Pharmacokinetic evaluation of LASSBio-579: an N-phenylpiperazine antipsychotic prototype

Bioanalytical LC-QTOF/MS Method for a N-phenylpiperazine Derivate (LQFM05): An Anxiolytic- and Antidepressant-like Prototype Drug Applied to Pharmacokinetic and Biodistribution Studies

The LQFM05 is a prototype drug designed for treatment of psychiatric disorders, such as schizophrenia, exhibiting anxiolytic- and antidepressant-like (12 or 24 µmol/kg) effects in classical behavioral tests. In order to evaluate its pharmacokinetic properties, a liquid chromatography method coupled to a quadrupole time of flight mass spectrometry system (LC-QTOF/MS) was developed and fully validated for LQFM05 analysis in rat plasma and tissue samples (brain, heart, liver, and kidneys). Liquid-liquid extraction, solid phase extraction and protein precipitation were assessed as clean-up procedures for biological samples and analyte enrichment. Plasma and tissue samples underwent protein precipitation as a preliminary step, using acetonitrile. Linearity was fully demonstrated for the dynamic range (10.0 to 900.0 ng/mL), with r² values higher than 0.99 (RSD_slope ≤ 2%, F_cal < F_tab, C_cal < C_tab). Biodistribution studies in rats revealed high brain tissue concentrations (12.4 µg/g), suggesting elevated drug affinity to the main therapeutic target tissue, showing a blood partition coefficient of 1.9. Kidneys also showed great exposure and tissue affinity, suggesting a potential extrahepatic clearance. Likewise, all examined tissues exhibited satisfactory LQFMF05 distribution. The mass fragmentation spectrum indicated the presence of its main metabolite, LQFM235, yielded by high hepatic hydroxylation route, an equally bioactive derivative. Lastly, the developed LC-QTOF/MS method was shown to be sensitive (LOQ = 10 ng/mL), precise and accurate for LQFM05 determination in tissue homogenates and plasma samples.

Preclinical pharmacokinetics of a promising antineoplastic prototype piperazine-containing compound (LQFM018) in rats by a new LC-MS/MS bioanalytical method

LQFM018 is a novel antineoplastic prototype, showing an expressive drug-triggered K562 leukemic cells death mechanism, through necroptotic signaling. Due to its promising effect, this study aimed to evaluate the pharmacokinetics of LQFM018 in rats, using a new validated bioanalytical LC-MS/MS-based method. Chromatographic column was an ACE® C18 (100 mm × 4.6 mm, 5 µm) eluted by a mobile phase composed of ammonium acetate 2 mM and formic acid 0.025%:methanol (50:50, v/v), under flow of 1.2 mL/min and injection volume of 3.0 µL. LQFM018 was extracted from rat plasma by a simple liquid-liquid method, using MTBE solvent. Rats were administered intraperitoneally at LQFM018 100 mg/kg dose and blood samples were collect at times of 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 h. Bioanalytical-LC-MS/MS-based method was rapid, high throughput and sensitive with a good linearity ranging from 10 (LLOQ) to 15000 ng/mL, besides precise and accurate, ranging of 0.8-7.3% and 96.8-107.6%, respectively. The prototype LQFM018 was rapid and well absorbed, and highly distributed, apparently due to its high lipid solubility. These features are primordial for an anticancer agent in the treatment of deep tumors, such as bone marrow neoplasms, in which the drug might permeate easily tissue barriers. Also, LQFM018 has demonstrated a high clearance, according to a low t_1/2in rats, indicating a relative fast elimination phase related to a possible intense hepatic biotransformation. These information support further studies to establish new understands on pharmacokinetics of promising antineoplastic prototype LQFM018 from preclinical and clinical evaluations.

