Hromatografske metode za predviđanje apsorpcije leka posle oralne primene

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

Derivati tiazolidindiona - mehanizam delovanja, biotransformacija i neželjena dejstva

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

A new simple liquid chromatographic assay for gentamicin in presence of methylparaben and propylparaben

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

Partitioning of quinapril anion between cetyltrimethylammonium bromide micelles and water

The interaction of the anion of quinapril (QUIN), angiotensin converting enzyme (ACE) inhibitor, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was studied as a model system for drug/membrane interactions. From the dependence of differential absorbance at λ=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 Kb was obtained.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Primena hromatografskih tehnika u optimizaciji procesa prečišćavanja amida kortienske kiseline iz hidrokortizona i etil estra L-glicina

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 %

Sinteza i fizičko‐hemijska karakterizacija tri novosintetisana derivata sulfhidroksamske kiseline kao potencijalnih dualnih inhibitora enzima ciklooksigenaze‐2 i 5‐lipooksigenaze

Inflammatory mediators derived from arachidonic acid by the enzymes cyclooxygenase (COX) and lipoxygenase (LOX) are involved in the pathogenesis of various inflammatory diseases. Inhibition of the COX pathway is thought to lead to potentiation of the LOX pathway, and inhibition of both pathways represents a rational approach to the design and development of more effective and safer anti-inflammatory drugs (1). The aim of this study was the synthesis and physico-chemical characterization of 1f, 1g and 1h derivatives derived from a previously conducted 3D-QSAR study and molecular docking (2). The sulfhydroxamic acid derivative 1f was synthesized in a two-step process. Sulfonyl chloride was synthesized from commercially available sulfonic acid and thionyl chloride in the presence of a catalytic amount of DMF. Sulfhydroxamic acid was further obtained from previously synthesized sulfonyl chloride and hydroxylamine hydrochloride in the presence of 10% NaHCO3 solution. Sulfhydroxamic acid derivatives, 1g and 1h were synthesized from commercially available sulfonyl chlorides and hydroxylamine hydrochloride in the presence of 10% NaHCO3 solution. The reaction mixtures were purified by liquid-liquid extraction and preparative TLC to give derivatives 1f, 1g, 1h in yields: 26%, 53% and 63%. The structure and purity of the synthesized compounds were confirmed by determination of the melting points and spectroscopic techniques (ATR-FTIR, 1H-NMR, 13C-NMR, MS/MS). Based on a previously conducted in silico study, the voluminous sulfhydroxamic group is responsible for iron chelation within 5-LOX active center and for COX-2 selectivity, as COX-2 has wider side pocket, so potent inhibition of COX-2 and 5-LOX enzymes is expected.Inflamatorni medijatori koji nastaju iz arahidonske kiseline posredstvom enzima ciklooksigenaze (COX) i lipooksigenaze (LOX) učestvuju u patogenezi brojnih inflamatornih oboljenja. Smatra se da inhibicija COX puta dovodi do potenciranja LOX puta, te inhibicija oba puta predstavlja racionalan pristup dizajniranja i razvoja novih, efikasnijih i bezbednijih antiinflamatornih lekova (1). Cilj rada je bila sinteza i fizičko-hemijska karakterizacija derivata 1f, 1g i 1h proisteklih iz prethodno sprovedene 3D-QSAR studije i molekulskog docking-a (2). Derivat sulfhidroksamske kiseline 1f je sintetisan u dvostepenom postupku pri čemu se najpre iz komercijalno dostupne sulfonske kiseline i tionil hlorida u prisustvu katalitičke količine DMF dobija odgovarajući sulfonil hlorid. Odgovarajuća sulfhidroksamska kiselina (1f) se dobija u drugom koraku iz prethodno sintetisanog sulfonil hlorida i hidroksilamin-hidrohlorida u prisustvu 10% rastvora NaHCO3 . Derivati sulfhidroksamske kiseline, 1g i 1h su sintetisani jednostepenim postupkom iz komercijalno dostupnih sulfonil hlorida i hidroksilamin-hidrohlorida u prisustvu 10% rastvora NaHCO3 . Nakon postupka sinteze jedinjenja su prečišćena tečno-tečnom ekstrakcijom i preparativnom TLC pri čemu se dobijaju derivati 1f, 1g, 1h u prinosima 26%, 53% i 63%. Struktura i čistoća sintetisanih jedinjenja je potvrđena određivanjem temperature topljenja i spektroskopskim (ATR-FTIR, 1 H-NMR, 13 C-NMR, MS/MS) tehnikama. Na osnovu prethodno sprovedene in silico studije, voluminozni centar i sulfhidroksamska grupa sintetisanih derivata su odgovorni za COX-2 selektivnost zbog prisustva šireg vezivnog mesta unutar COX-2 enzima, dok sulfhidroksamska grupa unutar 5-LOX enzima helira gvožđe aktivnog centra i inhibira enzim, te se očekuje potentna dualna COX-2 i 5-LOX inhibitorna aktivnost sintetisanih derivata.VIII Kongres farmaceuta Srbije sa međunarodnim učešćem, 12-15.10.2022. Beogra

Radiofarmaceutici za hepatobilijarnu scintigrafiju - analozi iminodisirćetne kiseline obeleženi tehnecijumom-99m

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

Synthesis and RP-TLC lipophilicity evaluation of a novel fluocinolon acetonide soft drug derivative

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

Derivative spectrophotometric determination of partition coefficient of hydrochlorothiazide between cetyltrimethylammonium bromide micelles and water

The interaction of hydrochlorothiazide (HCT), benzothiadiazine diuretic, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was studied as a model system for drug/membrane interactions. From the dependence of first order derivative amplitude 1 D250.1 on CTAB concentration, by using mathematical models based on the partition of the drug between micellar and aqueous pseudo-phase, CTAB/water partition coefficient Kp was calculated.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

RP-HPLC određivanje vitamina B1, B3, B6, folne kiseline i B12 multivitaminskih tableta

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