Synthesis, Biological, Spectroscopic and Computational Investigations of Novel N-Acylhydrazone Derivatives of Pyrrolo[3,4-d]pyridazinone as Dual COX/LOX Inhibitors.

Secure and efficient treatment of diverse pain and inflammatory disorders is continually challenging. Although NSAIDs and other painkillers are well-known and commonly available, they are sometimes insufficient and can cause dangerous adverse effects. As yet reported, derivatives of pyrrolo[3,4-d]pyridazinone are potent COX-2 inhibitors with a COX-2/COX-1 selectivity index better than meloxicam. Considering that N-acylhydrazone (NAH) moiety is a privileged structure occurring in many promising drug candidates, we decided to introduce this pharmacophore into new series of pyrrolo[3,4-d]pyridazinone derivatives. The current paper presents the synthesis and in vitro, spectroscopic, and in silico studies evaluating the biological and physicochemical properties of NAH derivatives of pyrrolo[3,4-d]pyridazinone. Novel compounds 5a-c-7a-c were received with high purity and good yields and did not show cytotoxicity in the MTT assay. Their COX-1, COX-2, and 15-LOX inhibitory activities were estimated using enzymatic tests and molecular docking studies. The title N-acylhydrazones appeared to be promising dual COX/LOX inhibitors. Moreover, spectroscopic and computational methods revealed that new compounds form stable complexes with the most abundant plasma proteins-AAG and HSA, but do not destabilize their secondary structure. Additionally, predicted pharmacokinetic and drug-likeness properties of investigated molecules suggest their potentially good membrane permeability and satisfactory bioavailability.

New approaches to tumor therapy with siRNA-decorated and chitosan-modified PLGA nanoparticles.

Objective: In this study, we aimed to develop a candidate modifited polymeric nanoparticle (NP) system that will kill cancer cells by facilitated to apoptosis and also reduce pain. Significance: The primary goal of treatment, especially for metastatic cancers, is to control the growth of the cancer and to alleviate the symptoms. Pain is one of the commonest symptoms of cancer. In cancer treatment, directing cancer cells to death while simultaneously relieving pain will be a new approach. Methods: Chitosan-modified PLGA NPs were prepared using an nanoprecipitation technique. The NPs were loaded with flurbiprofen and decorated with folic acid. STAT3-siRNA was adsorbed to these polymeric NPs using antisense technology. Results: The NPs were small in size (176.9-220.3 nm) with positive zeta potential (+14.1 mV to +27.2 mV). They had high loading capacity and prolonged release properties over 144 hours. Cytotoxicity studies performed with siRNA showed effective electrostatic interaction due to the positively charged NPs. Folic acid facilitated entry into cancer cells and helped to kill them. Conclusion: The formulation we developed is a potential carrier system for both treatment of cancer and prevention of pain, especially for metastatic cancers.

Polyfluorinated salicylic acid derivatives as analogs of known drugs: Synthesis, molecular docking and biological evaluation.

We have developed the convenient methods for synthesis of polyfluorosalicylic acids and their derivatives. For the first time the biological properties of polyfluorosalicylates were investigated in vitro (permeability through the biological membranes, COX-1 inhibitory action) and in vivo (anti-inflammatory, analgesic activities, acute toxicity). Molecular docking of polyfluorinated salicylates confirmed in vitro and in vivo experiments.

Pharmacokinetics and efficacy of intraocular flurbiprofen.

