In vitro uptake and transport studies of PEG-PLGA polymeric micelles in respiratory epithelial cells

Recent progress in stimuli-responsive polymeric micelles for targeted delivery of functional nanoparticles

Stimuli-responsive polymeric micelles have emerged as a revolutionary approach for enhancing the in vivo stability, biocompatibility, and targeted delivery of functional nanoparticles (FNPs) in biomedicine. This article comprehensively reviews the preparation methods of these polymer micelles, detailing the innovative strategies employed to introduce stimulus responsiveness and surface modifications essential for precise targeting. We delve into the breakthroughs in utilizing these micelles to selectively deliver various FNPs including magnetic nanoparticles, upconversion nanoparticles, gold nanoparticles, and quantum dots, highlighting their transformative impact in the biomedical realm. Concluding, we present an insight into the current research landscape, addressing the challenges at hand, and envisioning the future trajectory in this burgeoning domain. Join us as we navigate the exciting confluence of polymer science and nanotechnology in reshaping biomedical solutions.

Evaluation of Brain Targeting and Antipsychotic Activity of Nasally Administrated Ziprasidone Lipid-Polymer Hybrid Nanocarriers

The feasibility of using lipid-polymer hybrid (LPH) nanocarriers as a potential platform for the intranasal delivery of ziprasidone (ZP), a second-generation antipsychotic, was explored. Different ZP-loaded LPH composed of a PLGA core and cholesterol-lecithin lipid coat were prepared using a single step nano-precipitation self-assembly technique. Modulation of polymer, lipid and drug amounts, as well as stirring-speed-optimized LPH with a particle size of 97.56 ± 4.55 nm and a ZP entrapment efficiency (EE%) of 97.98 ± 1.22%. The brain deposition and pharmacokinetics studies proved the efficiency of LPH to traverse the blood-brain barrier (BBB) following intranasal delivery with a 3.9-fold increase in targeting efficiency compared to the intravenous (IV) ZP solution with a direct nose-to-brain transport percentage (DTP) of 74.68%. The ZP-LPH showed enhanced antipsychotic activity in terms of animals' hypermobility over an IV drug solution in schizophrenic rats. The obtained results showed that the fabricated LPH was able to improve ZP brain uptake and proved its antipsychotic efficiency.

Transcellular Transport Behavior of the Intact Polymeric Mixed Micelles with Different Polymeric Ratios

In order to better promote the application of the polymeric mixed micelles (PMMs) in oral delivery, in addition to focusing on the improvement of micellar structural stability, it is necessary to obtain the absorption characteristics of the intact micellar particles. In this work, the transport behavior across Caco-2 cells of FS/PMMs composed of Pluronic F127 and Solutol HS15 was tracked by encapsulating an environment-responsive probe into the particles. The specific property of the probe is the water-initiated aggregation-caused quenching (ACQ) ability, by which integral particles can be identified accurately. The influence of polymeric ratios (FS) on the transcellular behavior of FS/PMMs was explored and the single pass intestinal perfusion experiment was used to further illustrate it. Moreover, pharmacokinetics parameters were detected to analyze the relationship among FS ratios, transport behavior, and pharmacokinetic parameters. FS ratios were found to hardly affect the endocytosis pathways and intracellular itinerary of FS/PMMs, but do affect the proportion of each path. FS/PMMs with high HS15 content, namely System-I, were found to primarily undergo receptor-mediated endocytosis pathway and be less susceptible to lysosomal degradation, which would lead to more absorption and higher Cmax and AUC than drug suspension. In contrast, despite System-II with high F127 content cannot contribute to drug plasma concentration, it can prolong the in vivo retention time. These findings provided evidence for the role of polymeric ratios in modulating the transcellular absorption and pharmacokinetic parameters of the drug-loaded PMMs, and would be a step forward in helping PMMs' design to enhance oral drug delivery.

