Purpose: P-glycoprotein (Pgp) antagonists have had unpredictable pharmacokinetic interactions requiring reductions of chemotherapy. We report a phase I study using tariquidar (XR9576), a potent Pgp antagonist, in combination with vinorelbine. Experimental Design: Patients first received tariquidar alone to assess effects on the accumulation of 99m Tc-sestamibi in tumor and normal organs and rhodamine efflux from CD56+ mononuclear cells. In the first cycle, vinorelbine pharmacokinetics was monitored after the day 1 and 8 doses without or with tariquidar. In subsequent cycles, vinorelbine was administered with tariquidar. Tariquidar pharmacokinetics was studied alone and with vinorelbine. Results: Twenty-six patients were enrolled. Vinorelbine 20 mg/m 2 on day 1 and 8 was identified as the maximum tolerated dose (neutropenia). Nonhematologic grade 3/4 toxicities in 77 cycles included the following: abdominal pain (4 cycles), anorexia (2), constipation (2), fatigue (3), myalgia (2), pain (4) and dehydration, depression, diarrhea, ileus, nausea, and vomiting, (all once). A 150-mg dose of tariquidar: (1) reduced liver 99m Tc-sestamibi clearance consistent with inhibition of liver Pgp; (2) increased 99m Tcsestamibi retention in a majority of tumor masses visible by 99m Tc-sestamibi; and (3) blocked Pgp-mediated rhodamine efflux from CD56+ cells over the 48 hours examined. Tariquidar had no effects on vinorelbine pharmacokinetics. Vinorelbine had no effect on tariquidar pharmacokinetics. One patient with breast cancer had a minor response, and one with renal carcinoma had a partial remission. Conclusions: Tariquidar is a potent Pgp antagonist, without significant side effects and much less pharmacokinetic interaction than previous Pgp antagonists. Tariquidar offers the potential to increase drug exposure in drug-resistant cancers.

Cu-Catalysed reversible-deactivation radical polymerisation of hydrophobic methacrylate monomers in anhydrous alcohols has been expanded to explore the scope of this unusual choice of solvent. A range of linear methacrylic homopolymers with well-targeted molecular weight and low dispersity (Đ = 1.12-1.53) have been generated in anhydrous methanol and isopropanol with relative ease. These solvents are normally considered antisolvents and employed to precipitate such polymers; therefore, our studies have assessed the polymerisation reaction mixture homogeneity and extent of reaction control. Statistical copolymerisations with the bi-functional monomer, ethylene glycol di-methacrlylate (EGDMA), has led to branched statistical copolymers with weight average molecular weights up to M w = 1.76 × 10 6 g mol −1 ; subsequent triple-detection size exclusion chromatography studies have provided insight into the impact of monomer structure on the extent of branching within the final isolated polymers. The ability to control branched copolymer molecular weights under these conditions through variation of EGDMA concentrations was seen to be highly dependent on methacrylate monomer chemistry. A number of factors which are likely to effect branching reactions during the polymerisation of hydrophobic methacrylates in anhydrous alcohols are discussed. † Electronic supplementary information (ESI) available: Experimental details, NMR spectra, TD-SEC analyses, additional figures and calculations. See

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Anhydrous methanol, a traditional precipitant for poly(n-butyl methacrylate), has been shown to be an excellent synthesis solvent using ATRP, generating high molecular weights and low dispersities (up to 76 000 g mol−1 and as low as 1.02).