PURPOSE: Intravitreal delivery of non-steroidal anti-inflammatory drugs could be an effective way to treat macular edema caused by posterior segment inflammation. In this study, we evaluated the intravitreal bioavailability and anti-inflammatory efficacy of flurbiprofen in rabbit eyes. METHODS: For pharmacokinetics, 0.1 ml of 7.66 mg/ml flurbiprofen solution was injected intravitreally and vitreous drug levels were analyzed at specific time points using LC-MS technique. For efficacy, 100 ng lipopolysaccharide of E.coli was injected intravitreally in rabbits to induce inflammation. The animals were separated in three groups and received intraocular flurbiprofen, dexamethasone and PBS to serve as control. Complete ocular examination and total cell count in aqueous fluid were determined to evaluate the extent of inflammation. Eyes were then enucleated for histopathology analysis. The efficacy in the uveitis model was determined by clinical signs of inflammation, total leukocyte count and histology findings. RESULTS: No adverse events were observed during pharmacokinetic assessment. No signs of inflammation, hemorrhage or retina detachment were detected. The recovery of flurbiprofen from vitreous samples was 92.6%. The half-life of flurbiprofen was estimated to be 1.92 h with an elimination constant rate (K) of 0.36. Treatment with intraocular injections of flurbiprofen and dexamethasone significantly reduced total leukocyte count in a manner comparable to dexamethasone [reduction of 96.84% (p < 0.05) and 97.44% (p < 0.05), respectively]. Histologic studies demonstrated significantly less signs of ocular inflammation after flurbiprofen injection compared to control eyes. CONCLUSIONS: Flurbiprofen is effective in suppressing inflammation in this experimental uveitis model. In our experimental setting, intravitreal flurbiprofen seem to have a therapeutic result comparable to dexamethasone. However, the half-life of the drug remains short, necessitating further research to prolong its presence in the vitreous cavity.

Evaluation of the dose-response relationship of oral robenacoxib in urate crystal-induced acute stifle synovitis in dogs.

The objective of the study was to establish the dose-response relationship for robenacoxib, a selective cyclooxygenase (COX)-2 inhibitor, in a urate crystal model of acute synovitis. In a randomized partial Latin square design trial, 12 beagle dogs were administered orally single doses of robenacoxib (0.5, 1, 2, 4 and 8 mg/kg), placebo and the positive control meloxicam (0.1 mg/kg), 3 h after injection of sodium urate crystals into a stifle joint. Dogs were assessed for weight bearing on a force plate and by subjective clinical orthopaedic observations. Robenacoxib produced dose-dependent improvement in weight bearing, and decreased pain on palpation and joint swelling, over the dose range 0.5-2 mg/kg with no further increase in effect over the range 2-8 mg/kg. For weight bearing on the force plate, the ED50 of robenacoxib was 0.6-0.8 mg/kg. The onset of action and time to peak effect of robenacoxib were faster (respectively, 2-2.5 h and 3-5 h) than for meloxicam (respectively, 3 h and 6 h). Robenacoxib significantly inhibited COX-2 at all doses, with dose-related activity. Robenacoxib did not inhibit COX-1 over the dose range 0.5-4 mg/kg, but produced transient inhibition at 8 mg/kg. In conclusion, oral administration of robenacoxib over the dose range 0.5-8 mg/kg demonstrated significant analgesic and anti-inflammatory efficacy in dogs.

Synthesis, anti-inflammatory, ulcerogenic and cyclooxygenase activities of indenopyrimidine derivatives.

Objective of the present work was to evaluate the anti-inflammatory, ulcerogenicity and cyclooxygenase activity of indenopyrimidine derivatives. Anti-inflammatory activity of the tested compounds is investigated by carrageenan-induced rat paw edema assay. Compounds A1, A6, A7 and A12 exhibit the comparable anti-inflammatory activity (79.33-81.33%) to the standard drug diclofenac sodium (85.33%), while A6, A7, A9, A12 and A14 show better ulcer index than the reference standard diclofenac sodium. To rationalize the anti-inflammatory activity, docking experiments are performed to study the ability of these compounds to bind into the active site of COX-2 enzyme.

Evaluation of systemic absorption and renal effects of topical ophthalmic flurbiprofen and diclofenac in healthy cats.

