Cyclooxygenase (COX) Inhibitors and the Newborn Kidney

Pyridazine and pyridazinone derivatives: Synthesis and in vitro investigation of their anti-inflammatory potential in LPS-induced RAW264.7 macrophages

New pyridazine and pyridazinone derivatives 3a-g, 4a-f, 6a, and 6b were designed and synthesized. Cell viability of all compounds was established based on the viability of lipopolysaccharide-induced RAW264.7 macrophage cells determined via the MTT assay. In vitro inhibition assays on human COX-1 and COX-2 enzymes were conducted to probe the newly synthesized compounds' anti-inflammatory activity. The half maximal inhibitory concentration values for the most active compounds, 3d, 3e, and 4e towards COX-2 were 0.425, 0.519, and 0.356 µM, respectively, in comparison with celecoxib. The newly synthesized compounds' ability to inhibit the production of certain proinflammatory cytokines, such as inducible nitric oxide synthase, tumor necrosis factor-α, interleukin-6, and prostaglandin-E2, was also estimated in lipopolysaccharide-induced macrophages (RAW264.7 cells). Compounds 3d and 3e were identified as the most potent cytokine production inhibitors. The results of molecular modeling studies suggested that these compounds were characterized by a reasonable binding affinity toward the active site of COX-2, when compared to a reference ligand. These results might be taken into consideration in further investigations into new anti-inflammatory agents.

Epoxidase inhibitor-aspirin resistance and the relationship with genetic polymorphisms: a review

Strokes are the leading cause of death in most regions of the world. Epoxidase inhibitors include the drug aspirin (acetylsalicylic acid). Aspirin is widely used as first-line treatment for the prevention of cardiovascular and cerebrovascular diseases in at-risk patients. However, patients using conventional doses of aspirin can still develop ischaemic cardiovascular and cerebrovascular diseases, a phenomenon known as aspirin resistance. The occurrence of aspirin resistance hinders the prevention and treatment of ischaemic cardiovascular and cerebrovascular diseases. There are many factors affecting aspirin resistance, such as sex, drug dose, metabolic disease, genetic polymorphisms, drug interactions and pharmacokinetics. Genetic polymorphism refers to the simultaneous and frequent presence of two or more discontinuous variants or genotypes or alleles in a population of organisms. Platelets contain a large number of highly polymorphic transmembrane glycoprotein receptors encoded by two or more isomeric alleles. Changes in gene polymorphisms in various pathways during platelet aggregation can lead to aspirin resistance. This narrative review describes the gene polymorphisms that have been demonstrated to be significantly associated with aspirin resistance. Research on the mechanisms of aspirin resistance and increased knowledge should provide accurate drug guidance in individuals that require first-line antiplatelet therapy.

Use of Antibiotics in Preterm Newborns

Due to complex maturational and physiological changes that characterize neonates and affect their response to pharmacological treatments, neonatal pharmacology is different from children and adults and deserves particular attention. Although preterms are usually considered part of the neonatal population, they have physiological and pharmacological hallmarks different from full-terms and, therefore, need specific considerations. Antibiotics are widely used among preterms. In fact, during their stay in neonatal intensive care units (NICUs), invasive procedures, including central catheters for parental nutrition and ventilators for respiratory support, are often sources of microbes and require antimicrobial treatments. Unfortunately, the majority of drugs administered to neonates are off-label due to the lack of clinical studies conducted on this special population. In fact, physiological and ethical concerns represent a huge limit in performing pharmacokinetic (PK) studies on these subjects, since they limit the number and volume of blood sampling. Therapeutic drug monitoring (TDM) is a useful tool that allows dose adjustments aiming to fit plasma concentrations within the therapeutic range and to reach specific drug target attainment. In this review of the last ten years’ literature, we performed Pubmed research aiming to summarize the PK aspects for the most used antibiotics in preterms.

