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Apart from cytotoxicity, inhibitors of the COX-2 enzyme have demonstrated additional effects important for cancer treatment (such as radiosensitization of tumor cells and cell antimigratory effects); however, the relationship between the inhibition of other inflammation-related enzyme 5-LOX inhibitors and anticancer activity is still not well understood. In our study, the cytotoxicity of thirteen COX-2 and 5-LOX inhibitors previously presented by our group (1-13) was tested on three cancer cell lines (HCT 116, HT-29 and BxPC-3) and one healthy cell line (MRC-5). Compounds 3, 5, 6 and 7 showed moderate cytotoxicity, but good selectivity towards cancer cell lines. IC50 values were in the range of 22.99-51.66 µM (HCT 116 cell line), 8.63-41.20 µM (BxPC-3 cell line) and 24.78-81.60 µM (HT-29 cell line; compound 7 > 100 µM). In comparison to tested, commercially available COX-2 and 5-LOX inhibitors, both cytotoxicity and selectivity were increased. The addition of compounds 6 and 7 to irradiation treatment showed the most significant decrease in cell proliferation of the HT-29 cell line (p < 0.001). The antimigratory potential of the best dual COX-2 and 5-LOX inhibitors (compounds 1, 2, 3 and 5) was tested by a wound-healing assay using the SW620 cell line. Compounds 1 and 3 were singled out as compounds with the most potent effect (relative wound closure was 3.20% (24 h), 5,08% (48 h) for compound 1 and 3.86% (24 h), 7.68% (48 h) for compound 3). Considering all these results, compound 3 stood out as the compound with the most optimal biological activity, with the best dual COX-2 and 5-LOX inhibitory activity, good selectivity towards tested cancer cell lines, significant cell antimigratory potential and a lack of toxic effects at therapeutic doses.

Gentamicin sulfate is a potent broad spectrum aminoglycoside antibiotic which is used against Gram- positive and Gram-negative bacteria. A simple, isocratic HPLC method for separation, identification and determination of gentamicin and parabens (methylparaben and propylparaben) was developed and validated. To our knowledge there is no report about simultaneous determination of those three ana- lytes in pharmaceutical products. The optimum chromatographic conditions were achieved on CN column with a mobile phase consisting of 0.15% triethylamine in 10 mM KH 2 PO4 aqueous solution (final pH 3.0 adjusted with H 3 PO 4 ) and methanol in the ratio 70:30 (v/v), providing selective quan- tification of analytes within 5 min. The method was successfully validated according to ICH guidelines acceptance criteria in terms of selectivity, linearity, accuracy, precision and robustness. The linearity of the method was proved in defined concentrations ranges for gentamicin (0.32–1.04 mg mL1 ), meth- ylparaben (0.0072–0.0234 mg mL1 ) and propylparaben (0.0008–0.0026 mg mL1 ). Relative standard deviations calculated for all analytes in precision testing were <2% (analysis repeatability) and <3% (intermediate precision). Recovery values were between 98.87% and 101.67%. Chromatographic pa- rameters are not significantly influenced by small variations of column temperature, pH and molarity of KH2 PO 4 . Finally, the method was successfully applied for quantitative determination of gentamicin and parabens in commercially available solution for injection. Proposed HPLC method is found to be promising in terms of simplicity, analysis times and non-use of derivatization and ion-pair agents.

Drug discovery and development is a very challenging, expensive and time-consuming process. Impressive technological advances in computer sciences and molecular biology have made it possible to use computer-aided drug design (CADD) methods in various stages of the drug discovery and development pipeline. Nowadays, CADD presents an efficacious and indispensable tool, widely used in medicinal chemistry, to lead rational drug design and synthesis of novel compounds. In this article, an overview of commonly used CADD approaches from hit identification to lead optimization was presented. Moreover, different aspects of design of multitarget ligands for neuropsychiatric and anti-inflammatory diseases were summarized. Apparently, designing multi-target directed ligands for treatment of various complex diseases may offer better efficacy, and fewer side effects. Antipsychotics that act through aminergic G protein-coupled receptors (GPCRs), especially dopamine D2 and serotonin 5-HT2A receptors, are the best option for treatment of various symptoms associated with neuropsychiatric disorders. Furthermore, multi-target directed cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibitors are also a successful approach to aid the discovery of new anti-inflammatory drugs with fewer side effects. Overall, employing CADD approaches in the process of rational drug design provides a great opportunity for future development, allowing rapid identification of compounds with the optimal polypharmacological profile., Proces otkrića i razvoja lekova je veoma zahtevan, skup i dugotrajan. Veliki tehnološki napredak u molekularnoj biologiji i kompjuterskim naukama je omogućio primenu metoda kompjuterski potpomognutog dizajniranja lekova (CADD) u različitim fazama procesa otkrića i razvoja lekova. Danas CADD predstavlja efikasnu i nezamenljivu alatku, koja se široko koristi u medicinskoj hemiji za racionalni dizajn i sintezu novih jedinjenja. U ovom preglednom radu biće prikazani CADD pristupi koji se najčešće koriste od procesa identifikacije hit jedinjenja do optimizacije lead jedinjenja. Pored toga, biće predstavljeni različiti aspekti u dizajnu višeciljnih liganada za neuropsihijatrijske i inflamatorne bolesti. Pokazano je da su ova jedinjenja veoma efikasna u lečenju složenih bolesti zbog veće efikasnosti i manje neželjenih efekata koje izazivaju. Antipsihotici koji deluju preko aminergičnih G-protein spregnutih receptora (GPCR), posebno preko dopaminskih D2 i serotoninskih 5-HT2A receptora, predstavljaju najbolju opcija za lečenje različitih simptoma povezanih sa neuropsihijatrijskim poremećajima. Pored toga, dizajn i sinteza dualnih inhibitora ciklooksigenaze-2 (COX-2) i 5lipoksigenaze (5-LOX) takođe predstavlja uspešan pristup u otkrivanju novih antiinflamatornih lekova sa manje neželjenih efekata. Na kraju se može zaključiti da primena CADD metoda u procesu racionalnog dizajniranja lekova pruža značajnu priliku za dalji napredak jer omogućava brzu identifikaciju jedinjenja sa optimalnim polifarmakološkim profilom.

A series of eleven 9-acridinyl amino acid derivatives were synthesized using a two-step procedure. Cytotoxicity was tested on the K562 and A549 cancer cell lines and normal diploid cell line MRC5 using the MTT assay. Compounds 6, 7, 8 and 9 were the most active, with IC50 values comparable to or lower than that of chemotherapeutic agent amsacrine. 8 and 9 were especially effective in the A549 cell line (IC50 ≈ 6 μM), which is of special interest since amsacrine is not sufficiently active in lung cancer patients. Cell cycle analysis revealed that 7 and 9 caused G2/M block, amsacrine caused arrest in the S phase, while 6 and 8 induced apoptotic cell death independently of the cell cycle regulation. In comparison to amsacrine, 6, 7, 8, and 9 showed similar inhibitory potential towards topoisomerase II, whereas only 7 showed DNA intercalation properties. In contrast to amsacrine, 6, 7, 8 and 9 showed a lack of toxicity towards unstimulated normal human leucocytes.

The electrochemical behavior of 9-chloroacridine (9Cl-A), a precursor molecule for synthesis of acridine derivatives with cytostatic activity, is a complex, pH-dependent, diffusion-controlled irreversible process. Oxidation of 9Cl-A initiates with the formation of a cation radical monomer, continues via the formation of a dimer subsequent oxidation to new cation radical. Reduction of 9Cl-A produces radical monomers which are stabilized by dimer formation. The investigation was performed using cyclic, differential pulse and square wave voltammetry at a glassy carbon electrode. The interaction between 9Cl-A and double-stranded DNA (dsDNA) was investigated using a multilayer dsDNA-electrochemical biosensor and 9Cl-A solutions from 1.0×10-7M (the lowest 9Cl-A concentration whose interaction with DNA was possible to detect) up to 1×10-4M. These allowed the binding constant, K=3.45×105M-1 and change in Gibbs free energy of the formed adsorbed complex to be calculated. Complex formation was a spontaneous process proceeding via 9Cl-A intercalation into dsDNA inducing structural changes. The intercalation of 9Cl-A into dsDNA was supported by molecular docking analysis. The combination of simple methodology and the use of biosensors to investigate DNA interactions is a powerful tool to offer insight into aspects of drug design during pharmaceutical development.

