Pharmacokinetics and four-week repeated-dose toxicity of hyaluronic acid and ketorolac combination following intra-articular administration in normal rats.

Intra-articular (IA) injection of hyaluronic acid (HA) in combination with nonsteroidal anti-inflammatory drugs, such as ketorolac (KL), have been clinically investigated to provide more rapid and profound pain relief in patients with osteoarthritis. However, its safety, local tolerance, and potential for pharmacokinetic interaction have not been assessed. In this study, the pharmacokinetics and toxicity of a combination of HA and KL were evaluated in normal rats following four-week repeated-dose injection. Rats received HA or KL alone at 4 mg/kg or 16 mg/kg, respectively, or HA/KL combination at 4/4 mg/kg, 4/8 mg/kg, or 4/16 mg/kg on a weekly basis. The rats exhibited temporal, reversible changes in hematology, serum chemistry, and urinalysis caused primarily by KL treatment. No deleterious effects were observed on the joint following repeated IA HA/KL administration, which showed only minimal to mild levels of temporary inflammatory changes in synovial membrane. The plasma KL level following IA injection rose as fast as that of intra-muscular injection, with no alteration with the co-administered HA. In conclusion, repeated IA administration of HA/KL combination was tolerated well in normal rats, encouraging future studies of IA injection of HA/KL combination on osteoarthritis-induced animal models and even patients.

Oxidative stress and genotoxicity induced by ketorolac on the common carp Cyprinus carpio.

The nonsteroidal anti-inflammatory drug ketorolac is extensively used in the treatment of acute postoperative pain. This pharmaceutical has been found at concentrations of 0.2-60 µg/L in diverse water bodies around the world; however, its effects on aquatic organisms remain unknown. The present study, evaluated the oxidative stress and genotoxicity induced by sublethal concentrations of ketorolac (1 and 60 µg/L) on liver, brain, and blood of the common carp Cyprinus carpio. This toxicant induced oxidative damage (increased lipid peroxidation, hydroperoxide content, and protein carbonyl content) as well as changes in antioxidant status (superoxide dismutase, catalase, and glutathione peroxidase activity) in liver and brain of carp. In blood, ketorolac increased the frequency of micronuclei and is therefore genotoxic for the test species. The effects observed were time and concentration dependent. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1035-1043, 2016.

Photochemical toxicity of drugs intended for ocular use.

The present investigation was undertaken to evaluate the possible ocular phototoxicity of drugs used in ophthalmic formulations. Sulphacetamide, ketoconazole, voriconazole, diclofenac, and ketorolac were assessed in the concentrations available in the market for their ocular use. The suitable models viz Hen's Egg Test Chorioallantoic Membrane (HET-CAM) test, Isolated Chicken Eye (ICE) test, and Red Blood Cell (RBC) haemolysis test as recommended by ECVAM, ICCVAM, and OECD guidelines were performed. Results of HET-CAM and ICE tests suggest that sulphacetamide is moderately toxic in the presence of light/UV-A and very slightly irritant without irradiation. Ketoconazole and voriconazole were found slightly irritant in presence of light/UV-A and non-irritant in dark. Diclofenac and ketorolac demonstrated slight irritancy in the light and were found to be non-irritant in dark. The results suggest that some of the drugs have potential toxic effect in the presence of light. The extent of phototoxicity might get extended when used for longer time. The recommendation is that these drugs should be stored and used in the dark for a specified time and be labelled with specific instructions for patients, especially for those working longer in the sunlight.

Differential involvement of mitochondrial dysfunction, cytochrome P450 activity, and active transport in the toxicity of structurally related NSAIDs.

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of pain and inflammation. However, this group of drugs is associated with serious adverse drug reactions. Previously, we studied the mechanisms underlying toxicity of the NSAID diclofenac using Saccharomycescerevisiae as model system. We identified the involvement of several mitochondrial proteins, a transporter and cytochrome P450 activity in diclofenac toxicity. In this study, we investigated if these processes are also involved in the toxicity of other NSAIDs. We divided the NSAIDs into three classes based on their toxicity mechanisms. Class I consists of diclofenac, indomethacin and ketoprofen. Mitochondrial respiration and reactive oxygen species (ROS) play a major role in the toxicity of this class. Metabolism by cytochrome P450s further increases their toxicity, while ABC-transporters decrease the toxicity. Mitochondria and oxidative metabolism also contribute to toxicity of class II drugs ibuprofen and naproxen, but another cellular target dominates their toxicity. Interestingly, ibuprofen was the only NSAID that was unable to induce upregulation of the multidrug resistance response. The class III NSAIDs sulindac, ketorolac and zomepirac were relatively non-toxic in yeast. In conclusion, we demonstrate the use of yeast to investigate the mechanisms underlying the toxicity of structurally related drugs.

Development and characterization of mucoadhesive microspheres for nasal delivery of ketorolac.

The objective of the present investigation was to prepare mucoadhesive microspheres of ketorolac for nasal administration by means of a solvent evaporation technique using carbopol (CP), polycarbophil (PL) and chitosan (CS) as mucoadhesive polymers. The prepared microspheres were characterized for morphology, swelling behavior, mucoadhesion, interaction studies, drug encapsulation efficiency, in vitro drug release, release kinetics, and ex vivo nasal cilio toxicity studies. The effects of various process variables on the particle size of the microspheres were investigated. Drug encapsulation efficiency and particle size of the microspheres ranged from 52-78% w/w and 14-46 microm respectively. Interaction studies revealed that there were no drug-polymer interactions. The in vitro release profiles showed prolonged-release of the drug. In vitro release data showed a good fit with the Higuchi model, and indicated Fickian diffusion. No severe damage was found to the integrity of nasal mucosa after ex vivo experiments.

