drugs are restricted due to their hydrophobic nature, requiring use of harmful organic solvents for administration, and poor selectivity and pharmacokinetics resulting in off-target toxicity and inefficient therapies. A wide variety of carrier-based nanoparticles have been developed to tackle these issues, but such strategies often fail to encapsulate drug efficiently and require significant amounts of inorganic and/or organic nanocarriers which may cause toxicity problems in the long term. Preparation of nano-formulations for the delivery of water insoluble drugs without using carriers is thus desired, requiring elegantly designed strategies for products with high quality, stability and performance. These strategies include simple self-assembly or involving chemical modifications via coupling drugs together or conjugating them with various functional molecules such as lipids, carbohydrates and photosensitizers. During nanodrugs synthesis, insertion of redox-responsive linkers and tumor targeting ligands endows them with additional characteristics like on-target delivery, and conjugation with immunotherapeutic reagents enhances immune response alongside therapeutic efficacy. This review aims to summarize the methods of making carrier-free nanodrugs from hydrophobic drug molecules, evaluating their performance, and discussing the advantages, challenges, and future development of these strategies.

Mathematical modeling in cancer nanomedicine: a review

Cancer continues to be among the leading healthcare problems worldwide, and efforts continue not just to find better drugs, but also better drug delivery methods. The need for delivering cytotoxic agents selectively to cancerous cells, for improved safety and efficacy, has triggered the application of nanotechnology in medicine. This effort has provided drug delivery systems that can potentially revolutionize cancer treatment. Nanocarriers, due to their capacity for targeted drug delivery, can shift the balance of cytotoxicity from healthy to cancerous cells. The field of cancer nanomedicine has made significant progress, but challenges remain that impede its clinical translation. Several biophysical barriers to the transport of nanocarriers to the tumor exist, and a much deeper understanding of nano-bio interactions is necessary to change the status quo. Mathematical modeling has been instrumental in improving our understanding of the physicochemical and physiological underpinnings of nanomaterial behavior in biological systems. Here, we present a comprehensive review of literature on mathematical modeling works that have been and are being employed towards a better understanding of nano-bio interactions for improved tumor delivery efficacy.

Adverse event profiles of solvent-based and nanoparticle albumin-bound paclitaxel formulations using the Food and Drug Administration Adverse Event Reporting System

Objectives

Paclitaxel is a highly effective antitumor agent with notable adverse events, including hypersensitivity reactions, peripheral neuropathy, arthralgia, myalgias, and neutropenia. Solvent-based paclitaxel causes severe allergic, hypersensitivity, and anaphylactic reactions. Nanoparticle albumin-bound paclitaxel was recently developed and provides an advantage over solvent-based paclitaxel in avoiding solvent/surfactant-related adverse events. The aim of this study was to assess the adverse event profiles of solvent-based paclitaxel and nanoparticle albumin-bound paclitaxel formulations using data from the spontaneous adverse event reporting system of the US Food and Drug Administration Adverse Event Reporting System database.

Methods

This study relied on Medical Dictionary for Regulatory Activities preferred terms and standardized queries, and calculated the reporting ratio and reporting odds ratios of paclitaxel formulations.

Results

Of 8,867,135 reports recorded in the US Food and Drug Administration Adverse Event Reporting System database from January 2004 to December 2016, 3469 and 4447 adverse events corresponded to solvent-based paclitaxel and nanoparticle albumin-bound paclitaxel, respectively. Reporting odds ratios (95% confidence interval) for anaphylactic reaction (standardized MedDRA query code: 20000021) associated with the use of solvent-based paclitaxel and nanoparticle albumin-bound paclitaxel were 1.69 (1.56-1.84) and 0.75 (0.68-0.83), respectively. Reporting odds ratio signal for anaphylactic reaction was not detected for nanoparticle albumin-bound paclitaxel. Reporting odds ratios (95% confidence interval) for acute renal failure (standardized MedDRA query code: 20000003) associated with the use of solvent-based paclitaxel and nanoparticle albumin-bound paclitaxel were 0.75 (0.58-0.98) and 1.60 (1.37-1.89), respectively.

