Site–Specific (Targeted) Drug Delivery in Cancer Therapy

Nanomaterial-enabled drug transport systems: a comprehensive exploration of current developments and future avenues in therapeutic delivery

Over the years, nanotechnology has gained popularity as a viable solution to address gene and drug delivery challenges over conventional methods. Extensive research has been conducted on nanosystems that consist of organic/inorganic materials, drugs, and its biocompatibility become the primary goal of improving drug delivery. Various surface modification methods help focus targeted and controlled drug release, further enabling multidrug delivery also. This newer technology ensures the stability of drugs that can unravel the mechanisms involved in cellular processes of disease development and its management. Tailored medication delivery provides benefits such as therapy, controlled release, and reduced adverse effects, which are especially important for controlling illnesses like cancer. However, multifunctional nanocarriers that possess high viscoelasticity, extended circulation half-life, biocompatibility, and biodegradability face some challenges and limitations too in human bodies. To produce a consistent therapeutic platform based on complex three-dimensional nanoparticles, careful design and engineering, thorough orthogonal analysis methods, and reproducible scale-up and manufacturing processes will be required in the future. Safety and effectiveness of nano-based drug delivery should be thoroughly investigated in preclinical and clinical trials, especially when considering biodistribution, targeting specific areas, and potential immunological toxicities. Overall, the current review article explores the advancements in nanotechnology, specific to nanomaterial-enabled drug delivery systems, carrier fabrication techniques and modifications, disease management, clinical research, applications, limitations, and future challenges. The work portrays how nanomedicine distribution affects healthcare with an emphasis on the developments in drug delivery techniques.

Selective delivery of imaging probes and therapeutics to the endoplasmic reticulum or Golgi apparatus: Current strategies and beyond

To maximize therapeutic effects and minimize unwanted effects, the interest in drug targeting to the endoplasmic reticulum (ER) or Golgi apparatus (GA) has been recently growing because two organelles are distributing hubs of cellular building/signaling components (e.g., proteins, lipids, Ca2+) to other organelles and the plasma membrane. Their structural or functional damages induce organelle stress (i.e., ER or GA stress), and their aggravation is strongly related to diseases (e.g., cancers, liver diseases, brain diseases). Many efforts have been developed to image (patho)physiological functions (e.g., oxidative stress, protein/lipid-related processing) and characteristics (e.g., pH, temperature, biothiols, reactive oxygen species) in the target organelles and to deliver drugs for organelle disruption using organelle-targeting moieties. Therefore, this review will overview the structure, (patho)physiological functions/characteristics, and related diseases of the organelles of interest. Future direction on ER or GA targeting will be discussed by understanding current strategies and investigations on targeting, imaging/sensing, and therapeutic systems.

Artificial protein coronas: directing nanoparticles to targets

The protein corona surrounding nanoparticles (NPs) offers exciting possibilities for targeted drug delivery. However, realizing this potential requires direct evidence of corona-receptor interactions in vivo; a challenge hampered by the limitations of in vitro settings. This opinion proposes that utilizing engineered protein coronas can address this challenge. Artificial coronas made of selected plasma proteins retain their properties in vivo, enabling manipulation for specific receptor targeting. To directly assess corona-receptor interactions mimicking in vivo complexity, we propose testing artificial coronas with recently adapted quartz crystal microbalance (QCM) setups whose current limitations and potential advancements are critically discussed. Finally, the opinion proposes future experiments to decipher corona-receptor interactions and unlock the full potential of the protein corona for NP-based drug delivery.

Locoregional drug delivery for cancer therapy: Preclinical progress and clinical translation

Systemic drug delivery is the current clinically preferred route for cancer therapy. However, challenges associated with tumor localization and off-tumor toxic effects limit the clinical effectiveness of this route. Locoregional drug delivery is an emerging viable alternative to systemic therapies. With the improvement in real-time imaging technologies and tools for direct access to tumor lesions, the clinical applicability of locoregional drug delivery is becoming more prominent. Theoretically, locoregional treatments can bypass challenges faced by systemic drug delivery. Preclinically, locoregional delivery of drugs has demonstrated enhanced therapeutic efficacy with limited off-target effects while still yielding an abscopal effect. Clinically, an array of locoregional strategies is under investigation for the delivery of drugs ranging in target and size. Locoregional tumor treatment strategies can be classified into two main categories: 1) direct drug infusion via injection or implanted port and 2) extended drug elution via injected or implanted depot. The number of studies investigating locoregional drug delivery strategies for cancer treatment is rising exponentially, in both preclinical and clinical settings, with some approaches approved for clinical use. Here, we highlight key preclinical advances and the clinical relevance of such locoregional delivery strategies in the treatment of cancer. Furthermore, we critically analyze 949 clinical trials involving locoregional drug delivery and discuss emerging trends.