Safety of intravitreal ketorolac and diclofenac: an electroretinographic and histopathologic study.

OBJECTIVE: To determine the clinical, histologic, and electroretinographic effects in the rabbit retina of escalating doses of two intravitreally delivered nonsteroidal anti-inflammatory drugs (NSAIDs): ketorolac and diclofenac. METHODS: Right eyes received a single 0.1 mL injection of either ketorolac (500-6000 microg/0.1 mL) or diclofenac (300-1500 microg/0.1 mL) prepared in balanced salt solution (BSS). Left eyes served as controls and received BSS. Dark- and light-adapted electroretinograms (ERG) were obtained at baseline and 4 and 8 weeks postinjection. Enucleated eyes were examined histologically. RESULTS: Ophthalmic examinations demonstrated no signs of intraocular inflammation or retinal toxicity. Intraocular pressure measurements remained similar between NSAID injected and control eyes. Histologic and ERG studies of eyes injected with 6000 microg ketorolac and >or=500 microg diclofenac demonstrated toxicity. In contrast, doses up to 3000 microg ketorolac demonstrated enhanced b-wave amplitude responses. Delayed drug toxicity was observed for the highest doses of both NSAIDs. CONCLUSIONS: Intravitreal 3000 microg ketorolac and 300 microg diclofenac were nontoxic in this animal study, and may offer an effective and safer alternative to intravitreal corticosteroids.

Ketorolac-dextran conjugates: synthesis, in vitro and in vivo evaluation.

Ketorolac is a non-steroidal anti-inflammatory drug. Dextran conjugates of ketorolac (KD) were synthesized and characterized to improve ketorolac aqueous solubility and reduce gastrointestinal side effects. An N-acylimidazole derivative of ketorolac (KAI) was condensed with a model carrier polymer, dextran of different molecular masses (40000, 60000, 110000 and 200000). IR spectral data confirmed formation of ester bonding. Ketorolac contents were evaluated by UV-spectrophotometric analysis. The molecular mass was determined by measuring viscosity using the Mark-Howink-Sakurada equation. In vitro hydrolysis studies were performed in aqueous buffers (pH 1.2, 7.4, 9) and in 80% (V/V) human plasma (pH 7.4). At pH 9, a higher rate of ketorolac release from KD was observed as compared to aqueous buffer of pH 7.4 and 80% human plasma (pH 7.4), following first-order kinetics. In vivo biological screening in mice and rats indicated that conjugates retained analgesic and anti-inflammatory activities with significantly reduced ulcerogenicity compared to the parent drug.

Intrathecal ketorolac in dogs and rats.

This study was conducted to assess spinal safety of the cyclo-oxygenase inhibitor ketorolac in dogs and rats. Beagle dogs were prepared with lumbar intrathecal catheters and received continuous spinal infusions of 5 mg/ml ketorolac (N = 6), 0.5 mg/ml ketorolac (N = 8), or saline vehicle (N = 6) at 50 microl/h (1.2 ml/day) for 28 days. No systematic drug or dose-related changes were observed in motor function, heart rate, or blood pressure. Histological examination revealed a mild pericatheter reaction in all groups with no drug or dose related effect upon spinal pathology at the lumbar site of highest drug concentration. Cisternal CSF protein was elevated for all treatment groups at necropsy, and cisternal glucose was within normal range for all treatment groups, though three dogs displayed decreases in cisternal glucose. Significant reductions in hematocrit were noted, and increased incidence of gastric bleeding at necropsy was observed in animals receiving ketorolac. Intrathecal ketorolac kinetics revealed a biphasic clearance: t1/2 s = 10.3 and 53 min, respectively. After initiation of infusion (0.5 mg and 5 mg/ml/50 microl/h), lumbar CSF concentrations of ketorolac were 3.8 and 52.7 microg/ml, respectively. Bolus and continuous infusion of intrathecal ketorolac resulted in significant reduction of lumbar CSF PGE2 concentrations. In rats, with intrathecal catheters, four daily bolus deliveries of saline or ketorolac (5 mg/ml/10 microl) had no effect upon spinal histology or upon spinal cord blood flow. These data indicate that intrathecal ketorolac in two species at the dose/concentrations employed does not induce evident spinal pathology but diminishes spinal prostaglandin release.

Pharmacological profile of parecoxib: a novel, potent injectable selective cyclooxygenase-2 inhibitor.

The antinociceptive, anti-inflammatory, antipyretic effects along with gastric safety profile of parecoxib, a novel, potent selective cyclooxygenase-2 inhibiting prodrug, and those of ketorolac, a nonselective cyclooxygenase inhibitor, were evaluated in various animal models. Parecoxib (up to 20 mg/kg, i.v.) had no effect in two acute pain models, namely, the acetic acid-induced writhing (visceral pain) and the formalin test (tonic pain). However, ketorolac (up to 10 mg/kg, i.v.) showed marked antinociceptive effects in these models. In the models of carrageenan-provoked inflammatory hyperalgesia and inflammation, and in lipopolysaccharide-induced pyrexia, parecoxib significantly reversed all the behavioral changes and it was found to be more potent than ketorolac. Further, ketorolac (10 mg/kg, i.v.) produced visible gastric lesions with prominent petechiae and hemorrhagic streaks. However, parecoxib was without any effect on gastric mucosa. The present results showed that the cyclooxygenase-2 inhibitor, parecoxib, when administered parenterally, has potent antihyperalgesic, anti-inflammatory, antipyretic effects and has a better safety profile than with ketorolac, with sparing of cyclooxygenase-1 in the stomach in these animal models.