A simple and convenient reversed-phase high-performance liquid chromatography (RP-HPLC) method for simultaneous separation, identification, and determination of sodium metabisulfite and sodium benzoate in pharmaceutical formulation has been developed and validated. Chromatographic separation was achieved on RP column Zorbax Extend C-18 (150 x 4.6 mm i.d., 3.5 mu m particles), and mixture of 0.1% phosphoric acid and acetonitrile in the ratio 62: 38 (v/v) was used as a mobile phase. The flow rate was set at 1.0 mL/min with detection wavelength of 275 nm. The method was successfully validated according to International Conference on Harmonization (ICH) guidelines acceptance criteria. The method is selective, as no interferences were observed at retention times corresponding to these analytes. Results of regression analyses (r) and statistical insignificance of calibration curve intercepts (p) proved linearity of the method in defined concentration ranges for sodium metabisulfite and sodium benzoate (0.05-0.15 mg/mL). Relative standard deviations calculated for both analytes in precision testing were below the limits defined for active pharmaceutical ingredients (analysis repeatability: lt 2%; intermediate precision: lt 3%). Recovery values were between 98.16% and 101.94%. According to results of robustness testing, chromatographic parameters are not significantly influenced by small variation of acetonitrile content in mobile phase, column temperature, and flow rate. Finally, the method was applied for quantitative determination of investigated preservatives in real sample analysis.

Acetylsalicylic acid belongs to nonsteroidal anti-inflammatory drugs with antiinflammatory, analgesic and antipyretic properties. The aim of this work was development and validation of HPLC method for qualitative and quantitative analysis of acetylsalicylic acid and its major degradation product, salicylic acid, in dosage forms. The optimal separation was achived using Zorbax Eclipse XDB-C18 Analytical column (4,6x150 mm, particle size 5 μm) thermostated at 35°C. Mobile phase consisted of eluents A and B in ratio 65:35 (V/V). As the eluent A, water of HPLC purity and 85% phosphoric acid in ratio 80:0.5 (V/V) were used, while acetonitrile was used as the eluent B. The flow rate was 1.0 mL/min and UV detection was performed at 240 nm. The method was validated in terms of selectivity, linearity, precision, accuracy and robustness for both analytes, as well as limits of detection and quantification for salicylic acid. The obtained results meet the requirements of analytical procedures validation. The proposed HPLC method was applied in qualitative and quantitative analysis of acetylsalicylic and salicylic acids in six different forms of drugs. All obtained results meet the requirements of manufacturer specifications. The established HPLC method was found to be rapid, simple, accurate and selective for simultaneous determination of acetylsalicylic and salicylic acids in dosage forms., Acetilsalicilna kiselina pripada grupi nesteroidnih antiinflamatornih lekova koji ispoljavaju antiinflamatorno, analgetičko i antipiretičko delovanje. Cilj ovog rada je bio razvoj i validacija HPLC metode za kvalitativnu i kvantitativnu analizu acetilsalicilne kiseline i njenog degradacionog proizvoda, salicilne kiseline, u doziranim oblicima. Optimalno razdvajanje ispitivanih analita postignuto je na koloni Zorbax Eclipse XDB-C18 Analytical (4,6x150 mm, veličina čestica 5 μm) na temperaturi od 35°C. Mobilnu fazu čine smeša A i B u odnosu 65:35 (V/V). Smeša A je voda HPLC čistoće i 85% fosforna kiselina u odnosu 80:0,5 (V/V), a B je acetonitril. Protok je bio 1,0 mL/min, a talasna dužina detekcije 240 nm. Metoda je validirana i ispitani su sledeći parametri validacije: selektivnost, linearnost, preciznost, tačnost i robusnost za oba analita, kao i limiti detekcije i kvantifikacije za salicilnu kiselinu. Dobijene vrednosti su u skladu sa definisanim kriterijumima za validaciju metode. Predložena HPLC metoda je primenjena za kvalitativnu i kvantitativnu analizu acetilsalicilne i salicilne kiseline u šest različitih komercijalnih preparata. Svi rezultati ispitivanja su u dozvoljenim granicama specifikacija proizvođača. Predložena HPLC metoda pod datim eksperimentalnim uslovima predstavlja brz, jednostavan, tačan i selektivan postupak za istovremeno određivanje acetilsalicilne i salicilne kiseline u doziranim oblicima.

The biological activity of three previously synthesized 17 beta-carboxamide glucocorticoids (BG, BEG, and MPEA) was tested in vitro on mitogen stimulated and non-stimulated peripheral blood mononuclear cells (MNCs) and granulocytes from human healthy donors, and the results were compared to the conventional glucocorticoid dexamethasone. The tested 17 beta-carboxamide glucocorticoids did not induce decreases in MNC viability and proliferation, while modulation of reactive oxygen species (ROS) synthesis in granulocytes was dependent on the cell donor. The obtained results indicate the possibility of avoidance of strong lymphocyte suppression, which is generally recognized during administration of conventional glucocorticoids. Furthermore, the metabolism of the tested derivatives was predicted in silico. The predicted metabolites were synthesized and the in silico results were confirmed by in vitro evaluation of the metabolism of BG, BEG, and MPEA in human serum and in cultures of peripheral blood MNCs. The results of the biological activity and metabolism evaluation and of previous in vivo evaluations of biological activity indicate the soft drug nature of BG, BEG, and MPEA. In order to be fully considered as soft glucocorticoids, further investigations on the toxicity and activity of the formed metabolites are required.

Acridine ring can be found in molecules used in many different spheres, including industry and medicine. Nowadays, even acridines with antibacterial activity are of research interest due to increasing bacterial resistance. Some acridine derivatives showed antimalarial or antiviral activity. Acridine derivatives were also investigated for antitumor activity due to the interaction with topoisomerase II and DNA base pairs. Considering these possible uses of acridine derivatives, this work was made as overview of all significant structure characteristics for specific action of these compounds.

The biological activity of three previously synthesized 17 beta-carboxamide glucocorticoids (BG, BEG, and MPEA) was tested in vitro on mitogen stimulated and non-stimulated peripheral blood mononuclear cells (MNCs) and granulocytes from human healthy donors, and the results were compared to the conventional glucocorticoid dexamethasone. The tested 17 beta-carboxamide glucocorticoids did not induce decreases in MNC viability and proliferation, while modulation of reactive oxygen species (ROS) synthesis in granulocytes was dependent on the cell donor. The obtained results indicate the possibility of avoidance of strong lymphocyte suppression, which is generally recognized during administration of conventional glucocorticoids. Furthermore, the metabolism of the tested derivatives was predicted in silico. The predicted metabolites were synthesized and the in silico results were confirmed by in vitro evaluation of the metabolism of BG, BEG, and MPEA in human serum and in cultures of peripheral blood MNCs. The results of the biological activity and metabolism evaluation and of previous in vivo evaluations of biological activity indicate the soft drug nature of BG, BEG, and MPEA. In order to be fully considered as soft glucocorticoids, further investigations on the toxicity and activity of the formed metabolites are required.

Octanol-water partition coefficients (log Po/w) of fifteen previously synthesized 17 beta-carboxamide glucocorticoid derivatives and prednisolone were determined using shake-flask method. The retention behavior of selected compounds was tested in five reversed-phased thin-layer chromatography (RP-TLC) systems, consisting of water and organic solvent (acetonitrile, acetone, ethanol 96%, methanol, or tetrahydrofuran), and chromatography parameters (R-M(0), S, and C-0) were calculated. Simple linear regression (SLR) analysis was performed, and the correlation between log Po/w and chromatography parameters was tested. The most appropriate RP-TLC system for log Po/w prediction was that consisting of water and ethanol 96% as the mobile phase. Statisitical evaluation of the quality of models created using this system proved their reliability for log Po/w prediction of new 17 beta-carboxamide glucocorticoid derivatives, and the model with the most favorable statistical parameters was underlined.