The structures of eleven (4-phen-yl)piperazinium salts containing organic anions

Eleven (4-phen-yl)piperazinium salts containing organic anions have been prepared and structurally characterized, namely, 4-phenyl-piperazin-1-ium 4-fluoro-benzoate monohydrate, C10H15N2 +·C7H4FO2 -·H2O, 1; 4-phenyl-piperazin-1-ium 4-bromo-benzoate monohydrate, C10H15N2 +·C7H4BrO2 -·H2O, 3; 4-phenyl-piperazin-1-ium 4-iodo-benzoate, C10H15N2 +·C7H4IO2 -, 4; 4-phenyl-piperazin-1-ium 4-nitro-benzoate, C10H15N2 +·C7H4NO4 -, 5; 4-phenyl-piperazin-1-ium 3,5-di-nitro-salicylate, C10H15N2 +·C7H3N2O7 -, 6; 4-phenyl-piperazin-1-ium 3,5-di-nitro-benzoate, C10H15N2 +·C7H3N2O6 -, 7; 4-phenyl-piperazin-1-ium picrate, C10H15N2 +·C6H2N3O7 -, 8; 4-phenyl-piperazin-1-ium benzoate monohydrate, C10H15N2 +·C7H5O2 -·H2O, 9; 4-phenyl-piperazin-1-ium p-toluene-sulfonate, C10H15N2 +·C7H7O3S-, 10; 4-phenyl-piperazin-1-ium tartarate monohydrate, C10H15N2 +·C4H5O6 -·H2O, 11; and 4-phenyl-piperazin-1-ium fumarate, C10H15N2 +·C4H3O4 -, 12. Compounds 1 and 3-12 are all 1:1 salts with the acid proton transferred to the phenyl-piperaizine basic N atom (the secondary amine) with the exception of 3 where there is disorder in the proton position with it being 68% attached to the base and 32% attached to the acid. Of the structures with similar stoichiometries only 3 and 9 are isomorphous. The 4-phenyl substituent in all cases occupies an equatorial position except for 12 where it is in an axial position. The crystal chosen for structure 7 was refined as a non-merohedral twin. There is disorder in 5, 6, 10 and 11. For both 5 and 6, a nitro group is disordered and was modeled with two equivalent orientations with occupancies of 0.62 (3)/0.38 (3) and 0.690 (11)/0.310 (11), respectively. For 6, 10 and 11, this disorder is associated with the phenyl ring of the phenyl-piperazinium cation with occupancies of 0.687 (10)/0.313 (10), 0.51 (7)/0.49 (7) and 0.611 (13)/389 (13), respectively. For all salts, the packing is dominated by the N-H⋯O hydrogen bonds formed by the cation and anion. In addition, several structures contain C-H⋯π (1, 3, 4, 8, 9, 10, and 12) and aromatic π-π stacking inter-actions (6 and 8) and one structure (5) contains a -NO2⋯π inter-action. For all structures, the Hirshfeld surface fingerprint plots show the expected prominent spikes as a result of the N-H⋯O and O-H⋯O hydrogen bonds.

Synthesis and crystal structures of 1-benzoyl-4-(4-nitro-phen-yl)piperazine and 1-(4-bromo-benzo-yl)-4-phenyl-piperazine at 90 K

Synthesis and crystal structures of 1-benzoyl-4-(4-nitro-phen-yl)piperazine, C17H17N3O3, (I) and 1-(4-bromo-benzo-yl)-4-phenyl-piperazine, C17H17BrN2O, (II) are described. Compounds I and II crystallize in the ortho-rhom-bic and monoclinic crystal systems with space groups Pna21 (Z' = 2, I) and P21 (Z' = 1, II), respectively. The crystal of II was a two-component aggregate, treated as a 'twin' for data-acquisition purposes. There are no conventional hydrogen bonds in either I or II, but there are weaker C-H⋯O contacts. Each mol-ecule consists of a central piperazine ring in a chair conformation, with either benzoyl and nitro-phenyl (I) or 4-bromo-benzoyl and phenyl (II) groups attached to different nitro-gen atoms of the piperazine. The various atom-atom contact coverages as qu-anti-fied by Hirshfeld surface analysis fingerprint plots are given.

Crystal-structure studies of 4-phenyl-piperazin-1-ium 4-eth-oxy-benzoate monohydrate, 4-phenyl-piperazin-1-ium 4-meth-oxy-benzoate monohydrate, 4-phenyl-piperazin-1-ium 4-methyl-benzoate monohydrate and 4-phenyl-piperazin-1-ium tri-fluoro-acetate 0.12-hydrate

In this study, four new piperazinium salts, namely, 4-phenyl-piperazin-1-ium 4-eth-oxy-benzoate monohydrate, C9H9O3·C10H15N2·H2O (I); 4-phenyl-piperazin-1-ium 4-meth-oxy-benzoate monohydrate, C10H15N2·C8H7O3·H2O (II); 4-phenyl-piperazin-1-ium 4-methyl-benzoate monohydrate, C10H15N2·C8H7O2·H2O (III); and 4-phenyl-piperazin-1-ium tri-fluoro-acetate 0.12 hydrate, C10H15N2·C2F3O2·0.12H2O (IV), have been synthesized. The single-crystal structures of these compounds reveal that all of them crystallize in the triclinic P space group and the crystal packing of (I)-(III) is built up of ribbons formed by a combination of hydrogen bonds of type N-H⋯O, O-H⋯O and other weak inter-actions of type C-H⋯O and C-H⋯π, leading to a three-dimensional network. In the crystal of (IV), the cations and the anions are connected by C-H⋯O, N-H⋯O and C-H⋯F hydrogen bonds and by C-H⋯π inter-actions, forming sheets which in turn inter-act to maintain the crystal structure by linking through the oxygen atoms of water mol-ecules and van der Waals inter-actions, giving the whole structure.

