Browsing by Subject "Doxycycline"
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- PublicationOpen AccessA Fast and Accurate Method for the Quantification of Doxycycline in Goat Plasma and Milk by HPLC Using a Fluorescence Detector(2024-12-17) Martínez, José; Hernandis, Verónica; Badillo, Elena; Escudero, Elisa; Yuste Pérez, María Teresa; Galecio, Juan Sebastián; Marín, Pedro; FarmacologíaDoxycycline is an antimicrobial agent used in veterinary medicine to treat a variety of bacterial infections. To date, no analytical technique utilising HPLC with fl uorescence detection has been documented for the quantifi cation of doxycycline concentrations in goat plasma or milk. Consequently, the objective of the present study was to propose a rapid HPLC assay with fl uorescence detection for the quantifi cation of doxycycline in the aforementioned samples, thereby facilitating the conduct of pharmacokinetic studies and the detection of residues in diverse goat tissues. Proteins were precipitated with methanol and trifl uoroacetic acid in a single step. Doxycycline was separated on a XBRIDGE C18 column using an isocratic method. Sample volume injected into the HPLC system was 50 µl. Fluorescence detection was conducted with an excitation wavelength of 380 nm and an emission wavelength of 520 nm. The retention times of doxycycline and danofl oxacin (internal standard) were determined to be 8.0 and 5.5 minutes, respectively. The calibration curves for plasma and milk exhibited linearity over the concentration range of 0.1 to 2 μg/mL. The limit of detection was 0.065 μg/ mL, while the limit of quantifi cation was 0.1 μg/mL in both matrices. The accuracy and precision of the method were consistently within the limits of 10.9% for plasma and 10.5% for milk. The fi ndings of this study may be employed in the quantifi cation of doxycycline in goat plasma and milk, thus facilitating the conduct of pharmacokinetic studies.
- PublicationOpen AccessDisposition kinetics and bioavailability of doxycycline after parenteral administrations in ewes(Elsevier, 2024-09-10) Martínez, José; Escudero Pastor, Elisa; Badillo Puerta, Elena; Yuste Pérez, María Teresa; Galecio Naranjo, Juan Sebastian; Marín Carrillo, Pedro; FarmacologíaDoxycycline is a tetracycline, which have been marketed in different species for treating infections caused by susceptible bacteria. There is limited information on the disposition kinetics of this drug in ewes and this antimicrobial may be useful against several sheep pathogens that are common causes of morbidity and economic loss. Therefore, the aim of this work was to establish the pharmacokinetics of doxycycline after intravenous (IV) and extravascular (subcutaneous (SC) and intramuscular (IM)) administrations in this species. A cross-over model was designed (n = 6). Doxycycline was dosed at 5 mg/kg for IV administration and 20 mg/kg for extravascular administrations. Non-compartmental pharmacokinetic methods were used to calculate plasma concentration-time data. The value of apparent volume of distribution (Vz) suggests a moderate distribution of this antibiotic in sheep, with a value of 0.84 L/kg. The maximum concentrations achieved after extravascular administrations (Cmax) were similar, with no significant differences between the two routes of administration (IM and SC). However, doxycycline absorption was slower after SC administration than after IM administration, taking twice as long to reach maximum plasma concentration (tmax). Bioavailabilities after extravascular routes of administration were low and after IM administration doxycycline caused lameness in all animals. Therefore, the SC administration showed a better profile with respect to pharmacokinetic properties and safety. Future studies on the susceptibility of isolated sheep pathogens to doxycycline are needed to establish appropriate dosing regimens.
- PublicationOpen AccessPharmacokinetics of Doxycycline in Plasma and Milk after Intravenous and Intramuscular Administration in Dairy Goats(MDPI, 2024) Martínez, José; Escudero, Elisa; Badillo, Elena; Yuste Pérez, María Teresa; Galecio, Juan Sebastián; Marin, Pedro; FarmacologíaDoxycycline is a second-generation tetracycline, marketed in different species for treating infections caused by susceptible bacteria. Little information is available on the pharmacokinetics of doxycycline in lactating goats. The objective of this study was to establish the disposition kinetics of doxycycline after parenteral administration (intravenous and intramuscular) in dairy goats and its elimination in milk. A cross-over model was designed (n = 6). Doxycycline was dosed at 5 mg/kg for intravenous administration and 20 mg/kg for extravascular administrations. Noncompartmental pharmacokinetic methods were used to calculate plasma concentration–time data. The Vz value suggests a moderate distribution of this antibiotic in goats, with a value of 0.85 L/kg. A low bioavailability (F = 45.60%) of doxycycline following an intramuscular injection was observed, with all animals exhibiting signs of lameness. Doxycycline rapidly crossed the blood–milk barrier, but exposure to the antimicrobial and the concentrations reached in milk were lower than those obtained in plasma. Although PK/PD ratios may be low with the pharmacokinetic data obtained with this formulation of doxycycline, at this dose and route of administration, doxycycline after IM administration could be useful for infections by moderate or highly susceptible bacteria in the mammary gland of goats. However, it may be necessary to test different doses of doxycycline or other routes of administration to achieve better surrogate markers and to establish repeated dosing regimens and clinical efficacy.
- PublicationOpen AccessThe Addition of Lactobacillus spp., Enrofloxacin or Doxycycline Negatively Affects the Viability of Mycoplasma bovis in Diluted Bovine Semen(MDPI, 2020-05-13) Gómez-Martín, Ángel; Bataller, Esther; Gomis Almendro, Jesús; Sánchez López, Antonio; Gadea Mateos, Joaquín; Vieira, Luis Alberto; García Roselló, Empar; de la Fe Rodríguez, Christian; García-Galán Pérez, Ana; Sanidad AnimalMycoplasma bovis is an important etiologic agent of bovine mycoplasmosis in cattle. Different transmission routes have been described, including those related to reproduction. The presence of mycoplasma in semen has led to its appearance in infection-free areas through artificial insemination (AI). Semen was recently reported to be the initial source of two M. bovis mastitis outbreaks in two closed dairy herds in Finland. This questions the effectiveness of the antimicrobials currently used in semen extenders to control the pathogens in contaminated semen. They should be re-evaluated, or alternative measures to antimicrobials should be tested to obtain M. bovis-free semen. This in vitro study aimed to assess different strategies to reduce the risk of transmission of M. bovis through AI technologies. The viability of M. bovis (PG45, NCTC 10131) in bull semen diluted (DS) in a Tris-citrate-fructose solution was tested, after the addition of enrofloxacin, doxycycline or a Lactobacillus spp.-based probiotic. The data show the susceptibility of the pathogen to the addition of 0.125 μg/mL of enrofloxacin or 0.0625 μg/mL of doxycycline and to the addition of the probiotic at a concentration of 3.24 × 106 colony forming units (CFU)/mL or 3.24 × 108 CFU/mL in DS. The Tris-citrate-fructose medium negatively affected the viability of M. bovis, although this effect was lower than that observed after the addition of the probiotic and antimicrobials (p < 0.05). Our results may support new strategies for reducing the risk of M. bovis transmission through AI.