EGFR targeted delivery of paclitaxel and parthenolide co-loaded in PEG-Phospholipid micelles enhance cytotoxicity and cellular uptake in non-small cell lung cancer cells

Natural and Synthetic Micelles for Delivery of Small Molecule Drugs, Imaging Agents and Nucleic Acids

The poor solubility, lack of targetability, quick renal clearance, and degradability of many therapeutic and imaging agents strongly limit their applications inside the human body. Amphiphilic copolymers having self-assembling properties can form core-shell structures called micelles, a promising nanocarrier for hydrophobic drugs, plasmid DNA, oligonucleotides, small interfering RNAs (siRNAs) and imaging agents. Fabrication of micelles loaded with different pharmaceutical agents provides numerous advantages including therapeutic efficacy, diagnostic sensitivity, and controlled release to the desired tissues. Moreover, due to their smaller particle size (10-100 nm) and modified surfaces with different functional groups (such as ligands) help them to accumulate easily in the target location, enhancing cellular uptake and reducing unwanted side effects. Furthermore, the release of the encapsulated agents may also be triggered from stimuli-sensitive micelles at different physiological conditions or by an external stimulus. In this review article, we discuss the recent advancement in formulating and targeting different natural and synthetic micelles including block copolymer micelles, cationic micelles, and dendrimers-, polysaccharide- and protein-based micelles for the delivery of different therapeutic and diagnostic agents. Finally, their applications, outcomes, and future perspectives have been summarized.

Recent Advances in the Local Drug Delivery Systems for Improvement of Anticancer Therapy

The conventional anticancer chemotherapies not only cause serious toxic effects, but also produce resistance in tumor cells exposed to long-term therapy. Usually, the killing of metastasized cancer cells requires long-term therapy with higher drug doses, because the cancer cells develop resistance due to the induction of poly-glycoproteins (P-gps) that act as a transmembrane efflux pump to transport drugs out of the cells. During the last few decades, scientists have been exploring new anticancer drug delivery systems such as microencapsulation, hydrogels, and nanotubes to improve bioavailability, reduce drug-dose requirement, decrease multiple drug resistance, and to save normal cells as non-specific targets. Hopefully, the development of novel drug delivery vehicles (nanotubes, liposomes, supramolecules, hydrogels, and micelles) will assist to deliver drug molecules at the specific target site and reduce the undesirable side effects of anticancer therapies in humans. Nanoparticles and lipid formulations are also designed to deliver small drug payload at the desired tumor cell sites for their anticancer actions. This review will focus on the recent advances in the drug delivery systems, and their application in treating different cancer types in humans.

Development and validation of a HPLC-UV method for the simultaneous detection and quantification of paclitaxel and sulforaphane in lipid based self-microemulsifying formulation

Paclitaxel (PTX) and sulforaphane (SFN) are known anticancer molecules. Their activity was found to be potentiated when tested concurrently. Only recently, however, a novel SFN enabled PTX self-microemulsifying formulation (SMEDDS) was developed for their simultaneous delivery. This necessitated the development of an analytical method for the simultaneous detection and quantitation of PTX and SFN. In this study, a simple and sensitive isocratic high performance liquid chromatography-ultraviolet (HPLC-UV) analytical method was developed and validated per International Conference on Harmonization guidelines to satisfy this objective. Its application was demonstrated when quantifying the amount of PTX and SFN released from the SMEDDS in various dissolution media. The separation of the analytes was performed with the aid of a reversed phase C18 column at ambient temperature using a 60:40 mixture of acetonitrile and KH2PO4 buffer (pH 5.0) as the mobile phase. PTX and SFN peaks were detected at 202 nm with high resolution without interference from excipients. This method showed linearity within 2.5-100 μg/mL range with r2 > 0.999. The limit of detection and lower limit of quantitation were 0.1638 and 0.4964 μg/mL for PTX and 0.4419 and 1.3389 μg/mL for SFN, respectively. A total of 98-101% of the injected samples was recovered with RSD of 0.06-0.68% indicating the suitability of the method for the simultaneous detection and quantitation of the molecules in dissolution media.

Development and evaluation of paclitaxel nanoemulsion for cancer therapy

Tocosol™ is a tocopherol-based paclitaxel (PTX) nanoemulsion consisting of α-tocopherol (α-T) isomer of vitamin E as a solubilizer and vitamin E TPGS as the primary emulsifier. Despite its positive attributes in early clinical studies, it failed the pivotal phase III clinical trials. The long-term goal of this work was to reformulate Tocosol™. In this study, Tocosol™ formulation was optimized by replacing the α-T isomer with the more pharmacological active isomer γ-tocotrienol (γ-T₃), and the surfactant vitamin E TPGS was replaced with in-house designed PEGylated γ-T₃ surfactant. The reformulated paclitaxel γ-T₃/PEGylated γ-T₃ -based nanoemulsion was significantly more active against pancreatic tumor cell lines than α-T/Vitamin E TPGS based formulation (IC₅₀ = 0.5 μM and 1.1 μM, respectively). Furthermore, the reformulated product showed an average size of 220 ± 6 nm with surface charge equal to -42 ± 2 mV. The optimized product was physically and chemically stable over 6 months per ICH storage condition guidelines.

