Including Information on the Therapeutic Window in Bioequivalence Acceptance

Light-triggered Janus nanomotor for targeting and photothermal lysis of pathogenic bacteria

The rapid photothermal lysis of Escherichia coli O157:H7 treated with light-triggered Janus nanomotors was visualized by Hilbert differential contrast transmission electron microscopy (HDC-TEM). The extraordinary advantage of this high-resolution microscopic technique was that it revealed the detailed ultrastructure alterations of the treated cells at a state close to their native one. The micrographs demonstrated that Janus nanomotors (mesoporous silica nanoparticles with gold hemisphere and half-capped with cysteamine) were able to target and bind to the pathogenic E. coli. The biorecognition reaction proceeded at slightly acid pH thankful to the formed electrostatic adhesion between positively charged amino groups on nanoparticles surface and the negatively charged cell envelope. The exposure of labeled cells to near infrared laser irradiation leaded to occurrence of effective photothermal damage of their plasma membranes, which was enough strong to lyse bacteria. It was because of the overheating obtained by the photon-to-thermal conversion reaction generated by the surface plasmon resonance response of Janus nanomotors. The good efficiency of photothermal lysis to inactivate E. coli O157:H7 was confirmed by staining with LIVE/DEAD viability kit and quantification of the few survived cells in epifluorescence microscope. Furthermore, HDC-TEM images of ice-embedded inhibited bacteria documented the labeling, membrane disruptions and lysis due to the designed operation of Janus nanomotors. The reported microscopic technique provides a novel strategy for developing of Janus nanomachines as promising platform for nondrug treatment and defeating of antibiotic-resistant pathogenic microorganisms.

Vorapaxar, an oral PAR-1 receptor antagonist, does not affect the pharmacokinetics and pharmacodynamics of warfarin

PURPOSE

Vorapaxar is an orally active protease-activated receptor 1 (PAR-1) antagonist that inhibits thrombin-induced platelet aggregation. This open-label study assessed the pharmacokinetics and pharmacodynamics of single-dose warfarin in the presence/absence of multiple-dose vorapaxar in 12 healthy men.

METHODS

Subjects received two treatments separated by ≥ 7-day washout: Treatment A warfarin 25 mg (Day 1); Treatment B vorapaxar 2.5 mg/day on Days 1-6 and vorapaxar 40 mg coadministered with warfarin 25 mg (Day 7). R-warfarin, S-warfarin, and prothrombin time (PT) were assayed predose and up to 120 h postdose.

RESULTS

The geometric mean ratio (GMR) as a percentage (warfarin + vorapaxar/warfarin) was calculated. The GMR (90 % CIs) estimates of C(max) were 105 (99, 111) and 105 (99, 112) for R- and S-warfarin, respectively. The GMR (90 % CIs) estimates of AUC(0-∞) were 108 (101, 116) and 105 (96, 115) for R- and S-warfarin, respectively. The GMR (95 % CIs) estimates of AUC(0-120 h) for PT and INR were 97 (95, 98) and 96 (94, 98), respectively.

CONCLUSION

Results of this study indicate that vorapaxar has no meaningful effect on the pharmacokinetics or pharmacodynamics of warfarin, suggesting that the coadministration of these two drugs or vorapaxar coadministered with other CYP2C9/CYP2C19 substrates is unlikely to cause a clinically significant pharmacokinetic drug interaction.