Effect of dose on the intravenous pharmacokinetics of tolfenamic acid in goats

Plasma and Milk Pharmacokinetics and Estimated Milk Withdrawal Time of Tolfenamic Acid in Lactating Sheep

OBJECTIVE

This study aimed to investigate the plasma and milk pharmacokinetics, as well as the withdrawal time (WT) from milk of tolfenamic acid (2 and 4 mg/kg) following intravenous (IV) administration to eight healthy lactating Akkaraman sheep.

METHODS

The trial was conducted in two periods in accordance with a crossover pharmacokinetic design. The concentrations of tolfenamic acid in the plasma and milk were determined using high-pressure liquid chromatography and evaluated using non-compartmental analysis. The WT of tolfenamic acid in milk was calculated using the WT 1.4 software.

RESULTS

Compared to the 2 mg/kg dose, plasma volume of distribution at steady state (from 0.43 to 0.50 L/kg), terminal elimination half-life (from 2.41 to 4.14 h) and dose-normalized area under the plasma concentration-time curve (AUC0-∞, from 9.46 to 30.11 h µg/mL) increased, whereas total body clearance (from 0.21 to 0.13 L/h/kg) decreased at the 4 mg/kg dose. The peak milk concentration (Cmax) and AUC0-∞ values in milk were 0.26 µg/mL and 0.28 h µg/mL, respectively, for 2 mg/kg, and 0.43 µg/mL and 0.55 h µg/mL, respectively, for 4 mg/kg. Although the dose-normalized Cmax of milk decreased depending on the dose, no difference was observed in dose-normalized AUC0-∞. The AUC0-∞ milk/AUC0-∞ plasma ratio was 0.03 for 2 mg/kg and 0.02 for 4 mg/kg. The WT values calculated for milk at dosages of 2 and 4 mg/kg were 3 and 4 h, respectively.

CONCLUSIONS

A decrease in plasma elimination and an increase in plasma concentration of tolfenamic acid were observed depending on the dose. Tolfenamic acid lowly passed into sheep's milk at 2 and 4 mg/kg doses. This study may provide valuable information for clinicians' decision-making processes.

Pharmacokinetics of tolfenamic acid in ducks (Anas platyrhynchos domestica) after different administration routes

1. The objective of this research was to compare the pharmacokinetics and bioavailability of tolfenamic acid, analgesic, antipyretic and anti-inflammatory compound, after administration through different routes to Pekin ducks. The investigation was carried out over four time periods using a randomised cross-pharmacokinetic design.2. Tolfenamic acid was administered to ducks intravenously, intramuscularly, subcutaneously and orally at a dose of 2 mg/kg. Tolfenamic acid analysis was performed using HPLC-UV and pharmacokinetic data were conducted by non-compartmental analysis.3. The total clearance, volume of distribution at steady state and terminal elimination half-life after intravenous administration were 0.14 l/h/kg, 0.29 l/kg and 1.80 h, respectively. The peak plasma concentration and bioavailability for intramuscular, subcutaneous and oral administration were 4.59, 3.55 and 2.23 μg/ml and 93.62, 74.30 and 43.43%, respectively.4. Tolfenamic acid was absorbed rapidly, eliminated quickly and exhibited a small distribution volume in Pekin ducks. Pharmacokinetic parameters, including maximum concentration, area under the plasma concentration - time curve and bioavailability, were found to be different in ducks from other bird species.

Pharmacokinetics, bioavailability and plasma protein binding of tolfenamic acid in rainbow trout (Oncorhynchus mykiss)

BACKGROUND

Although research on the mechanism and control of pain and inflammation in fish has increased in recent years, the use of analgesic drugs is limited due to the lack of pharmacological information about analgesic drugs. Tolfenamic acid is a non-steroidal anti-inflammatory drug and can be used in fish due to its low side effect profile and superior pharmacokinetic properties.