OBJECTIVE: To investigate systemic absorption and renal effects of topically applied ophthalmic flurbiprofen and diclofenac in healthy cats. ANIMALS STUDIED: Twelve domestic shorthair cats. PROCEDURES: Cats were randomly assigned to two treatment groups (n = 6) and administered one drop (approximately 40 µL) of either flurbiprofen 0.03% or diclofenac 0.1% in both eyes four times daily (6 am, 12 pm, 6 pm, and 12 am) for 14 days. Blood samples were collected on days 0, 4, 8, 14, 16, and 17 and analyzed by liquid chromatography and mass spectrometry for flurbiprofen and diclofenac plasma concentrations. A complete blood count (CBC), serum chemistry, and urinalysis were analyzed at the beginning of the study (Day 0) and at the end of topical drug administration (Day 15). RESULTS: Both drugs demonstrated systemic absorption. Flurbiprofen was detected (mean ± SD) at day 4 (237 ± 65 ng/mL), day 8 (396 ± 91 ng/mL), day 14 (423 ± 56 ng/mL), day 16 (350 ± 66 ng/mL), and day 17 (270 ± 62 ng/mL), and diclofenac was detected (mean ± SD) at day 4 (130 ± 44 ng/mL), day 8 (131 ± 25 ng/mL), day 14 (150 ± 36 ng/mL), and sporadically on day 16 [corrected]. Flurbiprofen plasma concentration decreased slowly over 48 h after the last dose. No clinically significant abnormalities were noted in the serum blood urea nitrogen, creatinine, or urine specific gravity at the end of topical drug administration compared to the beginning of the study. CONCLUSIONS: Flurbiprofen and diclofenac were systemically absorbed after topical administration four times daily to both eyes of healthy cats. Flurbiprofen reached higher plasma concentrations compared to diclofenac.

Analgesic Effect of the Newly Developed S(+)-Flurbiprofen Plaster on Inflammatory Pain in a Rat Adjuvant-Induced Arthritis Model.

Preclinical Research This article describes the properties of a novel topical NSAID (Nonsteroidal anti-inflammatory drug) patch, SFPP (S(+)-flurbiprofen plaster), containing the potent cyclooxygenase (COX) inhibitor, S(+)-flurbiprofen (SFP). The present studies were conducted to confirm human COX inhibition and absorption of SFP and to evaluate the analgesic efficacy of SFPP in a rat adjuvant-induced arthritis (AIA) model. COX inhibition by SFP, ketoprofen and loxoprofen was evaluated using human recombinant COX proteins. Absorption of SFPP, ketoprofen and loxoprofen from patches through rat skin was assessed 24 h after application. The AIA model was induced by injecting Mycobacterium tuberculosis followed 20 days later by the evaluation of the prostaglandin PGE2 content of the inflamed paw and the pain threshold. SFP exhibited more potent inhibitory activity against COX-1 (IC50 = 8.97 nM) and COX-2 (IC50 = 2.94 nM) than the other NSAIDs evaluated. Absorption of SFP was 92.9%, greater than that of ketoprofen and loxoprofen from their respective patches. Application of SFPP decreased PGE2 content from 15 min to 6 h and reduced paw hyperalgesia compared with the control, ketoprofen and loxoprofen patches. SFPP showed analgesic efficacy, and was superior to the ketoprofen and loxoprofen patches, which could be through the potent COX inhibitory activity of SFP and greater skin absorption. The results suggested SFPP can be expected to exert analgesic effect clinically.

Pharmacokinetic and bioequivalence studies of immediate release diclofenac potassium tablets (50mg) in healthy volunteers.

This study was conducted with the aim to determine the pharmacokinetic and bioequivalence of diclofenac potassium 50 mg test (F4) tablet formulation with reference product (Caflam). Present study was single dose, randomized, two phase cross over design, conducted in 12 healthy Pakistani volunteers and planned in accordance with FDA guidelines. In this study a simple, selective, sensitive and reproducible HPLC procedure was developed and validated for the estimation of diclofenac potassium in plasma. The process was validated in the range of 50 - 0.05 µg.mL-1 and used in bioequivalence trial of two products. Multiple blood samples were collected at various time points (0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12 and 14 hr after treating volunteers with test (F4) and marketed reference brand. Plasma separation and deproteination were carried out with acetonitrile; samples (20µL) were injected using the validated HPLC method. Various pharmacokinetic parameters (compartmental and noncompartmental) were estimated using KineticaTM 4.4.1 (Thermo Electron Corp. USA). Bioequivalence among the products was established by calculating the 90% CI with log and non log transformed data for Cmaxcalc, Tmaxcalc, AUC0-∞, AUCtot and AUClast using two way ANOVA and Schirmann's Two one sided t- test. No significant difference was found between log and non-log data. The 90% confidence interval values using log transformed data for AUC0-∞ (0.997-1.024), AUCtot (1.004-1.031), AUClast (0.997 -1.024), Cmaxcalc (0.994-1.007) and Tmaxcalc (0.996-1.013) for the trial and reference products were found within the FDA acceptable limits of 0.8-1.25. Results were further verified by the Schirmann's one-sided t test. Results showed the bioequivalence of test and reference formulations. Both the products were well tolerated.

