Pharmacokinetic modeling and simulation of etodolac following single oral administration in dogs

1. Etodolac is a nonsteroidal anti-inflammatory drug with selective cyclooxygenase-2 inhibition to treat pain and inflammation associated with osteoarthritis in humans and dogs. The aim of the study was to investigate the pharmacokinetics of etodolac following single oral administration of 200?mg to 10 healthy beagle dogs.

2. The plasma concentrations of etodolac were detected using liquid chromatography-tandem mass spectrometry. Pharmacokinetic analysis was conducted using the noncompartmental method and modeling approaches.

3. Etodolac was rapidly absorbed (T_max?=?0.85?h, K_a?=?1.49?h^?1) and slowly eliminated (T_1/2?=?39.55?h) following oral administration to the dogs. A two-compartment pharmacokinetic model with first-order absorption and elimination rate constants was successfully explained for the pharmacokinetic aspects of etodolac in dogs. From a Monte Carlo simulation (1000 repetitions), the accumulation index and AUC_τ at steady state were predicted as 1.60 [90% confidence intervals (CI), 1.24–2.81] and 408.18?ng·hr/mL [90% CI, 271.26–590.58?ng·hr/mL], respectively.

4. This study will help to enact a more accurate optimal dosing regimen of etodolac in dogs with osteoarthritis, and may be useful in developing a novel formulation of etodolac for human in the future.

     