Micro-nanoemulsion and nanoparticle-assisted drug delivery against drug-resistant tuberculosis: recent developments

Tuberculosis (TB) is a major global health problem and the second most prevalent infectious killer after COVID-19. It is caused by Mycobacterium tuberculosis (Mtb) and has become increasingly challenging to treat due to drug resistance. The World Health Organization declared TB a global health emergency in 1993. Drug resistance in TB is driven by mutations in the bacterial genome that can be influenced by prolonged drug exposure and poor patient adherence. The development of drug-resistant forms of TB, such as multidrug resistant, extensively drug resistant, and totally drug resistant, poses significant therapeutic challenges. Researchers are exploring new drugs and novel drug delivery systems, such as nanotechnology-based therapies, to combat drug resistance. Nanodrug delivery offers targeted and precise drug delivery, improves treatment efficacy, and reduces adverse effects. Along with nanoscale drug delivery, a new generation of antibiotics with potent therapeutic efficacy, drug repurposing, and new treatment regimens (combinations) that can tackle the problem of drug resistance in a shorter duration could be promising therapies in clinical settings. However, the clinical translation of nanomedicines faces challenges such as safety, large-scale production, regulatory frameworks, and intellectual property issues. In this review, we present the current status, most recent findings, challenges, and limiting barriers to the use of emulsions and nanoparticles against drug-resistant TB.

Cation-stimulated drug delivery via lipid assembly comprising macrocyclized disaccharides - A DFT study

In the attempt to create a delivery system for an alkali-cation stimulated drug release, a computational study was conducted, aiming for the evaluation of synthetic access towards glycolipid crown ethers analogs and their potential for coordination-induced changes of packing constraints for molecular assemblies. The results disfavor amide-linkages for the creation of macrocycles around the inter-glycosidic bond of a disaccharide. Conformational changes upon cation coordination of the macrocycle decrease the intersection area for easily accessible macrocycles based on lactose. This leads to shrinking intersection areas upon alkali complexation. Maltose-based analogs, on the other hand, exhibited the targeted increase of the glycolipid intersection area and, hence, may be considered as a promising resource.

Recent progress in tannic acid based approaches as a natural polyphenolic biomaterial for cancer therapy: A review

Significant advancements have been noticed in cancer therapy for decades. Despite this, there are still many critical challenges ahead, including multidrug resistance, drug instability, and side effects. To overcome obstacles of these problems, various types of materials in biomedical research have been explored. Chief among them, the applications of natural compounds have grown rapidly due to their superb biological activities. Natural compounds, especially polyphenolic compounds, play a positive and great role in cancer therapy. Tannic acid (TA), one of the most famous polyphenols, has attracted widespread attention in the field of cancer treatment with unique structural, physicochemical, pharmaceutical, anticancer, antiviral, antioxidant and other strong biological features. This review concentrated on the basic structure along with the important role of TA in tuning oncological signal pathways firstly, and then focused on the use of TA in chemotherapy and preparation of delivery systems including nanoparticles and hydrogels for cancer therapy. Besides, the application of TA/Fe3+ complex coating in photothermal therapy, chemodynamic therapy, combined therapy and theranostics is discussed.

Recent Advances in Polycaprolactones for Anticancer Drug Delivery

Poly(ε-Caprolactone)s are biodegradable and biocompatible polyesters that have gained considerable attention for drug delivery applications due to their slow degradation and ease of functionalization. One of the significant advantages of polycaprolactone is its ability to attach various functionalities to its backbone, which is commonly accomplished through ring-opening polymerization (ROP) of functionalized caprolactone monomer. In this review, we aim to summarize some of the most recent advances in polycaprolactones and their potential application in drug delivery. We will discuss different types of polycaprolactone-based drug delivery systems and their behavior in response to different stimuli, their ability to target specific locations, morphology, as well as their drug loading and release capabilities.

Pharmacokinetic variables of medium molecular weight cross linked chitosan nanoparticles to enhance the bioavailability of 5-fluorouracil and reduce the acute oral toxicity

To prepare glutaraldehyde-based cross-linked medium molecular weight chitosan nanoparticles encapsulated with 5-Fluorouracil (5-FU), to overcome dosing frequency as well as reducing acute oral toxicity and poor bioavailability of the drug. Medium molecular weight chitosan nanoparticles (MMWCH-NPs) were prepared by reverse micelles method based on glutaraldehyde (GA) cross-linking and optimized by the process as well as formulation variables like a various drug to polymer ratio, cross-linker volumes, varying stirring speeds (rpm), different time of rotation/stirring, respectively and their effects on the mean particles size distribution and entrapment efficiency %EE and %LC of NPs. Characterization of formulations was done by FTIR studies, TEM, PXRD, TGA, Stability, and dissolution drug release studies were performed by dialysis bag technique at both pH (1.2 & 7.4) and acute oral toxicity studies in albino rabbits. The formulated nanoparticles showed a smooth morphology with smaller particle size distribution (230-550 nm), zeta potential (-15 to -18 mV) required to achieve enhanced permeation and retention effect (EPR), entrapment efficiency (%EE 12-59%). These NPs exhibited a controlled drug release profile with 84.36% of the drug over a period of 24 h. Drug release data were fitted to different kinetic models which predominantly followed Fickian diffusion mechanism (R2 = 0.972-0.976, N = 0.326-0.256). The optimized formulation (5-FU6) was observed under DSC/TGA, TEM. PXRD curves, FTIR, which confirmed thermal stability, structural integrity, amorphous state, compatibility between drug and polymer of optimized (5-FU6) as well as reduced acute oral toxicity in albino rabbits. Cross-linked medium molecular weight chitosan nanoparticles are nontoxic, well-tolerated therefore could be the future candidate for therapeutic effects as novel drug delivery carrier for anticancer drug(s).

