Novel urea and bis-urea primaquine derivatives with hydroxyphenyl or halogenphenyl substituents: Synthesis and biological evaluation.

A series of novel compounds 3a-j and 6a-j with primaquine and hydroxyl or halogen substituted benzene moieties bridged by urea or bis-urea functionalities were designed, synthesized and evaluated for biological activity. The title compounds were prepared using benzotriazole as the synthon, through several synthetic steps. 3-[3,5-Bis(trifluoromethyl)phenyl]-1-{4-[(6-methoxyquinolin-8-yl)amino]pentyl}urea (3j) was the most active urea and 1-[({4-[(6-methoxyquinolin-8-yl)amino]pentyl}carbamoyl)amino]-3-[3-(trifluoromethyl)phenyl]urea (6h) the most active bis-urea derivative in antiproliferative screening in vitro against eight tested cancer cell lines. Urea derivatives 3a-g with hydroxy group or one halogen atom showed moderate antiproliferative effects against all the tested cell lines, but stronger activity against breast carcinoma MCF-7 cell line, while trifluoromethyl derivatives 3h-j showed antiproliferative effects against all the tested cell lines in low micromolar range. Finally, bis-ureas with hydroxy and fluoro substituents 6a-d showed extreme selectivity and chloro or bromo derivatives 6e-g high selectivity against MCF-7 cells (IC50 0.1-2.6 µM). p-Fluoro derivative 6d, namely 3-(4-fluorophenyl)-1-[({4-[(6-methoxyquinolin-8-yl)amino]pentyl}carbamoyl)amino]urea, is the most promising compound. Further biological experiments showed that 6d affected cell cycle and induced cell death of MCF-7 cell line. Due to its high activity against MCF-7 cell line (IC50 0.31 µM), extreme selectivity and full agreement with the Lipinski's and Gelovani's rules for prospective small molecular drugs, 6d may be considered as a lead compound in development of breast carcinoma drugs. Urea 3b and almost all bis-ureas showed high antioxidant activity in DPPH assay, but urea derivatives were more active in lipid peroxidation test. Only few compounds exhibited weak inhibition of soybean lipoxygenase. Compound 3j exhibited the strongest antimicrobial activity in susceptibility assay in vitro (MIC = 1.6-12.5 µg ml-1).

[Preparation and testing of buffers for fibrinogen]. / Izrada i ispitivanje pufera za fibrinogen.

Chloride-citrate-glucose solution was used in fibrinogen preparation for intravenous administration. Concentrated hydrochloric acid previously used for preparation of buffers for fibrinogen has been replaced by the diluted one enabling easier and more precise buffer pH regulation and faster fibrinogen dissolution. Procedure for spectrophotometric determination of the total citrate ion buffer system, sodium-citrate and citric acid was developed. Obtained results were within the prescribed limits but the ones obtained by officinal titration in non-aqueous medium were significantly decreased. Glucose was determined before sterilization by polymetric, and after sterilization by iodometric procedure. Chloride content was determined by coulometric titration and sodium content by flame photometry. Used analytic methods are simple and obtained results accurate and reproducible.

[The stability of the oxime Hi-6 in eyedrops]. / Stabilnost oksima HI-6 u kapima za oci.

The stability of an efficacious antidote in the treatment of organophosphorous poisoning--HI-6 has been examined in aqueous solutions of eye drops by accelerated stability tests. Disintegration kinetics has been examined at the increased temperatures and pH value of isotonic solution of 25 mg/ml concentration in ampules. First order hydrolysis is larger than in the known oximes: pralidoxime, obidoxime and other due to unfavourable physicochemical properties of HI-6. The period of 44 days which is necessary for reduction of exime concentration in eye drops for 10% at 25 degrees C is not enough for preservation of reliable solution and because of that it should be prepared whenever necessary.