Profile of etodolac: Pharmacokinetic evaluation in special populations

The pharmacokinetics of etodolac, a new nonsteroidal anti-inflammatory drug, were compared in normal subjects, in patients with renal and hepatic disease, and in elderly patients. In 28 normal subjects, orally administered etodolac was rapidly absorbed. By 1.2 hours after ingestion of a 200 mg dose, the maximum serum concentration (C_max) averaged 15.9 g/ml, with more than 99% of the drug bound to serum protein. Clearance was primarily hepatic. The mean half-life (t_1/2) was 6 to 7 hours. There were no apparent differences in C_max, the time at which C_max occurred (t_max), area under the serum concentration/time curve (AUC_0–24), or t_1/2 between groups of young men (n=20), elderly men (n=24), and elderly men with osteoarthritis (n=20), after a single dose of etodolac or after 7 days of subchronic administration. Moreover there was no evidence of accumulation. There also were no differences in C_max, t_max, AUC_0–24 or t_1/2 between groups of normal subjects (n=10) and patients with mild-to-moderate renal impairment (n=10). Patients with end-stage renal disease who were receiving chronic hemodialysis had the same mean serum concentration of free drug as normal subjects, even though mean serum levels of protein-bound etodolac were slightly lower than those in the normal subjects. The only significant (p<0.05) difference between patients with stable hepatic cirrhosis and normal, age-matched subjects was a slightly shorter t_max in the cirrhotic subjects (1.1 vs. 1.4 hours). These findings suggest that no alteration of etodolac dosage would be necessary in these high-risk groups.Die pharmakokinetischen Parameter von Etodolac, einem neuen, nichtsteroidalen entzündungshemmenden Therapeutikum, wurden an gesunden Probanden, an Patienten mit Leber- und Nierenleiden und an Älteren Patienten untersucht. Orale Etodolac Gaben wurden von den 28 gesunden Probanden schnell resorbiert. Nach einer einmaligen Dosis von 200 mg betrug nach 1,2 Stunden die durchschnittliche maximum Serumkonzentration (C_max) 15,9 g/ml, wobei mehr als 99% des Medikaments an das Serumprotein gebunden war. Clearance erfolgte hauptsÄchlich über die Niere. Die mittlere Eliminationshalbwertszeit (t_1/2) variierte zwischen 6 und 7 Stunden. In Bezug auf C_max, dem Zeitpunkt an dem C_max auftrat (t_max), FlÄche unter der Serumkonzentrationskurve (AUC_0–24) und t_1/2 wurden keine offensichtliche Unterschiede festgestellt zwischen der Gruppe junger MÄnnern (n=20), Älterer MÄnner (n=24) und Älteren MÄnnern mit Osteoarthritis (n=20) nach einer einmaligen Etodolac-Gabe oder nach 7 tÄgiger subchronischer Dosierung. Es bestanden auch keine Anzeichen einer Kumulation. ZusÄtzlich wurden auch keine Unterschiede in C_max, t_max, AUC_0–24 und t_1/2 zwischen der Gruppe gesunder Probanden (n=10) und der Patientengruppe mit leichten bis mÄigen NierenfunktionsschÄden (n=10) beobachtet. Im mittleren Serumspiegel des nicht gebundenen Medikaments in Patienten im Endstadium der Nierenerkrankung, die mit Langzeitdialyse behandelt wurden, konnte kein Unterschied im Vergleich zu gesunden Probanden festgestellt werden, obwohl der mittlere Serumspiegel für proteingebundenes Etodolac in den Patienten etwas niedriger lag als in gesunden Probanden. Der einzige signifikante Unterschied (p<0.05) zwischen Patienten mit stabilisierter Leberzirrhose und gleichaltrigen Probanden war eine etwas kürzere t_max in den Zirrhosepatienten (1,1 versus 1,4 Stunden). Diese Ergebnisse beweisen, dakeine Notwendigkeit vorliegt, die Etodolac-Dosierung für diese Risikogruppen zu modifizieren.Se comparó la farmacocinética de etodolac, un fármaco antiinflamatorio no esteroide nuevo, en sujetos normales y en pacientes con enfermedad renal y hepática y en pacientes ancianos. Etodolac administrado por vía oral a 28 sujetos normales fue rápidamente absorbido. A las 1,2 horas siguientes a la administración de una dosis de 200 mg, la concentración sérica máxima (C_max) alcanzó un promedio de 15,9 g/ml, con más del 99% del fármaco unido a la proteína sérica. La eliminación fue principalmente hepática. La vida media (t_1/2) fue 6–7 horas. No se observaron diferencias en C_max, en el tiempo en el cual se produjo C_max, en el área bajo la curva de concentración sérica/tiempo (ABC_0–24) ni en t_1/2 entre los grupos de hombres jóvenes (n=20), de hombres ancianos (n=24) y de hombres ancianos con osteoartritis (n=20), después de la administración de una dosis Única o después de 7 días de administración subcrónica de etodolac. Además, no hubo evidencia de