Surface-engineered liposomes for dual-drug delivery targeting strategy against Methicillin-resistant Staphylococcus aureus (MRSA)

This study focused on the encapsulation of vancomycin (VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine, formed by conjugation of DAPT and N-hydroxysuccinimidyl-polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphoethanolamine. This formulation is capable of providing controlled and targeted drug delivery to the bacterial cytoplasm. We performed MALDI-TOF, NMR and FTIR analyses to confirm the conjugation of the targeting ligand via the formation of amide bonds. Approximately 45% of VAN could be loaded into the aqueous cores, whereas 90% DAPT was detected using UV–vis spectrophotometry. In comparison to free drugs, the formulations controlled the release of drugs for > 72 h. Additionally, as demonstrated using CLSM and flow cytometry, the resulting formulation was capable of evading detection by macrophage cells. In comparison to free drugs, red blood cell membrane–DAPT–VAN liposomes, DAPT liposomes, and VAN liposomes reduced the MIC and significantly increased bacterial permeability, resulting in > 80% bacterial death within 4 h. Cytotoxicity tests were performed in vitro and in vivo on mammalian cells, in addition to hemolytic activity tests in human erythrocytes, wherein drugs loaded into the liposomes and RBCDVL exhibited low toxicity. Thus, the findings of this study provide insight about a dual antibiotic targeting strategy that utilizes liposomes and red blood cell membranes to deliver targeted drugs against MRSA.

Tumor-Specific Delivery of 5-Fluorouracil-Incorporated Epidermal Growth Factor Receptor-Targeted Aptamers as an Efficient Treatment in Pancreatic Ductal Adenocarcinoma Models

BACKGROUNDS & AIMS

Fluoropyrimidine c (5-fluorouracil [5FU]) increasingly represents the chemotherapeutic backbone for neoadjuvant, adjuvant, and palliative treatment of pancreatic ductal adenocarcinoma (PDAC). Even in combination with other agents, 5FU efficacy remains transient and limited. One explanation for the inadequate response is insufficient and nonspecific delivery of 5FU to the tumor.

METHODS

We designed, generated, and characterized 5FU-incorporated systematic evolution of ligands by exponential enrichment (SELEX)-selected epidermal growth factor receptor (EGFR)-targeted aptamers for tumor-specific delivery of 5FU to PDAC cells and tested their therapeutic efficacy in vitro and in vivo.

RESULTS

5FU-EGFR aptamers reduced proliferation in a concentration-dependent manner in mouse and human pancreatic cancer cell lines. Time-lapsed live imaging showed EGFR-specific uptake of aptamers via clathrin-dependent endocytosis. The 5FU-aptamer treatment was equally effective in 5FU-sensitive and 5FU-refractory PDAC cell lines. Biweekly treatment with 5FU-EGFR aptamers reduced tumor burden in a syngeneic orthotopic transplantation model of PDAC, in an autochthonously growing genetically engineered PDAC model (LSL-KrasG12D/+;LSL-Trp53flox/+;Ptf1a-Cre [KPC]), in an orthotopic cell line-derived xenograft model using human PDAC cells in athymic mice (CDX; Crl:NU-Foxn1nu), and in patient-derived organoids. Tumor growth was significantly attenuated during 5FU-EGFR aptamer treatment in the course of follow-up.

CONCLUSIONS

Tumor-specific targeted delivery of 5FU using EGFR aptamers as the carrier achieved high target specificity; overcame 5FU resistance; and proved to be effective in a syngeneic orthotopic transplantation model, in KPC mice, in a CDX model, and in patient-derived organoids and, therefore, represents a promising backbone for pancreatic cancer chemotherapy in patients. Furthermore, our approach has the potential to target virtually any cancer entity sensitive to 5FU treatment by incorporating 5FU into cancer cell-targeting aptamers as the delivery platform.

Anti-EGFR-mAb and 5-Fluorouracil Conjugated Polymeric Nanoparticles for Colorectal Cancer

BACKGROUND

Due to the higher intake of junk food and unhealthy lifestyle, the percentage of U.S. adults aged 50 to 75 years who were up-to-date with colorectal cancer screening increased 1.4 percentage points, from 67.4% in 2016 to 68.8% in 2018. This represents an additional 3.5 million adults screened for colorectal cancer. This is a severe concern of this research, and an attempt was made to prepare a target-specific formulation that could circumvent chemotherapy-related compilation and improvise higher cellular uptake. The fundamental agenda of this research was to prepare and develop Anti-EGFR mAb and 5-Fluorouracil (5-FU) fabricated polymeric nanoparticles for colorectal cancer.

