New antimicrobial drugs

Donosi se kratki prikaz novih antibiotika koji su u razdoblju od 2000. do 2005. godine registrirani u Republici Hrvatskoj. Navedene su osnovne farmakokinetske karakteristike moksifloksacina, linezolida, levofloksacina, cefipima i telitromicina. Spomenuti su i noviji antibiotici koji su registrirani ili čekaju registraciju u drugim zemljama svijeta kao što su tigecyklin, quinupristin/dalfopristin, daptomycin, ertapenem, doripenem, dalbavancin, gemifloksacin, gatifloksacin, sitafloksacin, sparfloksacin, fosfamicin, ceftizoksim alapivoksil. Navedeni su i lijekovi koji se sada nalaze u fazi kliničkih i predkliničkih ispitivanja, od kojih većina još nema svoje ime nego su označeni brojevima i/ili slovima. Za ove posljednje dvije grupe lijekova su navedene pripadnosti grupama, a za sve tri grupe osnovne indikacije za njihovu primjenu. Raspravljeni su i problemi koji su doveli do zastoja u razvoju antimikrobnih lijekova i sve veća potreba za razvojem novih moćnih antibiotika, kako bi se riješio problem rezistentnih bakterija kojih je svakim danom sve više. Prikazani su i osnovni budući trendovi koji će dovesti do razvoja novih antimikrobnih lijekova.In this article we present a brief summary of new antibiotics that were registered in Republic of Croatia in period from 2000.–2005. We stated the basic pharmacokinetic characteristics of moxifloxacine, linezolide, levofloxacine, cefipime, and telitromycine. We mentioned newer antibiotics that are registered or are waiting registration in other countries around the world like: tigecycline, quinupristine/dalfopristine, daptomycine, ertapeneme, doripeneme, dalbavancine, gemifloxacine, gatifloxacine, sitafloxacine, sparfloxacine, fosfamycine, ceftizoksim alapivoksil. Finally we listed antibiotics that are currently in various stages preclinical and clinical development around the world, most of that are still coded with numbers and/or letters. For antibiotics from the last two groups we mentioned their antibiotic classes, and for all three groups we listed their clinical indications. We discussed problems that lead to a hold in antibiotic development, and the growing need for development of newer potent antibiotics as a solution for the problem of resistant bacteria more of which emerge every day. We mentioned the basic future trends that will lead to development of newer antimicrobial drugs

Metal-to-insulator transition and magnetic ordering in CaRu_{1-x}Cu_xO_3

CaRuO_3 is perovskite with an orthorhombic distortion and is believed to be close to magnetic ordering. Magnetic studies of single crystal and polycrystalline CaRu_{1-x}Cu_xO_3 (0\le x \le 15 at.%Cu) reveal that spin-glass-like transition develops for x\le 7 at.%Cu and obtained value for effective magnetic moment p_{eff}=3.55 mu_B for x=5 at.% Cu, single crystal, indicates presence of Ru^{5+}. At higher Cu concentrations more complex magnetic behaviors are observed. Electrical resistivity measured on polycrystalline samples shows metal-to-insulator transition (MIT) at 51 K for only 2 at.% Cu. Charge compensation, which is assumed to be present upon Cu^{2+/3+} substitution, induces appearance of Ru^{5+} and/or creation of oxygen vacancies in crystal structure. Since the observed changes in physical properties are completely attributable to the charge compensation, they cannot be related to behaviors of pure compound where no such mechanism is present. This study provides the criterion for "good" chemical probes for studying Ru-based perovskites.Comment: 12 pages, 7 figure