Clinical pharmacology of etoricoxib

Etoricoxib enhances aryl hydrocarbon receptor activity

Etoricoxib is a nonsteroidal anti-inflammatory drug (NSAID) that possesses properties that include reducing inflammation and relieving pain and fever. Etoricoxib is an oral medication that selectively inhibits cyclooxygenase-2 with high efficacy. Controversies about its cardiovascular side effects have long existed. The aryl hydrocarbon receptor (AhR) is a cytoplasmic receptor that plays a key role in the metabolism of xenobiotics and many physiological functions. 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) is a tryptophan metabolite and endogenous AhR agonist. Activation of AhR by its ligand induces upregulation of AhR-targeted cytochrome P450 (CYP) 1A1 expression. We found that etoricoxib (10-60 μM) induced CYP1A1 mRNA and protein expressions and the transcriptional activity of AhR mediated by the aryl hydrocarbon response element (AHRE) in both mouse Hepa-1c1c7 and human HepG2 cells. Its induction did not appear in AhR signaling-deficient cells, and was inhibited by the AhR antagonist, CH-223191. Etoricoxib was able to induced the translocalization of AhR from cytosol into nucleus. Etoricoxib also worked synergistically with ITE to further increase the expression of CYP1A1 mRNA and protein in human cells. The synergistic effect was higher in cells with than cells without overexpression of AhR. In summary, etoricoxib is an agonist of AhR in both mouse and human cells. Etoricoxib has a synergistic effect on ITE-induced CYP1A1 expression in human cells. The effect of etoricoxib on AhR and ITE on endothelial cells and cardiomyocytes should be further elucidated to in hope to clarify the mechanism of increased cardiovascular events in COX-2 inhibitors and etoricoxib.

A Comparative Study on Cyclodextrin Derivatives in Improving Oral Bioavailability of Etoricoxib as a Model Drug: Formulation and Evaluation of Solid Dispersion-Based Fast-Dissolving Tablets

Etoricoxib, as a model drug, has a poor solubility and dissolution rate. Cyclodextrin derivatives can be used to solve such a problem. A comparative study was run on three cyclodextrin derivatives, namely β-CD, HP β-CD, and SBE β-CD, to solve the drug problem through the formulation of solid dispersions and their preparation into fast-dissolving tablets. Preparations utilized different (1:1, 1:2, and 1:4) drug:carrier ratios. Nine fast-dissolving tablets (containing 1:4 drug: carrier) were formulated using Prosolv ODT® and/or F-melt® type C as super-disintegrants. Optimized formulation was chosen based on a 32 factorial design. The responses chosen were the outcomes of the in vitro evaluation tests. The optimized formulation that had the highest desirability (0.86) was found to be SD-HP3, which was prepared from etoricoxib: HP β-CD at a 1:4 ratio using equal amounts of Prosolv ODT® and F-melt® type C. An in vivo evaluation of SD-HP3 on a rabbit model revealed its superiority over the marketed product Arcoxia®. SD-HP3 showed a significantly lower Tmax (13.3 min) and a significantly higher Cmax (9122.156 μg/mL), as well as a significantly higher AUC, than Arcoxia®. Thus, the solubility, dissolution, and bioavailability of etoricoxib were significantly enhanced.

Formulation and Characterization of Solid Dispersions of Etoricoxib Using Natural Polymers

Objectives

The main objective of the present investigation to develop and evaluate solid dispersions of BCS Class II drugs etoricoxib employing various natural polymers, compatible with conventional manufacturing method to enhance solubility of poorly soluble drugs.

Materials and Methods

In this study, etoricoxib solid dispersion were prepared using xanthan gum, gaur gum and acacia and their combinations by solvent evaporation method. Solid dispersions and pure etoricoxib in the form of powder were characterized in comparison with pure drug and corresponding physical mixtures in the same ratios by Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC), powder X-ray diffractogram, and in vitro drug release.

Results

Solid dispersion (ET11) prepared with 1: 2: 2: 2 drug carrier ratios were showed highest solubility in different solvents. Hence the solid dispersion (ET11) of 1: 2: 2: 2 ratios were selected for characterization. The DSC study indicated that the crystalline nature of etoricoxib was reduced to amorphous. The diffraction pattern of the solid dispersions in each figure indicates that diffraction peaks at 2ɵ values has less intensity than that of pure drugs. This indicated that the crystalline nature of drug sample was converted to amorphous with ET11. Scanning electron microscope photographs of solid dispersion seem to be more porous in nature. From the in vitro drug release profile, it can be seen that formulation ETM11 shows higher dissolution rate i.e. 98.2±1.3% compared with other formulations. It is predicted that, increasing concentration of carrier, increases the drug dissolution rate.