Nanostructures for drug delivery in respiratory diseases therapeutics: Revision of current trends and its comparative analysis

Respiratory diseases are leading causes of death and disability in developing and developed countries. The burden of acute and chronic respiratory diseases has been rising throughout the world and represents a major problem in the public health system. Acute respiratory diseases include pneumonia, influenza, SARS-CoV-2 and MERS viral infections; while chronic obstructive pulmonary disease (COPD), asthma and, occupational lung diseases (asbestosis, pneumoconiosis) and other parenchymal lung diseases namely lung cancer and tuberculosis are examples of chronic respiratory diseases. Importantly, chronic respiratory diseases are not curable and treatments for acute pathologies are particularly challenging. For that reason, the integration of nanotechnology to existing drugs or for the development of new treatments potentially benefits the therapeutic goals by making drugs more effective and exhibit fewer undesirable side effects to treat these conditions. Moreover, the integration of different nanostructures enables improvement of drug bioavailability, transport and delivery compared to stand-alone drugs in traditional respiratory therapy. Notably, there has been great progress in translating nanotechnology-based cancer therapies and diagnostics into the clinic; however, researchers in recent years have focused on the application of nanostructures in other relevant pulmonary diseases as revealed in our database search. Furthermore, polymeric nanoparticles and micelles are the most studied nanostructures in a wide range of diseases; however, liposomal nanostructures are recognized to be some of the most successful commercial drug delivery systems. In conclusion, this review presents an overview of the recent and relevant research in drug delivery systems for the treatment of different pulmonary diseases and outlines the trends, limitations, importance and application of nanomedicine technology in treatment and diagnosis and future work in this field.

Utilization of Polymeric Micelles as a Lucrative Platform for Efficient Brain Deposition of Olanzapine as an Antischizophrenic Drug via Intranasal Delivery

Schizophrenia is a mental disorder characterized by alterations in cognition, behavior and emotions. Oral olanzapine (OZ) administration is extensively metabolized (~up to 40% of the administrated dose). In addition, OZ is a P-glycoproteins substrate that impairs the blood–brain barrier (BBB) permeability. To direct OZ to the brain and to minimize its systemic side effects, the nasal pathway is recommended. OZ-loaded polymeric micelles nano-carriers were developed using suitable biodegradable excipients. The developed micelles were physicochemically investigated to assess their appropriateness for intranasal delivery and the potential of these carriers for OZ brain targeting. The selected formula will be examined in vivo for improving the anti-schizophrenic effects on a schizophrenia rat model. The binary mixture of P123/P407 has a low CMC (0.001326% w/v), which helps in maintaining the formed micelles’ stability upon dilution. The combination effect of P123, P407 and TPGS led to a decrease in micelle size, ranging between 37.5–47.55 nm and an increase in the EE% (ranging between 68.22–86.84%). The selected OZ–PM shows great stability expressed by a suitable negative charge zeta potential value (−15.11 ± 1.35 mV) and scattered non-aggregated spherical particles with a particle size range of 30–40 nm. OZ–PM maintains sustained drug release at the application site with no nasal cytotoxicity. In vivo administration of the selected OZ–PM formula reveals improved CNS targeting and anti-schizophrenia-related deficits after OZ nasal administration. Therefore, OZ–PM provided safe direct nose-to-brain transport of OZ after nasal administration with an efficient anti-schizophrenic effect.

In vitro and ex vivo models in inhalation biopharmaceutical research - advances, challenges and future perspectives

Oral inhalation results in pulmonary drug targeting and thereby reduces systemic side effects, making it the preferred means of drug delivery for the treatment of respiratory disorders such as asthma, chronic obstructive pulmonary disease or cystic fibrosis. In addition, the high alveolar surface area, relatively low enzymatic activity and rich blood supply of the distal airspaces offer a promising pathway to the systemic circulation. This is particularly advantageous when a rapid onset of pharmacological action is desired or when the drug is suffering from stability issues or poor biopharmaceutical performance following oral administration. Several cell and tissue-based in vitro and ex vivo models have been developed over the years, with the intention to realistically mimic pulmonary biological barriers. It is the aim of this review to critically discuss the available models regarding their advantages and limitations and to elaborate further which biopharmaceutical questions can and cannot be answered using the existing models.

