Dynamic and Assembly Characteristics of Deep-Cavity Basket Acting as a Host for Inclusion Complexation of Mitoxantrone in Biotic and Abiotic Systems

We describe the preparation, dynamic, assembly characteristics of vase-shaped basket 13- along with its ability to form an inclusion complex with anticancer drug mitoxantrone in abiotic and biotic systems. This novel cavitand has a deep nonpolar pocket consisting of three naphthalimide sides fused to a bicyclic platform at the bottom while carrying polar glycines at the top. The results of 1 H Nuclear Magnetic Resonance (NMR), 1 H NMR Chemical Exchange Saturation Transfer (CEST), Calorimetry, Hybrid Replica Exchange Molecular Dynamics (REMD), and Microcrystal Electron Diffraction (MicroED) measurements are in line with 1 forming dimer [12 ]6- , to be in equilibrium with monomers 1(R) 3- (relaxed) and 1(S) 3- (squeezed). Through simultaneous line-shape analysis of 1 H NMR data, kinetic and thermodynamic parameters characterizing these equilibria were quantified. Basket 1(R) 3- includes anticancer drug mitoxantrone (MTO2+ ) in its pocket to give stable binary complex [MTO⊂1]- (Kd =2.1 μM) that can be precipitated in vitro with UV light or pH as stimuli. Both in vitro and in vivo studies showed that the basket is nontoxic, while at a higher proportion with respect to MTO it reduced its cytotoxicity in vitro. With well-characterized internal dynamics and dimerization, the ability to include mitoxantrone, and biocompatibility, the stage is set to develop sequestering agents from deep-cavity baskets.

Synthesis and Investigation of Anti-Inflammatory Activity of New Thiourea Derivatives of Naproxen

The aim of the study was a synthesis and investigation of the dose-dependent anti-inflammatory effect of new thiourea derivatives of naproxen with selected aromatic amines and esters of aromatic amino acids. The results of the in vivo study indicate that derivatives of m-anisidine (4) and N-methyl tryptophan methyl ester (7) showed the most potent anti-inflammatory activity four hours after injection of carrageenan, with the percentage of inhibition of 54.01% and 54.12%, respectively. In vitro assays of COX-2 inhibition demonstrated that none of the tested compounds achieved 50% inhibition at concentrations lower than 100 µM. On the other hand, the aromatic amine derivatives (1-5) accomplished significant inhibition of 5-LOX, and the lowest IC₅₀ value was observed for compound 4 (0.30 μM). High anti-edematous activity of compound 4 in the rat paw edema model, together with potent inhibition of 5-LOX, highlight this compound as a promising anti-inflammatory agent.

Validation of a high-performance thin-layer chromatographic method for trace analysis for some generic drugs affecting gastrointestinal function

To prevent cross-contamination between pharmaceutical products manufactured with the same equipment, cleanup procedures must be introduced before the manufacture of a new product begins. From an analytical point of view, it is crucial to select and validate a suitable analytical method to determine contaminants in the rinse water, swabs, and the placebo of the next product. High performance thin-layer chromatography (HPTLC) was chosen in our laboratory for this purpose and was optimized to meet the requirements of trace determination. The method was validated in terms of the limit of detection, limit of quantitation (LOQ), linearity close to the LOQ, sample preparation from the swab media and from the placebo of the next product made with the same equipment (recovery), precision, selectivity (interference from the swab and placebo matrixes), resolution (from related compounds), and robustness. The HPTLC method was applied to 2 different generic drugs affecting gastrointestinal function--the water-soluble H2-receptor antagonist ranitidine hydrochloride (RHCl) and the water-insoluble choleretic drug ursodeoxycholic acid (UDCA). Chromatography was performed on silica plates by using toluene-methanol-diethylamine (9 + 1 + 1, v/v/v) and n-heptane-ethyl acetate-glacial acetic acid (5 + 5 + 1, v/v/v) as the mobile phases for RHCl and UDCA, respectively. RHCl was measured in situ at 320 nm, whereas the detection of UDCA was performed at 502 nm after postchromatographic derivatization. The method was used for the determination of RHCl and UDCA in the swabs, the final rinse water, and the placebo batch after the cleanup process.