The biological activity of three previously synthesized 17 beta-carboxamide glucocorticoids (BG, BEG, and MPEA) was tested in vitro on mitogen stimulated and non-stimulated peripheral blood mononuclear cells (MNCs) and granulocytes from human healthy donors, and the results were compared to the conventional glucocorticoid dexamethasone. The tested 17 beta-carboxamide glucocorticoids did not induce decreases in MNC viability and proliferation, while modulation of reactive oxygen species (ROS) synthesis in granulocytes was dependent on the cell donor. The obtained results indicate the possibility of avoidance of strong lymphocyte suppression, which is generally recognized during administration of conventional glucocorticoids. Furthermore, the metabolism of the tested derivatives was predicted in silico. The predicted metabolites were synthesized and the in silico results were confirmed by in vitro evaluation of the metabolism of BG, BEG, and MPEA in human serum and in cultures of peripheral blood MNCs. The results of the biological activity and metabolism evaluation and of previous in vivo evaluations of biological activity indicate the soft drug nature of BG, BEG, and MPEA. In order to be fully considered as soft glucocorticoids, further investigations on the toxicity and activity of the formed metabolites are required.

Type 2 diabetes is a metabolic syndrome characterized by relative insulin deficiency, insulin resistance and increased hepatic glucose output. Medications used to treat the disease (hypoglycemic agents) are divided in seven distinct classes. One of those classes, thiazolidindiones ('glitazones'), are known as insulin sensitizers and act mainly by improving peripheral uptake and utilization of glucose in muscle and fat, finally decreasing liver glucose production. These drugs activate one or more peroxisome proliferator-activated receptors (PPARs), which regulate gene expression in response to ligand binding. The thiazolidindiones differ by the nature of the groups attached to the 2,4-thiazolidindione nucleus. These agents are extensively metabolized with all metabolic changes occurring on thiazolidine ring or adjacent aryl group. Considerable interest in the metabolism of troglitazone exists, because hepatic toxicity may be associated with a quinone-type metabolite of troglitazone. Thiazolidindiones (rosiglitazone and pioglitazone) have been approved for monotherapy and combination therapy with metformin, sulfonylureas or insulin. Unfortunately, some studies and metaanalyses suggested that both drugs improve a number of cardiovascular risk factors and enhance incidence of heart failure., Dijabetes tipa 2 je metaboličko oboljenje koje karakteriše relativni nedostatak insulina, rezistencija na insulin i povećano oslobađanje glukoze iz jetre. Lekovi koji se koriste u terapiji ovog oboljenja (hipoglikemici) mogu se klasifikovati u sedam različitih grupa. Tiazolidindioni (glitazoni) povećavaju osetljivost na insulin, preuzimanje i potrošnju glukoze u mišićima i masnom tkivu, a sve to utiče na smanjeno oslobađanje glukoze iz jetre. Ovi lekovi su agonisti PPAR receptora (receptori aktivirani proliferatorom peroksizoma) i dovode do transkripcije gena uključenih u metabolizam glukoze i lipida. Tiazolidindioni se međusobno razlikuju po strukturi supstituenata na 2,4-tiazolidindionu. Podležu intenzivnom metabolizmu u jetri, sa svim metaboličkim promenama na tiazolidinskom prstenu ili susednoj aril grupi. Postoji veliko interesovanje za metabolizam troglitazona, jer se njegova hepatotoksičnost povezuje sa metabolitom troglitazona tipa hinona. Tiazolidindioni (rosigltazon i pioglitazon) su odobreni kao monoterapija ili u kombinaciji sa metforminom, derivatima sulfonilureje ili insulinom. Nažalost, novija istraživanja i meta-analize ukazale su na to da oba leka povećavaju faktore kardiovaskularnog rizika i učestalost srčane insuficijencije.

Biopartitioning micellar chromatography (BMC), which is useful to mimic the drug partitioning process in biological systems, was used as a method for determination of partition coefficients micelle/water (P-m/w) of a set of structurally diverse drugs. BMC is a chromatographic system consisting of polyoxyethylene (23) lauryl ether (Brij 35) micellar mobile phase prepared in physiological conditions and C-18 reversed stationary phase. The retention factors were determined for all selected and studied compounds and a correlation between P-m/w and oral drug absorption values were obtained. In order to study the similarity between the BMC system and other natural systems of biomembranes, the retention data on BMC were compared with permeability data obtained in Parallel artificial membrane permeation assays (PAMPA lipid model). Molecular descriptors that are believed to influence trans-cellular transport and oral drug absorption have been calculated in order to obtain a predictive and reliable model for drug permeability. Results presented in this paper indicate that a proposed descriptor for hydrophobicity P-m/w, provided, from a statistical point of view, is a better model than other hydrophobicity descriptors.

Analytical quality by design (AQbD)-oriented liquid chromatographic method development for determination of telmisartan and its impurities A, C, and 1 is determination is presented. Step-by-step process was conducted in order to define reliable design space. At the beginning, critical process parameters with the highest influence on method performance were defined: acetonitrile content in the first (ACN 1) and second (ACN 2) gradient step and time (t (2)) the second gradient step. These factors were varied according to Box-Behnken plan of experiments and their influence on retention times of impurities A and C, S value between telmisartan and impurity 1 and peak capacity were followed. In this way, the relationship between the critical process parameters and critical quality attributes was established. The obtained mathematical models and Monte Carlo simulations were used to identify the design space. Fractional factorial design was applied for experimental robustness testing, and the method was validated to verify the adequacy of selected optimal conditions. Finally, all validation parameters were tested, and adequacy of the method was confirmed. Applicability as a routine method was confirmed by analysis of commercially available tablets.

Today with the development of combinatorial chemistry hundreds and hundreds of compounds that have potential biological activity are synthesized. The studies which include the selection of drug candidates and the study of their pharmacological properties are time consuming, expensive and usually require the use of experimental animals. For ethical and/or economical reasons, a great deal effort is currently being made to develop in vitro systems and provide primary information about the capability of new compounds in the first steps of drug development. Chromatographic models to predict drug absorption are experimentally easier than membrane-based permeability assays, because of their simplicity, accuracy and avoidance of experimental animals. Different chromatographic systems have been proposed to predict oral drug absorption. The use of conventional reversed-phase columns only has proven to provide adequate correlations for homologous series of compounds. The inclusion of amphiphilic structures in the stationary and/or mobile phases is a pre-requisite to emulate interactions of drugs with the phospholipids bilayers in the membranes., Savremeni razvoj kombinatorijalne hemije omogućio je sintezu velikog broja jedinjenja sa potencijalnom biološkom aktivnošću. Ispitivanja koja uključuju izbor jedinjenja i studije farmakoloških osobina su dugotrajna, skupa i obično zahtevaju primenu eksperimentalnih životinja. Iz etičkih i/ili ekonomskih razloga, veliki napori ulažu se u razvoj in vitro sistema koji mogu da pruže značajne informacije u ranim fazama razvoja leka. Hromatografski modeli za predviđanje apsorpcije leka su eksperimentalno jednostavni, tačni i ne zahtevaju primenu eksperimentalnih životinja. Primena reverznofaznih hromatografskih sistema dala je dobre korelacije samo za homologe serije jedinjenja. Uvođenje amfifilnih struktura u stacionarnu i/ili mobilnu fazu je bitan uslov za simulaciju interakcija farmakološki aktivnih jedinjenja sa fosfolipidnim dvoslojem u membrani.

In this study, the interaction of valsartan (VAL), an angiotensin II receptor antagonist, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated. The effect of cationic micelles on spectroscopic and acid-base properties of VAL was carried out using UV spectrophotometry at physiological conditions (pH 7.4). The binding of VAL to CTAB micelles implied a shift in drug acidity constant (pK(a)(water) - pK(a)(micelle) = 1.69) proving the great affinity of VAL dianion for the positively charged CTAB micelle surface. To quantify the degree of VAL/CTAB interaction, two constants were calculated by using mathematical models: micelle/water partition coefficient (K-x) and drug/micelle binding constant (K-b). The decrease of K-x with VAL concentration, obtained by using pseudo-phase model, is consistent with an adsorption-like phenomenon. From the dependence of differential absorbance at lambda = 295 nm on CTAB concentration, by using mathematical model that treats the solubilization of VAL dianion as its binding to specific sites in the micelles (Langmuir adsorption isotherm), the binding constant (K-b = (2.50 +/- 10.49) x 10(4) M-1) was obtained. Binding constant VAL/CTAB was also calculated using micellar liquid chromatography (MLC).

