Pharmacokinetics of meloxicam after oral administration of a granule formulation to healthy horses

Pharmacokinetic evaluation of meloxicam following intravenous and intramuscular administration in Crocodylus siamensis, a freshwater crocodile

The pharmacokinetics of meloxicam (MLX) remain largely unexplored in reptiles, particularly in Siamese crocodiles (Crocodylus siamensis). This study characterized the pharmacokinetic profiles of MLX following intravenous (IV) and intramuscular (IM) administration in Siamese crocodiles. Fifteen Siamese crocodiles were divided into three groups (n = 5) using a randomization procedure according to a parallel study design. MLX was administered IV at 0.2 mg/kg b.w. or IM at two different doses (0.2 mg/kg b.w. or 0.4 mg/kg b.w.). Plasma concentrations of MLX were measured using a validated high-performance liquid chromatography method with UV detection. The pharmacokinetic parameters were analyzed using a non-compartment model. The elimination half-life (t1/2λz) was long for all administration routes, with values of 132.34 hr (IV), 121.35 h (IM 0.2 mg/kg b.w.), and 181.44 hr (IM 0.4 mg/kg b.w.). The volumes of distribution (Vd) and clearance (Cl) after IV administration were 104.59 mL/kg and 0.55 mL/hr/kg, respectively. Based on these results, there was an extended t1/2λz of MLX in this species of freshwater crocodiles, highlighting significant differences in drug disposition compared to other reptilian and non-reptilian species. The findings contribute to an understanding of MLX pharmacokinetics in this animal species, and emphasize that the selection of the optimal dose of MLX should be considered based on disposition kinetics, efficacy, safety, and species-specific differences. Further investigation is required to identify the effective plasma concentration, which is critical for establishing the appropriate dose for the management of pain and inflammation.

Pharmacokinetics of Meloxicam in Different Animal Species: A Comprehensive Review

Meloxicam is a non-steroidal anti-inflammatory in the oxicam group. It has been extensively used in human and veterinary medicine for their anti-inflammatory, analgesic and antipyretic activities. Meloxicam has shown high therapeutic potential for disorders such as osteoarthritis, musculoskeletal disorder, acute respiratory infection, puerperal septicemia, mastitis and mastitis-metritis-agalactia syndrome. Although meloxicam pharmacokinetic has been described for numerous species, no paper summarizes the existing literature on this field. Thus, the aim of this review was to carry out a review of the literature on the pharmacokinetics of meloxicam in different animal species and gather the data in a single review article. A comprehensive review of the available literature in the PubMed, Web of Science and Scopus databases was performed. Meloxicam shows good bioavailability after oral and parenteral administration in most animal species (85-95%), with the lowest values in sheep after oral administration. It presents a rapid distribution with a small volume of distribution, which can be attributed to relatively high ionization state of meloxicam at physiological pH and its high plasma protein binding (close to 99%). It is extensively metabolized in the liver in several inactive polar metabolites, which are excreted, like unchanged meloxicam in urine and feces. Meloxicam also shows a long elimination half-life and low clearance.

The Clinical Pharmacology and Therapeutic Evaluation of Non-Steroidal Anti-Inflammatory Drugs in Adult Horses

This review firstly examines the underlying pathophysiology of pain and inflammation associated with orthopedic disease and endotoxemia. Then, it reviews the clinical pharmacology (pharmacokinetics and pharmacodynamics) of both conventional and non-conventional NSAIDs in the adult horse, and finally provides an overview of different modalities to evaluate the therapeutic efficacy of NSAIDs in research.

Preliminary Investigation into a Novel Sustained-Release Formulation of Meloxicam in Sheep (Ovis aries)-Pharmacokinetic Profile

Simple Summary

Meloxicam is an effective non-steroidal anti-inflammatory drug (NSAID) suitable for ameliorating pain in sheep. Pain caused by husbandry procedures and other inflammatory conditions in sheep can persist for an extended time beyond the duration of action of currently available formulations of NSAIDs. This study investigates a novel sustained-release formulation of meloxicam to determine its potential for extended pain alleviation. Compared to a conventional formulation of meloxicam, the sustained-release formulation provided extended half-life making it a suitable candidate for providing extended pain relief.

Abstract

This study is a preliminary investigation describing the pharmacokinetic profile of a novel subcutaneous sustained-release meloxicam formulation (SRMF) in sheep. Six merino ewe hoggets (41.5 ± 4.6 kg) were treated with a novel subcutaneous SRMF at 2 mg/kg bodyweight (BW). Blood samples were collected at t = 0, 2, 4, 6, 8, 10, 12, 24, 48, 96, 144, 168, 192, and 336 h following treatment, and interstitial (ISF) fluid samples were collected at periods of 8 to 12 h, 12 to 24 h, 24 to 48 h, 48 to 52 h, and 92 to 96 h following treatment. High-pressure liquid chromatography (HPLC) analysis with ultraviolet detection was utilised to determine the concentration of meloxicam in plasma and ISF. The SRMF exhibited the following mean (±SD) pharmacokinetic indices: C_max of 1.58 μg/mL (±0.82 μg/mL) at a T_max of 10.0 h (±1.79 h), and half life (t_1/2) of 31.4 h (±13.17 h) in sheep plasma. Interstitial fluid samples were collected from three of the six sheep, with a decrease in meloxicam concentration exhibited over 52 h. This study demonstrates a variable extended t_1/2, a delayed T_max, and a lower C_max of the SRMF, as compared to that of a conventional meloxicam formulation (CMF) in sheep, as previously referenced (t_1/2: 14.28 h; T_max: 5 h; C_max: 15.94 μg/mL). Further research to determine the clinical efficacy and safety of the SRMF in sheep is warranted.