Model-based analysis of thromboxane B2 and prostaglandin E2 as biomarkers in the safety evaluation of naproxen.

The assessment of safety in traditional toxicology protocols relies on evidence arising from observed adverse events (AEs) in animals and on establishing their correlation with different measures of drug exposure (e.g., Cmax and AUC). Such correlations, however, ignore the role of biomarkers, which can provide further insight into the underlying pharmacological mechanisms. Here we use naproxen as a paradigm drug to explore the feasibility of a biomarker-guided approach for the prediction of AEs in humans. A standard toxicology protocol was set up for the evaluation of effects of naproxen in rat, in which four doses were tested (7.5, 15, 40 and 80 mg/kg). In addition to sparse blood sampling for the assessment of exposure, thromboxane B2 and prostaglandin E2 were also collected in satellite groups. Nonlinear mixed effects modelling was used to evaluate the predictive performance of the approach. A one-compartmental model with first order absorption was found to best describe the pharmacokinetics of naproxen. A nonlinear relationship between dose and bioavailability was observed which leads to a less than proportional increase in naproxen concentrations with increasing doses. The pharmacodynamics of TXB2 and PGE2 was described by direct inhibition models with maximum pharmacological effects achieved at doses >7.5 mg/kg. The predicted PKPD relationship in humans was within 10-fold of the values previously published. Moreover, our results indicate that biomarkers can be used to assess interspecies differences in PKPD and extrapolated data from animals to humans. Biomarker sampling should be used systematically in general toxicity studies.

Influence of CYP2C8 polymorphisms on the hydroxylation metabolism of paclitaxel, repaglinide and ibuprofen enantiomers in vitro.

CYP2C8 plays an important role in the metabolism of various drugs, such as paclitaxel, repaglinide and ibuprofen. Polymorphisms in the CYP2C8 gene were shown to influence interindividual differences in the pharmacokinetics of paclitaxel, repaglinide and ibuprofen enantiomers. In this study, three CYP2C8 allelic variants (CYP2C8.2, CYP2C8.3 and CYP2C8.4) and wild-type CYP2C8 (CYP2C8.1) were co-expressed for the first time with human cytochrome P450 oxidoreductase (POR) and cytochrome b5 by using a baculovirus-assisted insect cell expression system. Further, the effects of genotype-phenotype correlations of CYP2C8 alleles on the metabolism of paclitaxel, repaglinide and ibuprofen enantiomers were evaluated. The CLint values of CYP2C8.2, CYP2C8.3 and CYP2C8.4 for paclitaxel were 47.7%, 64.3% and 30.2% of that of CYP2C8.1 (p<0.01). The CLint values of CYP2C8.2 and CYP2C8.4 for repaglinide were 77.9% and 80.2% of that of CYP2C8.1 (p<0.05), respectively, while the CLint value of CYP2C8.3 was 1.31-fold higher than that of CYP2C8.1 (p<0.05). The relative CLint values of CYP2C8.2, CYP2C8.3 and CYP2C8.4 were 110.5%, 72.3% and 49.7% of that of CYP2C8.1 and were 124.6%, 83.4% and 47.4% of that of CYP2C8.1 for R-ibuprofen and S-ibuprofen, respectively. Comparing hydroxylation by CYP2C8.1 and CYP2C8.3 resulted in higher and lower intrinsic clearance of repaglinide and ibuprofen enantiomers, respectively. These in vitro findings were consistent with the pharmacokinetics in volunteers who were heterozygous or homozygous carriers of CYP2C8*3. The results of this study provide useful information for predicting CYP2C8 phenotypes and may contribute to individualized drug therapy in the future.

A diclofenac suppository-nabumetone combination therapy for arthritic pain relief and a monitoring method for the diclofenac binding capacity of HSA site II in rheumatoid arthritis.