In this study, the interaction of hydrochlorothiazide (HCT), benzothiadiazine diuretic, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated. The effect of cationic micelles on the spectroscopic and acid-base properties of HCT was studied at pH 10.5. The binding of HCT to CTAB micelles implied a shift in drug acidity constant (pK(a)(water) - pK(a)(micelle) =0.46) proving the greater affinity of HCT dianion for the positively charged CTAB micelle surface. From the dependence of differential absorbance at lambda = 355 nm on CTAB concentration, by using mathematical model that treats the solubilization of HCT dianion as its binding to specific sites in the micelles (Langmuir adsorption isotherm), the binding constant K-b = (1.17 +/- 0.16) x 10(4) mol(-1) dm(3) was obtained. By using pseudo-phase model, the partition coefficient between the bulk water and CTAB micelles, K-x, was calculated from both differential absorbance Delta A(355), K-x =(6.18 +/- 0.64) x 10(4) mol((1) dm(3), and first-order derivative amplitude D-1(250.1), K-x =(5.47 +/- 0.56) x 10(4) mol((1) dm(3).

A simple, precise and sensitive reverse-phase high performance liquid chromatographic (RP-HPLC) method has been developed for the quantitation of bifonazole, an imidazole antifungal, simultaneously with benzyl alcohol, used as preservative, in pharmaceutical formulations. Method employed Zorbax Eclipse XDB-C18 (250x4.6 mm i.d., 5 mu m) column, methanol-ammonium acetate (pH 2; 65 mM) (65:35, v/v, pH(*) 3.6) as mobile phase with flow rate of 1 mL min(-1) and variable UV detection at 220 and 252 nm. The proposed method was validated by testing its linearity, selectivity, recovery, repeatability, LOD/LOQ values and it was successfully employed for the determination of bifonazole and benzyl alcohol in pharmaceutical cream-based formulations.

In this paper optimization and validation of a new RP-HPLC method for simultaneous determination of bisoprolol fumarate, hydrochlorothiazide and impurities A, L, K and B are presented. Factors which could have significant influence on separation were selected: percentage of mobile phase B [acetonitrile-ammonium dihydrogen phosphate/orthophosphoric acid buffer solution (80:20, v/v)] at defined t (1) and t (2) of the gradient, ammonium dihydrogen phosphate concentration and pH value of the buffer solution (mobile phase A). Selected factors were varied according to Box-Behnken plan of experiments and their influence on critical pairs separation was investigated. DerringerA ' s desirability function was used for selection of optimal chromatographic conditions. Finally, optimal values of investigated factors were 34.4 % (t (1)) and 38.0 % (t (2)) of mobile phase B, 46.5 mM ammonium dihydrogen phosphate concentration and pH 3.35. The method was successfully validated according to ICH guidelines acceptance criteria for robustness, selectivity, linearity, accuracy and precision. Small variations of selected chromatographic parameters did not affect qualitative and quantitative system responses significantly, which proved the method's robustness. Limits of quantification (LOQ) and detection (LOD) for impurities were determined and LOQ values were the first points in linearity testing. Linearity was confirmed by r a parts per thousand yen 0.9945 (impurities) and r = 0.9998 (active substances). Accuracy was confirmed by calculated recoveries [93.5-107.1 % (impurities) and 98.1-101.9 % (active substances)]. Precision was tested at three levels: injection repeatability, analysis repeatability and intermediate precision. Calculated relative standard deviations were less than 1, 2 and 3 %, respectively. Finally, the method was applied to real sample analysis.

Cortienic acid was obtained by periodic acid oxidation of fluocinolone acetonide, whereas corresponding amide was synthesized from the cortienic acid and ethyl ester of b-alanine by dicyclohexylcarbodiimide - hydroxybenzotriazole coupling procedure. Lipophilicity of the amide was evaluated by using reversed-phase thin-layer chromatography systems, consisting of ethanol and water in various ratios, and was higher in comparison to fluocinolone acetonide and cortienic acid.

The proposed method for the determination of fluocortolone is based on the formation of a stable, yellow coloured hydrazone product with 1,4-dihydrazinophthalazine as the reagent. Heating at 85 °C for 2 h was found to be necessary to ensure optimal hydrazone formation in acidified 1-propanol as the solvent. The detection limit was 1.2 μg/ml. This method when applied for the determination of fluocortolone in pharmaceutical formulations gave precise and reproducible results., Predložena spektrofotometrijska metoda određivanja fluokortolona se zasniva na građenju žuto obojenog proizvoda tipa hidrazona sa 1,4-dihidrazinoftalazinom kao reagensom. Metoda je reproduktivna kada se reakcija izvodi iz 1-propanola kome je dodata koncentrovana kiselina, uz zagrevanje na 85 °C u toku 2 sata. Limit detekcije iznosi 1,2 μg/ml. Predložena spektrofotometrijska metoda je primenjena za određivanje sadržaja fluokortolona u farmaceutskim oblicima.

Fluocortolone and its esters are synthetic corticosteroids used topically in the treatment of various skin disorders. A method that can be successfully used for the separation and determination of fluocortolone pivalate and fluocortolone hexanoate in suppositories was developed. This method is based on reverse-phase HPLC on Supelcosil LC-18 (25 cm x 4.6 mm, 5 mu m), using methanol-acetonitrile-water-glacial acetic acid (17: 46:37:0.4 v/v/v/v) as mobile phase at a flow rate of 3.0 ml/min. Detection was carried out using a UV detector at 238 nm. The method developed was validated, and calibration curves were established dependent on peak area. The validated ranges for fluocortolone pivalate and fluocortolone hexanoate are 15-305 mu g/ml (r = 0.9995) and 15-315 mu g/ml (r = 0.9996), respectively. The limits of detection and the limits of quantification for both esters were also determined.

The L-phenylalanine methyl ester derivative of dexamethasone-derived cortienic acid (DF) was synthesized and its crystal structure characterized by the X-ray diffraction method. The crystal system is orthorhombic with space group P2(1)2(1)2(1) and cell constants a = 8.2969(3) angstrom, b = 18.9358(8) angstrom, c = 20.0904(6) angstrom, V = 3156.4(2) angstrom(3) and Z = 4. Ring A of the steroid nucleus and phenyl ring in the 17 beta-side chain are almost planar. Rings B and C have a slightly distorted chair conformation, whereas ring D has an envelope conformation. The packing of DF is characterized by a network of intermolecular hydrogen bonds involving the O4 atom from one side of the steroid nucleus and O1 and F1 atoms from the other side as hydrogen bond acceptors. Apart from the intermolecular hydrogen bonds in the crystal packing, there are also numerous intramolecular hydrogen bonds of the N-H center dot center dot center dot O, C-H center dot center dot center dot O and C-H center dot center dot center dot F type. The local anti-inflammatory activity of DF was evaluated using the croton oil-induced ear oedema test. This derivative achieved maximal inhibition of ear oedema at significantly lower concentration in comparison with dexamethasone.

The L-phenylalanine methyl ester derivative of dexamethasone-derived cortienic acid (DF) was synthesized and its crystal structure characterized by the X-ray diffraction method. The crystal system is orthorhombic with space group P2(1)2(1)2(1) and cell constants a = 8.2969(3) angstrom, b = 18.9358(8) angstrom, c = 20.0904(6) angstrom, V = 3156.4(2) angstrom(3) and Z = 4. Ring A of the steroid nucleus and phenyl ring in the 17 beta-side chain are almost planar. Rings B and C have a slightly distorted chair conformation, whereas ring D has an envelope conformation. The packing of DF is characterized by a network of intermolecular hydrogen bonds involving the O4 atom from one side of the steroid nucleus and O1 and F1 atoms from the other side as hydrogen bond acceptors. Apart from the intermolecular hydrogen bonds in the crystal packing, there are also numerous intramolecular hydrogen bonds of the N-H center dot center dot center dot O, C-H center dot center dot center dot O and C-H center dot center dot center dot F type. The local anti-inflammatory activity of DF was evaluated using the croton oil-induced ear oedema test. This derivative achieved maximal inhibition of ear oedema at significantly lower concentration in comparison with dexamethasone.