Toward Multitasking Pharmacological COX-Targeting Agents: Non-Steroidal Anti-Inflammatory Prodrugs with Antiproliferative Effects

The antitumor activity of certain anti-inflammatory drugs is often attributed to an indirect effect based on the inhibition of COX enzymes. In the case of anti-inflammatory prodrugs, this property could be attributed to the parent molecules with mechanism other than COX inhibition, particularly through formulations capable of slowing down their metabolic conversion. In this work, a pilot docking study aimed at comparing the interaction of two prodrugs, nabumetone (NB) and its tricyclic analog 7-methoxy-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-one (MC), and their common active metabolite 6-methoxy-2-naphthylacetic acid (MNA) with the COX binding site, was carried out. Cytotoxicity, cytofluorimetry, and protein expression assays on prodrugs were also performed to assess their potential as antiproliferative agents that could help hypothesize an effective use as anticancer therapeutics. Encouraging results suggest that the studied compounds could act not only as precursors of the anti-inflammatory metabolite, but also as direct antiproliferative agents.

New insights into the obligatory nature of cyclooxygenase-2 and PGE2 during early chick embryogenesis

Temporal expression patterns and activity of two cyclooxygenase (COX-1 and COX-2) isoforms were analysed during early chick embryogenesis to evaluate their roles in development. COX-2 inhibition with etoricoxib resulted in significant structural anomalies such as anophthalmia (born without one or both eyes), phocomelia (underdeveloped or truncated limbs), and gastroschisis (an opening in the abdominal wall), indicating its significance in embryogenesis. Furthermore, the levels of PGE₂, PGD₂, PGF_2α, and TXB₂ were assessed using quantitative LC-MS/MS to identify which effector prostanoid (s) had their synthesis initiated by COX-2. COX-2 inhibition was only shown to reduce the level of PGE₂ significantly_, and hence it could be inferred that the later could be largely under the regulation of activated COX-2 in chick embryos. The compensatory increase in the activity of COX-1 observed in the etoricoxib-treated group helped to maintain the levels of PGD₂, PGF_2α, and TXB₂. Though the roles of these three prostanoids in embryogenesis need to be further clarified, it appears that their contribution to the observed developmental anomalies is minimal. This study has shown that COX-2 is functionally active during chick embryogenesis, and it plays a central role in the structural configuration of several organs and tissues through its downstream effector molecule PGE₂.

Late Acetaminophen Therapy for Patent Ductus Arteriosus in the Preterm Neonate

OBJECTIVE

In preterm infants, the standard pharmacologic treatment for a hemodynamically significant patent ductus arteriosus (hsPDA) is either ibuprofen or indomethacin. However, these medications may be less effective after 2 weeks of age. We investigated the use of acetaminophen in hsPDA closure beyond 2 weeks of age.

METHODS

An observational study of 11 infants, <30 weeks' gestation at birth and postnatal age > 2 weeks, who received acetaminophen treatment for their hsPDA. Echocardiograms (ECHOs), B-type natriuretic peptide (BNP) levels, and the fraction of inspired oxygen (FiO₂) were obtained before and after treatment to analyze ductal characteristics. Renal and liver functions were monitored pretreatment and posttreatment to look for potential medication side effects.

RESULTS

Of the 10 infants with ECHO data for before and after acetaminophen treatments, 4/10 (40%) had a decrease in PDA size, with no infants having complete closure immediately posttreatment. Eight of 11 (73%) infants had a decreased FiO₂ requirement after treatment. Of the 5 infants with pretreatment and posttreatment BNP data, 2/5 (40%) infants had a decrease in BNP level. One infant received an additional course of acetaminophen. Four infants underwent a surgical ligation. Two infants died. No medication side effects occurred with regard to hepatic and renal function.

CONCLUSION

Acetaminophen is a safe and effective pharmacologic treatment to reduce the significance of the hsPDA in some infants beyond 2 weeks of age, as shown by ECHO and BNP data.

Synopsis of arachidonic acid metabolism: A review

Arachidonic acid (AA), a 20 carbon chain polyunsaturated fatty acid with 4 double bonds, is an integral constituent of biological cell membrane, conferring it with fluidity and flexibility. The four double bonds of AA predispose it to oxygenation that leads to a plethora of metabolites of considerable importance for the proper function of the immune system, promotion of allergies and inflammation, resolving of inflammation, mood, and appetite. The present review presents an illustrated synopsis of AA metabolism, corroborating the instrumental importance of AA derivatives for health and well-being. It provides a comprehensive outline on AA metabolic pathways, enzymes and signaling cascades, in order to develop new perspectives in disease treatment and diagnosis.

