Dig Liver Dis. 2000 Oct;32(7):583-94.
Gastroprotective and ulcer healing effects of nitric oxide-releasing non-steroidal anti-inflammatory drugs.

Brzozowski T, Konturek PC, Konturek SJ, Sliwowski Z, Drozdowicz D, Kwiecien S, Pajdo R, Ptak A, Pawlik M, Hahn E.

Department of Physiology, Jagiellonian University School of Medicine, Cracow, Poland.

BACKGROUND & AIM: New class of nitric oxide-releasing non-steroidal anti-inflammatory drugs was shown to inhibit cyclooxygenase and prostaglandin generation without causing mucosal damage but whether these agents are capable of affecting gastric mucosal damage induced by strong irritants and healing of chronic gastric ulcers remains to be studied. In this investigation, effects of nitric oxide-releasing aspirin and nitric oxide-releasing naproxen were compared with those of native agents on gastric lesions provoked by 100% ethanol and on healing of chronic acetic acid ulcers. RESULTS: Both, nitric oxide-releasing aspirin and naproxen dose-dependently attenuated ethanol-induced damage and produced a significant rise in gastric blood flow but did not delay healing of gastric ulcers while native aspirin and naproxen had no influence on ethanol-induced gastric damage but significantly prolonged ulcer healing, reduced gastric blood flow and suppressed mucosal generation of prostaglandin E2. The gastroprotective and hyperaemic effects of both nitric oxide-non-steroidal anti-inflammatory drugs were completely abolished by ODQ, an inhibitor of guanylyl cyclase-cGMP system but not influenced by suppression of nitric oxide-synthase with L-NNA. The damaging effects of native acetyl salicylate acid or naproxen were aggravated by acidification of these non-steroidal anti-inflammatory drugs but the exogenous acid added to nitric oxide-acetyl salicylate acid or nitric oxide-naproxen failed to influence their effect. Despite inhibiting of PGE2 generation, both nitric oxide-releasing derivatives and native aspirin and naproxen failed to affect expression of cyclooxygenase-1 mRNA but upregulated the cyclooxygenase-2 mRNA. Concurrent inhibition of cyclooxygenase-2 by selective inhibitor NS-398 which by itself delayed ulcer healing and attenuated the gastric blood flow at ulcer margin, significantly worsened the effects of these nitric oxide-non-steroidal anti-inflammatory drugs and their parent drugs on ulcer healing and the gastric blood flow at the ulcer margin. CONCLUSIONS: 1) Coupling of nitric oxide to aspirin or naproxen attenuates ethanol-induced damage, possibly due to an increase in gastric microcirculation mediated by excessive release and action of nitric oxide that probably compensates for PG deficiency induced by non-steroidal anti-inflammatory drugs; and 2) nitric oxide-non-steroidal anti-inflammatory drug, unlike classic non-steroidal anti-inflammatory drugs, does not affect intact gastric mucosa and fails to delay the healing of pre-existing ulcers.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11142556&dopt=Abstract Naproxen Naprosyn


leo-pharma.com

The reactive metabolite S-naproxen-beta-1-O-acyl glucuronide was purified from human urine using solid phase extraction (SPE) and preparative HPLC. The structure was confirmed by 600 MHz 1H NMR. Directly coupled 600 MHz HPLC-1H NMR was used to assign the peaks in chromatograms obtained when analysing a sample containing S-naproxen aglycone and the 1-, 2-, 3-, and 4-isomers of S-naproxen-beta-1-O-acyl glucuronide in two simple isocratic reversed phase HPLC-systems. Using mobile phase 1 (50 mM formate buffer pH 5.75/acetonitrile 75:25 v/v) the elution order was: 4-O-acyl isomers, beta-1-O-acyl glucuronide, 3-O-acyl isomers, 2-O-acyl isomers, and S-naproxen aglycone. Using mobile phase II (25 mM potassium phosphate pH 7.40/acetonitrile 80:20 v/v) the elution order was: alpha/beta-4-O-acyl isomers, S-naproxen aglycone, beta-1-O-acyl glucuronide, 3-O-acyl isomers, and alpha/beta-2-O-acyl isomers. In both systems the elution order for the 2-, 3- and 4-O-acyl isomers corresponded with previously published results for 2-, 3-, and 4-fluorobenzoic acid glucuronide isomers determined by reversed phase HPLC-1H NMR (U.G. Sidelmann, S.H. Hansen, C. Gavaghan, A.W. Nicholls, H.A.J. Carless, J.C. Lindon, I.D. Wilson, J.K. Nicholson, J. Chromatogr. B Biomed. Appl. 685 (1996) 113-122]. The alpha-1-O-acyl isomer was found to be present at approximately 3% of the initial S-naproxen-beta-1-O-acyl glucuronide concentration in the glucuronide isomer mixture after 6 h of incubation at pH 7.40 and 37 degrees C. In both HPLC systems it eluted just before the beta-1-O-acyl glucuronide well separated from other isomers. Investigators should consider the possible formation of a alpha-1-O-acyl isomer when studying glucuronide reactivity and degradation.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11199227&dopt=Abstract Naproxen Naprosyn





Pediatrics. 2001 Mar;107(3):519-23.
Analysis of nonsteroidal antiinflammatory drugs in meconium and its relation to persistent pulmonary hypertension of the newborn.

