Flávia De Toni Uchôa

Lipid-core nanocapsules restrained the indomethacin ethyl ester hydrolysis in the gastrointestinal lumen and wall acting as mucoadhesive reservoirs.

The aim of this work was to investigate if the indomethacin ethyl ester (IndOEt) released from lipid-core nanocapsules (NC) is converted into indomethacin (IndOH) in the intestine lumen, intestine wall or after the particles reach the blood stream. NC-IndOEt had monomodal size distribution (242 nm; PDI 0.2) and zeta potential of -11 mV. The everted rat gut sac model showed IndOEt passage of 0.16 micromol m(-2) through the serosal fluid (30 min). From 15 to 120 min, the IndOEt concentrations in the tissue increased from 6.13 to 27.47 micromol m(-2). No IndOH was formed ex vivo. A fluorescent-NC formulation was used to determine the copolymer bioadhesion (0.012 micromol m(-2)). After NC-IndOEt oral administration to rats, IndOEt and IndOH were detected in the gastrointestinal tract (contents and tissues). In the tissues, the IndOEt concentrations decreased from 459 to 5 microg g(-1) after scrapping, demonstrating the NC mucoadhesion. In plasma (peripheric and portal vein), in spleen and liver, exclusively IndOH was detected. In conclusion, after oral dosing of NC-IndOEt, IndOEt is converted into IndOH in the intestinal lumen and wall before reaching the blood stream. The complexity of a living system was not predicted by the ex vivo gut sac model.

Preclinical pharmacokinetic and pharmacodynamic evaluation of thiazolidinone PG15: an anti‐inflammatory candidate

Objectives Novel 5‐benzilidene thiazolidinones have been synthesized and exhibited anti‐inflammatory activity. In this work one of the compounds of the thiazolidinone chemical series, (5Z,E)‐3‐[2‐(4‐chlorophenyl)‐2‐oxoethyl]‐5‐(1H‐indol‐3‐ ylmethylene)‐thiazolidine‐2,4‐dione (PG15) was investigated aiming to determine the drugs anti‐inflammatory potential in pre‐clinical studies.

Highlights in the solid-phase organic synthesis of natural products and analogues

In this manuscript, we disclose solid-phase organic syntheses (SPOS) of small-molecules of some secondary metabolites, such as alkaloids, polyamines, steroids, terpenes, and flavonoids, described in the literature since 2000. A number of elegant, efficient and challenging syntheses on solid support will be presented.

Development and Validation of LC-MS/MS Method for the Simultaneous Determination of Quinine and Doxycycline in Pharmaceutical Formulations

Abstract A fast, sensitive, and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of quinine and doxycycline in pharmaceutical formulations. The LC-MS/MS method was carried out on a Sun Fire Waters C18 column (50 mm × 3.0 mm I.D.) and the mobile phase consisted of acetonitrile:0.1% formic acid (75:25, v/v), run at a flow rate of 0.45 mL/min (split 1:3). The injection volume was 10 µL for both standard and samples. The triple quadrupole mass spectrometer equipped with an electrospray source in positive mode (ES+) was set up in multiple reaction monitoring mode (MRM), monitoring the transitions of 325.0 > 307.0 and 445.0 > 428.1, for quinine and doxycycline, respectively. The total analysis time was 2 min and the method was linear in the concentration range of 10–1500 ng/mL for both compounds. Method validation investigated parameters such as the specificity, linearity, precision, accuracy, and robustness, giving results within the acceptable range. Moreover, the proposed method was successfully applied for determination of quinine and doxycycline in nanocapsule formulations to support the quality control.

Pre-clinical pharmacokinetics evaluation of an anticonvulsant candidate benzaldehyde semicarbazone free and included in β-cyclodextrin