OBJECTIVE

The main objective of this research was to prepare and evaluate more target specific formulation for the treatment of colorectal cancer. PLGA and PEG-based polymeric nanoparticles are capable of preventing opsonization via the reticuloendothelial system. Hence, prepared polymeric nanoparticles are capable of higher cellular uptake.

METHODS

The Poly(d,1-lactide-co-glycolide) (PLGA) and Polyethylene Glycol (PEG) were combined utilizing the ring-opening polymerization method. The presence of PEG prevents opsonization and distinguished blood concentration along with enhanced targeting. The presence of PLGA benefits in the sustained release of polymeric formulations. The optimized formulation (5-FU-PLGA- PEG-NP) was lyophilized using 4% trehalose (cryoprotectants) and conjugated with Anti- EGFR mAb on its surface to produce Anti-EGFR-5-FU-PLGA-PEG-NP; the final formulation, which increases target specificity and drug delivery system of nanoparticles.

RESULTS

The spherical shaped optimized formulation, 5-FU-PLGA-PEG-NP-3 was found to have higher percentage drug entrapment efficacy (71.23%), higher percentage drug content (1.98 ± 0.34%) with minimum particles size (252.3nm) and anionic zeta potential (-31.23mV). The IC₅₀ value of Anti-EGFR-5-FU-PLGA-PEG-NP was 1.01μg/mL after 48 hours incubation period in the HCT 116 cell line, indicating higher anticancer effects of the final formulation.

CONCLUSION

From the outcomes of various experiments, it was concluded that Anti-EGFR-5-FUPLGA- PEG-NP has biphasic drug release kinetics, higher cellular uptake and higher cytotoxicity. Therefore, anti-EGFR-5-FU-PLGA-PEG-NP holds excellent potential for drug delivery to EGFR positive colorectal cancer cells.

Ferrocifen Loaded Lipid Nanocapsules: A Promising Anticancer Medication against Multidrug Resistant Tumors

Resistance of cancer cells to current chemotherapeutic drugs has obliged the scientific community to seek innovative compounds. Ferrocifens, lipophilic organometallic compounds composed of a tamoxifen scaffold covalently bound to a ferrocene moiety, have shown very interesting antiproliferative, cytotoxic and immunologic effects. The formation of ferrocenyl quinone methide plays a crucial role in the multifaceted activity of ferrocifens. Lipid nanocapsules (LNCs), meanwhile, are nanoparticles obtained by a free organic solvent process. LNCs consist of an oily core surrounded by amphiphilic surfactants and are perfectly adapted to encapsulate these hydrophobic compounds. The different in vitro and in vivo experiments performed with this ferrocifen-loaded nanocarrier have revealed promising results in several multidrug-resistant cancer cell lines such as glioblastoma, breast cancer and metastatic melanoma, alone or in combination with other therapies. This review provides an exhaustive summary of the use of ferrocifen-loaded LNCs as a promising nanomedicine, outlining the ferrocifen mechanisms of action on cancer cells, the nanocarrier formulation process and the in vivo results obtained over the last two decades.

Enhanced Effect of Polyethyleneimine-Modified Graphene Oxide and Simvastatin on Osteogenic Differentiation of Murine Bone Marrow-Derived Mesenchymal Stem Cells

Statin derivatives traditionally have been used for the treatment of hyperlipidemia, but recent studies have shown their ability to regulate bone metabolism and promote bone growth. In this study, simvastatin (Sim), a new therapeutic candidate for bone regeneration, was combined with graphene oxide (GO), which has recently attracted much interest as a drug delivery method, to produce a compound substance effective for bone regeneration. To create a stable and homogenous complex with Sim, GO was modified with polyethylenimine, and the effect of modification was analyzed using Fourier transform infrared spectroscopy, zeta potential, and cytotoxicity testing. More specifically, the osteogenic differentiation potential expected by the combination of the two effective materials for osteogenic differentiation, GO and Sim, was evaluated in mesenchymal stem cells. Compared with control groups with GO and Sim used separately, the GO/Sim complex showed excellent osteogenic differentiation properties, with especially enhanced effects in the complex containing < 1 μM Sim.

Functionalized graphene oxide as a vehicle for targeted drug delivery and bioimaging applications

Graphene oxide (GO) has attracted tremendous attention as a most promising nanomaterial among the carbon family since it emerged as a polynomial functional tool with rational applications in diverse fields such as biomedical engineering, electrocatalysis, biosensing, energy conversion, and storage devices. Despite having certain limitations due to its irreversible aggregation performance owing largely to the strong van der Waals interactions, efforts have been made to smartly engineer its surface chemistry for realistic multimodal applications. The use of such GO-based engineered devices has increased rapidly in the last few years, principally due to its excellent properties, such as huge surface area, honeycomb-like structure allowing vacant interstitial space to accommodate compounds, sp2 hybridized carbon, improved biocompatibility and cell surface penetration due to electronic interactions. Amongst multifaceted GO dynamics, in this review, attempts are made to discuss the advanced applications of GO or graphene-based materials (GBNs) in the biomedical field involving drug or therapeutic gene delivery, dual drug or drug-gene combination targeting, special delivery of drug cocktails to the brain, stimuli-responsive release of molecular payloads, and Janus-structured smart applications for polar-nonpolar combination drug loading followed by targeting together with smart bioimaging approaches. In addition, the advantages of duel-drug delivery systems are discussed in detail. We also discuss various electronic mechanisms, and detailed surface engineering to meet microcosmic criteria for its utilization, various novel implementations of engineered GO as mentioned above, together with discussions of its inevitable toxicity or disadvantages. We hope that the target audience, belonging to biomedical engineering, pharmaceutical or material science fields, may acquire relevant information from this review which may help them design future studies in this field.