OBJECTIVES

The pharmacokinetics, bioavailability and plasma protein binding of tolfenamic acid were investigated following single intravascular (IV), intramuscular (IM) and oral administration of 2 mg/kg in rainbow trout at 13 ± 0.5°C.

METHODS

The experiment was carried out on a total of 234 rainbow trout (Oncorhynchus mykiss). Tolfenamic acid was administered to fish via IV, IM and oral route at a dose of 2 mg/kg. Blood samples were taken at 13 different sampling times until the 72 h after drug administration. The plasma concentrations of tolfenamic acid were quantified using high pressure liquid chromatography-ultraviolet (UV) and pharmacokinetic parameters were assessed using non-compartmental analysis.

RESULTS

The elimination half-life (t1/2ʎz) of tolfenamic acid for IV, IM and oral routes was 3.47, 6.75 and 9.19 h, respectively. For the IV route, the volume of distribution at a steady state and total body clearance of tolfenamic acid were 0.09 L/kg and 0.03 L/h/kg, respectively. The peak plasma concentration and bioavailability for IM and oral administration were 8.82 and 1.24 µg/mL, and 78.45% and 21.48%, respectively. The mean plasma protein binding ratio of tolfenamic acid in rainbow trout was 99.48% and was not concentration dependent.

CONCLUSIONS

While IM route, which exhibits both the high plasma concentration and bioavailability, can be used in rainbow trout, oral route is not recommended due to low plasma concentration and bioavailability. However, there is a need to demonstrate the pharmacodynamic activity of tolfenamic acid in rainbow trout.

Treatment of Pain in Birds

This article provides an overview of the current understanding of evidence-based clinical analgesic use in birds. The field of avian analgesia has dramatically expanded during the last 20 years, affording more options for alleviating both acute and chronic pain. These options include opioids, nonsteroidal anti-inflammatory drugs, local anesthetics, and/or other drugs like gabapentin, amantadine, and cannabinoids, acting at different points in the nociceptive system thereby helping to provide greater pain relief while reducing the risk of adverse effects when combined.

Pharmacokinetics of intravenous meloxicam, ketoprofen and tolfenamic acid in chukar partridge (Alectoris chukar)

1. The aim of this study was to determine the pharmacokinetics of meloxicam (MLX, 1 mg/kg body weight (BW)), ketoprofen (KETO, 2 mg/kg BW), and tolfenamic acid (TA, 2 mg/kg BW) in chukar partridge (Alectoris chukar) following intravenous (IV) administration.2. Twenty-four healthy chukar partridges were randomly divided into three equal groups (n = 8) as MLX, KETO and TA. Plasma concentrations of MLX, KETO and TA were measured using high-performance liquid chromatography-ultraviolet detection and analysed using non-compartmental analysis.3. No adverse effects were determined in chukar partridges after IV administration of MLX, KETO and TA. MLX, KETO and TA were detected in plasma up to 10, 12 and 12 h, respectively. The terminal elimination half-life of MLX, KETO and TA was 1.22, 1.77 and 1.95 h, respectively. MLX, KETO and TA exhibited volumes of distribution at a steady-state of 0.03, 0.23 and 0.41 l/kg BW, respectively. The total plasma clearance of MLX, KETO and TA was 0.02, 0.11 and 0.15 l/h/kg, respectively. The extraction ratios for MLX, KETO and TA were calculated as 0.002, 0.011 and 0.016, respectively.4. MLX, KETO and TA offer treatment in chukar partridges for various conditions with an absence of adverse reactions and properties such as short elimination half-life and low volume of distribution. However, there is a need to establish the safety and adverse effects of repeated administration, pharmacokinetics of other administration routes and pharmacological efficacy of MLX, KETO and TA in chukar partridges.

