Pharmacokinetics and distribution of sulphadimidine in plasma,milk and uterine fluid of female buffaloes

The pharmacokinetics of sulphadimidine after a single dose (200 mg/kg i.v.) was studied in five healthy lactating buffaloes. The study revealed that the drug attained its peak concentration of 314.0±13.0, 242.4±3.0 and 100.2±2.5 g/ml at 15 min, 30 min and 12 h in plasma, milk and uterine fluid, respectively. The pharmacokinetic parameters calculated by a 2-compartment open model gave values for t₁, t₁ and vd_area of 2.10±0.36 h, 12.36±0.57 h and 1.23±0.07 L/Kg, respectively. A high vd_area as well as a value of 0.74±0.08 for K₁₂:K₂₁- (tissue Plasma) indicates better penetration of the drug into the different body fluids and tissues, which is further supported by a high concentration obtained in milk and uterine fluid. The therapeutic concentration (50 g/ml) was maintained for around 24 h in plasma and milk and 12 h in uterine fluid. The results suggest that, apart from its use in systemic infections, the drug can be effectively used by the i.v. route in uterine and mammary gland infections. The dosages for maintaining concentration of 50 g/ml, 100 g/ml and 150 g/ml at convenient dosage intervals of 12 and 24 h were also determined.     

复方磺胺间甲氧嘧啶(CO.SMM)缓释型注射液在水牛体内的血浆药动学

为研究复方磺胺间甲氧嘧啶（CO．SMM）缓释型注射液的药代动力学规律，选择健康水牛8头，随机分成2组（n=4），对照组和试验组分别按50mg／kg剂量肌注单方SMM和CO．SMM缓释型注射液，采用高效液相色谱法测定血浆药物浓度。利用药代动力学程序软件3P97处理药时数据，计算药代动力学参数。结果显示：（1）肌注单方SMM注射液后药时数据符合一级吸收二室开放模型，t1/2Ka 0．47h，t1／2 β 3．25h，AUC261．19h·μg·mL^-1，Vd0．89L／kg，CLB0．19L·kg^-1·h，tmax 1．02h，Cmax76．85mg／L。（2）肌注CO．SMM缓释型注射液后，SMM药时数据符合一级吸收一室开放模型，t1／2Ka 0．41h，t1/2β 11．46h，AUC 1107h·μg·mL，Vd0．75L·kg^-1，CLB0．05L·kg^-1·h^-1，tmax 2．03h，Cmax 59．24μg·mL；肌注CO．SMM缓释型注射液后，TMP药时数据符合一级吸收二室开放模型，t1／2Ka 0．87h，t1／2β19．59h，AUC83．66h·μg·mL^-1，Vd16．89L·kg^-1，CLB0．60L·kg^-1·h^-1，tmax2．95h，Cmax 4．15μg·mL^-1。结果表明，CO．SMM缓释型注射液肌注水牛后SMM在体内消除缓慢，达峰时间延迟，血药浓度平稳，具有缓释、增效的作用。     

Efficiency of uterine fluid cytology in the diagnosis of subclinical endometritis in the water buffalo (Bubalus bubalis)

This study compared endometrial cytology vis‐a‐vis uterine fluid cytology for assessment of uterine health in clinically normal and subclinical endometritis (SE)‐affected buffaloes. Uterine fluid samples and endometrial samples were collected from the buffaloes (n = 38) at oestrus using blue sheath and cytobrush, respectively. The smears were stained with Field stain for 3 minutes, and a minimum of 400 cells were counted in each smear for determination of the percentage of polymorphonuclear (PMN) leucocyte. The incidence of subclinical endometritis, based on the cytobrush cytology, was 23.08%. The correlation between cytobrush cytology with uterine fluid cytology was positive and significant (r = .37; p = .02). The ratio of PMN leucocyte in cytobrush cytology to uterine fluid cytology was 1:2.4. ROC analysis revealed that the threshold value of 6.16% PMN leucocyte in uterine fluid cytology showed a diagnostic sensitivity and specificity of 100% in differentiating normal from SE‐affected buffaloes. In conclusion, collection of uterine fluid was easier compared to collection of endometrial samples using cytobrush and the percentage of PMN leucocyte in uterine fluid cytology can be used as a tool for diagnosis of subclinical endometritis in buffaloes.     