Determination of free bile acids in pharmaceuticals by thin layer chromatography and high performance liquid chromatography

High-performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD) and thin layer chromatography with flame ionization detection (TLC-FID) have been applied to the separation of five main free bile acids present in humans: cholic (CA), chenodeoxycholic (CDCA), deoxycholic (DCA), lithocholic (LCA) and ursodeoxycholic (UDCA) acid. HPLC separation was performed on Biospher Si 100 column using a mixture of n-heptane, isopropanol, ethylacetate, methanol and glacial acetic acid as a mobile phase. All the compounds were separated in less than 12 minutes by using a gradient elution mode. TLC-FID separation was performed on S-II Chromarods with a mixture of isooctane, ethylacetate and glacial acetic acid as a mobile phase. HPLC-ELSD method was applied to the determination of CDCA and UDCA in pharmaceuticals and their purity control when LCA, DCA and CA were considered as impurities.

Quantitative structure-chromatographic retention relationship study of six underivatized equine estrogens

Underivatized estrone (ES), equilin (EQ), equilenin (EQN) and their corresponding 17 alpha-diols 17 alpha-estradiol (ESD), 17 alpha-dihydroequilin (DHEQ) and 17 alpha-dihydroequilenin (DHEQN) were separated by TLC, RP-HPLC and capillary GC. Their dipole moments (mu) and Randić's connectivity indices ((1)chi) were determined as parameters of importance for the separation. The number of H atoms was taken as an additive structural parameter of importance for the quantitative structure-chromatographic retention relationship study (QSRR). Principal component analysis (PCA) was applied in order to find similarities and dissimilarities between 9 TLC and 10 RP-HPLC systems. PCA indicated that proton donor-proton acceptor interactions play the most important role for the TLC and RP-HPLC separation. The two-dimensional non-linear map of PC variables showed that the keto-estrogens (ES, EQ and EQN) and the corresponding diols (ESD, DHEQ and DHEQN) form two separate clusters. The relationship between GC retention of equine estrogens characterized by Kováts indices (KI), their (1)chi and mu was expressed by the equation KI/100 = al(1)chi+ b/mu(2) + c. The biological activity of the estrogens was related to log 1/mu(2).

Densitometric determination of conjugated oestrogens in the raw material and in pharmaceutical preparations

A densitometric method for determination of complex mixtures of conjugated oestrogens in raw material and tablets was developed. The proposed procedure comprised hydrolysis of sodium sulphate esters of oestrone, equilin, 17 alpha-oestradiol, equilenin, 17 alpha-dihydroequilin and 17 alpha-dihydroequilenin, the chloroform extraction of free oestrogens and methyltestosterone (internal standard) and separation on TLC plates using chloroform-cyclohexane-dioxane-triethylamine (4.5:4.1:0.6, v/v) as the solvent for development. Quantitative assay was achieved by direct scanning of the oestrogen spots at 280 nm. The proposed method is simple, rapid, reproducible and adequate to control the content of conjugated oestrogens in the raw material and in pharmaceutical preparations.

Spectrophotometric determination of procaine hydrochloride by means of iron (3+)-4-aminobenzohydroxamic acid complex

A rapid, simple and reproducible method is presented, for the determination of procaine hydrochloride in bulk and in pharmaceutical preparations containing also corbadrine or caffeine. The method is based on the conversion of procaine into the corresponding hydroxamic acid which reacts with iron (III) forming a complex of violet colour stable at pH 2.0, with a maximum absorption at a wavelength of 540 nm, and with molar absorptivity (epsilon = 0.43 X 10(3) l mol-1 cm-1). The minimum detectable amount was 1.47 X 10(-4) M/l, and Lambert-Beer law is obeyed in the range 2.93 X 10(-4) - 4.106 X 10(-3) M/l. By the application of Bent-French method it has been established that the stoichiometric ratio of 4-aminobenzohydroxamic acid and iron (3+) in the complex is 3:1. No interference with degradation product of procaine (4-aminobenzoic acid) was observed.

Fluorodensitometric determination of conjugated estrogens in raw material and in pharmaceutical preparations

A simple, rapid and reproducible fluorodensitometric method for the determination of conjugated estrogens has been developed. The proposed procedure includes the following steps: extraction, hydrolysis of sodium sulphate esters of estrone, equilin, equilenin and their 17-alpha-hydroxy derivatives, separation of the liberated 3-phenolic steroids and in situ measurement of fluorescence. The fluorescence emission was measured after spraying the spots of estrone and estradiol with 2,4-dinitrophenyl-hydrazine in sulphuric acid-ethanol medium and equilin and 17-alpha-dihydroequilin with phosphoric acid and sodium hydroxide solution, respectively. Equilenin and 17-alpha-dihydroequilenin were determined by measuring the native fluorescence. The method applied to the determination of raw material and tablets provided results which agreed well with the stated content and the requirements of USP XXI for conjugated estrogens.