Diclofenac suppository, a non-steroidal anti-inflammatory drug (NSAID), is used widely in rheumatoid arthritis (RA) patients with severe arthritic pain. As the binding percentage of diclofenac to serum proteins is high, its free (unbound) concentration after rectal administration is low. To increase temporarily the free concentration of diclofenac and to enhance its analgesic effect by inhibiting the protein binding of diclofenac, the analgesic effect of diclofenac was examined before and after the start of an inhibitor administration to RA patients with insufficient control of arthritic pain, and the protein binding capacity of diclofenac was evaluated. Binding experiments were performed by ultrafiltration, and arthritic pain was recorded by the face scale. Free fractions of diazepam and diclofenac were augmented by increasing 6-methoxy-2-naphthylacetic acid (6-MNA; the active metabolite of the NSAID nabumetone) concentrations. The free fraction of diazepam increased after the start of nabumetone administration to RA patients, and arthritic pain relief was observed. These results suggest that 6-MNA has an inhibitory effect on the protein binding of diclofenac and the free fraction of diazepam can be used to evaluate the binding capacity of diclofenac. It is considered that diclofenac suppository-nabumetone combination therapy and the method for protein binding monitoring by diazepam can positively benefit RA patients with insufficient control of arthritic pain.

Powdered self-emulsified lipid formulations of meloxicam as solid dosage forms for oral administration.

The objectives of this study were to prepare a powdered self-emulsified (SEDDS) formulation of meloxicam and to compare its oral bioavailability against commercial Mobic tablets. The SEDDS formulation was prepared by in situ salt formation of meloxicam in a blend of lipid excipients and aqueous tris (hydroxymethyl) aminomethane solution. The liquid SEDDS was subsequently adsorbed on silica powder and was tested for size, flow, and crystal growth. The flowability index of the powdered SEDDS was borderline acceptable. Absence of crystal growth with storage was confirmed by DSC and PXRD studies. Dissolution of meloxicam from the powdered SEDDS was >90% vs. <12% for powdered meloxicam and <80% for the commercial tablets. Stability of the powdered formulations after storage in gelatin and HPMC capsules was also evaluated to study the effect of water migration from the fill into capsule shells. Capsules softened to a different extent as a function of fill material with HPMC capsules showing greater resistance to water migration. Finally, oral bioavailability of the formulations was evaluated in beagle dogs. Powdered meloxicam SEDDS formulation showed a 1.3-fold increase in AUC vs. commercial Mobic® tablets. Overall, this study described a novel SEDDS formulation of meloxicam and outlined a systematic approach to adsorbing and testing the flow and stability behavior of powdered SEDDS formulations.

Chemoprevention, chemotherapy, and chemoresistance in colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related death in industrialized countries. Chemoprevention is a promising approach, but studies demonstrating their usefulness in large populations are still needed. Among several compounds with chemopreventive ability, cyclooxygenase inhibitors have received particular attention. However, these agents are not without side effects, which must be weighed against their beneficial actions. Early diagnosis is critical in the management of CRC patients, because, in early stages, surgery is curative in >90% of cases. If diagnosis occurs at stages II and III, which is often the case, neoadjuvant chemotherapy and radiotherapy before surgery are, in a few cases, recommended. Because of the high risk of recurrence in advanced cancers, chemotherapy is maintained after tumor resection. Chemotherapy is also indicated when the patient has metastases and in advanced cancer located in the rectum. In the last decade, the use of anticancer drugs in monotherapy or in combined regimens has markedly increased the survival of patients with CRC at stages III and IV. Although the rate of success is higher than in other gastrointestinal tumors, adverse effects and development of chemoresistance are important limitations to pharmacological therapy. Genetic profiling regarding mechanisms of chemoresistance are needed to carry out individualized prediction of the lack of effectiveness of pharmacological regimens. This would minimize side effects and prevent the selection of aggressive, cross-resistant clones, as well as avoiding undesirable delays in the use of the most efficient therapeutic approaches to treat these patients.

Pharmacokinetic, distribution, metabolism, and excretion of (Z)-2-amino-1,5-dihydro-1-methyl-5-[4-(mesyl)benzylidene]-4H-imidazol-4-one mesilate (ZLJ-601) in Sprague-Dawley rats.