Development of D-melittin polymeric nanoparticles for anti-cancer treatment

Melittin, the primary peptide component of bee venom, is a potent cytolytic anti-cancer peptide with established anti-tumor activity. However, practical application of melittin in oncology is hampered by its strong, nonspecific hemolytic activity and intrinsic instability. To address these shortcomings, delivery systems are used to overcome the drawbacks of melittin and facilitate its safe delivery. Yet, a recent study revealed that encapsulated melittin remains immunogenic and can act as an adjuvant to elicit a fatal antibody immune response against the delivery carrier. We discovered that substitution of l-amino acids with d-amino acids mitigates this problem: D-melittin nanoformulations induce significantly decreased immune response, resulting in excellent safety without compromising cytolytic potential. We now report the first application of D-melittin and its micellar formulations for cancer treatment. D-melittin was delivered by a pH-sensitive polymer carrier that (i) forms micellar nanoparticles at normal physiological conditions, encapsulating melittin, and (ii) dissociates at endosomal pH, restoring melittin activity. D-melittin micelles (DMM) exhibits significant cytotoxicity and induces hemolysis in a pH-dependent manner. In addition, DMM induce immunogenic cell death, revealing its potential for cancer immunotherapy. Indeed, in vivo studies demonstrated the superior safety profile of DMM over free peptide and improved efficacy at prohibiting tumor growth. Overall, we present the first application of micellar D-melittin for cancer therapy. These findings establish a new strategy for safe, systemic delivery of melittin, unlocking a potential pathway toward clinical translation for cytotoxic peptides as anti-cancer agents. which can revolutionize in vivo delivery of therapeutic peptides and peptide antigens.

Nebulization of Risedronate Sodium Microspheres for Potential Attenuation of Pulmonary Emphysema: a Promising New Insight of Alveolar Macrophage Apoptosis

Risedronate sodium (RS) is a potent nitrogen-containing bisphosphonate which is known to induce osteoclast apoptosis. As a drug repurposing approach, the current work explored the potential of nebulizable RS-chitosan (CS) microspheres to induce alveolar macrophage apoptosis. RS-CS microspheres were assessed for lung deposition, cytotoxicity, and cellular uptake percentage in Calu-3 cells. The potential of nebulizable microspheres for treating elastase-induced emphysema in rats was investigated, compared to RS marketed oral tablets®, with respect to histopathological, immunohistochemical, and flow cytometric studies. The in vitro lung deposition pattern suggested deep alveolar deposition of RS microspheres, with respect to high FPF% and suitable MMAD (66% and 1.506 μm, respectively, at a flow rate of 28.3 L min^-1). No apparent cytotoxicity was observed, with a cell viability > 90%. The inhalation of RS-CS microspheres was suggested to inhibit airspace enlargement and lung rarefaction after elastase instillation and reduce the macrophage accumulation in alveolar parenchyma. Immunohistochemical and cytometric analyses revealed significant low expression levels of CD68 and CD11b surface markers, respectively, with significantly (P < 0.05) lower detected numbers of intact alveolar macrophages following inhalation of RS-CS microspheres. The nebulization of RS-CS microspheres could induce apoptosis in alveolar macrophages and be promisingly adopted for attenuation of pulmonary emphysema.

Liposome-Coated Arsenic-Manganese Complex for Magnetic Resonance Imaging-Guided Synergistic Therapy Against Carcinoma

Purpose

A liposome-coated arsenic-manganese complex, denoted as LP@MnAs_x was constructed for the targeted delivery of arsenic trioxide (ATO) against carcinoma.

Methods

Arsenite, the prodrug of ATO, was encapsulated within a liposome via electrostatic interaction with the manganese ions. The as-prepared material was characterized with dynamic light scattering and transmission electron microscopy. The entrapment efficiency and drug loading of arsenic in the carrier were measured using inductively coupled plasma spectrometry. The in vitro release of arsenic was evaluated by using the dialysis bag method. Furthermore, the Fenton-like activity and in vitro cytodynamics research of LP@MnAs_x were monitored in this work. And the cellular uptake study was used to investigate the in vitro entry mechanism. Furthermore, the cytotoxicity, cell apoptosis and cell cycle study were performed to evaluate the tumor-killing efficiency. Also, the pharmacokinetic and antitumor studies were investigated in HepG2 tumor-bearing nude mice.