Boron nitride nanotubes as containers for targeted drug delivery of doxorubicin

Using molecular dynamics simulations, the adsorption and diffusion of doxorubicin drug molecules in boron nitride nanotubes are investigated. The interaction between doxorubicin and the nanotube is governed by van der Waals attraction. We find strong adsorption of doxorubicin to the wall for narrow nanotubes (radius of 9 Å). For larger radii (12 and 15 Å), the adsorption energy decreases, while the diffusion coefficient of doxorubicin increases. It does, however, not reach the values of pure water, as adsorption events still hinder the doxorubicin mobility. It is concluded that nanotubes wider than around 4 nm diameter can serve as efficient drug containers for targeted drug delivery of doxorubicin in cancer chemotherapy.

Stopped-flow chemiluminescence determination of the anticancer drug capecitabine: Application in pharmaceutical analysis and drug-delivery systems

Capecitabine is a chemotherapeutic agent used for the treatment of patients with metastatic cancers. This study aimed at determining the drug capecitabine in a simple chemiluminescence (CL) system of acidic potassium permanganate using the stopped-flow injection technique. Statistical methods were used to detect optimum conditions. The method showed two linear calibration ranges from 6.7 × 10^-6 to 6.7 × 10^-5 mol L^-1 and from 6.7 × 10^-5 to 2.7 × 10^-3 mol L^-1 with a detection limit of 1.5 × 10^-6 mol L^-1 . Chitosan-modified magnetic nanoparticles were studied in the drug-delivery experiments. According to the pH sensitivity of chitosan and low pH values in tumour cells, the chitosan-coated magnetic nanoparticles could provide a good targeting drug-delivery system to tumour sites. To evaluate the applicability of the method, the capecitabine-loaded magnetic chitosan nanoparticles were synthesized with two different cross-linkers; loading and releasing rates of the drug were investigated using the proposed CL method and an ultraviolet-visible light spectrophotometric method (absorption at 305 nm). The results showed a good correlation between the two methods, and it was found that the synthesized chitosan-modified magnetic nanoparticles could be used for pH-dependent release of capecitabine in cancer cells. Moreover, determination of capecitabine in tablets and synthetic samples was performed.

Targeted delivery and apoptosis induction of trans-resveratrol-ferulic acid loaded chitosan coated folic acid conjugate solid lipid nanoparticles in colon cancer cells

The present study is aimed to study and to evaluate the colon cancer targeting efficacy of chitosan-coated-trans-resveratrol (RSV) and ferulic acid (FER) loaded SLNs (solid lipid nanoparticles) that conjugated with folic acid (FA) (C-RSV-FER-FA-SLNs) in suitable models (in vitro). The FA conjugation is performed using co-encapsulation method of stearic acid. Similarly, the prepared SLNs are exhibited better stability even under acidic conditions to exhibit their potentials to use as drug delivery system. Further, the optimized formulations (SLNs) are tested for physiochemical characterizations, which include FTIR, XRD, ¹HNMR, particle size, zeta potential, and drug release. In vitro anti-cancer studies using HT-29 cells including, fluorescence staining, flow cytometry, and western blot analysis revealed that the C-RSV-FER-FA-SLNs effectively involved and increased cytotoxicity in cancer cells that leads to induction of apoptosis as compared to free RSV-FER. Thus, it is reported that, the good stability under acidic conditions of this C-RSV-FER-FA-SLNs may serve as a promising candidate for novel nanodrug formulations in cancer therapy.

Adsorption and Diffusion of Cisplatin Molecules in Nanoporous Materials: A Molecular Dynamics Study

Using molecular dynamics simulations, the adsorption and diffusion of cisplatin drug molecules in nanopores is investigated for several inorganic materials. Three different materials are studied with widely-varying properties: metallic gold, covalent silicon, and silica. We found a strong influence of both the van der Waals and the electrostatic interaction on the adsorption behavior on the pore walls, which in turn influence the diffusion coefficients. While van der Waals forces generally lead to a reduction of the diffusion coefficient, the fluctuations in the electrostatic energy induced by orientation changes of the cisplatin molecule were found to help desorb the molecule from the wall.

Potential applications of engineered nanoparticles in medicine and biology: an update

Nanotechnology advancements have led to the development of its allied fields, such as nanoparticle synthesis and their applications in the field of biomedicine. Nanotechnology driven innovations have given a hope to the patients as well as physicians in solving the complex medical problems. Nanoparticles with a size ranging from 0.2 to 100 nm are associated with an increased surface to volume ratio. Moreover, the physico-chemical and biological properties of nanoparticles can be modified depending on the applications. Different nanoparticles have been documented with a wide range of applications in various fields of medicine and biology including cancer therapy, drug delivery, tissue engineering, regenerative medicine, biomolecules detection, and also as antimicrobial agents. However, the development of stable and effective nanoparticles requires a profound knowledge on both physico-chemical features of nanomaterials and their intended applications. Further, the health risks associated with the use of engineered nanoparticles needs a serious attention.

