Supplementary data for the article: Cakić, N.; Verbić, T. Ž.; Jelić, R. M.; Platas-Iglesias, C.; Angelovski, G. Synthesis and Characterisation of Bismacrocyclic DO3A-Amide Derivatives - An Approach towards Metal-Responsive PARACEST Agents. Dalton Transactions 2016, 45 (15), 6555–6565. https://doi.org/10.1039/c5dt04625d

Supplementary material for: [https://doi.org/10.1039/c5dt04625d]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1911

Synthesis and characterisation of bismacrocyclic DO3A-amide derivatives – an approach towards metal-responsive PARACEST agents

[Abstract] Three new bismacrocyclic Ln3+ chelates consisting of triamide derivatives of cyclen with glycine, methyl and tert-butyl substituents (L1–3, respectively) linked to an acyclic EGTA-derived calcium chelator were synthesised as potential MRI contrast agents (EGTA – ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid). Eu3+ and Yb3+ complexes of L1–3 were investigated as chemical exchange saturation transfer (CEST) agents. Moderate to minor CEST effects were observed for Eu2L1, Eu2L2 and Yb2L2 complexes in the absence of Ca2+, with negligible changes upon addition of this metal ion. Luminescence steady-state emission and lifetime experiments did not reveal any changes in the coordination environment of the complexes, while the number of inner-sphere water molecules remained constant in the absence and presence of Ca2+. The protonation constants of Eu2L1 and Eu2L2 and stability constants of their complexes with Ca2+, Mg2+ and Zn2+ were determined by means of potentiometric titrations. The results show that the charge of the complex dramatically affects the protonation constants of the EGTA-binding unit. The stability constants of the complexes formed with Ca2+, Mg2+ and Zn2+ are several orders of magnitude lower than those of EGTA. These findings indicate that the nature of Ln3+ chelates and their charge are the main reasons for the observed results and weaker response of these EGTA-derived triamide derivatives compared to their tricarboxylate analogues

Acid–base equilibria of the Zn(II) and Fe(III) complexes with condensation products of 2-acetylpyridine and the dihydrazide of oxalic and malonic acid

Acid–base equilibria of Zn(II) and Fe(III) complexes with N',N'2-bis[(1E)-1-(2-pyridyl)ethylidene]ethanedihydrazide (ligand L1) and N',N'2-bis[(1E)-1-(2-pyridyl)ethylidene]propanedihydrazide (ligand L2), i.e., [Fe(L1)Cl2(H2O)], [Fe(L2)Cl(H2O)]2+, [Zn(L1)(H2O)3]+ and [Zn(L2)(H2O)2]2+, which expressed cytotoxic activity, were investigated in aqueous media. The equilibrium constants were determined potentiometrically at 25 °C at a constant ionic strength of 0.10 mol/dm3 (Na2SO4). The results showed that at pH < 8 both the Fe(III) complexes studied here have three, while [Zn(L1)(H2O)3]+ and [Zn(L2)(H2O)2]2+ have one and two titratable protons, respectively. Based on the obtained values for the equilibrium constants, protonation schemes of the examined complexes are proposed

Dejstvo tigeciklina na vezivanje fluorohinolona za humani serumski albumin

The co-administration of several drugs in multidrug therapy may alter the binding of each drug to human serum albumin (HSA) and, thus, their pharmacology effect. Therefore, in this study, the interaction mechanism between HSA and two fluoroquinolones (FQs), sparfloxacin (SPF) and levofloxacin (LVF), was investigated using fluorescence and absorption methods in the absence and presence of the competing drugtigecycline (TGC). The UV-Vis and fluorescence spectroscopy results showed that the fluorescence quenching of HSA was a result of the formation of the HSA-SPF and HSA-LVF complexes. The fluorescence quenching of HSA-TGC revealed that tigecycline can regulate the binding sites, binding mode and binding affinity of fl uoroquinolones. The binding constants (KA) and binding sites (n) of the interaction systems were calculated. The results confirmed that the KA values of the HSA-FQ system decreased in the presence of TGC, indicating that TGC can affect the binding ability of FQ for HSA. This interaction may increase the free plasma concentration of unbound FQ and enhance their pharmacology effect.Istovremena primena nekoliko lekova, u multilek terapiji, može izmeniti njihovo vezivanje za humani serumski albumin (HSA) i njihov farmakološki efekat. Zbog toga, u ovom radu je proučavan mehanizam interakcije između HSA i dva fluorohinolona (FQs): sparfloksacina (SPF) i levofloksacina (LVF) fluorescentnim i apsorpcionim metodama u odsustvu i prisustvu konkurentskog leka - tigeciklina (TGC). Rezultati UV-Vis i fluorescentne spektroskopije su pokazali da je gašenje fluorescencije u HSA rezultat formiranja HSA-SPF i HSA-LVF kompleksa. Gašenje fluoroscencije u HSA-TGC je pokazalo da tigeciklin može regulisati mesta vezivanja, način vezivanja i afinitet vezivanja fluorohinolona. Konstante vezivanja (KA) i broj vezujućih mesta (n) za interakcije u sistemu su izračunate. Rezultati su potvrdili da su vrednosti KA u HSA-FQ sistemu, smanjene u prisustvu TGC, a to ukazuje da TGC može da utiče na sposobnost vezivanja FQ za HSA. Ova interakcija može povećati slobodnu koncentraciju u plazmi nevezanog FQ i poboljšati njegov farmakološki efekat

