Šezdeseta obljetnica mature đaka Geodetske tehničke škole u Zagrebu

U radu je opisana proslava šezdesete obljetnice mature đaka Geodetske tehničke škole u Zagrebu

Identification of new process-related impurity in the key intermediate in the synthesis of TCV-116

Development of safe and effective drugs requires complete impurity evaluation and, therefore, knowledge about the formation and elimination of impurities is necessary. During impurity profiling of a key intermediate during synthesis of candesartan cilexetil (1-(((cyclohexyloxy)carbonyl)oxy)ethyl 1-((2\u27-(2H-tetrazol-5-yl)-[1,1\u27-biphenyl]-4-yl)methyl)-2-ethoxy-1H-benzo[d]imidazole-7-carboxylate, TCV-116), a novel compound, which had not been reported previously, was observed. Structural elucidation of impurity was achieved by liquid chromatography hyphenated to different high resolution mass analyzers. Based on exact mass measurements and fragmentation pattern, a chloroalkyl carbonate ester analogue of the intermediate was identified. Structure of the impurity was confirmed by mass spectrometric and NMR analyses of the target substance. Identified impurity could represent a hazard if it is transferred to the final API stage and its presence should be kept below allowed limits. Further investigation could reveal whether bis(1-chloroethyl) carbonate is a precursor to impurity formation. Therefore, synthesis should be regulated so as to minimize impurity production. Analysis of the final product indicated that the amount of impurity did not exceed 50 mg L-1, which represents the detection limit, determined according to the signal/noise ratio

The Synthesis and Hybridization Studies of Oligodeoxyribonucleotides Containing the 2\u27-Deoxyguanosine Modification, 8-Aza-3-deaza-2\u27-deoxyguanosine

Chemical and physical properties of the modified nucleoside 8-aza-3-deaza-2’-deoxyguanosine (1) are described. From the amino protected nucleoside 1a, phosphoramidite 3 was prepared, and oligo-deoxyribonucleotides were synthesized. Duplexes containing compound 1 are slightly less stable than the natural duplex

Poly(D,L-lactide-co-glycolide)/hydroxyapatite core–shell nanosphere. Part 2: Simultaneous release of a drug and a prodrug (clindamycin and clindamycin phosphate)

The novel concept of a simultaneous, controlled release of a drug and a prodrug with different physico-chemical properties was applied in order to prolong the release period of antibiotics and estimate their high local concentrations, which are the necessary preconditions for the treatment of some chronic infection diseases. For this purpose poly(D,L-lactide-co-glycolide)/hydroxyapatite (PLGA/HAp) core–shell nanostructures were used as the carrier of clindamycin-base, as a drug, and clindamycin-2-phosphate, as a prodrug model. As a result, a two-step release was observed: the controlled release of the more soluble phosphate form and the sustained release of the less-soluble base form of clindamycin, resulting in a high overall concentration of the released drug during the period of 30 days in vitro. The HAp phase within the PLGA core–shells, applied as a drug carrier, delayed the process of the degradation of the polymer; however, the presence of the drug affected the process of degradation and this influence was the dominant factor in the control over the degradation of the polymer phase of PLGA/HAp and the consequent kinetics of the drug release