(Z)-2-amino-1,5-dihydro-1-methyl-5-[4-(mesyl)benzylidene]-4H-imidazol-4-one mesilate (ZLJ-601) is an imidazolone COX/5-LOX inhibitor, which has excellent anti-inflammatory activity with an improved gastrointestinal safety profile. The purpose of this study was to evaluate the in vivo absorption, distribution, metabolism, and excretion of ZLJ-601 in Sprague-Dawley rats. After intravenous or intragastric administration to rats, the concentration of ZLJ-601 in plasma, bile, urine, feces and various types of tissues was detected by LC-MS. We also conducted the identification of metabolites using tandem mass spectrometry. After the intravenous administration, the t(1/2) ranged from 38.71 to 42.62 min and the AUC increased in a dose-proportional manner. After oral dosing, the plasma level of ZLJ-601 peaked at 28.33 min, having a C(max) value of 0.26 mg/l, and the bioavailability was only 4.92%. The highest tissue concentration of ZLJ-601 was observed in lung and kidney, but it was not found in brain. The majority of unchanged ZLJ-601 was excreted in urine (∼35.87%) within 36 h. Two main metabolites are the hydroxylation product and the glucuronide conjugate of the hydroxylation product.

Prediction of time-dependent interaction of aspirin with ibuprofen using a pharmacokinetic/pharmacodynamic model.

WHAT IS KNOWN AND OBJECTIVE: Low-dose aspirin is widely used for prevention of thrombosis, but combined use of aspirin with non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, reduces the antiplatelet effect of aspirin. However, there has been no report describing the effects of the timing of the ibuprofen dose on the degree of interaction between low-dose aspirin and ibuprofen. The purpose of this study was to predict the time-course of the antiplatelet effect of low-dose aspirin when ibuprofen is administered as a single dose or repeatedly in combination with aspirin at various time intervals. METHODS: We simulated ex vivo platelet aggregation using a previously developed pharmacokinetic (PK)/pharmacodynamic (PD) model. RESULTS AND DISCUSSION: The antiplatelet effect of low-dose aspirin (81 mg) was predicted to be markedly reduced when ibuprofen (200 mg; the usual prescribed dose in Japan) was administered 1 h or less after aspirin, but not when it was administered more than 2 h after the administration of aspirin. Moreover, the administration of ibuprofen up to 12 h before aspirin completely abrogated the antiplatelet effect of aspirin. When ibuprofen (200 mg) was administered three times daily for 3 days (day 1 to day 3) on a background of continuous low-dose aspirin (81 mg) once daily, 2 h after aspirin, no reduction in the antiplatelet effect of aspirin was predicted on day 1, but a reduction is predicted from day 2, with no return to the initial level until more than 3 days after discontinuation of ibuprofen. A marked reduction in the antiplatelet effect of aspirin was also seen on the same schedule when the dosage of ibuprofen was 150 mg, which is the dose used in over-the-counter (OTC) preparations. WHAT IS NEW AND CONCLUSION: This study indicates that the antiplatelet effect of low-dose aspirin can be markedly reduced with combined use of ibuprofen, depending on the timing of co-administration. As even the lower OTC dose of ibuprofen (150 mg) was enough to affect the antiplatelet effect of aspirin, health professionals should take into account patients' use of OTC ibuprofen when prescribing low-dose aspirin.

High on treatment platelet reactivity.

The addition of clopidogrel to aspirin for patients undergoing percutaneous coronary intervention (PCI) had significantly reduced cardiovascular events. However, despite dual antiplatelet therapy ischaemic events still occur, especially stent thrombosis, which is associated with a high mortality rate. Inter-individual response to clopidogrel is highly variable. It was shown that 4-46% could be considered as high on treatment platelet reactivity (HTPR). Recent studies had demonstrated a relationship between HTPR and ischaemic events in the setting of PCI. Actually the assessment of platelet reactivity in routine practice and its interpretation to make a decision is a debatable issue.

In vitro/in vivo correlation of fast release mephenamic acid microspheres in humans.