The study aimed to investigate the pharmacokinetics and tissue distribution of the benzaldehyde semicarbazone (BS) a potential antiepileptic drug, administered as a free drug or complexed beta-cyclodextrin (BS/beta-CD). Free BS and BS/beta-CD were administered to male Wistar rats as a 10mg/kg intravenous bolus dose. For the oral route, 50mg/kg and 100mg/kg doses of the free drug and 50mg/kg of the complex were administrated and plasma concentrations were determinated by a validated HPLC-UV method. Individual profiles were evaluated by non-compartmental and compartmental analysis using Excel and Scientist, respectively. Free BS plasma protein binding was 34+/-5%. A one-compartmental model adequately described all the plasma profiles for both formulations. After intravenous (10mg/kg) and oral (50mg/kg) administration, the V(d) (1.6+/-0.5 and 2.2+/-0.8L/kg, respectively) and the Cl(tot) (1.4+/-0.5 and 1.8+/-0.5L/hkg, respectively) determinated for the BS/beta-CD complex were higher than those obtained for the free drug, but the t(1/2) (0.8+/-0.1h) was similar (p<0.05). The oral bioavailability of the BS/beta-CD complex (approximately 37%) was approximately 2-fold of the free BS ( approximately 20%). The higher drug brain penetration (2.8) after BS/beta-CD dosing and the longer mean residence time in this organ, regardless of the administration route, reveals that the complex may be a potential drug carrier for the central nervous system delivery of BS.

Reduction of carrageenan-induced acute pulmonary inflammation in mice by novel thiazolidinedione derivative LPSF/RA-4.

A number of studies have demonstrated the biological activities of peroxisome proliferator-activated receptors. However, few studies have addressed the effects of the agonists of these receptors on lung diseases. The aim of the present study was to evaluate the anti-inflammatory action of a novel synthetic thiazolidine derivative (5Z)-3-benzyl-5-(1H-indol-3-ylmethylene)-thiazolidine-2,4-dione (LPSF/RA-4) on acute lung inflammation (pleurisy) induced by carrageenan. Forty mice were randomly allocated to the following groups: (I) saline control group (sham); (II) carrageenan (CAR) group; (III) CAR+LPSF/RA-4 group treated with LPSF/RA-4 (60 μmol/kg); and (IV) INDO group treated with indometacin (5mg/kg). Total cell counts and the measure of nitric oxide (NO) were performed in pleural exudates. Lung fragments were processed for light microscopy, transmission electron microscopy, immunohistochemistry and Western blotting. The influx of leucocytes and NO levels were significantly reduced following treatment with LPSF/RA-4 and INDO. Histopathological and ultrastructural analyses of the CAR group revealed evident tissue alterations, such as oedema, infiltrates of inflammatory cells and emphysema. These alterations were significantly reduced in the groups treated with LPSF/RA-4 or INDO. Immunohistochemistry revealed an increase in inflammatory markers (COX-2, iNOS, TNF-α and IL-1β) in the lung tissue of the CAR group, whereas the groups treated with LPSF/RA-4 and INDO exhibited significant reductions in such immunomarkers. Western blot analysis revealed an increased expression of COX-2 and IL-1 in the CAR group, which was reduced by treatment with LPSF/RA-4. The present findings demonstrate the potent anti-inflammatory action of the novel derivative thiazolidinedione LPSF/RA-4 in acute lung injury induced by carrageenan.

DEVELOPMENT AND VALIDATION OF AN LC-MS/MS METHOD FOR THE PRE-CLINICAL PHARMACOKINETIC INVESTIGATION OF THE ANTICANCER CANDIDATE AC04 IN RODENTS

A liquid chromatography-tandem mass spectrometry method was developed for accurate quantification of the acridinic anticancer candidate AC04 (5-acridin-9-ylmethylene-3-(4-methyl-benzyl)-thiazolidine-2,4-dione) in rat plasma viewing the drugs pre-clinical pharmacokinetic investigation. The sample purification was performed by protein precipitation technique with acetonitrile, and terbinafine was used as the internal standard (IS). The chromatographic separation was achieved using an isocratic mobile phase consisting of a mixture of acetonitrile and 0.1% formic acid, (95:5, v/v) flowing through an ACE® C18 column (5 µm, 2.1 × 50 mm) at a flow rate of 0.45 mL/min. Mass spectrometer with electrospray ionization (ESI) monitored, in positive mode, the transitions m/z 411.1 > 104.8 and 292.4 > 142 for AC04 and internal standard, respectively. An extensive method validation was carried out in accordance with Food and Drug Administration (FDA) guidelines. The method showed linearity in the concentration range of 2.5–500.0 ng/mL with correlation coefficient 0.993. Intra- and inter-day precision were less than 8.5 and 3.7%, respectively. The applicability of the method for pharmacokinetic investigation was determined in a pilot investigation of AC04 plasma profiles after a 1.5 mg/kg intravenous administration to rats.