Nanosuspensions in Nanobiomedicine

The tremendous success in developing new nanomaterials and fostering technological innovation arises from the focus on interdisciplinary research and collaboration between physical and medical scientists. The concept of nano-medicine is one of the most important and exciting ideas ever generated by the applications of nanoscience. One of the most challenging tasks in the pharmaceutical industry is the formulation of poorly soluble drugs. The implication of conventional techniques for improving the solubility has gained limited success. Nanoparticles facilitate formulation with improved solubility and efficacy mainly through nanosuspension approach. Techniques such as media milling, high-pressure homogenization, and use of microemulsion have been used for production of nanosuspensions for a novel delivery system. Moreover, they are manoeuvred to patient-acceptable dosage forms like tablets, capsules, and lyophilized powder products. Nanosuspension technology has also been studied for active and passive targeted drug delivery systems, which the chapter highlights on various formulational perspectives and applications as a biomedicine delivery system.

Review: Advances in Intraperitoneal (Intracavitary) Administration of Synthetic Polymers for Immunotherapy and Chemotherapy

Intraperitoneal (IP) catheters linked to subcutaneous portals have made routine intracavitary chemotherapy or immunotherapy safe and convenient. The IP route is anatomically appropriate for adjuvant or palliative treatment of intracavitary disease. IP chemotherapy has been successfully applied to ovarian, mesothelial, and gastrointestinal tumors.

Data shows that IP divinyl ether/maleic anhydride copolymer. MVE-2 (MW 15,000), has distinct localizing and toxicologic differences from that given intravenously (IV). When MVE-2 is given IV renal injury is observed; this is not seen on IP administration. The highest IP concentrations are found in mediastinal and mesenteric nodes, thymus and testis while the highest IV MVE-2 accumulation is found in the liver, spleen, adrenal, and kidney.

The IP route for treatment of tumors allows for high local tumoricidal drug concentrations or for regionalized immunostimulation with activating polymers or leukokines. The IP space can provide an antitumor, and antiviral immunizing site and/or a source of activated antitumor peritoneal exudate cells. The use of IP chemotherapy readily permits systemic neutralization of drug toxicity and can provide high portal venous concentrations of drug for the treatment of early liver metastasis.

This review speaks to the convenience and safety of the IP intracavitary route which provides a new option for the clinical utilization of polymers where regionalized abdominal effects and improved therapeutic index are warranted. The biologic application of IP polymers requires polymer distribution and kinetic studies which will provide unique tissue concentrations for application to immunization, cancer treatment and other diseases.

Experimental and simulation studies on focused ultrasound triggered drug delivery

To improve drug delivery efficiency in cancer therapy, many researchers have recently concentrated on drug delivery systems that use anticancer drug loaded micro- or nanoparticles. In addition, induction methods, such as ultrasound, magnetic field, and infrared light, have been considered as active induction methods for drug delivery. Among these, focused ultrasound has been regarded as a promising candidate for the active induction method of drug delivery system because it can penetrate a deep site in soft tissue, and its energy can be focused on the targeted lesion. In this research, we employed focused ultrasound as an active induction method. For an anticancer drug loaded microparticles, we fabricated poly-lactic-co-glycolic acid docetaxel (PLGA-DTX) nanoparticle encapsulated alginate microbeads using the single-emulsion technique and the aeration method. To select the appropriate operating parameter for the focused ultrasound, we measured the pressure and temperature induced by the focused ultrasound at the focal area using a needle-type hydrophone and a digital thermal detector, respectively. Additionally, we conducted a simulation of focused ultrasound using COMSOL Multiphysics 4.3a. The experimental measurement results were compared with the simulation results. In addition, the drug release rates of the PLGA-DTX-encapsulated alginate microbeads induced by the focused ultrasound were tested. Through these experiments, we determined that the appropriate focused ultrasound parameter was peak pressure of 1 MPa, 10 cycle/burst, and burst period of 20 μSec. Finally, we performed the cell cytotoxicity and drug uptake test with focused ultrasound induction and found that the antitumor effect and drug uptake efficiency were significantly enhanced by the focused ultrasound induction. Thus, we confirmed that focused ultrasound can be an effective induction method for an anticancer drug delivery system.

