A combination drug delivery system employing thermosensitive liposomes for enhanced cell penetration and improved in vitro efficacy

Liposomes for drug delivery: review of vesicular composition, factors affecting drug release and drug loading in liposomes

Liposomes are considered among the most versatile and advanced nanoparticle delivery systems used to target drugs to specific cells and tissues. Structurally, liposomes are sphere-like vesicles of phospholipid molecules that are surrounded by equal number of aqueous compartments. The spherical shell encapsulates an aqueous interior which contains substances such as peptides and proteins, hormones, enzymes, antibiotics, antifungal and anticancer agents. This structural property of liposomes makes it an important nano-carrier for drug delivery. Extrusion is one of the most frequently used technique for preparing monodisperse uni-lamellar liposomes as the technique is used to control vesicle size. The process involves passage of lipid suspension through polycarbonate membrane with a fixed pore size to produce vesicles with a diameter near the pore size of the membrane used in preparing them. An advantage of this technique is that there is no need to remove the organic solvent or detergent from the final preparation. This review focuses on composition of liposome formulation with special emphasis on factors affecting drug release and drug-loading.

Nanoparticle-based materials in anticancer drug delivery: Current and future prospects

The past decade has witnessed a breakthrough in novel strategies to treat cancer. One of the most common cancer treatment modalities is chemotherapy which involves administering anti-cancer drugs to the body. However, these drugs can lead to undesirable side effects on healthy cells. To overcome this challenge and improve cancer cell targeting, many novel nanocarriers have been developed to deliver drugs directly to the cancerous cells and minimize effects on the healthy tissues. The majority of the research studies conclude that using drugs encapsulated in nanocarriers is a much safer and more effective alternative than delivering the drug alone in its free form. This review provides a summary of the types of nanocarriers mainly studied for cancer drug delivery, namely: liposomes, polymeric micelles, dendrimers, magnetic nanoparticles, mesoporous nanoparticles, gold nanoparticles, carbon nanotubes and quantum dots. In this review, the synthesis, applications, advantages, disadvantages, and previous studies of these nanomaterials are discussed in detail. Furthermore, the future opportunities and possible challenges of translating these materials into clinical applications are also reported.

Smart stimuli-responsive drug delivery systems in spotlight of COVID-19

The world has been dealing with a novel severe acute respiratory syndrome (SARS-CoV-2) since the end of 2019, which threatens the lives of many people worldwide. COVID-19 causes respiratory infection with different symptoms, from sneezing and coughing to pneumonia and sometimes gastric symptoms. Researchers worldwide are actively developing novel drug delivery systems (DDSs), such as stimuli-responsive DDSs. The ability of these carriers to respond to external/internal and even multiple stimuli is essential in creating "smart" DDS that can effectively control dosage, sustained release, individual variations, and targeted delivery. To conduct a comprehensive literature survey for this article, the terms "Stimuli-responsive", "COVID-19″ and "Drug delivery" were searched on databases/search engines like "Google Scholar", "NCBI", "PubMed", and "Science Direct". Many different types of DDSs have been proposed, including those responsive to various exogenous (light, heat, ultrasound and magnetic field) or endogenous (microenvironmental changes in pH, ROS and enzymes) stimuli. Despite significant progress in DDS research, several challenging issues must be addressed to fill the gaps in the literature. Therefore, this study reviews the drug release mechanisms and applications of endogenous/exogenous stimuli-responsive DDSs while also exploring their potential with respect to COVID-19.

Carbon Dots-Biomembrane Interactions and Their Implications for Cellular Drug Delivery

The effect of carbon dots (CDs) on a model blayer membrane was studied as a means of comprehending their ability to affect cell membranes. Initially, the interaction of N-doped carbon dots with a biophysical liposomal cell membrane model was investigated by dynamic light scattering, z-potential, temperature-modulated differential scanning calorimetry, and membrane permeability. CDs with a slightly positive charge interacted with the surface of the negative-charged liposomes and evidence indicated that the association of CDs with the membrane affects the structural and thermodynamic properties of the bilayer; most importantly, it enhances the bilayer's permeability against doxorubicin, a well-known anticancer drug. The results, like those of similar studies that surveyed the interaction of proteins with lipid membranes, suggest that carbon dots are partially embedded in the bilayer. In vitro experiments employing breast cancer cell lines and human healthy dermal cells corroborated the findings, as it was shown that the presence of CDs in the culture medium selectively enhanced cell internalization of doxorubicin and, subsequently, increased its cytotoxicity, acting as a drug sensitizer.

Microfluidic fabricated bisdemethoxycurcumin thermosensitive liposome with enhanced antitumor effect

Bisdemethoxycurcumin (BDMC) is the main active ingredient that is isolated from Zingiberaceae plants, wherein it has excellent anti-tumor effects. However, insolubility in water limits its clinical application. Herein, we reported a microfluidic chip device that can load BDMC into the lipid bilayer to form BDMC thermosensitive liposome (BDMC TSL). The natural active ingredient glycyrrhizin was selected as the surfactant to improve solubility of BDMC. Particles of BDMC TSL had small size, homogenous size distribution, and enhanced cultimulative release in vitro. The anti-tumor effect of BDMC TSL on human hepatocellular carcinomas was investigated via 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method, live/dead staining, and flowcytometry. These results showed that the formulated liposome had a strong cancer cell inhibitory, and presented a dose-dependent inhibitory effect on migration. Further mechanistic studies showed that BDMC TSL combined with mild local hyperthermia could significantly upregulate B cell lymphoma 2 associated X protein levels and decrease B cell lymphoma 2 protein levels, thereby inducing cell apoptosis. The BDMC TSL that was fabricated via microfluidic device were decomposed under mild local hyperthermia, which could beneficially enhance the anti-tumor effect of raw insoluble materials and promote translation of liposome.