Conclusion

This study has shown that the solid dispersion of etoricoxib using natural carrier can be promising formulation for solubility and dissolution enhancement. Natural polymers used have shown promising results in the modification of drug release from the formulations.

Changes in Physical Stability of Supercooled Etoricoxib after Compression

In the case of formulations with amorphous active pharmaceutical ingredients the risk of pressure-induced recrystallization should be carefully considered. We reported here that supercooled etoricoxib (ETB), which was found as a relatively stable system with low crystallization tendency at atmospheric pressure, crystallized quickly after compression. The observed strong pressure-dependence of the induction period suggests that during compression the first step of crystallization that is nucleation may be accelerated. To overcome the experimental challenge associated with studies at elevated temperatures and high pressures we applied broadband dielectric spectroscopy. Dielectric measurements gave us detailed insight into crystallization kinetics of ETB at varying ( T, p) conditions corresponding to the supercooled liquid state of a drug. We found that pressure-induced recrystallization of supercooled ETB, constituting a serious impediment from a technological point of view, can be efficiently inhibited when amorphous solid dispersion containing ETB and polymer polyvinylpyrrolidone PVP (10% w/w) was prepared. Besides, we performed the comprehensive analysis of molecular dynamics of both systems at elevated pressure to address some fundamental issues related to the pressure sensitivity of their supercooled dynamics.

Etoricoxib and the treatment of ankylosing spondylitis

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) are first-line therapies in the management of patients with ankylosing spondylitis. This chronic inflammatory skeletal disorder, a subtype of spondyloarthritis, is characterized by inflammatory back pain and affects young adults causing important suffering and disability. Long-term use of conventional NSAIDs is associated with a risk of gastrointestinal complications. Etoricoxib is a specific cyclooxygenase 2 inhibitor with strong anti-inflammatory effects and a favorable pharmacokinetic profile for the management of inflammatory disorders. The drug has been associated with reduced severe gastrointestinal adverse events. However, the cardiovascular safety of cyclooxygenase 2 inhibitors has been debated.

AREAS COVERED

This review discusses etoricoxib in the treatment of ankylosing spondylitis. Literature searches were performed in PubMed, Web of Science, and the Cochrane library based on the terms "etoricoxib" and "ankylosing spondylitis" or "spondyloarthritis" as well as "safety" and "side-effects."

EXPERT OPINION

Etoricoxib is useful in the first-line management of ankylosing spondylitis patients. Its anti-inflammatory effects and relative protection against severe gastrointestinal side effects should be balanced with negative effects on the cardiovascular system and an overall subjective tolerance not better than that of conventional NSAIDs. Whether etoricoxib will also become a mainstay in the prevention of structural damage in ankylosing spondylitis is not yet clear.

Solubility and dissolution enhancement of etoricoxib by solid dispersion technique using sugar carriers

The aim of the present study was to improve solubility and dissolution of the poorly aqueous soluble drug, etoricoxib by solvent evaporation technique using various sugar carriers, such as lactose, sucrose, and mannitol. Etoricoxib solid dispersions and their respective physical mixtures using lactose, sucrose, and mannitol were prepared in different ratios by solvent evaporation technique. The percent yield, drug content, saturation solubility, and in vitro dissolution of etoricoxib solid dispersions and physical mixtures were analyzed. Etoricoxib solid dispersions were characterized by FTIR spectroscopy, XRD, and DSC analysis. The FTIR spectroscopic analysis revealed the possibility of intermolecular hydrogen bonding in various solid dispersions. The XRD and DSC studies indicated the transformation of crystalline etoricoxib (in pure drug) to amorphous etoricoxib (in solid dispersions) by the solid dispersion technology. Both the aqueous solubility and dissolution of etoricoxib were observed in all etoricoxib solid dispersions as compared with pure etoricoxib and their physical mixtures. The in vitro dissolution studies exhibited improved dissolution in case of solid dispersion using lactose than the solid dispersions using both sucrose and mannitol. The in vitro dissolution of etoricoxib from these solid dispersions followed Hixson-Crowell model.