Results

The as-prepared LP@MnAs_x possessed a spherical morphology, uniformly distributed hydrodynamic diameter, and excellent drug-loading efficiency. LP@MnAs_x displayed robust stability and sustained-release profile under physiological environments. LP@MnAs_x could degrade with high sensitivity to the pH variation in the tumor microenvironment. As such, this could lead to a burst release profile of Mn²⁺ and arsenite to achieve a synergistic therapy of chemodynamic therapy and chemotherapy. When compared to the carrier-free arsenate, in vitro experiments revealed that LP@MnAs_x exhibited enhanced cellular uptake and tumor-killing efficiency. LP@MnAs_x also demonstrated significantly enhanced tumor-specific in vivo distribution of arsenic, prolonged systemic circulation lifetime, and increased accumulation at the tumor site.

Conclusion

Based on the experimental results, LP@MnAs_x is an ideal arsenic-based nanodelivery system, whereby it can improve the non-specific distribution of NaAsO₂ in vivo. Thus, this work can expand the research and application of arsenic trioxide against solid tumors.

Internalization and membrane activity of the antimicrobial peptide CGA-N12

Antimicrobial peptides (AMPs) are conventional antibiotic alternatives due to their broad-spectrum antimicrobial activities and special mechanisms of action against pathogens. The antifungal peptide CGA-N12 was originally derived from human chromogranin A (CGA) and consists of the 65th to 76th amino acids of the CGA N-terminal region. In the present study, we found that CGA-N12 had fungicidal activity and exhibited time-dependent inhibition activity against Candida tropicalis. CGA-N12 entered the cells to exert its antagonist activity. The internalization of CGA-N12 was energy-dependent and accompanied by actin cytoskeleton-, clathrin-, sulfate proteoglycan-, endosome-, and lipid-depleting agent-mediated endocytosis. Moreover, the CGA-N12 internalization pathway was related to the peptide concentration. The effects of CGA-N12 on the cell membrane were investigated. CGA-N12 at a low concentration less than 4 × MIC100 did not destroy the cell membrane. While with increasing concentration, the damage to the cell membrane caused by CGA-N12 became more serious. At concentrations greater than 4 × MIC100, CGA-N12 destroyed the cell membrane integrity. Therefore, the membrane activity of CGA-N12 is concentration dependant.

Nano-Strategies for Improving the Bioavailability of Inhaled Pharmaceutical Formulations

Pulmonary pharmaceutical formulations are targeted for the treatment of respiratory diseases. However, their application is limited due to the physiological characteristics of the lungs, such as branching structure, mucociliary and macrophages, as well as certain properties of the drugs like particle size and solubility. Nano-formulations can ameliorate particle sizes and improve drug solubility to enhance bioavailability in the lungs. The nano-formulations for lungs reviewed in this article can be classified into nanocarriers, no-carrier-added nanosuspensions and polymer-drug conjugates. Compared with conventional inhalation preparations, these novel pulmonary pharmaceutical formulations have their own advantages, such as increasing drug solubility for better absorption and less inflammatory reaction caused by the aggregation of insoluble drugs; prolonging pulmonary retention time and reducing drug clearance; improving the patient compliance by avoiding multiple repeated administrations. This review will provide the reader with some background information for pulmonary drug delivery and give an overview of the existing literature about nano-formulations for pulmonary application to explore nano-strategies for improving the bioavailability of pulmonary pharmaceutical formulations.

Exploration and insights into the cellular internalization and intracellular fate of amphiphilic polymeric nanocarriers