Stimuli-responsive liposomal nanoformulations in cancer therapy: Pre-clinical & clinical approaches

The site-specific delivery of antitumor agents is of importance for providing effective cancer suppression. Poor bioavailability of anticancer compounds and the presence of biological barriers prevent their accumulation in tumor sites. These obstacles can be overcome using liposomal nanostructures. The challenges in cancer chemotherapy and stimuli-responsive nanocarriers are first described in the current review. Then, stimuli-responsive liposomes including pH-, redox-, enzyme-, light-, thermo- and magneto-sensitive nanoparticles are discussed and their potential for delivery of anticancer drugs is emphasized. The pH- or redox-sensitive liposomes are based on internal stimulus and release drug in response to a mildly acidic pH and GSH, respectively. The pH-sensitive liposomes can mediate endosomal escape via proton sponge. The multifunctional liposomes responsive to both redox and pH have more capacity in drug release at tumor site compared to pH- or redox-sensitive alone. The magnetic field and NIR irradiation can be exploited for external stimulation of liposomes. The light-responsive liposomes release drugs when they are exposed to irradiation; thermosensitive-liposomes release drugs at a temperature of >40 °C when there is hyperthermia; magneto-responsive liposomes release drugs in presence of magnetic field. These smart nanoliposomes also mediate co-delivery of drugs and genes in synergistic cancer therapy. Due to lack of long-term toxicity of liposomes, they can be utilized in near future for treatment of cancer patients.

Enhanced Doxorubicin Delivery in Folate-Overexpressed Breast Cancer Cells Using Mesoporous Carbon Nanospheres

Nanoparticle-based drug delivery reveals the safety and effectiveness and avoids premature drug release from the nanocarrier. These nanoparticles improve the bioavailability and stability of the drug against chemical and enzymatic degradation and facilitate targeted drug delivery. Herein, targeted folic acid-conjugated oxidized mesoporous carbon nanospheres (Ox-MPCNPs) were successfully fabricated and developed as antitumoral doxorubicin delivery for targeted breast cancer therapy. Fourier transform infrared spectroscopy studies confirmed that the doxorubicin was successfully bound on the Ox-MPCNP through hydrogen bonding and π-π interactions. X-ray diffraction studies showed that the synthesized doxorubicin-loaded Ox-MPCNP is semi-crystalline. The surface morphology of the synthesized doxorubicin-loaded Ox-MPCNP (DOX/Ox-MPCNP-Cys-PAsp-FA) was studied by scanning electron microscopy and high-resolution transmission electron microscopy, which demonstrates a sphere-shaped morphology. The cytotoxic effects of DOX/Ox-MPCNP-Cys-PAsp-FA were studied in MCF-7 breast cancer cells using the CytoTox96 assay kit. The study confirmed the cytotoxic effects of the synthesized nanospheres in vitro. Moreover, DOX/Ox-MPCNP-Cys-PAsp-FA-treated cells displayed efficient cell apoptosis and cell death in flow cytometry analysis. The mitochondrial fragmentation and nucleus damages were further confirmed by fluorescence microscopy. Thus, the approach used to construct the DOX/Ox-MPCNP-Cys-PAsp-FA carrier provides excellent opportunities for the targeted treatment of breast cancer.

On-line dissolution analysis of multiple drugs encapsulated in electrospun nanofibers

Electrospun nanofiber is a very attractive material which can be used as the support to form multiple-drug dosage. Understanding the dissolution process of different active drug ingredients released from electrospun fibers is of great importance to control and evaluate the quality of medicated nanofibers. Here we present the first study of on-line automatic analysis of dissolution of multiple drugs in electrospun fiber mats. Single-needle electrospinning technology is utilized to combine polymers, hydrophilic polyvinylpyrrolidone (PVP) and hydrophobic polycaprolactone (PCL) as carrier to load three poorly water-soluble non-steroidal anti-inflammatory drugs (paracetamol, nimesulide, and ibuprofen). The loading of the drugs in PVP/PCL electrospun fibers are characterized by various techniques, including scanning electron microscopy, X-ray diffraction, Fourier infrared spectroscopy and differential scanning calorimetry. The in vitro dissolution is investigated by our home-made portable analyzer, which can simultaneously on-line determine multiple drugs released from the nanofibers by a single step. The analysis shows a wide linear detection range of the drugs with limit-of-detection (LOD) down to μg/mL-level. The dissolution profiles of three ingredients in nanofibers can be monitored every thirty seconds from the beginning to the end in the entire dissolution process from only one HSCE run. The kinetic information of the dissolution, including the dissolution curve, characteristic dissolution time and dissolution efficiency, is obtained and evaluated for different dissolution media, drug loading content and the ratio of PVP/PCL. Our study provides a promising method for rapid and accurate dissolution testing of nanofiber-based drugs, and would extend the applications of separation techniques in pharmaceutical analysis.