PEG-derivatized birinapant as a nanomicellar carrier of paclitaxel delivery for cancer therapy

A novel triblock amphiphilic copolymer (PAL-PEG-Birinapant) was designed and synthesized as a dual-functional micellar carrier utilizing birinapant (an inhibitor of inhibitor-of-apoptosis proteins) as a pH-sensitive segment and inhibitor-of-apoptosis proteins-targeting ligand. The mixed micelles comprised of PAL-PEG-Birinapant (PPB) and mPEG2k-PDLLA2k (MPP), named as PPB/MPP (2/1,w/w) micelles were developed for enhanced solubility and antitumor potency of hydrophobic drugs as paclitaxel (PTX). In vitro cell viability and cytotoxicity studies revealed that the PTX-loaded PPB/MPP micelles were more potent than the commercial PTX formulation (Taxol^®), as well as the in vitro cell apoptosis study. Clear differences in the intracellular uptake of free coumarin-6 (C6) solution and C6-loaded PPB/MPP micelles were observed and indicated that the PPB/MPP micelles could efficiently deliver chemical compound into tumor cells. PPB copolymer and PTX-loaded PPB/MPP micelles demonstrated an excellent safety profile with a maximum tolerated dose (MTD) of above 1.2 g copolymer/kg and above 100 mg PTX/kg in mice respectively in contrast to 20˜24 mg/kg of Taxol®. The near infrared (NIR) fluorescence imaging showed that PPB/MPP micelles persisted for a relatively long time in the circulation and accumulated preferentially in tumor tissue. Moreover, PTX loaded PPB/MPP micelles significantly inhibited the tumor growth both in MDA-MB-231 and Ramos cancer xenograft mice models without obvious toxicity. Collectively, our study presents a new dual-functional micelles that improve the therapeutic efficacy of PTX in vitro and in vivo.

Threatening cancer with nanoparticle aided combination oncotherapy

Employing combination therapy has become obligatory in cancer cases exhibiting high tumor load, chemoresistant tumor population, and advanced disease stages. Realization of this fact has now led many of the combination oncotherapies to become an integral part of anticancer regimens. Combination oncotherapy may encompass a combination of anticancer agents belonging to a similar therapeutic category or that of different therapeutic categories (e.g. chemotherapy + gene therapy). Differences in the physicochemical properties, pharmacokinetics and biodistribution pattern of different payloads are the major constraints that are faced by combination chemotherapy. Concordant efforts in the field of nanotechnology and oncology have emerged with several approaches to solve the major issues encountered by combination therapy. Unique colloidal behaviors of various types of nanoparticles and differential targeting strategies have accorded an unprecedented ability to optimize combination oncotherapeutic delivery. Nanocarrier based delivery of the various types of payloads such as chemotherapeutic agents and other anticancer therapeutics such as small interfering ribonucleic acid (siRNA), chemosensitizers, radiosensitizers, and antiangiogenic agents have been addressed in the present review. Various nano-delivery systems like liposomes, polymeric nanoparticles, polymerosomes, dendrimers, micelles, lipid based nanoparticles, prodrug based nanocarriers, polymer-drug conjugates, polymer-lipid hybrid nanoparticles, carbon nanotubes, nanosponges, supramolecular nanocarriers and inorganic nanoparticles (gold nanoparticles, silver nanoparticles, magnetic nanoparticles and mesoporous silica based nanoparticles) that have been extensively explored for the formulation of multidrug delivery is an imperative part of discussion in the review. The present review features the outweighing benefits of combination therapy over mono-oncotherapy and discusses several existent nanoformulation strategies that facilitate a successful combination oncotherapy. Several obstacles that may impede in transforming nanotechnology-based combination oncotherapy from bench to bedside, and challenges associated therein have also been discussed in the present review.

Strategies for the enhanced intracellular delivery of nanomaterials

The intracellular delivery of nanomaterials and drugs has been attracting increasing research interest, mainly because of their important effects and functions in several organelles. Targeting specific organelles can help treat or decrease the symptoms of diabetes, cancer, infectious, and autoimmune diseases. Tuning biological and chemical properties enables the creation of functionalized nanomaterials with enhanced intracellular uptake, ability to escape premature lysosome degradation, and to reach a specific target. Here, we provide an update of recent advances in the intracellular delivery mechanisms that could help drugs reach their target more efficiently.

Plant Secondary Metabolites as Anticancer Agents: Successes in Clinical Trials and Therapeutic Application

Cancer is a multistage process resulting in an uncontrolled and abrupt division of cells and is one of the leading causes of mortality. The cases reported and the predictions for the near future are unthinkable. Food and Drug Administration data showed that 40% of the approved molecules are natural compounds or inspired by them, from which, 74% are used in anticancer therapy. In fact, natural products are viewed as more biologically friendly, that is less toxic to normal cells. In this review, the most recent and successful cases of secondary metabolites, including alkaloid, diterpene, triterpene and polyphenolic type compounds, with great anticancer potential are discussed. Focusing on the ones that are in clinical trial development or already used in anticancer therapy, therefore successful cases such as paclitaxel and homoharringtonine (in clinical use), curcumin and ingenol mebutate (in clinical trials) will be addressed. Each compound’s natural source, the most important steps in their discovery, their therapeutic targets, as well as the main structural modifications that can improve anticancer properties will be discussed in order to show the role of plants as a source of effective and safe anticancer drugs.