Recent advances in the pharmacological management of pain

Pain is an unpleasant sensation that originates from ongoing or impending tissue damage. Management of different types of pain (acute, postoperative, inflammatory, neuropathic or cancer) is the most frequent issue encountered by clinicians and pharmacological therapy is the first line of approach for the treatment of pain. This review presents and discusses recent clinical advances regarding both the improvements in delivery of analgesic drugs and improvements in the design of analgesic molecules. The new modalities of administration of analgesics used in the clinic are reviewed, including skin patches, oral and mucosal sprays, transdermal delivery systems and intranasal administration. New insights are then presented on standard drugs used to relieve pain, such as opioids (including tramadol), NSAIDs including selective cyclo-oxygenase-2 inhibitors, paracetamol (acetaminophen), local anaesthetics and adjuvant analgesics such as antidepressants, anticonvulsants (gabapentin and pregabalin), cannabinoids, ketamine and others (e.g. nefopam). Although the understanding of pain mechanisms has improved significantly recently, much more is yet to be discovered and awaited. Broadening of our knowledge is needed to improve basic and clinical research in this field in order to better alleviate pain in millions of people.

The selective and non-selective cyclooxygenase inhibitors valdecoxib and piroxicam induce the same postoperative analgesia and control of trismus and swelling after lower third molar removal

We compared the clinical efficacy of orally administered valdecoxib and piroxicam for the prevention of pain, trismus and swelling after removal of horizontally and totally intrabony impacted lower third molars. Twenty-five patients were scheduled to undergo removal of symmetrically positioned lower third molars in two separate appointments. Valdecoxib (40 mg) or piroxicam (20 mg) was administered in a double-blind, randomized and crossed manner for 4 days after the surgical procedures. Objective and subjective parameters were recorded for comparison of postoperative courses. Both agents were effective for postoperative pain relief (N = 19). There was a similar mouth opening at suture removal compared with the preoperative values (86.14 +/- 4.36 and 93.12 +/- 3.70% of the initial measure for valdecoxib and piroxicam, respectively; ANOVA). There was no significant difference regarding the total amount of rescue medication taken by the patients treated with valdecoxib or piroxicam (173.08 +/- 91.21 and 461.54 +/- 199.85 mg, respectively; Wilcoxon test). There were no significant differences concerning the swelling observed on the second postoperative day compared to baseline measures (6.15 +/- 1.84 and 8.46 +/- 2.04 mm for valdecoxib and piroxicam, respectively; ANOVA) or on the seventh postoperative day (1.69 +/- 1.61 and 2.23 +/- 2.09 mm for valdecoxib and piroxicam, respectively; ANOVA). The cyclooxygenase-2 selective inhibitor valdecoxib is as effective as the non-selective cyclooxygenase inhibitor piroxicam for pain, trismus and swelling control after removal of horizontally and totally intrabony impacted lower third molars.

Diets and circadian rhythms: challenges from biology for medicine

Autoimmune diseases such as rheumatoid arthritis and gastrointestinal disorders such as stomach ulcers are often treated with drugs. NSAIDs, a common treatment in rheumatoid arthritis, may cause stomach ulcers which call for additional medications, notably antacids in the sense of drugs that suppress acid secretion by the stomach. Infection with Helicobacter pylori also plays a role in the ulcers. The infection is typically treated with antibiotics added to antacids. Considering NSAIDs and antacids, we suspect that overmedication is common to the extent that particular diets are a better option. Current research and current treatments with these drugs are also problematic since circadian rhythms are mostly disregarded. All the processes involved in the disorders treated show marked variations in the course of the day. Hence experiments conforming to the guidelines of evidence-based medicine, and treatments in line with them, have outcomes strongly depending on the time factor. This calls for reforms in medicine with fresh inputs from biology.

Reduced thromboxane biosynthesis in carriers of toll-like receptor 4 polymorphisms in vivo

The recent demonstration that platelets express a functional toll-like receptor 4 (TLR4) prompted us to explore the influence of TLR4 polymorphisms (Asp299Gly alone or in combination with Thr399Ile) on thromboxane A2 (TXA2) biosynthesis in vivo. In 17 subjects with TLR4 polymorphisms versus 17 wild type (untreated with aspirin, matched for age, sex, and cardiovascular risk factors), intima-media thickness in the common carotid arteries was significantly lower. Average urinary excretion of 11-dehydro-TXB2, an index of systemic biosynthesis of TX, was significantly reduced by 65%. The urinary excretion of 2,3-dinor-6-keto-prostaglandin F1α, an index of systemic biosynthesis of prostacyclin, was marginally depressed but the prostacyclin/TXA2 biosynthesis ratio was significantly higher than in wild type. Selective inhibition of cyclooxygenase 2-dependent prostacyclin (by rofecoxib or etoricoxib) was associated with increased urinary excretion of 11-dehydro-TXB2 in carriers of TLR4 polymorphisms, but not in wild-type, suggesting a restrainable effect of prostacyclin on platelet function in vivo in this setting. Reduced TXA2 biosynthesis may contribute to the protective cardiovascular phenotype of TLR4 polymorphisms.