acumulación. Tampoco se registraron diferencias en C_max, t_max, ABC_0–24 o t_1/2 entre los grupos de sujetos normales (n=10) y los pacientes con insuficiencia renal leve a moderada (n=10). Los pacientes con nefropatía terminal que estaban recibiendo hemodiálisis crónica tuvieron las mismas concentraciones séricas medias de fármaco libre que los sujetos normales, a pesar de que las concentraciones séricas medias de etodolac unido a proteina fueron levemente inferiores que en los sujetos normales. La Única diferencia significativa (p<0,05) entre los pacientes con cirrosis hepática estable y los sujetos normales de edad similar fue t_max ligeramente inferior en los sujetos cirróticos (1,1 vs 1,4 horas). Estos hallazgos sugieren que no es necesario modificar la dosis de etodolac para su uso en estos grupos de alto riesgo.La pharmacocinétique de l'étodolac, un anti-inflammatoire non stéroÏdien, a été comparé chez des sujets normaux et des patients présentant des affections rénales et hépatiques, et chez des malades âgés. Chez 28 sujets normaux, la résorption d'étodolac administré par voie orale a été rapide. Dès 1,2 heure suivant l'absorption d'une dose de 200 mg, la moyenne des concentration sériques maximales (C_max) était de 15,9 g/ml, plus de 99% pour cent du médicament étant liés aux protéines sériques. La clairance se fait surtout par voie hépatique. La demivie moyenne (t_1/2) était de 6 à 7 heures. Il n'y avait aucune différence apparente en ce qui concerne C_max, le temps d'apparition de C_max (t_max), l'aire sous la courbe concentration sérique/temps (AUC_0–24) ni t_1/2 entre les groupes d'hommes jeunes (n=20), d'hommes âgés (n=24), et d'hommes âgés atteints d'arthrose (n=20) à la suite d'une dose unique d'étodolac ou après 7 jours d'administration subchronique. De plus, aucune accumulation n'a été constatée. D'autre part, aucune différence de C_max, t_max, AUC_0–24 ni t_1/2 n'a été notée entre les groupes de sujets normaux (n=10) et de malades présentent des altérations rénales légères ou modérées (n=10). Les malades en insuffisance rénale terminale soumis à l'hémodialyse chronique ont présenté une concentration sérique moyenne de médicament libre analogue à celle des sujets normaux, mais la moyenne des taux sériques d'étodolac lié aux protéines était légèrement inférieure à celle observée chez les sujets normaux. La seule différence significative (p<0.05) entre les malades présentant une cirrhose hépatique stable et des sujets normaux appariés quant à l'âge était représentée par un t_max légèrement plus court chez les cirrhotiques (1,1 contre 1,4 heure). Ces données permettent de penser qu'aucune modification posologique de l'étodolac ne serait nécessaire pour ces groupes à haut risque.La farmacocinetica dell'etodolac, un nuovo farmaco anti-infiammatorio non steroidale è stata messa a confronto in gruppi normali, in pazienti affetti da malattia rénale ed epatica ed in pazienti anziani. In 28 soggetti normali l'etodolac somministrato oralmente è stato rapidamente assorbito. Dopo 1.2 ore dall'ingestione di una dose di 200 mg la massima concentrazione di siero (Cmax) presentava un valore medio di 15,9 mg/ml, con più del 99% del farmaco legato alla proteina del siero. La clearance era soprattutto a livello epatico. L'emivita media (t1/2) era di 6–7 ore. Non vi sono state evidenti differenze medie nei valori di concentrazione massima (Cmax), tempo (Tmax) al quale si aveva la Cmax, nella curva dell'area sotto concentrazione di siero/tempo (AUCo-24) oppure nel valore dell'emivita media (t1/2) tra gruppi di uomini giovani (n=20), uomini anziani (n=24) e anziani con osteoartrite (n=20), dopo una dose singola di etodolac o dopo 7 giorni di somministrazione subcronica. Inoltre non vi sono stati segni di accumulo. Per di più non vi sono state differenze nei valori di Cmax, tmax, AUCo-24 o t1/2 tra gruppi di soggetti normali (n=10) e pazienti con alterazioni renali da leggere a moderate (n=10). I pazienti con malattia renale all'ultimo stadio che ricevevano emodialisi cronica presentavano la stessa concentrazione media di siero di farmaco libero dei soggetti normali, anche se i livelli medi di siero di etodolac legato alle proteine erano leggermente inferiori a quelli di soggetti normali. L'unica differenza significativa (p<0.05) tra pazienti con cirrosi epatica stabile e soggetti normali della stessa età era nei tmax leggermente più brevi nei soggetti cirrotici (1.1. contro 1.4 ore). Questi risultati suggeriscono che nessuna alterazione del dosaggio di etodolac sarebbe necessaria in questi gruppi ad alto rischio.     