The L-phenylalanine methyl ester derivative of dexamethasone-derived cortienic acid (DF) was synthesized and its crystal structure characterized by the X-ray diffraction method. The crystal system is orthorhombic with space group P2(1)2(1)2(1) and cell constants a = 8.2969(3) angstrom, b = 18.9358(8) angstrom, c = 20.0904(6) angstrom, V = 3156.4(2) angstrom(3) and Z = 4. Ring A of the steroid nucleus and phenyl ring in the 17 beta-side chain are almost planar. Rings B and C have a slightly distorted chair conformation, whereas ring D has an envelope conformation. The packing of DF is characterized by a network of intermolecular hydrogen bonds involving the O4 atom from one side of the steroid nucleus and O1 and F1 atoms from the other side as hydrogen bond acceptors. Apart from the intermolecular hydrogen bonds in the crystal packing, there are also numerous intramolecular hydrogen bonds of the N-H center dot center dot center dot O, C-H center dot center dot center dot O and C-H center dot center dot center dot F type. The local anti-inflammatory activity of DF was evaluated using the croton oil-induced ear oedema test. This derivative achieved maximal inhibition of ear oedema at significantly lower concentration in comparison with dexamethasone.

Primena konvecionalnih glukokortikoida je pra'ena brojnim lokalnim i sistemskim neželjenim efektima..., The use of traditional glucocorticoids is accompained with various local and systemic side effects...

Primena konvecionalnih glukokortikoida je pra'ena brojnim lokalnim i sistemskim neželjenim efektima..., The use of traditional glucocorticoids is accompained with various local and systemic side effects...

In this paper, twenty-two 17 beta-carboxamide steroids were synthesized from five corticosteroids (hydrocortisone, prednisolone, methylprednisolone, dexamethasone and betamethasone) in two steps. The first step was periodic acid oxydation of these corticosteroids to corresponding cortienic acids and the second step was amidation of thus obtained cortienic acids with esterified L-amino acids. These compounds are potential soft corticosteroids with local anti-inflammatory activity in the skin. Parallel artificial membrane permeability assay (PAMPA) was applied in order to predict permeability and retention of these compounds in human skin. Comparison of permeability and retention parameters between 17 beta-carboxamide steroids and corresponding corticosteroids was performed. Compounds with significantly higher retention were identified and the derivative that does not have significantly higher permeability was underlined. Molecular structures of all compounds were optimized by use of Gaussian semiempirical/PM3 method. Geometrical, thermodynamic, physicochemical and electronical molecular parameters of the optimized structures were calculated and quantitative structure-property relationship (QSPR) analysis was performed in order to explain permeability and retention of these compounds. ANN-, PLS- and MLR-QSPR models were created. Quality of these models was evaluated by commonly used statistical parameters and the most reliable models were selected. Analyzing descriptors in the selected models, main molecular properties that influence permeability and retention in the PAMPA artificial membrane were identified. Based on these data, further structural modifications could be applied in order to increase retention without significant increase of permeability, which can positively affect potential local antiinflammatory activity of these compounds. Selected QSPR models could be used as in silico tool for predicting human skin permeability and retention of novel 17 beta-carb

Soft ('antedrug') glucocorticoids are pharmacologically active compounds which are biotransformed in a predictable and controllable way to inactive and non-toxic metabolites. Amides of cortienic acids (17(-carboxamide derivatives of glucocorticoids) are potential soft drugs with fewer side effects than traditional glucocorticoids. The purification of 17(- carboxamide derivatives of hydrocortisone was explained using the amide of hydrocortisonederived cortienic acid and ethyl ester of L-glycine as an example and performed by use of column chromatography and preparative thin-layer chromatography (TLC). The optimization of purification process was performed employing analytical TLC and reversed-phase highperformance liquid chromatography (RP-HPLC). The mobile phase that enables best chromatographic separation of the amide from impurities on TLC plate (chloroform-methanol (95:5 V/V)) was selected and modified (reduction of polarity and addition of glacial acetic acid) to be used for the column chromatography and preparative TLC purification. It was confirmed by use of RP-HPLC that purification procedures applied in this study resulted in pure (96.2 %) amide., Soft ('antedrug') glukokortikoidi su farmakološki aktivna jedinjenja koja se biotransformišu na predvidiv i kontrolisan način do neaktivnih i netoksičnih metabolita. Amidi kortienskih kiselina (17(-karboksamidni derivati glukokortikoida) su potencijalni soft lekovi sa manje neželjenih efekata u odnosu na konvencionalne glukokortikoide. Prečišćavanje 17(- karboksamidnih derivata hidrokortizona je prikazano na primeru amida kortienske kiseline iz hidrokortizona i etil estra L-glicina i vrši se primenom hromatografije na koloni i preparativne tankoslojne hromatografije (TLC). Optimizacija procesa prečišćavanja je izvršena primenom analitičke TLC i reverzno-fazne tečne hromatografije pod visokim pritiskom (RP-HPLC). Mobilna faza koja omogućuje najbolje hromatografsko razdvajanje amida od nečistoća na TLC pločici (hloroform-metanol (95:5 V/V) je odabrana i izvršena je njena modifikacija (smanjenje polarnosti, odnosno dodatak glacijalne sirćetne kliseline) u cilju prečišćavanja hromatografijom na koloni, odnosno preparativnom TLC. Primenom RP-HPLC je potvrđeno da su navedeni postupci prečišćavanja omogućili dobijanje amida stepena čistoće 96,2 %.

In this paper, human skin and corneal permeability of twenty-two newly synthesized 17 beta-carboxamide steroids was predicted using biopartitioning micellar chromatography (BMC). These compounds are potential soft glucocorticoids with local anti-inflammatory activity when applied to the skin or eye. BMC systems are used to simulate physicochemical properties of human skin (BMC-skin) and cornea (BMC-cornea). Micellar mobile phase, consisted of 0.04 M solution of polyoxyethylene (23) lauryl ether (Brij 35), was prepared at different pH values - 5.50 (BMC-skin) and 7.50 (BMC-cornea). Retention factors (k), obtained by use of BMC, were calculated for all newly synthesized 17 beta-carboxamide steroids as well as for parent glucocorticoids (hydrocortisone, prednisolone, methylprednisolone, dexamethasone and betamethasone). Good correlation was obtained between BMC-skin retention factors and permeability coefficients calculated by use of the artificial membrane that simulates stratum corneum of the human skin. Quantitative structure-retention relationship (QSRR) study was performed in order to explain retention factors of these compounds in the tested BMC systems. ANN-QSRR(k), PLS-QSRR(k) and MLR-QSRR(k) models, created by use of BMC-skin retention data, were compared and optimal model (PLS-QSRR(k)) was selected. Molecular descriptors of the selected model indicate that lipophilicity and number of short C C fragments of tested compounds have the strongest influence on the retention in the BMC-skin system and presumably on their in vivo permeability through human skin. The same model can be applied to the BMC-cornea system and the same conclusion can be drawn for corneal permeability. This model could be used as a predictive tool for the synthesis of novel 17 beta-carboxamide steroids with desirable permeability through human skin or cornea, depending on their potential pharmacological application.