Supplementary data for the article: Cakić, N.; Verbić, T. Ž.; Jelić, R. M.; Platas-Iglesias, C.; Angelovski, G. Synthesis and Characterisation of Bismacrocyclic DO3A-Amide Derivatives - An Approach towards Metal-Responsive PARACEST Agents. Dalton Transactions 2016, 45 (15), 6555–6565. https://doi.org/10.1039/c5dt04625d

Supplementary material for: [https://doi.org/10.1039/c5dt04625d]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1911

Procena renalne eliminacije inhibitora enzima koji konvertuje angiotensin sa odabranim molekulskim deskriptorima

Angiotensin-converting enzyme (ACE) inhibitors modulate the function of the renin-angiotensin-aldosterone system, and they are commonly prescribed antihypertensive drugs especially in patients with renal failure. In this study, the relationships between several molecular properties of eight ACE inhibitors (enalapril, quinapril, fosinopril, ramipril, benazepril, perindopril, moexipril, trandolapril) and their renal elimination data, from relevant literature, were investigated. The 'molecular descriptors of the ACE inhibitors, which included aqueous solubility data (logS); an electronic descriptor, polar surface area (PSA);, a constitutional parameter, molecular mass (Mr); and a geometric descriptor, volume value (Vol), as well as lipophilicity descriptors (logP values), were calculated using different software packages. Simple linear regression analysis showed the best correlation between renal elimination data and lipophilicity descriptor AClogP values (R2 = 0.5742). In the next stage of the study, multiple linear regression was applied to assess a higher correlation between the ACE inhibitors' renal elimination data and lipophilicity, AClogP, with one additional descriptor as an independent variable. Good correlations were established between renal elimination data from the literature and the AClogP lipophilicity descriptor using the constitutional parameter (molecular mass (R2 = 0.7425)) or the geometric descriptor (volume value (R2 = 0.7224)) as an independent variable. the application of computed molecular descriptors in evaluating drug elimination is of great importance in drug research.Inhibitori enzima koji konvertuje angiotenzin (ACE) modifikuju funkciju renin-angiotenzin-aldosteron sistema i predstavljaju često propisane lekova za sniženje pritiska, posebno kod pacijenata sa insuficijencijom bubrega. U ovom radu, za osam odabranih ACE inhibitora (enalapril, kvinapril, fosinopril, ramipril, benazepril, perindopril, moeksipril, trandolapril) ispitan je odnos između osobina njihovih molekula i njihove eliminacije putem bubrega. Za ispitivane inhibitore ACE korišć enjem različitih softverskih paketa izračunate su vrednosti nekoliko molekulskih deskriptora: rastvorljivost u vodi (logS), elektronski deskriptor - polarna površina molekula (PSA), molekulska masa (Mw), geometrijski deskriptor - volumen molekula (Vol) kao i deskriptor lipofilnosti (logP vrednosti). Primenom proste linearne regresione analize najbolja zavisnost dobijena je između podataka o eliminaciji inhibitora ACE putem bubrega i deskriptora lipofilnosti, AClogP vrednosti (R2 = 0.5742). U sledećoj fazi istraživanja primenjena je metoda višestruke regresione analize (MLR) kako bi se dobila bolja zavisnost između podataka o eliminaciji ACE inhibitora putem bubrega i njihove lipofilnosti (AClogP vrednosti) uz primenu dodatnog molekulskog deskriptora kao nezavisno promenljive. Dobre korelacije su dobijene između podataka o eliminaciji putem bubrega i deskriptora lipofilnosti AClogP, uz primenu molekulske mase (R2 = 0.7425) ili zapremine molekula (R2 = 0.7224) kao nezavisno promenljive. Mogućnost primene izračunatih molekulskih deskriptora u proceni eliminacije lekova je od velikog značaja u njihovom istraživanju

The influence of certain molecular descriptors of fecal elimination of angiotensin II receptor antagonists

