Simultaneous quantification of reparixin and paclitaxel in plasma and urine using ultra performance liquid chromatography-tandem mass spectroscopy (UHPLC-MS/MS): Application to a preclinical pharmacokinetic study in rats.

A liquid chromatography-tandem mass spectroscopy (LC-MS/MS) assay was developed and validated to simultaneously quantify anticancer drugs reparixin and paclitaxel in this study. The compounds were extracted from plasma and urine samples by protein precipitation with acetone (supplemented with 0.1% formic acid). Chromatographic separation was achieved using a C18 column, and drug molecules were ionized using dual ion source electrospray and atmospheric pressure chemical ionization (DUIS: ESI-APCI). Reparixin and paclitaxel were quantified using negative and positive multiple reaction monitoring (MRM) mode, respectively. Stable isotope palcitaxel-D5 was used as the internal standard (IS). The assay was validated for specificity, recovery, carryover and sample stability under various storage conditions; it was also successfully applied to measure drug concentrations collected from a pharmacokinetic study in rats. The results confirmed that the assay was accurate and simple in quantifying both reparixin and paclitaxel in plasma and urine with minimal sample pretreatment.

Nanocarrier-mediated drugs targeting cancer stem cells: an emerging delivery approach.

INTRODUCTION: Cancer stem cells (CSCs) play an important role in the development of drug resistance, metastasis and recurrence. Current conventional therapies do not commonly target CSCs. Nanocarrier-based delivery systems targeting cancer cells have entered a new era of treatment, where specific targeting to CSCs may offer superior outcomes to efficient cancer therapies. AREAS COVERED: This review discusses the involvement of CSCs in tumor progression and relevant mechanisms associated with CSCs resistance to conventional chemo- and radio-therapies. It highlights CSCs-targeted strategies that are either under evaluation or could be explored in the near future, with a focus on various nanocarrier-based delivery systems of drugs and nucleic acids to CSCs. Novel nanocarriers targeting CSCs are presented in a cancer-specific way to provide a current perspective on anti-CSCs therapeutics. EXPERT OPINION: The field of CSCs-targeted therapeutics is still emerging with a few small molecules and macromolecules currently proving efficacy in clinical trials. However considering the complexities of CSCs and existing delivery difficulties in conventional anticancer therapies, CSC-specific delivery systems would face tremendous technical and clinical challenges. Nanocarrier-based approaches have demonstrated significant potential in specific drug delivery and targeting; their success in CSCs-targeted drug delivery would not only significantly enhance anticancer treatment but also address current difficulties associated with cancer resistance, metastasis and recurrence.

Delivery to mitochondria: a narrower approach for broader therapeutics.

INTRODUCTION: Research has revealed a relationship between mitochondrial dysfunction and diseases such as diabetes, ischemia-reperfusion injury, cancer and many more. As a result, mitochondria have gained attention as a target organelle for the treatment of many diseases. Successful delivery of the drug molecule to the mitochondria could be achieved by keeping in mind the normal intracellular trafficking fate of molecules in cell as well as through the mitochondria and exploring the new possibilities to reach the target in an efficient manner. AREAS COVERED: This review covers important areas such as structure and physiology of mitochondria, mitochondrial genome and its role in the diseases led by mitochondrial dysfunction, generation of reactive oxygen species and its disbalance in pathophysiological conditions and apoptosis. Further, the review focuses on various human mitochondrial diseases, particularly cancer, and strategies and methods of targeting drug and genetic materials to mitochondria. Novel nanotechnology-based carriers for mitochondria delivery are discussed with an attempt of providing readers with a current and future prospective of mitochondrial therapeutics. EXPERT OPINION: Numerous investigators have attempted to establish a mitochondrial drug delivery system; still, many hurdles yet remain to be overcome before mitochondrial medicine reaches clinical applications. We need to develop a delivery system to encapsulate drugs, proteins and genes that would be practically viable for scale-up and strategies to target and regulate drug release to the cytosol after endosomal escape, and thereafter to deliver the released drug to the mitochondria. Current innovations in the nanotechnology could be effectively utilized with mitochondrial medicine for designing optimal nanoparticle drug delivery system for mitochondrial diseases on clinical setting.

Intracellular delivery of redox cycler-doxorubicin to the mitochondria of cancer cell by folate receptor targeted mitocancerotropic liposomes.

Cancer cells reflect higher level of ROS in comparison to the normal cell, so they become more vulnerable to further oxidative stress induced by exogenous ROS-generating agents. Through this a novel therapeutic strategy has evolved, which involves the delivery of redox cycler-doxorubicin (DOX) to the mitochondria of cancer cell where it acts as a source of exogenous ROS production. The purpose of this study is to develop a liposomal preparation which exhibits a propensity to selectively target cancer cell along with the potential of delivering drug to mitochondria of cell. We have rendered liposomes mitocancerotropic (FA-MTLs) by their surface modification with dual ligands, folic acid (FA) for cancer cell targeting and triphenylphosphonium (TPP) cations for mitochondria targeting. The cytotoxicity, ROS production and cell uptake of doxorubicin loaded liposomes were evaluated in FR (+) KB cells and found to be increased considerably with FA-MTLs in comparison to folic acid appended, mitochondria targeted and non-targeted liposomes. As confirmed by confocal microscopy, the STPP appended liposomes delivered DOX to mitochondria of cancer cell and also showed higher ROS production and cytotoxicity in comparison to folic acid appended and non-targeted liposomes. Most importantly, mitocancerotropic liposomes showed superior activity over mitochondria targeted liposomes which confirm the synergistic effect imparted by the presence of dual ligands - folic acid and TPP on the enhancement of cellular and mitochondrial delivery of doxorubicin in KB cells.