Molecular docking studies were performed on 18 17-carboxamide steroids in order to select compounds with potential local anti-inflammatory activity. These derivatives are amides of cortienic acids (obtained from hydrocortisone, prednisolone, and methylprednisolone) with methyl or ethyl esters of six amino acids. Interactions with the glucocorticoid receptor (GR), binding energies and ligand efficiency values of these compounds were compared with dexamethasone and cortienic acid obtained from prednisolone (inactive metabolite). On the basis of molecular docking studies, seven compounds were selected and their binding affinities for the GR were predicted by use of the exponential model created in this study. Subsequently, selected compounds were synthesized in good yields by use of modified N,N-dicyclohexylcarbodiimide (DCC)/1-hydroxybenzotriazole (HOBt) coupling procedure. Finally, the local anti-inflammatory activity of the synthesized compounds was examined by use of the croton oil-induced ear edema test. In vivo evaluation of systemic side effects as well as in silico prediction of metabolism were performed on the derivative with the best local anti-inflammatory activity. The combination of molecular docking studies and the exponential model for the GR binding affinity prediction could be used as an in silico tool for the rational design of novel 17-carboxamide steroids with potentially better biological profile than dexamethasone.

U ovoj doktorskoj disertaciji opisana je sinteza šest halkonskih intermedijera kao prekursora za sintezu šest novih aminoalkoksi derivata fenilpropiofenona i flavanona. Aminoalkoksi derivati fenilpropiofenona su strukturni analozi postojećeg antiaritmika Ic grupe, propafenona. U položaje 2 i 4 terminalnog benzenovog prstena uvođeni su supstituenti koji modifikuju hidrofobne i elektronske osobine molekula u cilju povećanja selektivnosti i potentnosti prema određenom tipu jonskog kanala. Sinteza propafenonskih derivata obuhvata pet faza: aldolnu kondenzaciju; katalitičku hidrogenizaciju; formiranje epoksida; aminolizu i građenje hidrohloridnih soli. Ako se alkalni, vodeno-etanolni rastvor trifluorometil halkona podvrgne dejstvu povišene temperature, nastaje flavanon koji hlađenjem kristališe u vidu igličastih kristala. Čistoća i struktura sintetisanih jedinjenja potvrđena je hromatografskim i spektroskopskim metodama, dok je struktura sintetisanog flavanona potvrđena i kristalografski. Vazorelaksantna aktivnost propafenona i novosintetisanih derivata (1-100 μM) ispitana je na izolovanoj aorti pacova sa i bez endotela, koja je prethodno prekontrahovana rastvorom fenilefrina (10 μM). Svih šest sintetisanih derivata, uključujući i propafenon, pokazali su doznozavisni vazorelaksantni efekat za koji je eksperimentalno potvrđeno da nije endotel zavisan. Učešće jonskih kanala u vazorelaksantnom mehanizmu dejstva derivata propafenona ispitano je u prisustvu: lidokaina, antagoniste Na+ kanala (3 mM), nifedipina, selektivnog antagoniste LCa2+ kanala (1 μM) i 4-aminopiridina (4-AP), neselektivnog antagoniste K+ kanala (3 mM). Dobijeni rezultati ukazuju da su jonski kanali uključeni u mehanizam vazorelaksantnog dejstva i da uvedene strukturne modifikacije u molekulu propafenona doprinose postizanju izvesnog stepena selektivnosti. 4-AP antagonizovao je efekat derivata koji u para položaju terminalnog benzenovog prstena ima –CH3 grupu (5PCH3). Srednja efektivna koncentracija za der

U ovoj doktorskoj disertaciji opisana je sinteza šest halkonskih intermedijera kao prekursoraza sintezu šest novih aminoalkoksi derivata fenilpropiofenona i flavanona. Aminoalkoksiderivati fenilpropiofenona su strukturni analozi postojećeg antiaritmika Ic grupe, propafenona.U položaje 2 i 4 terminalnog benzenovog prstena uvođeni su supstituenti koji modifikujuhidrofobne i elektronske osobine molekula u cilju povećanja selektivnosti i potentnosti premaodređenom tipu jonskog kanala. Sinteza propafenonskih derivata obuhvata pet faza: aldolnukondenzaciju; katalitičku hidrogenizaciju; formiranje epoksida; aminolizu i građenjehidrohloridnih soli. Ako se alkalni, vodeno-etanolni rastvor trifluorometil halkona podvrgnedejstvu povišene temperature, nastaje flavanon koji hlađenjem kristališe u vidu igličastihkristala. Čistoća i struktura sintetisanih jedinjenja potvrđena je hromatografskim ispektroskopskim metodama, dok je struktura sintetisanog flavanona potvrđena i kristalografski.Vazorelaksantna aktivnost propafenona i novosintetisanih derivata (1-100 μM) ispitana jena izolovanoj aorti pacova sa i bez endotela, koja je prethodno prekontrahovana rastvoromfenilefrina (10 μM). Svih šest sintetisanih derivata, uključujući i propafenon, pokazali su doznozavisnivazorelaksantni efekat za koji je eksperimentalno potvrđeno da nije endotel zavisan.Učešće jonskih kanala u vazorelaksantnom mehanizmu dejstva derivata propafenona ispitano jeu prisustvu: lidokaina, antagoniste Na+ kanala (3 mM), nifedipina, selektivnog antagoniste LCa2+kanala (1 μM) i 4-aminopiridina (4-AP), neselektivnog antagoniste K+ kanala (3 mM).Dobijeni rezultati ukazuju da su jonski kanali uključeni u mehanizam vazorelaksantnog dejstva ida uvedene strukturne modifikacije u molekulu propafenona doprinose postizanju izvesnogstepena selektivnosti. 4-AP antagonizovao je efekat derivata koji u para položaju terminalnogbenzenovog prstena ima –CH3 grupu (5PCH3). Srednja efektivna koncentracija za derivat5PCH3 (pEC50 4,41

Series of twelve chalcone and propafenone derivatives has been synthesized and evaluated for anticancer activities against Hela, Fem-X, PC-3, MCF-7, LS174 and K562 cell lines. The 2D-QSAR and 3D-QSAR studies were performed for all compounds with cytotoxic activities against each cancer cell line. Partial least squares (PLS) regression has been applied for selection of the most relevant molecular descriptors and QSAR models building. Predictive potentials of the created 2D-QSAR and 3D-QSAR models for each cell line were compared, by use of leave-one-out cross-validation and external validation, and optimal QSAR models for each cancer cell line were selected. The QSAR studies have selected the most significant molecular descriptors and pharmacophores of the chalcone and propafenone derivatives and proposed structures of novel chalcone and propafenone derivatives with enhanced anticancer activity on the HeLa, Fem-X, PC-3, MCF-7, LS174 and K562 cells.

The partition coefficients (log P) of theoretically possible alkyliodinated iminodiacetic acid (IDA) derivatives and commercial IDA derivatives were calculated using two computer programs: ChemSketch Log P and ChemOffice Ultra. Newly synthesized ligands (DIETHYLIODIDA and DIISOPROPYLIODIDA) with the highest calculated log P were labeled with technetium-99m. The biodistribution and the influence of bilirubin on their biokinetics were investigated in rats and compared to corresponding results for commercial Tc-99m-BROMIDA. Log P of Tc-99m-complexes of synthesized ligands were determined experimentally as well as the protein binding. In comparison to Tc-99m-BROMIDA, Tc-99m-DIETHYLIODIDA has: (a) better biliary excretion (2.76 +/- 0.15%ID/g versus 1.83 +/- 0.10%ID/g); (b) faster hepatic clearance (2.90 +/- 0.21%ID/g versus 7.47 +/- 0.70%ID/g) and decreased biliary excretion (for 14% versus 22%) in conditions of hyperbilirubinemia after 15 min. It is proved that Tc-99m-DIISOPROPYLIODIDA has a prolonged hepatic transit time and decreased biliary excretion.

The partition coefficients (log P) of theoretically possible alkyliodinated iminodiacetic acid (IDA) derivatives and commercial IDA derivatives were calculated using two computer programs: ChemSketch Log P and ChemOffice Ultra. Newly synthesized ligands (DIETHYLIODIDA and DIISOPROPYLIODIDA) with the highest calculated log P were labeled with technetium-99m. The biodistribution and the influence of bilirubin on their biokinetics were investigated in rats and compared to corresponding results for commercial Tc-99m-BROMIDA. Log P of Tc-99m-complexes of synthesized ligands were determined experimentally as well as the protein binding. In comparison to Tc-99m-BROMIDA, Tc-99m-DIETHYLIODIDA has: (a) better biliary excretion (2.76 +/- 0.15%ID/g versus 1.83 +/- 0.10%ID/g); (b) faster hepatic clearance (2.90 +/- 0.21%ID/g versus 7.47 +/- 0.70%ID/g) and decreased biliary excretion (for 14% versus 22%) in conditions of hyperbilirubinemia after 15 min. It is proved that Tc-99m-DIISOPROPYLIODIDA has a prolonged hepatic transit time and decreased biliary excretion. (c) 2012 Elsevier Ltd. All rights reserved.