Conclusion

This is the first study to evaluate the adverse event profile of nanoparticle albumin-bound paclitaxel using US Food and Drug Administration Adverse Event Reporting System data. Considering that the US Food and Drug Administration Adverse Event Reporting System database does not allow to infer causality or risk ranking, the different reporting frequencies of anaphylactic reaction and acute renal failure between solvent-based paclitaxel and nanoparticle albumin-bound paclitaxel must be further investigated via analytical observational research.

Development of polyvinylpyrrolidone/paclitaxel self-assemblies for breast cancer

The goal of this investigation was to develop and demonstrate a polymer/paclitaxel self-assembly (PTX-SA) formulation. Polymer/PTX-SAs were screened based on smaller size of formulation using dynamic light scattering analysis. Additionally, fluorescence microscopy and flow cytometry studies exhibited that polyvinylpyrrolidone (PVP)-based PTX-SAs (PVP/PTX-SAs) had superior cellular internalization capability in MCF7 and MDA-MB-231 breast cancer cells. The optimized PVP/PTX-SAs exhibited less toxicity to human red blood cells indicating a suitable formulation for reducing systemic toxicity. The formation of PVP and PTX self-assemblies was confirmed using fluorescence quenching and transmission electron microscopy which indicated that the PVP/PTX-SAs were spherical in shape with an average size range of 53.81 nm as detected by transmission electron microscopy (TEM). FTIR spectral analysis demonstrates incorporation of polymer and paclitaxel functional groups in PVP/PTX-SAs. Both proliferation (MTS) and clonogenic (colony formation) assays were used to validate superior anticancer activity of PVP/PTX-SAs in breast cancer cells over paclitaxel. Such superior anticancer activity was also demonstrated by downregulation of the expression of pro-survival protein (Bcl-xL), upregulation of apoptosis-associated proteins (Bid, Bax, cleaved caspase 7, and cleaved PARP) and β-tubulin stabilization. These results support the hypothesis that PVP/PTX-SAs improved paclitaxel delivery to cancer cells.

Doxorubicin-DNA adduct entrenched and motif tethered artificial virus encased in pH-responsive polypeptide complex for targeted cancer therapy

Doxorubicin is a broad spectrum anticancer antibiotic that possesses toxic effects such as cardiomyopathy, that even lead to congestive heart failure. Thus, the development of a new bio-inspired system is required, that retain the advantageous effect of doxorubicin while retarding the side effects. Hence, a system was developed that we describe 'doxorubicin-DNA adduct entrenched artificial virus encased in polypeptide complex'. The drug-DNA adduct (DDA) was prepared by a formaldehyde mediated reaction. A simple chloroform extraction method for the separation of DDA was developed. DDA was employed to self-assemble the folate tethered bovine serum albumin to form the protein coat in the proposed artificial virus. The folate tethered albumin provides an artificial virus concept, with tumor tissue targeting due to the presence of folate. The whole system was then encased in a pH-responsive polypeptide complex that dissolves in acidic pH, but not in basic pH. DDA was evaluated by UV-Vis spectrophotometry, spectrofluorimetry and high-performance liquid chromatography (HPLC). A promising drug release at physiological condition was observed from DDA. The developed system was evaluated by a developed and validated artificial cell apparatus that mimic the features of a cancer cell. The drug delivery system displayed a considerable amount of drug release within 24 h. Moreover, the developed artificial virus system reduced angiogenesis caused by tumor cells in chick chorioallantoic membrane. Histopathology of treated chicken heart slices demonstrated that the developed artificial virus system reduces the tissue deformation and apoptosis in heart tissue slices, thus providing a new approach to prevent Dox-induced cardiomyopathy.

131I-Traced PLGA-Lipid Nanoparticles as Drug Delivery Carriers for the Targeted Chemotherapeutic Treatment of Melanoma