Efficacy and Safety Profile of Diclofenac/Cyclodextrin and Progesterone/Cyclodextrin Formulations: A Review of the Literature Data

Background

According to health technology assessment, patients deserve the best medicine. The development of drugs associated with solubility enhancers, such as cyclodextrins, represents a measure taken in order to improve the management of patients. Different drugs, such as estradiol, testosterone, dexamethasone, opioids, non-steroidal anti-inflammatories (NSAIDs; i.e. diclofenac), and progesterone are associated with cyclodextrins. Products containing the association of diclofenac/cyclodextrins are available for subcutaneous, intramuscular, and intravenous administration in doses that range from 25 to 75 mg. Medicinal products containing the association of progesterone/cyclodextrins are indicated for intramuscular and subcutaneous injection at a dose equal to 25 mg.

Objectives and Methods

The effects of cyclodextrins have been discussed in the solubility profile and permeability through biological membranes of drug molecules. A literature search was performed in order to give an overview of the pharmacokinetic characteristics, and efficacy and safety profiles of diclofenac/hydroxypropyl-β-cyclodextrin (HPβCD) and progesterone/HPβCD associations.

Results

The results of more than 20 clinical studies were reviewed. It was suggested that the new diclofenac/HPβCD formulation gives a rapid and effective response to acute pain and, furthermore, has pharmacokinetic and efficacy/safety profiles comparable to other medicinal products not containing cyclodextrins. One of the principal aspects of these new diclofenac formulations is that in lowering the dose (lower than 50 mg) the drugs could be more tolerable, especially in patients with comorbid conditions. Moreover, results of studies investigating the characteristics of progesterone and cyclodextrins showed that the new formulation (progesterone/HPβCD 25 mg solution) has the same bioavailability as other products containing progesterone. It is more rapidly absorbed and allows the achievement of peak plasma concentrations in a shorter time. Finally, the new formulation of progesterone was shown to be safe and not inferior to other products already on the market, with the exception of progesterone administered vaginally.

Conclusions

As shown by the results of clinical studies presented in this review, the newly approved medicines containing cyclodextrins have been found to be as effective and as well-tolerated as other medicinal products that do not contain cyclodextrins. Moreover, the newly approved lower dose of diclofenac associated with cyclodextrins is consistent with the European Medicines Agency recommendations reported in the revision of the Assessment Report for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and Cardiovascular Risk. Finally, the use of cyclodextrins led to significant increases in solubility and bioavailability of drugs, such as diclofenac and progesterone, and improvement in the efficacy and safety of these drugs.

Immunohistochemical Labelling for Cyclo-oxygenase-2: Does the Positive Control Guarantee Standardized Results?

Since the identification of cyclo-oxygenase-2 as a potentially important therapeutic target in veterinary oncology, numerous studies on its expression have been conducted. Unfortunately, results have been heterogeneous and conclusions are difficult to draw. We tested the ability of a defined positive control to guarantee reproducibility of results among different laboratories. Valid positive controls were defined by positivity of the renal macula densa without background labelling. Fifteen colorectal tumours and 15 oral squamous cell carcinomas were labelled immunohistochemically by six European laboratories. Slides were evaluated in blinded fashion for percentage of positive cells and labelling intensity by three pathologists, and results were analyzed statistically for reproducibility and inter-reader variability. Macula densa positivity was an insufficiently sensitive control to guarantee reproducible results for percentage of positive cells and labelling intensity. Inter-reader variability was proven statistically, making the case for image analysis or other automated quantitative evaluation techniques.

Pharmacokinetics in neonatal prescribing: evidence base, paradigms and the future

Paediatric patients, particularly preterm neonates, present many pharmacological challenges. Due to the difficulty in conducting clinical trials in these populations dosing information is often extrapolated from adult populations. As the processes of absorption, distribution, metabolism and excretion of drugs change throughout growth and development extrapolation presents risk of over or underestimating the doses required. Information about the development these processes, particularly drug metabolism pathways, is still limited with weight based dose adjustment presenting the best method of estimating pharmacokinetic changes due to growth and development. New innovations in pharmacokinetic research, such as population pharmacokinetic modelling, present unique opportunities to conduct clinical trials in these populations improving the safety and effectiveness of the drugs used. More research is required into this area to ensure the best outcomes for our most vulnerable patients.