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PubMedDate not supplied

Liquid chromatographic determination of pentaerythritol tetranitrate in pharmaceuticals: collaborative study.

A liquid chromatographic (LC) method for the determination of pentaerythritol tetranitrate (PETN) in pharmaceutical formulations and the bulk drug triturate was evaluated in an interlaboratory study that included 12 participating laboratories. The procedure involves extraction of the active ingredient with mobile phase, followed by filtration of the extract and reverse-phase liquid chromatography using an octadecylsiliane bonded phase column and UV detection at 230 nm. The mobile phase composition is 35% water in acetonitrile (v/v). Three bulk drug samples (20, 20, and 35% PETN), 2 commercial tablet formulations (20 and 80 mg PETN/tablet), and 1 commercial capsule formulation (45 mg PETN/capsule) were analyzed in duplicate by the proposed method. Repeatability (sr, RSDr) and reproducibility (SR, RSDR) based on peak height measurement for these samples ranged from 0.0066 to 0.1806 (0.53-3.36%) and 0.0165 to 0.2075 (0.76-3.86%), respectively. Results for peak area measurements ranged from 0.0145 to 0.2011 (0.93-3.74%) and 0.0231 to 0.2091 (1.28-3.89%), respectively. The method has been approved interim official first action by AOAC.

Capsules↗

PubMedDate not supplied

Rapid microbial degradation of organic nitrates in rat excreta. Re-examination of the urinary and fecal metabolite profiles of pentaerythritol tetranitrate in the rat.

The in vitro stabilities of three organic nitrates, viz. pentaerythritol tetranitrate ( PETN ), nitroglycerin (NTG), and isosorbide dinitrate (ISDN) in rat urine, and of PETN in rat feces were examined. PETN , NTG, and ISDN degraded completely in rat urine following incubation for 24 hr at either 25 or 37 degrees C. Degradation of PETN , NTG, and ISDN was absent in sterilized urine under the same conditions. These data suggested that decomposition of organic nitrates in untreated urine was usually rapid and extensive, and was primarily of microbial origin. Stability of these organic nitrates could also be maintained when urine samples were stored in packed ice. Rapid and extensive microbial degradation of PETN was also found in rat fecal homogenates, suggesting the possibility of organic nitrate metabolism by intestinal microflora. The metabolic profiles of PETN in rat urine and feces following intra-arterial and oral dosing of this organic nitrate were then re-examined. The data confirmed a previous finding that in vivo PETN excretion in urine was minimal. However, contrary to data which showed about 8% fecal recovery after oral dosing, our results suggested a smaller (2%) fecal PETN recovery with oral dosing. It appeared likely then that unabsorbed PETN might be further metabolized by gut flora.

Administration, Oral↗

PubMed1984

The pharmacokinetics of meprobamate following its oral and rectal administration as a series of combinations with diphenhydramine, acetylsalicylic acid, codeine and pentaerythritol tetranitrate.

Studies in human volunteers of the pharmacokinetics of the active drugs in the formulations Visano-mini (meprobamate and diphenhydramine HCl), DoloVisano (meprobamate, diphenhydramine HCl, acetylsalicylic acid and codeine phosphate) and VisanoCor (meprobamate, diphenhydramine HCl and pentaerythritol tetranitrate (PETN], have demonstrated systemic absorption of each of the drugs from all of the formulations. Bioequivalence of meprobamate is indicated despite the drug combinations involved. Some differences in diphenhydramine pharmacokinetics are, however, apparent. The bioavailability of meprobamate administered rectally to human volunteers as the marketed preparations DoloVisano Suppositories and Dolo-Visano Suppositories sine codeino, is similar to that observed following oral administration.

Administration, Oral↗

PubMed1980

Antianginal effects of pentaerythritol tetranitrate.