Herein, folic acid (FA) conjugated Poly(d,l-lactide-co-glycolide) (PLGA)-lipid composites (FA-PL) were developed as nanocarriers for the targeted delivery of insoluble anti-cancer drug paclitaxel (PTX), resulting FA-PLP nanoparticles. Furthermore, ¹³¹I, as a radioactive tracer, was used to label FA-PLP nanoparticles (FA-PLP-¹³¹I) to evaluate their cell uptake activity, in vivo blood circulation, and biodistribution. The FA-PLP-¹³¹I nanoparticles had a spherical morphology with great stability, a narrow size distribution (165.6 and 181.2 nm), and -22.1 mV in average zeta potential. Confocal laser scanning microscopy indicated that the targeting molecule FA promotes PLP-¹³¹I uptake by melanoma B16F10 cells, which was further confirmed by the cell incorporation rate via ¹³¹I activity detection as measured by a gamma counter. FA-PLP-¹³¹I without PTX (FA-PL-¹³¹I) shows minor cytotoxicity, good biocompatibility, while FA-PLP-¹³¹I was demonstrated to have efficient cell viability suppression compared to free PTX and PLP-¹³¹I. Following intravenous injection, the blood circulation half-life of free PTX (t _1/2 = 5.4 ± 0.23 h) was prolonged to 18.5 ± 0.5 h by FA-PLP-¹³¹I. Through FA targeting, the tumor uptake of FA-PLP-¹³¹I was approximately 4.41- and 12.8-fold higher compared to that of PLP-¹³¹I and free PTX-¹³¹I, respectively. Moreover, following 40 days of treatment, FA-PLP-¹³¹I showed an improved tumor inhibition effect compared to free PTX and PLP-¹³¹I, with no relapse and no remarkable systemic in vivo toxicity. The results demonstrate that the ¹³¹I-labeled PLGA-lipid nanoparticle can be simultaneously applied for targeted drug delivery and reliable tracking of drugs in vivo.

Drug solubilization by complexation

Drugs must possess some solubility in water to be therapeutically effective after oral or topical administration to the eye, and drugs must be soluble to be formulated as aqueous solutions for, for example, parenteral delivery. A variety of methods can be applied to enhance aqueous solubility of poorly soluble drugs one of which is the usage of solubilizing complexing agents. There are numerous types of complexes and some are more water-soluble than others. Coordination complexes consist of drugs that act as complexing agents (i.e. ligands) and metal ions (i.e. substrates). Examples of coordination complexes are some water-soluble tetracycline-metal ion complexes. Organic molecular complexes can consist of a small substrate (i.e. the drug) and a small (e.g., caffeine) or a large (e.g., polyvinylpyrrolidone) ligand. In inclusion complexes the substrate is partly or completely enveloped by the complexing agent (e.g., cyclodextrin). Finally, pharmacosomes are drug-phospholipid complexes that can not only enhance aqueous solubility of poorly soluble drugs but also their solubility in organic solvents. This is a mini-review of solubilizing complexing agents that are or can be used in pharmaceutical products.

New methods in the diagnosis of cancer and gene therapy of cancer based on nanoparticles

Cancer is one of the leading cause of death in the world with the prevalence of >10 million mortalities annually. Current cancer treatments include surgical intervention, radiation, and taking chemotherapeutic drugs, which often kill the healthy cells and result in toxicity in patients. Therefore, researchers are looking for ways to be able to eliminate just cancerous cells. Intra-tumor heterogeneity of cancerous cells is the main obstacle on the way of an effective cancer treatment. However, better comprehension of molecular basis of tumor and the advent of new diagnostic technologies can help to improve the treatment of various cancers. Therefore, study of epigenetic changes, gene expression of cancerous cells and employing methods that enable us to correct or minimize these changes is critically important. In this paper, we will review the recent advanced strategies being used in the field of cancer research.

Biodegradable double nanocapsule as a novel multifunctional carrier for drug delivery and cell imaging

Highly-efficient delivery of macromolecules into cells for both imaging and therapy (theranostics) remains a challenge for the design of a delivery system. Here, we suggested a novel hybrid protein-lipid polymer nanocapsule as an effective and nontoxic drug delivery and imaging carrier. The biodegradable nanocapsules showed the typical double emulsion features, including fluorescently labeled bovine serum albumin shell, oil phase containing poly(lactic-co-glycolic acid) and linoleic acid, and inner aqueous phase. The nanocapsules were spherical in shape, with an average size of about 180 nm. Proteins packed into the inner aqueous phase of the nanocapsules could be delivered into cells with high efficiency, and the fluorescence of the fluorescently labeled bovine serum albumin could be used for tracing the protein migration and cellular location. Further studies suggested that the co-delivery of transcription factor p53 and lipophilic drug paclitaxel with the nanocapsules acted synergistically to induce Hela cell apoptosis, and the fluorescence of apoptotic cells was clearly observed under a fluorescence microscope. Such multifunctional delivery system would have great potential applications in drug delivery and theranostic fields.

