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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 C18 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 transcellular 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. [ABSTRACT FROM PUBLISHER]

Abstract: 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 () proving the great affinity of negatively charged QUIN ion for the positively charged CTAB micelle surface. The strong dependence of the partition coefficient on QUIN concentration, obtained by using pseudo-phase model, is consistent with an adsorption-like phenomenon. From the dependence of differential absorbance at 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 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. [Copyright &y& Elsevier]

Abstract: 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 (-=0.46) proving the greater affinity of HCT dianion for the positively charged CTAB micelle surface. From the dependence of differential absorbance at λ=355nm 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 Kb=(1.17±0.16)×104mol-1dm3 was obtained. By using pseudo-phase model, the partition coefficient between the bulk water and CTAB micelles, Kx, was calculated from both differential absorbance ΔA355, Kx=(6.18±0.64)×104mol(1dm3, and first-order derivative amplitude 1D250.1, Kx=(5.47±0.56)×104mol(1dm3. [Copyright &y& Elsevier]

A capillary zone electrophoresis (CZE) and a high-performance liquid chromatography (HPLC) method have been developed for identification and determination of ketoconazole, an imidazole antifungal, in pharmaceutical preparations. The suitabilities of both methods for quantitative determination of ketoconazole were approved through validation specification such as linearity, precision, accuracy, limit of detection and quantification. The proposed methods were used for determination of ketoconazole in commercial pharmaceutical dosage forms (tablets and creams). Under described conditions, CZE method is more selective, while the HPLC method is more sensitive. Both methods are rapid (tR(CZE)=5.14 min and tR(HPLC)=2.66 min), which is important for routine application. However, the HPLC method provides a repeatability of the quantitative analysis of ketoconazole in drug formulations below 1.5% relative standard deviation (R.S.D), while the repeatability of the CZE method is in the order of 2-3% R.S.D. [Copyright &y& Elsevier]

Evaluation of pharmacokinetic properties is a significant step at the early stages of drug development. In this study, an in vitro evaluation of the pharmacokinetic properties of five newly synthesized compounds was performed. These compounds belong to N-hydroxyurea and hydroxamic acid derivatives and analogs of NSAIDs indomethacin, flurbiprofen, diclofenac, ibuprofen, and naproxen (compounds 1, 2, 3, 11, and 12, respectively) with dual COX-2 and 5-LOX inhibitory activity. Two in vitro methods (biopartitioning micellar chromatography (BMC) and PAMPA) were used to evaluate passive gastrointestinal absorption, while high-performance affinity chromatography (HPAC) and differential pulse voltammetry (DPV) were used to evaluate binding to human serum albumin (HSA). The introduction of N-hydroxyurea and hydroxamic acid groups into the structure of NSAIDs decreases both expected passive gastrointestinal absorption (BMC k values were from 3.02 to 9.50, while for NSAIDs were from 5.29 to 13.36; PAMPA –logPe values were between 3.81 and 4.76, while for NSAIDs were ≤3.46) and HSA binding (HPAC logk values were from 2.03 to 9.54, while for NSAIDs were ≥11.03; DPV peak potential shifts were between 7 and 34, while for NSAIDs were ≥54). Structural modifications of all tested compounds that increase lipophilicity could be considered to enhance their passive gastrointestinal absorption. Considering lower expected HSA binding and higher lipophilicity of tested compounds compared to corresponding NSAIDs, it can be expected that the volume of distribution of compounds 1, 2, 3, 11, and 12 will be higher. Reduced HSA binding may also decrease interactions with other drugs in comparison to corresponding NSAIDs. All tested compounds showed significant microsomal instability (25.07–58.44% decrease in concentration) in comparison to indomethacin (14.47%) and diclofenac (20.99%). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Various dual inhibitors of COX-2 and 5-LOX enzymes have been developed so far in order to obtain more effective and safer anti-inflammatory drugs. The aim of this study was to design and synthesize new dual COX-2 and 5-LOX inhibitors, and to evaluate their enzyme inhibition potential and redox properties. Thirteen compounds (1–13) were designed taking into account structural requirements for dual COX-2 and 5-LOX inhibition and antioxidant activity, synthesized, and structurally characterized. These compounds can be classified as N-hydroxyurea derivatives (1, 2 and 3), 3,5-di-tert-butylphenol derivatives (4, 5, 6, 7 and 13), urea derivatives (8, 9 and 10) and "type B hydroxamic acids" (11 and 12). COX-1, COX-2 and 5-LOX inhibitory activities were evaluated using fluorometric inhibitor screening kits. The evaluation of the redox activity of newly synthesized compounds was performed in vitro in the human serum pool using redox status tests. The prooxidative score, the antioxidative score and the oxy-score were calculated. Seven out of thirteen synthesized compounds (1, 2, 3, 5, 6, 11 and 12) proved to be dual COX-2 and 5-LOX inhibitors. These compounds expressed good COX-2/COX-1 selectivity. Moreover, dual inhibitors 1, 3, 5, 11 and 12 showed good antioxidant properties. [ABSTRACT FROM AUTHOR]