The beneficial or deleterious effects of nanomedicines emerge from their complex interactions with intracellular pathways and their subcellular fate. Moreover, the dynamic nature of plasma membrane accounts for the movement of these nanocarriers within the cell towards different organelles thereby not only influencing their pharmacokinetic and pharmacodynamic properties but also bioavailability, therapeutic efficacy and toxicity. Therefore, an in-depth understanding of underlying parameters controlling nanocarrier endocytosis and intracellular fate is essential. In order to direct nanoparticles towards specific sub-cellular organelles the physicochemical attributes of nanocarriers can be manipulated. These include particle size, shape and surface charge/chemistry. Restricting the particle size of nanocarriers below 200 nm contributes to internalization via clathrin and caveolae mediated pathways. Similarly, a moderate negative surface potential confers endolysosomal escape and targeting towards mitochondria, endoplasmic reticulum (ER) and Golgi. This review aims to provide an insight into these physicochemical attributes of nanocarriers fabricated using amphiphilic graft copolymers affecting cellular internalization. Fundamental principles understood from experimental studies have been extrapolated to draw a general conclusion for the designing of optimized nanoparticulate drug delivery systems and enhanced intracellular uptake via specific endocytic pathway.

Passive internalization and active extrusion determines PLGA-nanoparticle concentration in cancer cell lines

Background: Poly(lactic-co-glycolic) acid nanoparticle (PLGA-NP) trafficking across cell membranes was investigated to confirm preliminary results that contradicted existing studies. Materials & methods: Uptake and retention of PLGA-NPs at 37 and 4°C in the presence and absence of metabolic inhibitors in various cell lines was estimated. Results: Pulse experiments with metabolic inhibitors and culturing at 4°C demonstrated the predominantly passive nature of PLGA-NP uptake. Chase experiments with metabolic inhibitors indicated the role of active exocytosis in the extrusion of these NPs. PLGA-NPs with ionic or nonionic hydrophilic coats with highly positive or negative ζ-potential also showed similar results. Conclusion: Our study opens up the possibility of modulation of active exocytosis to increase intracellular retention of NPs for an extended period of drug delivery.

In vitro evaluation of two different types of obidoxime-loaded nanoparticles for cytotoxicity and blood-brain barrier transport

Nerve agents (NA) are chemical warfare munitions and their exposure causes a progressive inhibition of acetylcholinesterase (AChE). This inhibition causes NA-induced brain damage in central nervous system (CNS). Oximes reactivate AChE in both the peripheral nervous system and the CNS. Transport of the oxime across the blood-brain barrier (BBB) in the existed therapeutic concentrations at the brain parenchyma determines the effectiveness of antidote therapy on respiratory depression and NA-induced brain damage. However, oximes could not cross the BBB in therapeutic concentrations. The aim of this study was to load AChE reactivator obidoxime chloride to PLGA and PEG-b-PLGA nanoparticles and to improve the BBB transport of the molecule. Brain microvascular endothelial cells were used as the BBB model. 79.3 ± 4.2% of obidoxime was released from PLGA nanoparticles and 88.2 ± 4.4% of obidoxime was released from PEG-b-PLGA nanoparticles within 24 h. It was found that PEG-b-PLGA nanoparticles were ideal drug carrier because of its low tissue toxicity, few side effects, and controllable drug release profile. Transport efficiency of obidoxime across the BBB is a major challenge in the prevention of the CNS, the effectiveness of NA poisoning and new strategies like using obidoxime-loaded PEG-b-PLGA nanoparticles could overcome this challenge for the management of NA-induced brain damage.

Endocytosis: The Nanoparticle and Submicron Nanocompounds Gateway into the Cell

Nanoparticles (NPs) and submicron particles are increasingly used as carriers for delivering therapeutic compounds to cells. Their entry into the cell represents the initial step in this delivery process, being most of the nanoparticles taken up by endocytosis, although other mechanisms can contribute to the uptake. To increase the delivery efficiency of therapeutic compounds by NPs and submicron particles is very relevant to understand the mechanisms involved in the uptake process. This review covers the proposed pathways involved in the cellular uptake of different NPs and submicron particles types as well as the role that some of the physicochemical nanoparticle characteristics play in the uptake pathway preferentially used by the nanoparticles to gain access and deliver their cargo inside the cell.