The partition coefficients (log P) of theoretically possible alkyliodinated iminodiacetic acid (IDA) derivatives and commercial IDA derivatives were calculated using two computer programs: ChemSketch Log P and ChemOffice Ultra. Newly synthesized ligands (DIETHYLIODIDA and DIISOPROPYLIODIDA) with the highest calculated log P were labeled with technetium-99m. The biodistribution and the influence of bilirubin on their biokinetics were investigated in rats and compared to corresponding results for commercial Tc-99m-BROMIDA. Log P of Tc-99m-complexes of synthesized ligands were determined experimentally as well as the protein binding. In comparison to Tc-99m-BROMIDA, Tc-99m-DIETHYLIODIDA has: (a) better biliary excretion (2.76 +/- 0.15%ID/g versus 1.83 +/- 0.10%ID/g); (b) faster hepatic clearance (2.90 +/- 0.21%ID/g versus 7.47 +/- 0.70%ID/g) and decreased biliary excretion (for 14% versus 22%) in conditions of hyperbilirubinemia after 15 min. It is proved that Tc-99m-DIISOPROPYLIODIDA has a prolonged hepatic transit time and decreased biliary excretion. (c) 2012 Elsevier Ltd. All rights reserved.

Hepatobiliary scintigraphy (Cholescintigraphy) is a nuclear imaging procedure for morphological and functional investigation of hepatobiliary system. 99mTc-IDA derivatives are commonly used for hepatobiliary imaging. Biological properties of IDA analogues are determined by chemical structure. Corresponding molecular mass, lipophilicity, protein binding, as well as nature and position of substituents attached to the phenyl ring have major influence on biokinetics (the degree of hepatic uptake and the rate of excretion, as well as urinary elimination) of the 99mTc-IDA complexes. Since bilirubin competes with IDA derivatives, hyperbilirubinemia represents the limiting factor in the application of 99mTc-IDA analogues as hepatobiliary imaging agents. This paper's goal is to give a review of the most important data about physico-chemical and biological properties of numerous 99mTc-IDA analogues which are synthesized and evaluated as potential radiopharmaceuticals, and also those which are commercially used as diagnostics agents. Of all IDA derivatives, 99mTc-mebrofenin is the agents of choice for hepatobiliary imaging in hiperbilirubinemia conditions., Hepatobilijarna scintigrafija (HBS) predstavlja značajnu nuklearno-medicinsku metodu za morfološka i funkciona ispitivanja hepatobilijarnog sistema. Uobičajeno se za ova ispitivanja koriste 99mTc-IDA analozi. Biološke osobine IDA analoga određene su njihovom hemijskom strukturom. Odgovarajuća molekulska masa, lipofilnost, proteinsko vezivanje, kao i vrsta i položaj supstituenata u aromatičnom sistemu imaju presudan uticaj na biokinetiku (visoko nakupljanje i brz transport kroz hepatocite, visoku bilijarnu i minimalnu renalnu ekskreciju) 99mTc-IDA kompleksa. Pošto bilirubin ulazi u kompeticiju sa IDA analozima, hiperbilirubinemija može ograničavati primenu 99mTc-IDA analoga kao hepatobilijarnih agenasa. Ovaj rad ima za cilj da pruži pregled najvažnijih podataka o fizičko-hemijskim i biološkim osobinama brojnih 99mTc-IDA analoga koji su sintetisani i ispitani kao potencijalni radiofarmaceutici, kao i onih koji se komercijalno koriste kao dijagnostička sredstva. Od svih IDA analoga, 99mTc-mebrofenin predstavlja agens izbora za hepatobilijarna ispitivanja u uslovima hiperbilirubinemije.

The permeation properties of twenty newly synthesized alpha-alkoxyalkanoyl and alpha-aryloxyalkanoyl C-21 esters of standard corticosteroids: Fluocinolone acetonide, dexamethasone, triamcinolone acetonide and hydrocortisone were established using a PAMPA assay (70% silicone oil and 30% isopropyl myristate). The data were compared with parent corticosteroids with addition of mometasone furoate and hydrocortisone acetate. All newly synthesized corticosteroid C-21 esters have effective permeability coefficients higher then -6, mostly followed with high values of retention factors and low permeation. The examined compounds were grouped through relationship between obtained retention factors and permeation parameters (groups I-III). The classification confirmed group I (membrane retentions as well as permeation lower then 30%) for all corticosteroid standards except mometasone furoate, a potent topical corticosteroid which, with high membrane retention (81%) and low permeation (7.7%) fits into group III. The largest number of new synthesized corticosteroids C-21 esters, among them all fluocinolone acetonide C-21 esters, have high membrane retentions (32.4%-86.5%) and low permeations (1.3%-27.1%), fitting in group III. The classification was related to previously obtained anti-inflammatory activity data for the fluocinolone acetonide C-21 esters series. According to the PAMPA results the new synthesized esters could be considered as potential new prodrugs with useful benefit/risk ratio.

In this study the solvolysis of newly synthesized fluocinolone acetonide C-21 esters was analysed in comparison with fluocinonide during a 24-hour period of time. The solvolysis was performed in an ethanol-water (90:10 v/v) mixture using the excess of NaHCO(3). The solvolytic mixtures of each investigated ester have been assayed by a RP-HPLC method using isocratic elution with methanol-water (75:25 v/v); flow rate 1 mL/min; detection at 238 nm; temperature 25 degrees C. Solvolytic rate constants were calculated from the obtained data. Geometry optimizations and charges calculations were carried out by Gaussian W03 software. A good correlation (R = 0.9924) was obtained between solvolytic rate constants and the polarity of the C-O2 bond of those esters. The established relation between solvolytic rate constant (K) and lipophilicity (cLogP) with experimental anti-inflammatory activity could be indicative for topical corticosteroid prodrug activation.

In this study the solvolysis of novel fluocinolone acetonide 21-(2'-phenoxypropionate) in comparison with fluocinonide was analyzed in order to evaluate this process as an in vitro model for prodrug activation. The solvolysis was performed in ethanol: water (90: 10 v/v) mixture using the excess of NaHCO3. The solvolytic mixtures of those esters with different lipophilicity were assayed by proposed RP-HPLC method using isocratic elution with methanol: water (75: 25 v/v); flow rate 1 mL min(-1), and detection at 238 nm. Solvolytic rate constants (at 25 degrees C) for novel prodrug fluocinolone acetonide 21-(2'-phenoxypropionate) (0.0434 h(-1)) and fluocinonide (0.0593 h(-1)) have been compared. This in vitro model of solvolysis and corresponding rate constants are in good correlation with our preliminary data of anti-inflammatory potencies of those prodrugs. Limits of detection, important for the initial stage of solvolysis, were experimentally determined with values of 4.10 mu M and 0.24 mu M for fluocinolone acetonide 21-(2'-phenoxypropionate) and fluocinonide, respectively.

A novel topical corticosteroid FA-21-PhP, 2-phenoxypropionate ester of fluocinolone acetonide, has been synthesized in order to investigate the possibility of decreasing systemic side effects. In this study model system for in vitro solvolytic reaction of FA-21-PhP has been analyzed in ethanol/water (90:10, v/v) with excess of sodium hydrogen carbonate. The selected conditions have been used as in vitro model for activation of corticosteroid C-21 ester prodrug. The second-order derivative spectrophotometric method (DS) using zero-crossing technique was developed for monitoring ternary mixture of solvolysis. Fluocinolone acetonide (FA) as a solvolyte was determined in the mixture in the concentration range 0.062-0.312 mM using amplitude (2)D(274.9G). Experimentally determined LOD value was 0.0295 mM. The accuracy of proposed DS method was confirmed with HPLC referent method. Peak area of parent ester FA-21-PhP was used for solvolysis monitoring to ensure the initial stage of changes. Linear relationship in HPLC assay for parent ester was obtained in the concentration range 0.054-0.54 mM, with experimentally determined LOD value of 0.0041 mM. Investigated solvolytic reaction in the presence of excess of NaHCO(3) proceeded via a pseudo-first-order kinetic with significant correlation coefficients 0.9891 and 0.9997 for DS and HPLC, respectively. The values of solvolysis rate constant calculated according to DS and HPLC methods are in good accordance 0.038 and 0.043 h(-1), respectively.