• Dual DNA gyrase and topoisomerase IV inhibitors; • Gastrointestinal absorption was predicted using PAMPA and BMC; • QSRR analysis was performed; • Descriptors with the highest influence on BMC retention were interpreted; DNA gyrase and topoisomerase IV play significant role in maintaining the correct structure of DNA during replication and they have been identified as validated targets in antibacterial drug discovery. Inadequate pharmacokinetic properties are responsible for many failures during drug discovery and their estimation in the early phase of this process maximizes the chance of getting useful drug candidates. Passive gastrointestinal absorption of a selected group of thirteen dual DNA gyrase and topoisomerase IV inhibitors was estimated using two in vitro tests – parallel artificial membrane permeability assay (PAMPA) and biopartitioning micellar chromatography (BMC). Due to good correlation between obtained results, passive gastrointestinal absorption of remaining ten compounds was estimated using only BMC. With this experimental setup, it was possible to identify compounds with high values of retention factors (k) and highest expected passive gastrointestinal absorption, and compounds with low values of k for which low passive gastrointestinal absorption is predicted. Quantitative structure-retention relationship (QSRR) modelling was performed by creating multiple linear regression (MLR), partial least squares (PLS) and support vector machines (SVM) models. Descriptors with the highest influence on retention factor were identified and their interpretation can be used for the design of new compounds with improved passive gastrointestinal absorption. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

• Investigation of DNA - acridine derivatives (ADs) interaction using SWV. • ADs concentration profile obtained with a DNA multilayer biosensor. • New data on the binding type and constants of association complexes. • Characteristics of association complexes depend on the concentration of the ADs. • Binding constants ranged 8.7 × 105 M−1 − 5.7 × 103 M−1; binding mode-intercalation. Electrochemical oxidation of newly synthesized acridine derivatives (ADs): PG, PA, EG and EA was studied using square wave voltammetry at a glassy carbon electrode. Oxidation occurs as an irreversible process for all ADs. The ADs interaction with DNA was investigated using multi-layer DNA electrochemical biosensor. The shift of dA peak in positive direction indicated that the type of interaction is most likely an intercalation. PG showed the widest range of concentration capable to interact with DNA (1 × 10−7 M − 2.5 × 10−4 M). Analysing l o g I c o m p l e x I D N A - I c o m p l e x vs l o g c A D plots, the binding constants were determined. For the lowest PG concentrations, obtained K value close to 106 M−1 refers to strong binding. The values of K for PA may be classified as medium strength, while EG and EA showed low K values. Our results unequivocally showed that the characteristics of association complexes may vary depending on the concentration of the interacting substance. The negative Δ G value for all ADs, (- 21 to - 34 kJ mol−1), confirms the process spontaneity. The best result, indicating the most stable formed complex with DNA adsorbed at the electrode surface, showed PG when present in low concentration, order of 10−7 M. The intercalation of ADs into DNA was supported by molecular docking analysis. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, human skin and corneal permeability of twenty-two newly synthesized 17β-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 0.04M 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 17β-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 17β-carboxamide steroids with desirable permeability through human skin or cornea, depending on their potential pharmacological application. [Copyright &y& Elsevier]

Abstract: In this paper, twenty-two 17β-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 17β-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 anti-inflammatory activity of these compounds. Selected QSPR models could be used as in silico tool for predicting human skin permeability and retention of novel 17β-carboxamide steroids without performing PAMPA experiments. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

• New data regarding the 9-chloroacridine (9Cl-A) oxidation and reduction mechanism. • Irreversible, diffusion-controlled process resulting in the dimer formation. • Investigation of DNA − 9Cl-A interaction using a multilayer biosensor. • Interaction with DNA detected at 1 × 10 - 7 M 9Cl-A. • The binding constant of the complex K = 3.45 × 10 5 M - 1 ; binding mode-intercalation. 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 - 7 M (the lowest 9Cl-A concentration whose interaction with DNA was possible to detect) up to 1 × 10 - 4 M. These allowed the binding constant, K = 3.45 × 10 5 M - 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. [ABSTRACT FROM AUTHOR]