Subcutaneous pharmacokinetics of the cardiac hormone vessel dilator

Vessel dilator, a hormone synthesized in the heart, eliminates 71% of human small-cell lung cancers and 67% of human breast cancers growing in mice when given subcutaneously (s.c.) via osmotic pumps. The pharmacokinetics of s.c. administered vessel dilator have not been evaluated previously. In the present study, the pharmacokinetics of vessel dilator following s.c. bolus (ScB) or 3 h s.c. infusion (ScI) were compared with those following i.v. bolus (IvB) administration in male Fischer 344 rats. The half-life (t½ ) of vessel dilator after ScI, IvB and ScB was 54, 43 and 30 min, respectively. The tmax for vessel dilator after IvB, ScB and ScI administration was 1.5, 23 and 156 min, respectively, whereas the corresponding Cmax values were 3749, 887 and 471 ng/L (normalized against the dose used for ScB and IvB). The area under the curve (AUC0-∞ ) for vessel dilator was 1166, 880 and 1652 ng h/mL (normalized) following IvB, ScB and ScI administration, respectively. The volume of distribution for vessel dilator was 2.38, 0.92 and 1.08 L following IvB, ScB and SCI administration, respectively; corresponding clearance values were 1.69, 1.50 and 0.78 L/h, respectively. Plasma concentrations of vessel dilator after each of the three methods of administration mirrored their predicted concentration-time profiles. We conclude that vessel dilator administered via ScI has a significantly greater AUC and t½ and slowed clearance compared with IvB or ScB administration (P < 0.001), suggesting that s.c. infusion is the preferred method of administration, based on pharmacokinetics, to treat cancers.

trans-2,5-Di-methyl-piperazine-1,4-diium dinitrate

In the structure of the title salt, C₆H₁₆N₂²⁺·2NO₃⁻, the cations are connected to the anions through bifurcated N—H⋯(O,O) and weak C—H⋯O hydrogen bonds, generating corrugated layers parallel to the (100) plane. The organic cation is centrosymmetric and the diprotonated piperazine ring adopts a chair conformation, with the methyl groups occupying equatorial positions.

1-Methyl-piperazine-1,4-dium bis-(hydrogen oxalate)

In the crystal structure of the title compound, C5H14N2 (2+)·2HC2O4 (-), the two crystallographically independent hydrogen oxalate anions are linked by strong inter-molecular O-H⋯O hydrogen bonds, forming two independent corrugated chains parallel to the b axis. These chains are further connected by N-H⋯O and C-H⋯O hydrogen bonds originating from the organic cations, forming a three-dimensional network. The diprotonated piperazine ring adopts a chair conformation, with the methyl group occupying an equatorial position.

1-Phenyl-piperazine-1,4-diium bis-(hydrogen sulfate)

In the title compound, C(10)H(16)N(2) (2+)·2HSO(4) (-), the S atoms adopt slightly distorted tetra-hedral geometry and the diprotonated piperazine ring adopts a chair conformation. In the crystal, the 1-phenyl-piperazine-1,4-diium cations are anchored between chains formed by the sulfate entities via inter-molecular bifurcated N-H⋯(O,O) and weak C-H⋯O hydrogen bonds. These hydrogen bonds contribute to the cohesion and stability of the network of the crystal structure.

4-Phenyl-piperazin-1-ium dihydrogen phosphate

The title compound, C₁₀H₁₅N₂⁺·H₂PO₄⁻, is built up from 4-phenyl­piperazin-1-ium cations and dihydrogen phosphate anions. The inter­connection between two adjacent anions is assured by two strong O—H⋯O hydrogen bonds, which lead to the formation of infinite wave-like chains which spread along the a axis. The organic cations connect these chains via N—H⋯O hydrogen bonds. The crystal cohesion and stability are ensured by electrostatic and van der Waals inter­actions which, together with N—H⋯O and O—H⋯O hydrogen bonds, build up a two-dimensional network.