In situ crosslinked smart polypeptide nanoparticles for multistage responsive tumor-targeted drug delivery

Smart tumor-targeted drug delivery is crucial for improving the effect of chemotherapy and reducing the adverse effects. Here, we synthesized a smart polypeptide copolymer based on n-butylamine-poly(L-lysine)-b-poly(L-cysteine) (PLL-PLC) with functionalization of folic acid (FA) and 1,2-dicarboxylic-cyclohexene anhydride (DCA) for multistage responsive tumor-targeted drug delivery. The copolymers (FA-PLL(DCA)-PLC) spontaneously crosslinked in situ to form redox and pH dual responsive FA-PLL(DCA)-PLC nanoparticles (FD-NPs), which had a reversible zeta potential around -30 mV at pH 7.4, but switched to +15 mV at pH 5.0. Moreover, FD-NPs effectively loaded DOX with a loading capacity at 15.7 wt%. At pH 7.4, only 24.5% DOX was released within 60 h. However, at pH 5.0, the presence of 10 mM DTT dramatically accelerated DOX release with over 90% of DOX released within 10 h. Although the FD-NPs only enhanced DOX uptake in FA receptor positive (FR(+)) cancer cells at pH 7.4, a weak acidic condition promoted FD-NP-facilitated DOX uptake in both FR(+) HeLa and FR(-) A549 cells, as well as significantly improving cellular binding and end/lysosomal escape. In vivo studies in a HeLa cancer model demonstrated that the charge-reversible FD-NPs delivered DOX into tumors more effectively than charge-irreversible nanoparticles. Hence, these multistage responsive FD-NPs would serve as highly efficient drug vectors for targeted cancer chemotherapy.

Design of Nanoparticle-Based Carriers for Targeted Drug Delivery

Nanoparticles have shown promise as both drug delivery vehicles and direct antitumor systems, but they must be properly designed in order to maximize efficacy. Computational modeling is often used both to design new nanoparticles and to better understand existing ones. Modeled processes include the release of drugs at the tumor site and the physical interaction between the nanoparticle and cancer cells. In this article, we provide an overview of three different targeted drug delivery methods (passive targeting, active targeting and physical targeting), compare methods of action, advantages, limitations, and the current stage of research. For the most commonly used nanoparticle carriers, fabrication methods are also reviewed. This is followed by a review of computational simulations and models on nanoparticle-based drug delivery.

Aptamer CaCO3 nanostructures: a facile, pH-responsive, specific platform for targeted anticancer theranostics

The application of cancer theranostics depends on the development of multifunctional nanostructured platforms for accurate cell targeting and controlled drug release, imaging, and therapy. Herein, a comprehensive, easily fabricated anticancer theranostic platform with a high drug-loading capacity, termed an aptamer-functionalized calcium carbonate (CaCO3 ) nanostructure (apt-CCN), is reported. Flow cytometry and confocal fluorescence microscopy studies demonstrate that apt-CCNs can specifically bind to target cancer cells, but not to control cells, and that they possess highly efficient internalization to target cancer cells. This smart nanostructure selectively reaches the lysosomes through receptor-mediated endocytosis and is responsive to the relatively low lysosome pH (4.5-5.5), which facilitates the release of doxorubicin. The apt-CCN platform offers targeted and efficient drug transport, as well as target-specific delivery of imaging agents for cancer diagnosis and therapy.

Physical energy for drug delivery; poration, concentration and activation

Techniques for controlling the rate and duration of drug delivery, while targeting specific locations of the body for treatment, to deliver the cargo (drugs or DNA) to particular parts of the body by what are becoming called "smart drug carriers" have gained increased attention during recent years. Using such smart carriers, researchers have also been investigating a number of physical energy forces including: magnetic fields, ultrasound, electric fields, temperature gradients, photoactivation or photorelease mechanisms, and mechanical forces to enhance drug delivery within the targeted cells or tissues and also to activate the drugs using a similar or a different type of external trigger. This review aims to cover a number of such physical energy modalities. Various advanced techniques such as magnetoporation, electroporation, iontophoresis, sonoporation/mechnoporation, phonophoresis, optoporation and thermoporation will be covered in the review. Special emphasis will be placed on photodynamic therapy owing to the experience of the authors' laboratory in this area, but other types of drug cargo and DNA vectors will also be covered. Photothermal therapy and theranostics will also be discussed.

Smart multifunctional nanostructure for targeted cancer chemotherapy and magnetic resonance imaging

Targeted chemotherapy and magnetic resonance imaging of cancer cells in vitro has been achieved using a smart multifunctional nanostructure (SMN) constructed from a porous hollow magnetite nanoparticle (PHMNP), a heterobifunctional PEG ligand, and an aptamer. The PHMNPs were prepared through a three-step reaction and loaded with the anticancer drug doxorubicin while being functionalized with PEG ligands. Targeting aptamers were then introduced by reaction with the PEG ligands. The pores of the PHMNPs are stable at physiological pH, but they are subject to acid etching. Specific binding and uptake of the SMN to the target cancer cells induced by aptamers was observed. In addition, multiple aptamers on the surface of one single SMN led to enhanced binding and uptake to target cancer cells due to the multivalent effect. Upon reaching the lysosomes of target cancer cells through receptor-mediated endocytosis, the relatively low lysosomal pH level resulted in corrosion of the PHMNP pores, facilitating the release of doxorubicin to kill the target cancer cells. In addition, the potential of using SMN for magnetic resonance imaging was also investigated.