In this study, the interaction of valsartan (VAL), an angiotensin II receptor antagonist, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated. The effect of cationic micelles on spectroscopic and acid-base properties of VAL was carried out using UV spectrophotometry at physiological conditions (pH 7.4). The binding of VAL to CTAB micelles implied a shift in drug acidity constant (pK(a)(water) - pK(a)(micelle) = 1.69) proving the great affinity of VAL dianion for the positively charged CTAB micelle surface. To quantify the degree of VAL/CTAB interaction, two constants were calculated by using mathematical models: micelle/water partition coefficient (K-x) and drug/micelle binding constant (K-b). The decrease of K-x with VAL concentration, obtained by using pseudo-phase model, is consistent with an adsorption-like phenomenon. From the dependence of differential absorbance at lambda = 295 nm on CTAB concentration, by using mathematical model that treats the solubilization of VAL dianion as its binding to specific sites in the micelles (Langmuir adsorption isotherm), the binding constant (K-b = (2.50 +/- 10.49) x 10(4) M-1) was obtained. Binding constant VAL/CTAB was also calculated using micellar liquid chromatography (MLC). (C) 2008 Elsevier B.V. All rights reserved.

The interaction of valsartan (VAL), an angiotensin II receptor antagonist, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated. To quantify the degree of VAL/CTAB interactions, two constants were calculated by using mathematical models: micelle/water partition coefficient and drug/micelle binding constant.

In this study, the interaction of valsartan (VAL), an angiotensin II receptor antagonist, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated. The effect of cationic micelles on spectroscopic and acid-base properties of VAL was carried out using UV spectrophotometry at physiological conditions (pH 7.4). The binding of VAL to CTAB micelles implied a shift in drug acidity constant (pK(a)(water) - pK(a)(micelle) = 1.69) proving the great affinity of VAL dianion for the positively charged CTAB micelle surface. To quantify the degree of VAL/CTAB interaction, two constants were calculated by using mathematical models: micelle/water partition coefficient (K-x) and drug/micelle binding constant (K-b). The decrease of K-x with VAL concentration, obtained by using pseudo-phase model, is consistent with an adsorption-like phenomenon. From the dependence of differential absorbance at lambda = 295 nm on CTAB concentration, by using mathematical model that treats the solubilization of VAL dianion as its binding to specific sites in the micelles (Langmuir adsorption isotherm), the binding constant (K-b = (2.50 +/- 10.49) x 10(4) M-1) was obtained. Binding constant VAL/CTAB was also calculated using micellar liquid chromatography (MLC). (C) 2008 Elsevier B.V. All rights reserved.

In this study, the interaction of the anion of quinapril (QUIN), angiotensin converting enzyme (ACE) inhibitor, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated. The effect of cationic micelles on the spectroscopic and acid-base properties of QUIN was studied at pH 8. The binding of QUIN anion to CTAB micelles implied a shift in drug acidity constant (pK(a)(water) - pK(a)(micelle) = 1.39) proving the great affinity of negatively charged QUIN ion for the positively charged CTAB micelle surface. The strong dependence of the partition coefficient K-x on QUIN concentration, obtained by using pseudo-phase model, is consistent with an adsorption-like phenomenon. From the dependence of differential absorbance at lambda = 272 nm on CTAB concentration, by using mathematical model that treats the solubilization of QUIN anion as its binding to specific sites in the micelles (Langmuir adsorption isotherm), the binding constant K-b = (2.3 +/- 0.4) x 10(3) mol(-1) dm(3) was obtained. QUIN-CTAB binding constant was also calculated from micellar liquid chromatography (MLC) and this method was found to be not accurate enough for its determination. (c) 2006 Elsevier Inc. All rights reserved.

In this study, the interaction of the anion of quinapril (QUIN), angiotensin converting enzyme (ACE) inhibitor, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated. The effect of cationic micelles on the spectroscopic and acid-base properties of QUIN was studied at pH 8. The binding of QUIN anion to CTAB micelles implied a shift in drug acidity constant (pK(a)(water) - pK(a)(micelle) = 1.39) proving the great affinity of negatively charged QUIN ion for the positively charged CTAB micelle surface. The strong dependence of the partition coefficient K-x on QUIN concentration, obtained by using pseudo-phase model, is consistent with an adsorption-like phenomenon. From the dependence of differential absorbance at lambda = 272 nm on CTAB concentration, by using mathematical model that treats the solubilization of QUIN anion as its binding to specific sites in the micelles (Langmuir adsorption isotherm), the binding constant K-b = (2.3 +/- 0.4) x 10(3) mol(-1) dm(3) was obtained. QUIN-CTAB binding constant was also calculated from micellar liquid chromatography (MLC) and this method was found to be not accurate enough for its determination. (c) 2006 Elsevier Inc. All rights reserved.

A simple and sensitive reversed-phase, ion-pair HPLC method was developed and validated for the simultaneous determination of B-group vitamins, thiamine chloride hydrochloride (B1), nicotinamide (B3), pyridoxine hydrochloride (B6) and folic acid in Pentovit® coated tablets. The cyanocobalamine (B12) was determined separately, because of its low concentration in the investigated multivitamin preparation. RP-HPLC analysis was per- formed with a LKB 2150 HPLC system, equipped with a UV/VIS Waters M 484 detector. The procedures for the determination of B1, B2, B6 and folic acid were carried out on a Supelcosil ABZ+ (15 cm 4.6 mm; 5 m) column with methanol-5mM heptanesulphonic acid sodium salt 0.1 % triethylamine TEA (25:75 V/V); pH 2.8 as the mobile phase. For the determination of B12 a Suplex pKb-100 (15 cm 4.6 mm; 5 m) column and methanol–water (22:78 V/V) as the mobile phase were used. The column effluents were monitored at 290 nm for B1, B3, B6 and folic acid, and at 550 nm for B12. The obtained results and statistical parameters for all the investigated vitamins of the B-group in Pentovit® coated tablets were satisfactory and ranged from 90.4 % to 108.5 % (RSD. from 0.5 % to 4.1 %). The parameters for the validation of the methods are given., Za istovremeno određivanje vitamina B-kompleksa, tiamin-hlorida-hidrohlorida (B1), nikotinamida (B3), piridoksin-hidrohlorida (B6) i folne kiseline u Pentovit® tabletama primenjena je i validirana jednostavna i osetqiva metoda reverzno-fazne jon-par tečne hromatografije pod visokim pritiskom. Zbog niske koncentracije u ispitivanom preparatu cijanokobalamin (B12) je određen pod drugim uslovima. Određivanje vitamina B1, B3, B6 i folne kiseline izvedeno je na LKB 2150 HPLC sistemu, sa UV/VIS Waters M 484 detektorom, korišćewem Supelcosil ABZ+ kolone (15 cm x 4,6 mm; 5 _m) sa mobilnom fazom metanol – 5 mM natrijum-heptansulfonat/0,1 % trietilamin (25:75 V/V) pri pH 2,8. Za određivanje vitamina B12 korišćena je kolona Suplex pKb-100 (15 cm x 4,6 mm; 5 nm) i mobilna faza metanol–voda (22:78 V/V). Vitamini B1, B3, B6 i folna kiselina detektovani su na 290 nm, a vitamin B12 na 550nm. Dobijene vrednosti sadržaja i statistički parametri za sve vitamine B-kompleksa u Pentovit® tabletama su zadovoljavajući i kreću se u opsegu od 90,4%do 108,5% (RSD od 0,5%do 4,1 %). Prikazani su i parametri za validaciju metode.