Alano MA, Ngougmna E, Ostrea EM Jr, Konduri GG.

Department of Pediatrics, Hutzel Hospital, Wayne State University, Detroit, Michigan 48201, USA.

OBJECTIVE: The objective of this study was to detect fetal exposure to nonsteroidal antiinflammatory drugs (NSAIDs) by meconium analysis and to determine the relationship between fetal exposure to NSAIDs and the development of persistent pulmonary hypertension of the newborn (PPHN). METHODS: In a case-control study of the inborn and outborn nurseries of a large urban medical center, meconium was collected from 101 newborn infants (40 with the diagnosis of PPHN based on clinical or echocardiographic criteria and 61 randomly selected, healthy, term infants [control]) and analyzed for NSAIDs (ibuprofen, naproxen, indomethacin, and aspirin) by gas chromatography/mass spectrometry. The risk of developing PPHN was determined in infants who were exposed antenatally to NSAID. RESULTS: Infants with PPHN (n = 40) had a mean gestation of 38.9 weeks and birth weight of 3524 g, which were similar to the those of the control group (n = 61). However, the incidence of low Apgar scores (</=6) at 1 minute and 5 minutes was significantly higher in the PPHN group than in the control group. The diagnoses associated with PPHN were primary PPHN (25%), meconium aspiration syndrome (35%), respiratory distress syndrome (20%), low Apgar score/asphyxia (12.5%), and pneumonia/sepsis (8%). Mean duration of ventilator support for the PPHN group was 11 days. Nitric oxide (NO) was given to 19 infants (47.5%) for a mean duration of 25.4 hours. Fourteen of the 19 infants who were treated with NO (74%) required extracorporeal membrane oxygenation, and 2 died. The overall incidence of positive NSAID in meconium in the study population (n = 101) was 49.5%: 22.8% were positive for ibuprofen, 18.8% for naproxen, 7.9% for indomethacin, and 43.6% for aspirin. There was poor agreement (Cohen's kappa = 0.09) between maternal history of NSAID use and NSAID detection in meconium. PPHN was significantly associated with 1) the presence of at least 1 NSAID in meconium (odds ratio [OR] = 21.47; 95% confidence interval [CI] = 7.12-64.71) or 2) the presence in meconium of aspirin (OR = 8.09; 95% CI = 3.27-20.10), ibuprofen (OR = 12.89; 95% CI 3.93-42.32), or naproxen (OR = 3.31; 95% CI = 1.17-9.33). By logistic regression analysis, low Apgar scores at 1 and 5 minutes and the antenatal exposure to aspirin, naproxen, and ibuprofen were significantly associated with PPHN and treatment with inhaled NO or extracorporeal membrane oxygenation. CONCLUSION: We confirm by meconium analysis the results of previous studies that demonstrated that the use of NSAIDs during pregnancy, particularly aspirin, ibuprofen, and naproxen, is high; is grossly underestimated by maternal history; and is significantly associated with PPHN. Thus, the easy access to over-the-counter NSAIDs of pregnant women should be reevaluated, and the potential dangers of these drugs to the newborn infant should be more effectively promoted.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11230592&dopt=Abstract Naproxen Naprosyn





J Pharmacol Exp Ther. 2001 Apr;297(1):198-205.
Pharmacokinetic/pharmacodynamic modeling of antipyretic and anti-inflammatory effects of naproxen in the rat.

Josa M, Urizar JP, Rapado J, Dios-Vieitez C, Castaneda-Hernandez G, Flores-Murrieta F, Renedo MJ, Troconiz IF.

Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Navarra, Pamplona 31080, Spain.