31 patients with confirmed angina pectoris and selected to form an homogenous group entered this double-blind study. Following a period of observation during which the patients were on a placebo and only took nitroglycerin to relieve pain, a randomized treatment of either dipyramidole (DPM) 75 mg or pentaerythritol tetranitrate (PETN) 80 mg 8-hourly was given during 4 weeks. At the end of this period the anti-anginal effects of the drugs were assessed, using the following criteria: incidence of anginal attacks, nitroglycerin consumption, number of attacks per days, changes in exercise capacity and changes in repolarization on ECG. PETN proved distinctly more effective than DPM. The number of attacks per week decreased from 11.5 to 1.5 under PETN and from 12.5 to 9 under DPM. Similarly, nitroglycerin weekly consumption fell from 8 to 1.5 tablets under PETN and from 9 to 7 tablets under DPM.

Adult↗

PubMed1980

[Pulmonary artery pressure measurement for assessment of bioavailability of isosorbide dinitrate and pentaerythritol tetranitrate (author's transl)].

In a double-blind cross-over study with 9 patients suffering from ischemic cardiomyopathy with cardiac failure, the effect of 3 different drug preparations on pulmonary artery pressure (PA-pressure) was studied. Iso-Ameritrat is a new drug-combination consisting of a sweet-tasting wrap containing 2.5 mg Isosorbide Dinitrate (ISDN) and of a bitter-tasting core containing 10 mg Pentaerythritol Tetranitrate (PETN) and 200 mg Meprobamate. A statistically significant decrease of PA-pressure values could be observed already 3 minutes after administration of Iso-Ameritrat. Within the next minutes this decrease even augmented and lasted over the whole period of measurement (30 minutes). After administration of the second drug preparation (Ameritrat), containing 10 mg PETN and 200 mg Meprobamate in the core, but not any nitrate in the wrap a slight but also statistically significant decrease of PA-pressure values could be documented. Therefore a sublingual resorption of PETN can be assumed. The precise beginning of the effect of PETN couldn't be assured, but it must be within 5 minutes. A thir preparation, containing only 200 mg Meprobamate in the bitter tasting core caused no significant decrease of PA-pressure values.

Adult↗

PubMed1977

Metabolism of pentaerythritol trinitrate.

The absorption, excretion, and biotransformation of 14C-labeled pentaerythritol (PE) trinitrate was studied in man. The administration of a single sublingual dose was followed by rapid absorption and extensive biotransformation. Six drug metabolites were identified. Final excretion of the drug and its metabolites was almost totally through the kidney. Low levels of unchanged drug were present in plasma and urine. PE mononitrate was the major drug metabolite in plasma and urine. Glucuronides of PE trinitrate, dinitrate, and mononitrate were identified for the first time in man. PE trinitrate glucuronide appeared in plasma rapidly and about 8% of the dose was excreted in urine. Reversible and irreversible pathways are proposed for the formation of the metabolites. The reconversion of PE trinitrate glucuronide to PE trinitrate is postulated to explain the duration of drug activity and excretion.

Adult↗

PubMed2001

Crystal structure of pentaerythritol tetranitrate reductase: "flipped" binding geometries for steroid substrates in different redox states of the enzyme.

Pentaerythritol tetranitrate reductase (PETN reductase) degrades high explosive molecules including nitrate esters, nitroaromatics and cyclic triazine compounds. The enzyme also binds a variety of cyclic enones, including steroids; some steroids act as substrates whilst others are inhibitors. Understanding the basis of reactivity with cyclic enones requires structural information for the enzyme and key complexes formed with steroid substrates and inhibitors. The crystal structure of oxidised and reduced PETN reductase at 1.5 A resolution establishes a close structural similarity to the beta/alpha-barrel flavoenzyme, old yellow enzyme. In complexes of oxidised PETN reductase with progesterone (an inhibitor), 1,4-androstadiene-3,17-dione and prednisone (both substrates) the steroids are stacked over the si-face of the flavin in an orientation different from that reported for old yellow enzyme. The specifically reducible 1,2 unsaturated bonds in 1,4-androstadiene-3,17-dione and prednisone are not optimally aligned with the flavin N5 in oxidised enzyme complexes. These structures suggest either relative "flipping" or shifting of the steroid with respect to the flavin when bound in different redox forms of the enzyme. Deuterium transfer from nicotinamide coenzyme to 1,4-androstadiene-3,17-dione via the enzyme bound FMN indicates 1alpha addition at the steroid C2 atom. These studies rule out lateral motion of the steroid and indicate that the steroid orientation is "flipped" in different redox states of the enzyme.