Pharmacokinetics of meloxicam, carprofen, and tolfenamic acid after intramuscular and oral administration in Japanese quails (Coturnix coturnix japonica)

The aim of this study was to determine the pharmacokinetics of meloxicam (MLX), carprofen (CRP), and tolfenamic acid (TA) in Japanese quails (Coturnix coturnix japonica) following intramuscular (IM) and oral administration at doses of 1, 10, and 2 mg/kg, respectively. A total of 72 quails were randomly divided into 3 equal groups as MLX, CRP, and TA. Each group was separated into two sub-groups that received IM and oral administration of each drug. Plasma concentrations of MLX, CRP, and TA were determined using HPLC-UV and analyzed by non-compartmental method. The t_1/2ʎz and MRT of MLX, CRP, and TA after oral administration were similar to those after IM administration. The V_darea /F of MLX, CRP, and TA after IM administration was 0.28, 2.05, and 0.20 L/kg. The Cl/F of MLX, CRP, and TA after IM administration was 0.12, 0.19, and 0.09 L/h/kg. MLX, CRP, and TA after oral administration showed significantly lower C_max and longer T_max compared with IM administration. The relative bioavailability of MLX, CRP, and TA following oral administration in quails was 76.13%, 61.46%, and 57.32%, respectively. The IM and oral route of MLX, CRP, and TA can be used for the treatment of various conditions in quails. However, further research is necessary to determine the pharmacodynamics and safety of MLX, CRP, and TA before use in quails.

Pharmacokinetics of tolfenamic acid after different administration routes in geese (Anser cygnoides)

The pharmacokinetics and bioavailability of tolfenamic acid were determined in geese (Anser cygnoides) following intravenous (IV), intramuscular (IM), subcutaneous (SC), and oral administrations at 2 mg/kg dose. In this study, eight healthy geese (3.5 ± 0.5 kg) were used. The study was performed in four periods according to a crossover design with a 15-day washout period between two administrations. The plasma concentrations of tolfenamic acid were analyzed using HPLC-UV, and pharmacokinetic parameters were calculated by noncompartmental analysis. The elimination half-life was 1.73, 2.51, 2.34, and 2.31 hr for IV, IM, SC, and oral routes, respectively. The volume of distribution at steady state and total clearance after IV administration were 0.25 L/kg and 0.16 L hr^-1  kg^-1 , respectively. The peak plasma concentrations of tolfenamic acid after IM, SC, and oral administrations were 4.89, 2.94, and 2.92 μg/ml at 0.25, 0.75, and 1 hr, respectively. The bioavailability was 87.91, 77.87, and 76.03% for the IM, SC, and oral routes, respectively. Tolfenamic acid, which exhibits the good bioavailability and plasma concentration following IM, SC, and oral administrations at 2 mg/kg dose, may be useful in the treatment of inflammatory disease conditions in geese.

Pharmacokinetics of tolfenamic acid in goats after different administration routes

The aim of this study was to determine the pharmacokinetics and bioavailability of tolfenamic acid in goats after intravenous (IV), intramuscular (IM), subcutaneous (SC), and oral (PO) administrations at 2 mg/kg dose. In this study, eight clinically healthy goats were used. The study comprised four periods, according to a crossover design with at least a 15-day washout period between treatments. Plasma concentrations of tolfenamic acid were determined by HPLC-UV, and the pharmacokinetic parameters were estimated using a non-compartmental method. Following IV administration, terminal elimination half-life, volume of distribution at steady state, and total clearance were 1.60 h, 0.37 L/kg, and 0.27 L/h/kg, respectively. The mean peak plasma concentration following IM, SC, and PO administrations was 1.77, 1.22, and 0.30 μg/ml, respectively. The mean bioavailability following IM, SC, and PO administrations was 64.46, 55.43, and 19.46%, respectively. The PO route, which exhibits both the low plasma concentration and bioavailability, is not recommended in goats. The IV, IM, and SC routes, which show comparable pharmacokinetic profiles, may be proposed for use in goats. However, the multi-dose and pharmacodynamic studies are necessary to establish more accurately its safety and efficacy in the goat.