高效液相色谱法测定依托度酸缓释片中的有关物质

目的:建立以高效液相色谱法测定依托度酸缓释片中有关物质的方法。方法:色谱柱为C18,流动相为甲醇-乙腈-0.055mol/L醋酸铵溶液(60∶40∶900)与甲醇-乙腈-0.5mol/L醋酸铵溶液(540∶360∶100),并进行梯度洗脱,流速为1.0ml/min,柱温为35℃,检测波长为220nm,进样量为10μl。结果:各项专属性试验中,依托度酸主峰与其它杂质峰均分离较好;3批样品中各杂质的检测均符合依托度酸缓释片中有关物质检查的要求。结论:本方法可用于依托度酸缓释片中有关物质的检测。     

A comparison of the effects of etodolac and ibuprofen on renal haemodynamics, tubular function, renin, vasopressin and urinary excretion of albumin and α-glutathione-S-transferase in healthy subjects: a placebo-controlled cross-over study

Background: Non-steroidal anti-inflammatory drugs (NSAIDs) are known to be potentially nephrotoxic agents. NSAIDs inhibit the enzyme cyclo-oxygenase and thereby block the prostagladin synthesis in the kidneys. Cyclo-oxygenase exists in two isoforms (COX-1 and COX-2). It has been proposed that NSAIDs with preferential COX-2 selectivity have fewer renal side effects than drugs with preferential COX-1 selectivity. Etodolac is a relative selective inhibitor of COX-2, while ibuprofen has a higher potency against COX-1 than COX-2. Objective: In this study, we compared the effects of etodolac and ibuprofen on renal function, plasma renin, plasma arginine vasopressin and the urinary excretion of albumin and α-glutathione-S-transferase (α-GST). Methods: In a randomised, double-blind, three-way crossover study with placebo, we compared the effects of 2 weeks of treatment with ibuprofen and etodolac on renal haemodynamics [glomerular filtration rate (GFR), renal plasma flow (RPF) and filtration fraction (FF)], tubular function and plasma concentrations of the hormones renin (PRC) and arginine vasopressin (AVP) in 18 healthy subjects. In addition, we examined the effects on the urinary excretion of albumin and α-GST as markers of renal injury. Results: No differences were found between the three treatments, placebo, ibuprofen and etodolac, in the effects on GFR, RPF, FF, free water clearance, urinary output or fractional excretion of potassium and sodium. However, ibuprofen, in contrast to etodolac, caused a significant decrease in both lithium clearance (−16% versus placebo) and the fractional excretion of lithium (−17% versus placebo), suggesting an increase in the re-absorption in the proximal tubuli. PRC was reduced significantly by ibuprofen (−32% versus placebo) but not etodolac. None of the drugs changed AVP. Fourteen days of treatment with ibuprofen caused a significant decrease (−47% versus placebo) in the urinary excretion of α-GST, while no changes were seen after etodolac. None of the drugs changed the urinary excretion of albumin. Conclusion: In conclusion, a 14-day administration of etodolac or ibuprofen in therapeutic doses did not affect the renal haemodynamics, the net excretion of electrolytes or the urinary excretion of albumin in healthy subjects. However, ibuprofen, in contrast to etodolac, caused a reduction in PRC, suggesting that COX-1 is involved in basal renin release in humans. Furthermore, ibuprofen decreased lithium excretion suggesting that COX-1 is involved in the re-absorption of sodium and/or water in the proximal tubuli. The reduction in the urinary excretion of α-GST by ibuprofen may be caused by an inhibition of the detoxification enzyme by ibuprofen. Overall the study indicates that only small differences in the effects of the two drugs on renal function in healthy subjects exist during a treatment period of 2 weeks. Received: 10 November 1999 / Accepted: 21 April 2000     

A comparison of etodolac (Ultradol®) with acetaminophen plus codeine (Tylenol #3) in controlling post-surgical pain in vasectomy patients

Summary

The efficacy and safety of etodolac (Ultradol®) and acetaminophen plus codeine [A + C (Tylenol #3)] in controlling post-surgical pain were compared in an open-label, randomized, parallel-group outpatient study. Patients who were voluntarily having a vasectomy performed for sterilization were assigned to receive either etodolac 200?mg (20 patients) or A + C (20 patients). All medication was taken as required for up to 7 days. Efficacy assessments were made at 1, 6 and 24 hours after surgery and included pain measurement (Likert Visual Analogue scale), patient and physician global assessments and time to analgesic relief. Safety assessments were made throughout the study and included vital signs and adverse event monitoring. Results of the study indicated that patients taking etodolac were more likely to say they could return to work 24 hours after their vasectomy (p = 0.04). There were no other statistically significant differences between the two groups of patients. The results from this study indicate that etodolac and A + C are equally efficacious and well-tolerated for the control of post-vasectomy pain and that patients may observe an increased benefit with etodolac by being able to return to work sooner.     

Reducing liver metastases of colon cancer in the context of extensive and minor surgeries through β-adrenoceptors blockade and COX2 inhibition

Liver metastases are a major cause of colorectal cancer death, and the perioperative period is believed to critically affect the metastatic process. Here we tested whether blocking excess release of catecholamines and prostaglandins during surgical procedures of different extent can reduce experimental liver metastasis of the syngeneic CT26 colon cancer in female and male BALB/c mice. Animals were either treated with the beta-blocker, propranolol, the COX-2 inhibitor, etodolac, both drugs, or vehicle. The role of NK cells in controlling CT26 hepatic metastasis and in mediating the effect of the drugs was assessed by in vivo depletion or stimulation of NK cells, using anti-asialo GM1 or CpG-C, respectively. Surgical extent was manipulated by adding laparotomy to small incision, extending surgical duration, and enabling hypothermia. The results indicated that combined administration of propranolol and etodolac, but neither drug alone, significantly improved host resistance to metastasis. These beneficial effects occurred in both minor and extensive surgeries, in both sexes, and in two tumor inoculation approaches. NK cell-mediated anti-CT26 activity is involved in mediating the beneficial effects of the drugs. Specifically, CpG-C treatment, known to profoundly activate mice marginating-hepatic NK cytotoxicity, reduced CT26 hepatic metastases; and NK-depletion increased metastases and prevented the beneficial effects of the drugs. Overall, given prevalent perioperative psychological and physiological stress responses in patients, and ample prostaglandin release by colorectal tumors and injured tissue, propranolol and etodolac could be tested clinically in laparoscopic and open colorectal surgeries, attempting to reduce patients’ metastatic disease.     