Androstadienes↗

PubMed1975

Exercise tolerance in patients with angina pectoris after pentaerythritol trinitrate and alprenolol studied by two different methods.

Exercise tolerance has been studied by two different methods, heart-rate-controlled exercise and stepwise increased load, in 12 patients with angina pectoris. The response to a beta-adrenergic blocking agent, alprenolol, and an alkyl nitrate derivative, pentaerythritol trinitrate (PETRIN) was studied by the two methods after double-blind administration of the drugs. Rating scales were used to quantitate the degree of dyspnoea, angina pectoris and tiredness in the legs. After PETRIN both methods showed significant increases in exercise tolerance (19 and 21 per cent). The heart-rate-controlled test showed a significant increase (33%) after alprenolol, but the change was not significant by the other method. In the patients studied, heart-rate-controlled exercise discriminated between active drug and placebo better than the stepwise increased load test, what might have been due to more optimal matching of the loads obtained in the heart-rate-controlled test. Indications are given about how to design an exercise study in patients with angina pectoris.

Aged↗

PubMed1975

Comparative vasodilator effects of nitroglycerin, pentaerythritol trinitrate and biometabolites, and other organic nitrates.

Previous studies in man have shown pentaerythritol (PE) trinitrate, given either sublingually or orally, produces a prolonged hypotensive effect. The coronary vasodilator and systemic vasodepressor activities of PE trinitrate and its metabolites, PE dinitrate, PE mononitrate and PE, were evaluated in dogs to determine whether the metabolites were active and contributory. Coronary vasodilator activity was estimated with a flow transducer placed on the left anterior descending artery, and reduction of arterial pressure was determined directly via the femoral artery. Quantitative comparisons were made from dose-response curves established for nitroglycerin (ng), PE nitrates, and other common organic nitrates after intrajugular administration. Increase of coronary blood flow and reduction of arterial pressure were proportionally related, and the proportionality was the same for all drugs. Relative to NG, the potency of PE trinitrate was about 20 percent, erythrityl tetranitrate 12 percent, and isosorbide dinitrate 3.5 percent. The ratios of vasodilator activity of PE trinitrate and its metabolities were: PE trinitrate 100; PE dinitrate 1.5; PE mononitrate 0.5; and PE O. Tachyphylaxis was observed after close-order injections of NG or PE trinitrate. In addition, there was cross tolerance between NG and PE trinitrate and also between PE trinitrate and its less active metabolites.

Animals↗

PubMed2001

The anomalous reactivity of the bis(dibutylstannylene) acetal of pentaerythritol: a case of triple activation.

The only dibutyltin derivative of pentaerythritol which is observed by refluxing with dibutyltin oxide in methanol is a bis(dibutylstannylene) acetal. This is converted to the expected dibenzyl ether with benzyl bromide, in the presence of tetraethylammonium bromide in boiling toluene, but benzoylation at room temperature gives a tribenzoate. A mechanism is suggested to account for this triple activation.

Acetals↗

PubMed1997

Pentaerythritol tetranicotinate (niceritrol) decreases plasma lipoprotein(a) levels.