Drug Delivery with Polymeric Nanocarriers-Cellular Uptake Mechanisms

Nanocarrier-based systems hold a promise to become “Dr. Ehrlich’s Magic Bullet” capable of delivering drugs, proteins and genetic materials intact to a specific location in an organism down to subcellular level. The key question, however, how a nanocarrier is internalized by cells and how its intracellular trafficking and the fate in the cell can be controlled remains yet to be answered. In this review we survey drug delivery systems based on various polymeric nanocarriers, their uptake mechanisms, as well as the experimental techniques and common pathway inhibitors applied for internalization studies. While energy-dependent endocytosis is observed as the main uptake pathway, the integrity of a drug-loaded nanocarrier upon its internalization appears to be a seldomly addressed problem that can drastically affect the uptake kinetics and toxicity of the system in vitro and in vivo.

3,5,4'-trimethoxy-trans-stilbene loaded PEG-PE micelles for the treatment of colon cancer

Background

3,5,4′-trimethoxy-trans-stilbene (BTM) is a methylated derivative of resveratrol. To improve the pharmaceutical properties of BTM, BTM loaded PEG-PE micelles (BTM@PEG-PE) were fabricated and its anti-cancer efficacy against colon cancer was evaluated.

Methods

BTM@PEG-PE micelles were prepared by the solvent evaporation method and were characterized by nuclear magnetic resonance (NMR), size, zeta potential, polymer disperse index (PDI) and transmission electron microscopy (TEM). Cellular uptake, cell viability assay, caspase-3 activity assay and flow cytometry were performed to evaluate the cell internalization and anti-cancer efficacy of BTM@PEG-PE micelles in vitro. Pharmacokinetic profiles of BTM and BTM@PEG-PE micelles were compared and in vivo anti-cancer therapeutic efficacy and safety of BTM@PEG-PE micelles on CT26 xenograft mice were evaluated.

Results

BTM was successfully embedded in the core of PEG-PE micelles, with a drug loading capacity of 5.62±0.80%. PEG-PE micelles facilitated BTM entering to the CT26 cells and BTM@PEG-PE micelles exerted enhanced anti-cancer efficacy against CT26 cells. BTM@PEG-PE micelles showed prolonged half-life and increased bioavailability. More importantly, BTM@PEG-PE micelles treatment suppressed tumor growth in tumor-bearing mice and prolonged survival with minimal damage to normal tissues.

Conclusion

Altogether, the BTM@PEG-PE micelles might be a promising strategy to enhance the pharmacokinetic and pharmacodynamic potentials of BTM for colon cancer therapy.

Preparation and Evaluation of mPEG-PLGA Block Copolymer Micelles Loaded with a Sarsasapogenin Derivative

Sarsasapogenin derivative 5n (SGD 5n) is a new compound with potent antitumor efficacy, but the low solubility severely affects its absorption and bioavailability. Therefore, the SGD 5n-loaded mPEG-PLGA block copolymer micelles were developed to improve the value of SGD 5n in clinical application. The polymeric micelles were prepared by an organic solvent evaporation method, and the encapsulation efficiency (EE), drug loading (DL), critical micelle concentrations (CMC), morphology, particle size, and zeta potential were determined. The cytotoxicity was examined by the MTT assay, and the cellular uptake study was performed by confocal laser scanning microscopy. A model of tumor-bearing mouse was established to study the antitumor activity in vivo. The results demonstrated that the particle size of the prepared micelle was 124.6 ± 9.6 nm, the encapsulation efficiency was 82.0 ± 2.9%, and the drug loading was 8.3 ± 0.4%. The results of cytotoxicity and cellular uptake demonstrated that the SGD 5n-loaded micelles could efficiently enter tumor cells, and the cellular uptake of SGD 5n presented concentration and time dependence. This study demonstrated that the prepared SGD 5n-loaded polymeric micelles had significant antitumor activity and provided a basis for clinical development of new compound SGD 5n.