Pre-clinical pharmacokinetics and acute toxicological evaluation of a monastrol derivative anticancer candidate LaSOM 65 in rats.

Abstract 1. The present work investigated the pharmacokinetic and tissue distribution as well as acute toxicity of a new chemical entity (NCE), the anticancer candidate LaSOM 65 in Wistar rats. 2. LaSOM 65 pharmacokinetics was investigated after intravenous (i.v., 1 mg/kg) and oral (p.o., 10 and 30 mg/kg) dosing. Tissue distribution was assessed after i.v. bolus dose. Acute toxicity was evaluated after i.v. (1, 2.5 and 5 mg/kg) and p.o. (50, 100 and 150 mg/kg) administration. 3. Short half-life (1.75 ± 0.71 h), a clearance of 0.85 ± 0.18 L/h/kg and a volume of distribution of 1.76 ± 0.24 L/kg were observed after i.v. dosing. The compound showed good bioavailability and linear pharmacokinetics after oral doses. The NCE distributes consistently in lung and fatty tissues, with penetration ratios of 2.7 and 1.4, respectively. The other tissues investigated presented smaller penetration ratios. Adverse clinical symptoms were observed only after i.v. administration, and regressed 3 h after dosing. Compared with controls, no statistical differences were found for serum analysis, body weight and relative organ weight, indicating no acute toxicological effects. 4. Overall, LaSOM 65 showed good pharmacokinetic characteristics and no signs of acute toxicity, indicating that it is a promising anticancer candidate.

Bioanalytical method for the quantification of the monastrol derivative anticancer candidate lasom 65 in pre-clinical pharmacokinetic investigations

A simple HPLC/UV method was developed for the determination of the anticancer candidate LaSOM 65 in rat plasma. Samples were cleaned by protein precipitation with acetonitrile (recovery > 95%), after which they were subjected to chromatography under the isocratic elution of an acetonitrile:water (45:55, v/v) solution with detection at 303 nm. The method was linear (r2 > 0.98) over the concentration range (0.05–2 µg mL−1) with intra- and inter-day precision ranging from 9.6% to 13.6% and 4.3% to 5.4%, respectively. The accuracy of the method ranged from 85% to 113.6%, and it showed sufficient sensitivity to determine pharmacokinetic parameters of LaSOM 65 after intravenous administration to Wistar rats.

Pre-clinical pharmacokinetics of the acridine antitumour candidate AC04 and its 1-oxo-metabolite plasma profile

This work aimed to investigate plasma pharmacokinetics and tissue distribution of a new acridine derivative 5-acridin-9-ylmethylene-3-(4-methyl-benzyl)-thiazolidine-2,4-dione (AC04) and its 1-oxo-AC04 metabolite disposition in Wistar rats. After a single AC04 1.5 mg/kg intravenous (i.v.) bolus dose, blood samples were taken up to 120 h. Plasma samples were deproteinization, and AC04 and metabolite were quantified by validated liquid chromatography in tandem with mass spectrometry method. Protein binding was determined by ultrafiltration. AC04 tissue disposition was evaluated after i.v. bolus dose. Individual AC04 concentration–time profiles were best fitted by a two-compartment model showing CLtot of 3.4 ± 3.4 L/h/kg, VdSS of 137.9 ± 91.4 L/kg, AUC0–∞ of 788 ± 483 ng·h/mL and a t1/2 of 45.5 ± 31.5 h. Protein binding was 98.1 ± 1.6%. AC04 showed higher penetration into the lung, spleen and liver, with AUC0–96 of 798,443, 263,211 and 303,722 ng·h/mL, respectively. The 1-oxo-AC04 metabolite represented 10% of AC04 plasma concentration, showing a t1/2 of 23.2 ± 10.4 h. These results suggest that, despite the small free plasma fraction, AC04 penetrates extensively reaching high concentrations in most tissues residing for a long time, which is important for its activity on solid tumours. All results combined indicate that AC04 is potentially a good antitumour candidate.