We determined the most effective dosage of pentaerythritol tetranicotinate (niceritrol) to reduce plasma lipoprotein(a) [Lp(a)] levels in 44 Japanese patients (16 men and 28 women; mean age, 59.2 +/- 10.8 years) with hyperlipidemia types IIa, IIb, and IV. Patients received oral niceritrol at a dosage of 750 mg (3 tablets)/d for 8 weeks, followed by 1,500 mg (6 tablets)/d for 8 weeks. Administration of niceritrol 750 mg/d for 8 weeks decreased total and low-density lipoprotein (LDL) cholesterol in patients with type IIa hyperlipidemia and decreased triglycerides in patients with type IV hyperlipidemia, but did not affect Lp(a). However, niceritrol 1,500 mg/d for 8 weeks decreased Lp(a) in patients with initial Lp(a) levels greater than 30 mg/dL in addition to decreasing total and LDL cholesterol and triglycerides. These results suggest that the effective dosage of niceritrol to reduce the serum Lp(a) concentration in Japanese hyperlipidemic patients with a high Lp(a) level (> or = 30 mg/dL) is greater than 1,500 mg/d.

Aged↗

PubMed2001

Synthesis of microbial poly(beta-hydroxybutyrate) modified with oligo(pentaerythritol ethoxylate) by Ralstonia eutropha.

Poly(beta-hydroxybutyrate) (PHB) modified with different amounts of pentaerythritol ethoxylate (PEE) has been synthesized using Ralstonia eutropha. The growth kinetics and the synthesis of PHB in the presence of PEE were modeled using appropriate differential equations for the mass balance of the two-stage process. The influence of PEE addition on the morphology of PHB was studied by various microscopic and scattering techniques. Light microscopic and wide-angle X-ray measurements indicated that the addition of PEE had a nucleating effect on the crystallization of PHB. The spherulite growth rate was widely independent of the PEE addition. The lamellae of PHB became more disordered when PEE was added as demonstrated by atomic force microscopy. Furthermore, small-angle X-ray data indicated a decrease in the long period with increasing PEE content of the modified PHB.

Crystallization↗

PubMed1998

Role of physical properties of glycidyl methacrylate- pentaerythritol triacrylate copolymers on immobilization of milk clotting protease from aspergillus niger MC4

The effect of cross-link density and amount of porogen on physical properties of the glycidyl methacrylate-pentaerythritol triacrylate (GMA-PETA) copolymer and intern on the immobilization of milk clotting protease from Aspergillus niger MC4 was studied. Almost quantitative expression of the milk clotting protease was achieved with copolymer of 251% cross-link density and generated with 65.4 mL of cyclohexanol as porogen. The pH of 4.0 and 18 h period were the best conditions for binding the milk clotting protease onto the polymer. The immobilized milk clotting protease prepared had an activity of 6000 units/g. The optimum pH and temperature ranges for both soluble and immobilized milk clotting protease preparations were pH 5.6-5.8 and 55-60 degreesC, respectively. Immobilized milk clotting protease was more stable than the soluble enzyme; the half-lives at pH 4.0 and 37 degreesC were 160 and 60 days, respectively. At pH 5.8 and 37 degreesC, the parameters favorable for milk clotting, the immobilized enzyme preparation did not exhibit any aspartic protease activity.

Journal Article↗

PubMed2006

Tricarboranyl pentaerythritol-based building block.

A new tricarborane building block based on pentaerythritol was prepared for applications in boron neutron capture therapy (BNCT). Its X-ray single-crystal structure revealed a high degree of steric congestion. To enable the attachment of the building block to other moieties, a succinimidyl linker has been introduced at the focal point, and a generation-2 hexacarborane-containing dendron carrying 60 boron atoms has been prepared using a 2,2-bis(hydroxymethyl)propionic acid core.

Boron Compounds↗

PubMed2006

Atoms-in-molecules study of intra- and intermolecular bonding in the pentaerythritol tetranitrate crystal.

Chemical bonding in the pentaerythritol tetranitrate crystal based on the experimental electron density obtained from X-ray diffraction data at 100 K and theoretical calculations at the experimental molecular geometry have been analyzed in terms of the Quantum Theory of Atoms in Molecules. Features of the intra- and intermolecular bond critical points and the oxygen atom lone-pair locations are discussed. Numerous intermolecular bonding interactions, including O...H and O...O, have been found and characterized. Atomic charges and atomic energies were integrated and compared with those for similar compounds. The N-O topological bond orders have been calculated for the first time, and the PETN atomic valences have been estimated.