OBJECTIVES: The objectives of this study were to assess the bioavailability of an optimized mephenamic acid (MFA) microspheres (test) against a Ponstan® capsule (reference) in healthy volunteers, and to establish a correlation with in vitro parameters. SUBJECTS AND METHODS: Four subjects received the test and reference (250 mg MFA each) in a randomized crossover design, separated by a 1-week washout period. The drug was analyzed in plasma by a specific high-performance liquid chromatographic method. The relevant pharmacokinetic parameters [maximum plasma concentration (C(max)), time of peak concentration (T(max)), area under plasma concentration-time curves from 0 to 12 h (AUC(0-12)) and area under plasma concentration-time curves from zero to ∞ (AUC(0-)∞)] were calculated from the plasma drug concentration-time data. RESULTS: The test product exhibited faster absorption (T(max) of 1.87 ± 0.482 vs. 2.14 ± 0.20 h; C(max) of 5.91 ± 0.604 vs. 3.58 ± 0.671 µg/ml) when compared to the reference. The relative bioavailability of the test compared to the reference capsule was 172%. Good correlations were established between the in vitro 90% dissolution (T90) and each of the AUC(0-12) and T(max), as well as between the percentage of drug released and plasma concentrations. CONCLUSION: The formulation of MFA microsphere with polyethylene glycol improved the dissolution rate and bioavailability of MFA, as evidenced by a higher C(max), AUC(0-12) and AUC(0-)∞, and shorter T(max) values. Good correlations between T90 and both AUC(0-12) and T(max) as well as between the percentage of drug released and plasma concentrations were achieved.

Effects of CYP2C9*1/*13 on the pharmacokinetics and pharmacodynamics of meloxicam.

AIMS: To determine the effects of the CYP2C9*1/*13 genotype on the pharmacokinetics and pharmacodynamics of meloxicam in Korean subjects. METHODS: Meloxicam (15 mg) was orally administered to 21 healthy Korean volunteers with either the CYP2C9*1/*1 or the CYP2C9*1/*13 genotype. Plasma meloxicam concentrations were analysed by HPLC-UV for 72 h after drug administration. The pharmacodynamic effects of meloxicam were determined by measuring TXB(2) generated in blood. RESULTS: The AUC(0,∞) and C(max) of meloxicam were 2.43- and 1.46-fold higher in the CYP2C9*1/*13 group than in the CYP2C9*1/*1 group, respectively. The oral clearance of meloxicam was significantly lower in the CYP2C9*1/*13 group (37.9% of wild type) than in the CYP2C9*1/*1 group. The t(1/2) of meloxicam was 1.84-fold longer in the CYP2C9*1/*13 group than in the CYP2C9*1/*1 group. The rate of TXB(2) production was significantly lower in the CYP2C9*1/*13 group than in the CYP2C9*1/*1 group. CONCLUSIONS: The CYP2C9*1/*13 genotype is associated with decreased metabolism and increased pharmacodynamic effects of meloxicam.

¹¹C-labeled analogs of indomethacin esters and amides for brain cyclooxygenase-2 imaging: radiosynthesis, in vitro evaluation and in vivo characteristics in mice.

There is great potential in the use of positron emission tomography (PET) and suitable radiotracers for the study of cyclooxygenase type 2 (COX-2) enzyme in living subjects. In the present study, we prepared and evaluated five ¹¹C-labeled ester and amide analogs derived from indomethacin as potential PET imaging agents for the in vivo visualization of the brain COX-2 enzyme. Five ¹¹C-labeled COX-2 inhibitors, with different lipophilicities and moderate COX-2 inhibitory activity, were prepared by treatment of the corresponding O-desmethyl precursors with [¹¹C]methyl triflate and purified by HPLC (radiochemical yields of 55-71%, radiochemical purity of >93%, and the specific activities of 22-331 GBq/µmol). In mice, radioactivity in the brain for all radiotracers was low, with very low brain-to-blood ratios. A clear inverse relationship was observed between brain uptake at 1 min postinjection and the lipophilicity (experimental log P7.4) of the studied ¹¹C-radiotracers. Pretreatment of mice with cyclosporine A to block P-glycoproteins caused a significant increase in brain uptake of radioactivity following injection of the ¹¹C-radiotracer compared to control. HPLC analysis showed that each radiotracer was rapidly metabolized, and a few metabolites, which were more polar than the original radiotracers, were found in both plasma and brain. No specific binding of the tracers towards the COX-2 enzyme in the brain was clearly revealed by in vivo blocking study. Further structural refinement of the tracer agent is necessary for better enhancement of brain uptake and for sufficient metabolic stability.