Comparative pharmacokinetics of meloxicam oil suspension in pigs at different dosages following intramuscular administration

This study aimed to evaluate the preliminary safety of self-developed meloxicam (MEL) oil suspension and determine the comparative pharmacokinetics of it at 0.8 and 2mg/kg body weight (b.w.) dosages in pigs following a single intramuscular administration. Six rabbits were used for the study of preliminary safety and six healthy pigs were used for pharmacokinetics study by a crossover design in two periods. The muscle irritation results showed that both of the MEL oil suspension and the conventional injection had no significant changes at the dosage of 0.4 mg/kg b.w.. However, at the dosage of 2 mg/kg b.w., both of the self-developed MEL oil suspension and the MEL conventional injection showed mild irritation to muscle. Plasma concentrations of MEL were measured by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The MEL plasma concentrations were quantified up to 30 h and 72 h after intramuscular administration at the low- and high-dosage, respectively. The difference was statistically significant (P < 0.05) between different dosages in pharmacokinetic parameters of t_1/2λz, C_max, AUC_0-t, AUC_0-μ, MRT, and V_d. The C_max values of MEL were 1.92 ± 0.34 μg/ml and 3.03 ± 1.25 μg/ml at dosages of 0.8 and 2 mg/kg b.w. while the t_max values were 3.25 ± 1.04 h and 4.00 ± 1.26 h, respectively. The pharmacokinetics results of self-developed MEL oil suspension demonstrated that the retention time of it in pigs was prolonged, showing the sustained-release effect. Therefore, Oil suspension was an ideal new drug loading form of MEL.

Analgesia for Sheep in Commercial Production: Where to Next?

Simple Summary

Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on industry to alleviate pain associated with husbandry practices, injury and illness. Although a number of analgesic solutions are now available for sheep, providing some amelioration of the acute pain responses, this review has highlighted a number of potential areas for further research.

Abstract

Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on livestock production industries to alleviate pain associated with husbandry practices, injury and illness. Over the past 15–20 years, there has been considerable research effort to understand and develop mitigation strategies for painful husbandry procedures in sheep, leading to the successful launch of analgesic approaches specific to sheep in a number of countries. However, even with multi-modal approaches to analgesia, using both local anaesthetic and non-steroidal anti-inflammatory drugs (NSAID), pain is not obliterated, and the challenge of pain mitigation and phasing out of painful husbandry practices remains. It is timely to review and reflect on progress to date in order to strategically focus on the most important challenges, and the avenues which offer the greatest potential to be incorporated into industry practice in a process of continuous improvement. A structured, systematic literature search was carried out, incorporating peer-reviewed scientific literature in the period 2000–2019. An enormous volume of research is underway, testament to the fact that we have not solved the pain and analgesia challenge for any species, including our own. This review has highlighted a number of potential areas for further research.

Pharmacokinetics of meloxicam after oral administration of a granule formulation to healthy horses

Background

Nonsteroidal anti‐inflammatory drugs are administered in horses for several systemic diseases. Selective cyclooxygenase‐2 inhibitors are preferred because of lower risk of adverse effects. Several meloxicam formulations have been tested in horses, but a recently marketed granule oral formulation has not been studied.

Objective

To characterize the pharmacokinetics of a novel granule meloxicam formulation in fasted and fed horses, and to compare pharmacokinetic features with oral suspension and tablets.

Animals

Seven healthy adult horses.

Methods

Meloxicam was administered at 0.6 mg/kg in fasted or fed horses. Blood samples were collected for pharmacokinetic analysis, and vital signs, hematology, and biochemistry variables were monitored for 72 hours.

Results

No adverse effects were detected. Volume of distribution and clearance after intravenous administration of meloxicam were 0.36 L/kg and 29.12 mL/h/kg, respectively, with a 12.39 hours of terminal half‐life. Protein binding was of 97%. Bioavailability was high for every oral formulation, ranging 70%‐110%, without feed effect. Because of a slower absorption, meloxicam after administration of granules had a longer half‐life (24 and 34 hours, fasted and fed, respectively) and mean residence time (31 and 47 hours), than suspension and tablets (ranging 10‐13 and 13‐15 hours, respectively). In addition, the time above therapeutic concentration was higher for the granule formulation than other formulations.

Conclusions and Clinical Importance

Granule formulation has different PK parameters compared to other oral formulations, which could enable this formulation to be used for different dosage regimens in order to reach a desired clinical effect or decrease the risk of adverse effects.