Pharmacokinetic/pharmacodynamic modeling was used to characterize the antipyretic and anti-inflammatory effects of naproxen in rats. An indirect response model was used to describe the antipyretic effects of naproxen after short intravenous infusions. The model assumes that basal temperature (T(a)) is maintained by the balance of fever mediators given by a constant (zero order) rate of synthesis (K(syn)), and a first order rate of degradation (K(out)). After an intraperitoneal injection of lipopolysaccharide, the change in T(a) was modeled assuming an increase in fever mediators described as an input rate function [IR(t)] estimated nonparametrically. An inhibitory E(max) model adequately described the inhibition of IR(t) by naproxen. A more complex model was used to describe the anti-inflammatory response of oral naproxen in the carrageenin-induced edema model. Before carrageenin injection, physiological conditions are maintained by a balance of inflammation mediators given by K(syn) and K(out) (see above). After carrageenin injection, the additional synthesis of mediators is described by IR(t) (see above). Such mediators induced an inflammatory process, which is governed by a first order rate constant (K(IN)) that can be inhibited by the presence of naproxen in plasma. The sigmoidal E(max) model also well described the inhibition of K(IN) by naproxen. Estimates for IC(50) [concentration of naproxen in plasma eliciting half of maximum inhibition of IR(t) or K(IN)] were 4.24 and 4.13 microg/ml, for the antipyretic and anti-inflammatory effects, respectively.

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Drug Dev Ind Pharm. 2001;27(3):221-5.
Naproxen availability from variable-dose and weight sustained-release tablets.

Amaral MH, Lobo JM, Ferreira DC.

Centro de Tecnologia do Medicamento, Faculty of Pharmacy of OPorto, Rua Anibal Cunha, 164, 4050-Porto, Portugal.

The aim of this work was to compare the naproxen availability from hydroxypropyl methylcellulose (HPMC) matrix tablets containing the same dose and a 2-fold weight variation (160 mg of naproxen in tablets weighting 250 and 500 mg) or with the same weight and a 2-fold dose variation (500 mg of weight and 160 or 320 mg of naproxen). The 2-fold weight variation in tablets with the same dose and also the 2-fold dose variation in tablets with the same weight did not affect the naproxen release. In addition, the release rate of two tablets of the same formulation and one tablet with a 2-fold dose and weight variation was not significantly different at the first minutes of the dissolution assay.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11291202&dopt=Abstract Naproxen Naprosyn





Arch Pharm (Weinheim). 2001 Mar;334(3):104-6.
Synthesis and cyclooxygenase inhibitory properties of novel (+) 2-(6-methoxy-2-naphthyl)propanoic acid (naproxene) derivatives.

Abadi AH, Laufer S, Lehmann J.

Institute of Pharmacy, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany.

Halomethylation of naproxene (1) occurs regioselectively in position 5 and subsequently--in situ or on treatment with silver nitrate--leads to naproxene-"dimers" with two naproxene units, 5,5'-connected through a ethenylene (3) and a methylene (4) bridge, respectively. Two of the new naproxene derivatives were screened for their cyclooxygenase inhibitory properties relative to naproxene. Both 5-chloromethyl naproxene (2) and 2-(5-((carboxyethyl)-2-methyloxynaphthyl)-6-methoxy-2-naphthyl)propanoic acid (4) were inactive in the concentration range of 0.1-10 mumole against both COX-1 and COX-2, indicating that bulky substituents in position 5 in naproxene are unfavourable for both COX-1 and COX-2 inhibition.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11315336&dopt=Abstract Naproxen Naprosyn





Pharmazie. 2001 Apr;56(4):321-4.
Naproxen-Eudragit microspheres: screening of process and formulation variables for the preparation of extended release tablets.

Zaghloul AA, Faltinek J, Vaithiyalingam SR, Reddy IK, Khan MA.

Texas Tech University Health Sciences Center, School of Pharmacy, Amarillo, USA.

The objectives of the present study were to screen the formulation and process variables for the preparation of extended release naproxen tablets with Eudragit L100-55. The tablets were prepared by compression of microspheres that were obtained by a coprecipitation technique. The process involved dissolution of naproxen and Eudragit L 100-55 in alcohol USP followed by the addition of an aqueous solution containing a surfactant and deaggregating agents. The mixture was stirred for a specified time period to obtain microspheres, which were filtered and air-dried to a constant weight. The microspheres were then compressed to obtain plain tablets with a diameter of 12 mm. A 7-factor 12-run Plackett-Burman screening design was employed to evaluate the main effects of homogenization time (X1), rate of water addition (X2), amount of polymer (X3), amount of precipitating solution (X4), concentration of electrolytes (X5), compression pressure (X6), and the concentration of lubricant (X7) on the rate of drug release. The response variable was cumulative percent of naproxen dissolved in 12 h in simulated intestinal fluid with constraints on responses that included percent yield, hardness, thickness, and the angle of repose. Mathematical relationship for percent of naproxen dissolved in 12 h (Y5) with various factors yielded the following polynomial equation; Y5 (% dissolved in 12 h) = 95.48 + 0.53 X1 + 3.51 X2 + 3.84 X3 - 3.80 X4 - 2.46 X5 - 2.90 X6 - 3.91 X7. The results showed that all the seven factors affected, with varying order, the release of naproxen from its compressed tablets.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11338673&dopt=Abstract Naproxen Naprosyn