Journal Article↗

PubMed2003

Molecular tectonics. Construction of porous hydrogen-bonded networks from bisketals of pentaerythritol.

2,4,8,10-Tetraoxaspiro[5,5]undecanes tetrasubstituted at the 3 and 9 positions with groups incorporating diaminotriazines can be used for the construction of extensively hydrogen-bonded networks by the strategy of molecular tectonics. Four such compounds, tectons 1-4, were made by short and efficient syntheses involving bisketalization of pentaerythritol and subsequent reactions. Unlike tectons typically used in previous studies, compounds 1-4 are flexible and chiral, and they orient four sticky diaminotriazine groups in a distorted tetrahedral geometry. Tecton 1 crystallizes from DMF/toluene as an inclusion compound of approximate composition 1.8DMF.xH2O. In the resulting structure, each tecton participates in a total of 16 hydrogen bonds. Eight of these bonds involve four principal neighbors, and the tectons linked in this way define a distorted diamondoid network. Despite 8-fold interpenetration, 60% of the volume of the network is available for including guests. The guests are disordered and occupy parallel helical channels that have cross sections of approximately 11 x 12 A2 at the narrowest points. These channels provide access to the interior of the crystals and permit guests to be exchanged quantitatively without loss of crystallinity. It is noteworthy that tecton 1, despite its flexibility, small size, and structural simplicity, is apparently unable to find a periodic three-dimensional structure in which the dictates of hydrogen bonding and close packing are satisfied simultaneously.

Journal Article↗

PubMed2004

Synthesis and characterization of pentaerythritol-derived oligoglycol and their application to catalytic Wittig-type reactions.

Several pentaerythritol-derived oligoglycols 1 with free hydroxyl groups are readily prepared by a convergent approach. Quantitative (13)C NMR proves to be an efficient tool for the characterization of oligoglycols. The corresponding telluride of oligoglycol 17 is synthesized and used as a good catalyst for Wittig-type reactions in preparing both disubstituted and trisubstituted olefins in good to high yields.

Journal Article↗

PubMed2005

Ab initio all-electron periodic Hartree-Fock study of hydrostatic compression of pentaerythritol tetranitrate.

We present a computational study of hydrostatic compression effects on the pentaerythritol tetranitrate (PETN) energetic material up to 22.7 GPa by means of the ab initio all-electron periodic Hartree-Fock quantum mechanical method with the STO-3G Gaussian basis set. We fitted the calculated volume-energy relation to the energy SJEOS polynomial function from which we obtained the compression dependence of the pressure (P), the bulk modulus (B), and its pressure derivative (B'). We also fitted the experimental volume-pressure relation to the pressure SJEOS polynomial function, which allowed us to calculate the experimental bulk modulus (B(exp)) and its pressure derivative (). Our calculated values, B = 6.73 GPa and B' = 24.63, are in reasonable agreement with the values B(exp) = 8.48 GPa and = 14.42 from our fit to the experimental X-ray data and with the value B(exp) = 9.8 GPa that was derived from the experimental elastic constants. In addition, we present a discussion on how the lattice vectors and the internal coordinates (i.e., bond lengths, bond angles, and torsion angles) of the C(CH(2)ONO(2))(4) molecules in the PETN lattice change during hydrostatic compression of the crystal. Our calculated results suggest that the C(CH(2)ONO(2))(4) molecules cannot be considered as being rigid but are in fact flexible, accommodating lattice compression through torsions, bendings in their bond angles, and contractions in their bond lengths. At pressures higher than about 8 GPa, however, both the C(CH(2)ONO(2))(4) molecules and the c lattice vector seem to stiffen somewhat. The a lattice vector does not exhibit this stiffening. As a consequence, the pressure dependence of the c/a ratio shows a minimum at about 8 GPa.

Journal Article↗