The effect of paclitaxel and nab-paclitaxel in combination with anti-angiogenic therapy in breast cancer cell lines

Taxanes represent a treatment of choice for metastatic breast cancer. Their combination with bevacizumab improved response rate and progression-free survival. We studied in vitro the effect on cell survival of the combination of either paclitaxel or nab-paclitaxel with bevacizumab and we investigated the biological factors involved in the response to treatments. We used two breast cancer cell lines, MCF7 (ER+/HER2-) and MDA-MB-231 (ER-/HER2-), co-cultured with or without HUVEC cells. We analysed cell survival by MTT test, VEGF secretion by ELISA and VEGFR, SPARC, MDR1 expression by western blot. Doses of both taxanes causing a 50 % growth inhibition were higher in MCF7 than MDA-MB-231, suggesting that taxanes are more effective in ER- cell lines. When both cell lines were grown as single culture, the combination bevacizumab+paclitaxel showed a similar anti-proliferative effect compared to paclitaxel alone. The association bevacizumab+nab-paclitaxel was more effective than nab-paclitaxel alone. An increased anti-proliferative effect of bevacizumab+paclitaxel was observed when MDA-MB-231 cells were cultured with HUVEC. We detected an induction of VEGF secretion when MDA-MB-231 cells were treated with either taxanes. Paclitaxel caused a reduction of VEGF in MCF7. SPARC resulted up-regulated in both cell lines treated with bevacizumab+nab-paclitaxel. Nab-paclitaxel seems to play an important role in inhibiting tumor proliferation through albumin-SPARC bound in association with bevacizumab compared to taxanes alone in both breast cancer cells. The addition of bevacizumab to paclitaxel increased its activity only in ER- cells. This difference might be due to their ER status.

Nanoparticle-based immunotherapy for cancer

The design of nanovaccines capable of triggering effective antitumor immunity requires an understanding of how the immune system senses and responds to threats, including pathogens and tumors. Equally important is an understanding of the mechanisms employed by tumor cells to evade immunity and an appreciation of the deleterious effects that antitumor immune responses can have on tumor growth, such as by skewing tumor cell composition toward immunologically silent tumor cell variants. The immune system and tumors engage in a tug-of-war driven by competition where promoting antitumor immunity or tumor cell death alone may be therapeutically insufficient. Nanotechnology affords a unique opportunity to develop therapeutic compounds than can simultaneously tackle both aspects, favoring tumor eradication. Here, we review the current status of nanoparticle-based immunotherapeutic strategies for the treatment of cancer, ranging from antigen/adjuvant delivery vehicles (to professional antigen-presenting cell types of the immune system) to direct tumor antigen-specific T-lymphocyte-targeting compounds and their combinations thereof.

Overview of nanoparticle albumin-bound paclitaxel in metastatic breast cancer

SUMMARY Breast cancer remains the most commonly diagnosed cancer in women in the USA and is estimated to be responsible for 14% of cancer-related deaths in 2012. Taxane chemotherapy agents are a mainstay of treatment for metastatic breast cancer, but unfortunately, significant toxicities can limit their use. Nanoparticle albumin-bound (nab)-paclitaxel is a formulation of paclitaxel that is bound to an albumin nanoparticle. This allows for improved solubility as well as higher plasma clearance and volume distribution without the hypersensitivity reactions and myelosuppression of standard Cremophor®-based paclitaxel. This article will review nanoparticle albumin-bound paclitaxel in the treatment of metastatic breast cancer.