Multimodal image-guided photothermal therapy mediated by 188Re-labeled micelles containing a cyanine-type photosensitizer

Multifunctional micelles loaded with the near-infrared (NIR) dye and labeled with the radionuclide rhenium-188 ((188)Re) have been developed to provide multimodalities for NIR fluorescence and nuclear imaging and for photothermal therapy (PTT) of cancer. The NIR dye, IR-780 iodide, allowed the micelles to have dual functions in cancer NIR imaging and PTT. The (188)Re-labeled IR-780 micelles enabled imaging by NIR fluorescence and by microSPECT to guide the delivery of drugs and to monitor in real-time the tumor accumulation, intratumoral distribution, and kinetics of drug release, which serve as a basis of specific photothermal injury to the targeted tissue. We also investigated the biodistribution, generation of heat, and photothermal cancer ablation of IR-780 micelles of both in vitro and in vivo xenografts. Histopathology observed irreversible tissue damage, such as necrotic features, decreased cell proliferation, increased apoptosis of cells, and increased expression of heat shock proteins in the PTT-treated tumors. The (188)Re-labeled IR-780 micelles offer multifunctional modalities for NIR fluorescence and nuclear imaging and for PTT of cancer.

Targeted delivery of low molecular drugs using chitosan and its derivatives

Chitosan has prompted the continuous impetus for the development of safe and effective drug delivery systems because of its unique physicochemical and biological characteristics. The primary hydroxyl and amine groups located on the backbone of chitosan allow for chemical modification to control its physical properties. When the hydrophobic moiety is conjugated to a chitosan molecule, the resulting amphiphile may form self-assembled nanoparticles that can encapsulate a quantity of drugs and deliver them to a specific site of action. Chemical attachment of the drug to the chitosan throughout the functional linker may produce useful prodrugs, exhibiting the appropriate biological activity at the target site. Mucoadhesive and absorption enhancement properties of chitosan increase the in vivo residence time of the dosage form in the gastrointestinal tract and improve the bioavailability of various drugs. The main objective of this review is to provide an insight into various target-specific carriers, based on chitosan and its derivatives, towards low molecular weight drug delivery. The first part of the review is concerned with the organ-specific delivery of low molecular drugs using chitosan and its derivatives. The subsequent section considers the recent developments of drug delivery carriers for cancer therapy with special focus on various targeting strategies.

Ligand-based targeted therapy for cancer tissue

BACKGROUND

Limited accessibility of drugs to the tumor tissues, the requirement of high doses, intolerable cytotoxicity, the development of multiple drug resistance and non-specific targeting are obstacles to the clinical use of cancer drugs and cancer therapy.

OBJECTIVE

Drug delivery through carrier systems to cancerous tissue is no longer simply wrapping up cancer drugs in a new formulation for different routes of delivery, rather the focus is on targeted cancer therapy.

METHODS

This review summarizes the exploitation of drug-loaded nanocarrier conjugates with various targeting moieties for the delivery and targeting of anticancer drugs and describes the current status of and challenges in the field of nanocarrier-aided drug delivery and drug targeting.

CONCLUSION

The discovery of targeting ligand to cancer cells and the development of ligand-targeted therapy will help us to improve therapeutic efficacy and reduce side effects. Unlike other forms of therapy, it will allow us to maintain quality of life for patients, while efficiently attacking the cancer tissue. It indicates that ligands have a pivotal role in cancer cell targeting.

Drug Nanoparticles: Formulating Poorly Water-Soluble Compounds

More than 40% of compounds identified through combinatorial screening programs are poorly soluble in water. These molecules are difficult to formulate using conventional approaches and are associated with innumerable formulation-related performance issues. Formulating these compounds as pure drug nanoparticles is one of the newer drug-delivery strategies applied to this class of molecules. Nanoparticle dispersions are stable and have a mean diameter of less than 1 micron. The formulations consist of water, drug, and one or more generally regarded as safe excipients. These liquid dispersions exhibit an acceptable shelf-life and can be postprocessed into various types of solid dosage forms. Drug nanoparticles have been shown to improve bioavailability and enhance drug exposure for oral and parenteral dosage forms. Suitable formulations for the most commonly used routes of administration can be identified with milligram quantities of drug substance, providing the discovery scientist with an alternate avenue for screening and identifying superior analogs. For the toxicologist, the approach provides a means for dose escalation using a formulation that is commercially viable. In the past few years, formulating poorly water-soluble compounds using a nanoparticulate approach has evolved from a conception to a realization whose versatility and applicability are just beginning to be realized.

Particle shape: a new design parameter for micro- and nanoscale drug delivery carriers

Encapsulation of therapeutic agents in polymer particles has been successfully used in the development of new drug carriers. A number of design parameters that govern the functional behavior of carriers, including the choice of polymer, particle size and surface chemistry, have been tuned to optimize their performance in vivo. However, particle shape, which may also have a strong impact on carrier performance, has not been thoroughly investigated. This is perhaps due to the limited availability of techniques to produce non-spherical polymer particles. In recent years, a number of reports have emerged to directly address this bottleneck and initial studies have indeed confirmed that particle shape can significantly impact the performance of polymer drug carriers. This article provides a review of this field with respect to methods of particle preparation and the role of particle shape in drug delivery.