Lorazepam in the treatment of anxiety

Summary

A double-blind study in 50 patients suffering from anxiety was carried out using lorazepam, a new benzodiazepine, and diazepam. The two drugs appeared to be equally effective in all respects and no drug-induced changes were noted from urine examination or in blood-pressure recordings.     

Synthesis,Cytotoxicity, and Pro‐Apoptosis Activity of Etodolac Hydrazide Derivatives as Anticancer Agents

Etodolac hydrazide and a novel series of etodolac hydrazide‐hydrazones 3 – 15 and etodolac 4‐thiazolidinones 16 – 26 were synthesized in this study. The structures of the new compounds were determined by spectral (FT‐IR, ¹H NMR, ¹³C NMR, HREI‐MS) methods. Some selected compounds were determined at one dose toward the full panel of 60 human cancer cell lines by the National Cancer Institute (NCI, Bethesda, USA). 2‐(1,8‐Diethyl‐1,3,4,9‐tetrahydropyrano[3,4‐b]indole‐1‐yl)acetic acid[(4‐chlorophenyl)methylene]hydrazide 9 demonstrated the most marked effect on the prostate cancer cell line PC‐3, with 58.24% growth inhibition at 10^?5 M (10 µM). Using the MTT colorimetric method, compound 9 was evaluated in vitro against the prostate cell line PC‐3 and the rat fibroblast cell line L‐929, for cell viability and growth inhibition at different doses. Compound 9 exhibited anticancer activity with an IC₅₀ value of 54 µM (22.842 µg/mL) against the PC‐3 cells and did not display any cytotoxicity toward the L‐929 rat fibroblasts, compared to etodolac. In addition, this compound was evaluated for caspase‐3 and Bcl‐2 activation in the apoptosis pathway, which plays a key role in the treatment of cancer.     

Determination of enantiomeric impurity of etodolac by capillary electrophoresis using (2-hydroxypropyl)-β-cyclodextrin

A capillary electrophoresis method was developed to determine the impurity of etodolac enantiomers. (2-Hydroxypropyl)-beta-cyclodextrin (HP-beta-CD) was used as a chiral selector and ketoprofen as an internal standard to improve the peak area precision. The seperation of the etodolac enantiomers was achived within 35 min at 15 degrees C and its highest resolution was about 4.0 using phosphate buffer (0.1 M, pH 6.0) with 15 mM HP-beta-CD and UV detection at 225 nm with a reference wavelength at 360 nm. This method allowed determination of 0.2% of (R)-(-)-etodolac in (S)-(+)-etodolac and method validation showed adequate linearity over the required range.     

Worldwide experience with etodolac (Lodine?) 300 mg b.i.d. in the treatment of osteoarthritis

Worldwide experience with the conventional formulation of etodolac (300 mg b.i.d.) was reviewed in 12 randomized, double-blind, parallel-group studies in patients with osteoarthritis (OA) of the hip or knee. The studies were conducted in 13 countries at 59 sites, and 1289 patients were enrolled. The results of 9 comparative and 3 placebo-controlled clinical studies were examined to compare the efficacy and safety of etodolac versus piroxicam, naproxen, indomethacin, indomethacin sustained-release (SR), and diclofenac SR. Efficacy assessments were made at pretreatment screening, baseline, and every 2 weeks thereafter during treatment until study completion up to 4, 6, or 8 weeks. The primary efficacy assessments were the patient's and physician's global evaluations, pain intensity and night pain, or joint tenderness and walking pain. Safety was assessed with reference to study events, reports of laboratory results, and vital signs measurements. Patients in all active treatment groups showed prompt response to therapy. According to the physicians' global evaluation, at least 64% of all etodolac-treated patients and 62% of all active-reference preparation-treated patients had improved by the end of the study. Similar results were seen in the patients' global evaluation. All of the study drugs were well tolerated. Eight (8%) percent of the etodolac-treated patients withdrew because of study events. The proportions of patients treated with active reference preparations and placebos who withdrew because of study events ranged from 3% to 18%. The results reported in this review indicate that etodolac (300 mg b.i.d.) is effective and safe in the treatment of the signs and symptoms of OA and that it compares favorably with piroxicam, naproxen, indomethacin, indomethacin SR, and diclofenac SR.