Endocytosis of gene delivery vectors: from clathrin-dependent to lipid raft-mediated endocytosis

The ideal nonviral vector delivers its nucleic acid cargo to a specific intracellular target. Vectors enter cells mainly through endocytosis and are distributed to various intracellular organelles. Recent advances in microscopy, lipidomics, and proteomics confirm that the cell membrane is composed of clusters of lipids, organized in the form of lipid raft domains, together with non-raft domains that comprise a generally disordered lipid milieu. The binding of a nonviral vector to either region can determine the pathway for its endocytic uptake and subsequent intracellular itinerary. Given this model of the cell membrane structure, endocytic pathways should be reclassified in relation to lipid rafts. In this review, we attempt to assess the currently recognized endocytic pathways in mammalian cells. The endocytic pathways are classified in relation to the membrane regions that make up the primary endocytic vesicles. This review covers the well-recognized clathrin-mediated endocytosis (CME), phagocytosis, and macropinocytosis in addition to the less addressed pathways that take place in lipid rafts. These include caveolae-mediated, flotillin-dependent, GTPase regulator associated with focal adhesion kinase-1 (GRAF1)-dependent, adenosine diphosphate-ribosylation factor 6 (Arf6)-dependent, and RhoA-dependent endocytic pathways. We summarize the regulators associated with each uptake pathway and methods for interfering with these regulators are discussed. The fate of endocytic vesicles resulting from each endocytic uptake pathway is highlighted.

Overcoming the stromal barrier: technologies to optimize drug delivery in pancreatic cancer

Pancreatic cancer has historically proven resistant to anticancer agents. On the one hand, drugs might be more efficient if higher levels could be achieved at the tumor site rather than the normal tissues. On the other hand, the thick stroma and the relative absence of abundant vessels may account at least partially for the failure of successive clinical trials to demonstrate effective treatments in this type of malignancy. In this context, the development and testing in clinical trials of treatment strategies that aim to optimize drug delivery is an important target in improving the prognosis of patients with pancreatic cancer.

Nanoparticle-based biocompatible and targeted drug delivery: characterization and in vitro studies

Paclitaxel nanoparticles (PAX NPs) prepared with the size of 110 ± 10 nm and ζ potential of -40 ± 3 mV were encapsulated in synthetic/biomacromolecule shell chitosan, dextran-sulfate using a layer-by-layer self-assembly technique. Zeta potential measurements, analysis of X-ray photoelectron spectroscopy, and scanning electron microscopy confirmed the successful adsorption of each layer. Surface modifications of these core-shell NPs were performed by covalently conjugating with poly(ethylene glycol) (H(2)N-PEG-carboxymethyl, M(w) 3400) and fluorescence labeled wheat germ agglutinin (F-WGA) to build a biocompatible and targeted drug delivery system. 32% of PAX was released from four bilayers of biomacromolecule assembled NPs within 8 h as compared with >85% of the drug released from the bare NPs. Moreover, high cell viability with PEG conjugation and high binding capacity of WGA-modified NPs with Caco-2 cells were observed. This biocompatible and targeted NP-based drug delivery system, therefore, may be considered as a potential candidate for the treatment of colonic cancer and other diseases.

Overcoming in vivo barriers to targeted nanodelivery

Nanoparticles have been investigated as promising nanocarriers for delivery of imaging and therapeutic agents for several decades, but have met with limited success. Although enormous progress in the fields of nanotechnology and nanoscience has been achieved, basic discoveries have not yet translated into effective targeted therapies. Nanoparticles can potentially improve the pharmacokinetics and pharmacodynamics of drugs; however, the complexity of in vivo systems imposes multiple barriers that severely inhibit efficiency and have to be overcome to fully exploit the theoretical potential of nanoparticles. Here, we address two major challenges to effective systemic nanodelivery. Both limited penetration across the vascular endothelium and uptake by the reticuloendothelial system (RES) substantially impede effectiveness of nanoparticle delivery into tissues. Although the design of nanoparticles with extended circulation half-life is essential, it is not sufficient for effective penetration of nanoparticles across the formidable barrier formed by the vascular endothelium. Current nanodelivery systems rely on passive transvascular exchange and tissue accumulation. They require high dosages to create large concentration gradients that drive nanoparticles passively across the blood-tissue interface. However, passive accumulation has resulted in only a fractional dosage of nanoparticles penetrating into target tissue. This inevitably diminishes therapeutic efficacy and aggravates potential side effects. Although there are multiple ways to augment passive delivery, active delivery of targeted nanoparticles across the vascular endothelium could significantly increase the therapeutic index and decrease side effects of nanoparticle-based drug delivery systems. Use of active transendothelial transport pathways, such as caveolae, may provide an effective solution to both target and deliver nanoparticles.