Angiotensin II receptor antagonists (ARBs) modulate the function of the renin-angiotensin-aldosterone system and are commonly prescribed antihypertensive drugs, especially in patients with renal failure. In this study, the relationship between several molecular properties of seven ARBs (candesartan, eprosartan, irbesartan, losartan, olmesartan, telmisartan, valsartan) and their fecal elimination data obtained from the literature were investigated. The ARB molecular descriptors were calculated using three software packages. Simple linear regression analysis showed the best correlation between fecal elimination data and lipophilicity descriptor, ClogP values (R-2 = 0.725). Multiple linear regression was applied to examine the correlation of ARBs' fecal elimination data with their lipophilicity and one additional, calculated descriptor. The best correlation (R-2 = 0.909 with an acceptable probability value, P lt 0.05) was established between the ARB fecal elimination data and their lipophilicity and aqueous solubility data. Applying computed molecular descriptors for evaluating drug elimination is of great importance in drug research

The effect of the molecular properties of calcium channel blockers on their elimination route

Calcium channel blockers (CCBs) are among the most widely used drugs in cardiovascular medicine. In this study, nine CCBs (amlodipine, felodipine, isradipine, nicardipine, nifedipine, nimodipine, nisoldipine, verapamil and diltiazem) were investigated to assess the relationship between their molecular properties and elimination data obtained from literature. The descriptors of the molecular properties of CCBs were calculated using three software packages. The relationship between computed molecular properties and elimination data collected from relevant literature, initially investigated with simple linear regression analysis, showed poor correlation (R-2 lt 0.25). Application of molecular weight or volume data as additional independent variable, multiple linear regression (MLR) revealed better correlations (R-2 similar to 0.38) between CCB renal and fecal elimination data and their lipophilicity. Excluding nimodipine from the calculations resulted in more acceptable correlations. The best correlations were established after computed lipophilicity descriptor and molecular weight were applied (R-2 = 0.66 with acceptable probability value)

Estimation of plasma protein binding of selected antipsychotics using computed molecular properties

The plasma protein binding (PPB) data of twelve antipsychotics (aripiprazole, clozapine, olanzapine, quetiapine, risperidone, sertindole, ziprasidone, chlorpromazine, flupentixol, fluphenazine, haloperidol, zuclopenthixol) were estimated using computed molecular descriptors, which included the electronic descriptor - polar surface area (PSA), the constitutional parameter - molecular weight (Mw), the geometric descriptor - volume value (Vol), the lipophilicity descriptor (logP) and aqueous solubility data (logS), and the acidity descriptor (pK(a)). The relationships between computed molecular properties of the selected antipsychotics and their PPB data were investigated by simple linear regression analysis. Low correlations were obtained between the PPB data of the antipsychotics and PSA, Mw, Vol, pKa, logS (R lt 0.30) values, while relatively higher correlations (0.35 lt R-2 lt 0.70) were obtained for the majority of logP values. Multiple linear regression (MLR) analysis was applied to access reliable correlations of the PPB data of the antipsychotics and the computed molecular descriptors. Relationships with acceptable probability values (P lt 0.05) were established for five lipophilicity descriptors (logP values) with application of the acidity descriptor (pKa) as independent variables: AlogP (R-2=0.705), XlogP3 (R-2=0.679), ClogP (R-2=0.590), XlogP2 (R-2=0.567), as well as for the experimental lipophilicity parameter, logPexp (R-2=0.635). The best correlations obtained in MLR using AlogP and pKa as independent variables were checked using three additional antipsychotics: loxapine, sulpiride and amisulpride, with the PPB values of 97%, "less than" 40% and 17%, respectively. Their predicted PPB values were relatively close to the literature data. The proposed technique confirmed that lipophilicity, together with acidity significantly influences the PPB of antipsychotics. The described procedure can be regarded as an additional in vitro approach to the modeling of the investigated group of drugs

Relationship between the bioavailability and molecular properties of angiotensin II receptor antagonists

In the present study, we investigated the relationships between several molecular properties and bioavailability data for seven of the most commonly prescribed angiotensin II receptor antagonists (also known as angiotensin II receptor blockers (ARBs) or sartans), candesartan, eprosartan, irbesartan, losartan, olmesartan, telmisartan and valsartan. The molecular descriptors of ARBs are:, aqueous solubility (logS values), polar surface area (PSA), molecular weight (Mw), volume value (Vol), lipophilicity (logP values) and the acidity descriptor (pK(a1)). The respective descriptors were calculated using four different software packages. The relevant bioavailability data were obtained from literature. Among calculated molecular descriptors, simple linear regression analysis showed the best correlation between bioavailability data and the lipophilicity descriptor, logP (R-2 = 0.568). Multiple linear regression established good correlations between bioavailability and the lipophilicity descriptor, logP, using the molecular weight, Mw, or the acidity descriptor, pK(a1), as an additional, independent variable (with R-2 = 0.661 and 0.682, respectively). Finally, excluding candesartan from the calculations resulted in a very good correlation (R-2 = 0.852) between the remaining ARB bioavailability and molecular descriptors MlogP and Mw as independent variables, determined by multiple linear regression