Puerarin-loaded PEG-PE micelles with enhanced anti-apoptotic effect and better pharmacokinetic profile

Puerarin (PUE) is the most abundant isoflavonoid in kudzu root. It is widely used as a therapeutic agent for the treatment of cardiovascular diseases. However, the short elimination half-life, poor-bioavailability, and acute intravascular hemolysis of PUE are the main obstacles to its widespread clinical applications. Whereas PEG-PE micelles possess the ability to release medicine slowly, enhance the cellular uptake of drugs and improve their biocompatibility. Therefore, it was aim to fabricate puerarin-loaded PEG-PE (PUE@PEG-PE) micelles to improve the pharmaceutical properties of drugs. It can be observed from the TEM images that PUE@PEG-PE micelles appeared obvious core-shell structure and remained well-dispersed without aggregation and adhesion. PUE was successfully embedded in the core of PEG-PE micelles, which was confirmed by FT-IR and ¹H NMR spectra. In vitro studies showed that PUE@PEG-PE micelles exhibited a sustained release behavior in pH 7.4 PBS buffer and decreased hemolysis rate of PUE. Compared with PUE, PUE@PEG-PE micelles showed a 3.2-fold increase in the half-life of PUE and a 1.58-fold increase in bioavailability. In addition, the PUE@PEG-PE micelles exerted enhanced protective effect against isoprenaline-induced H9c2 cells apoptosis compared with PUE, as evident by decreased percentage of Hoechst-positive cells, Caspase 3 activity, Bax expression, and increased Bcl-2 expression. Notably, the PEG-PE micelles exhibited favorable cellular uptake efficiency on H9c2 cells, and this may account for their enhanced anti-apoptotic effect of the incorporated drug. Altogether, the PUE@PEG-PE micelles were not only able to control the drug release but also offered promise to enhance the pharmacokinetic and pharmacodynamic potential of PUE.

Evaluation of Anti-Tumor Efficacy of Vorinostat Encapsulated Self-Assembled Polymeric Micelles in Solid Tumors

Vorinostat (VOR), a potent HDAC inhibitor, suffers from low solubility and poor absorption, which hinders its successful application in therapy, especially in the treatment of solid tumors. In this study, an effort to improve the physicochemical characteristics of VOR was made by encapsulating it in PEG-PLGA copolymeric micelles. VOR-loaded PEG-PLGA micelles (VOR-PEG-PLGA) were produced by thin-film hydration and physicochemically characterized. The PEG-PLGA micelles had an average size of 124.06 ± 2.6 nm, polydispersity index of 0.27 ± 0.1, and entrapment efficiency of 90 ± 2.1%. Micelles were characterized by TEM, DSC, and drug release studies. The drug release occurred in a sustained manner up to 72 h from PEG-PLGA micelles. In the in vitro cell-based studies using human breast cancer (MDA MB 231) and murine melanoma (B16F10) cell lines, VOR-PEG-PLGA micelles exhibited superior cellular internalization, enhanced cytotoxic activity, and greater apoptosis compared to free drug. Percent cell killing of 54.9% for VOR-PEG-PLGA-treated cells was observed after 24 h compared to 36% for free VOR in MDA MB 231 cell line. Further, significant tumor suppression was witnessed in B16F10 tumor-bearing mice treated with VOR-PEG-PLGA micelles with a 1.78-fold reduction in tumor volume compared to free VOR-treated animals. Overall, the VOR-PEG-PLGA micelles improved the biopharmaceutical properties of VOR, which resulted in enhanced anti-tumor efficacy. Therefore, the newly developed nano-formulation of VOR could be considered as an effective treatment option in solid tumors.

Compatibility of PEGylated Polymer Nanoparticles with the Biophysical Function of Lung Surfactant

To minimize an unwanted interference of colloidal drug delivery vehicles with the biophysical functionality of lung surfactant, the surface of polymer nanoparticles was modified with poly(ethylene glycol) (PEGylation). Plain poly(lactide) nanoparticles provoked a statistically relevant decrease in the surface activity of the naturally derived lung surfactant, Alveofact. By contrast, the extent of lung surfactant inhibition induced by PEGylated polymer nanoparticles was significantly attenuated. Here, escalations of the PEG coating layer thickness (>3 nm, with a chain-to-chain distance of ≤4 nm) on the colloidal surface were capable of circumventing bioadverse effects. Accordingly, polymer nanoparticles equipped with PEG chains with a molecular weight above 2-5 kDa were compatible with the biophysical function of Alveofact. Overall, PEGylation of polymer nanoparticles presents a promising approach for the development of inhalation nanomedicines revealing negligible effects on the surface activity of the lining layer present in the deep lungs.