Pharmacokinetics of streptomycin with particular reference to its distribution in plasma,milk and uterine fluid of shebuffaloes

The study elucidated the pharmacokinetics of streptomycin in healthy lactating she-buffaloes after a single intramuscular (IM) injection (10 mg/kg). The drug attained its peak concentrations of 24.39±2.67, 0.45±0.05 and 5.06±0.18 g/ml at 1, 4 and 1 hour in plasma, milk and uterine fluid respectively. Calculations based on the assumption of a 2-compartment model gave a plasma t1/2 () of 4.01±0.44 h and an apparent volume of distribution [Vd(area)] of 0.47±0.06 l/kg. The drug was detectable in the plasma, milk and uterine fluid for 30, 8 and 12 hours, respectively. A therapeutic concentration of the drug was maintained for 6 to 7 hours in the plasma and for around 1 hour only in the uterine fluid. However, a therapeutic level could not be achieved in milk at any time. The results suggest that the drug can be used clinically by the IM route against streptomycin susceptible systemic infections but not those in the uterus and mammary gland.     

Interrelationship between milk constituents,serum oestradiol and vaginal mucus indicators of oestrus in Egyptian buffaloes

The intensity of heat signs in buffaloes is generally low and the incidence of suboestrus varied from 15 to 73% (Buffalopedia). The objective of this study was to investigate the feasibility of monitoring the changes in some milk constituents, oestradiol levels and electrical conductivity of vaginal mucus during peri‐oestrous period in prediction of the timing of oestrus in buffaloes. Twenty‐one Egyptian buffaloes aged 3–9 year, 1st–6th lactations, were examined by oestrous detector and ultrasonographically for monitoring the ovarian and uterine activity for 7 days around the time of standing oestrus. Sodium, potassium, chloride and lactose were assayed in aqueous phase of milk; besides, oestradiol was estimated in serum. Current results declared highly significant acute changes in milk constituents at the time of oestrus characterized by peaking of chloride and sodium levels and lowering of potassium and lactose values. The alternation in milk composition when arranged in decreasing order of magnitude, sodium was the highest (77.78 ± 0.69%), followed by chloride (61.60 ± 1.52%) and potassium (?58.14 ± 10.89%). Concomitantly, milk lactose decreased by 26.07 ± 7.97% compared to baseline levels. Synchronously, vaginal electrical resistance (VER) showed a significant (p < 0.01) decrease, but serum oestradiol 17β levels surged (59.93 ± 7.29 pg/ml) on day of oestrus. Serum oestradiol level was negatively correlated with VER (r = ?0.577), potassium (r = ?0.661), positively correlated with chloride (r = 0.707) and sodium (r = 0.579) and not correlated with lactose levels. These results for the first time suggested that the changes in constituents of milk during peri‐oestrous period may be used as a practical non‐invasive indicator for oestrous detection and prediction of ovulation in Egyptian buffaloes.     

Biochemical analysis of uterine fluid for identification of indicators for subclinical endometritis in the water buffalo (Bubalus bubalis)

Alterations in biochemical constituents of uterine fluid have been suggested for diagnosis of subclinical uterine infection in the bovine. This study was undertaken to investigate whether uterine fluid biomolecules could act as tool for diagnosis of subclinical endometritis in the buffalo. Uterine fluid samples from normal (n = 22) and subclinical endometritis (n = 18; diagnosed based on uterine cytology)‐affected buffaloes were subjected to biochemical analysis. Among the different biochemical constituents estimated, urea, urea N, cholesterol, total bilirubin and alkaline phosphatase (ALP) concentrations were significantly (p < 0.05) higher in uterine fluid obtained from subclinical endometritis‐affected buffaloes. The extent of difference between normal and subclinical endometritis‐affected buffaloes was highest in ALP (69%) followed by cholesterol (55%), bilirubin (48%), urea (30%) and urea N (30%) concentrations. Receiver operating characteristic (ROC) analysis indicated that the likelihood ratio (LR) was 3.63 for urea, indicating that buffaloes having less than the threshold concentration (47.5 mg/dl) of urea in their uterine fluid were at 3.6 times more risk to be affected with SE. The LRs for urea N, cholesterol, ALP and bilirubin were 2.33, 2.54, 2.12 and 1.65, respectively. It was concluded that ALP, urea, urea N and cholesterol concentrations in uterine fluid may serve as an aid for diagnosing subclinical endometritis in the buffalo.     

Preliminary observations on plasma fibrinogen and plasma protein concentrations and on plasma protein: Fibrinogen ratios in clinically healthy buffaloes

The plasma fibrinogen concentration, the total plasma protein concentration and the plasma protein to fibrinogen ratio (PP:F) were determined in clinically healthy Nili Ravi buffaloes. The plasma fibrinogen concentrations in calves, lactating and non-lactating buffaloes were 513±62, 615±90 and 544±74 mg/dl, respectively, and were statistically different (p<0.05). Total plasma protein concentrations in these animals were 7.15±0.28, 9.32±0.53 and 8.79±0.58 g/dl. PP:F for all animals was between 11 and 19. Fibrinogen levels were positively correlated with plasma protein (r=0.59) and negatively correlated with PP:F (r=–0.59).Abbreviations PP:F plasma protein to fibrinogen ratio     

Disposition of ampicillin trihydrate in plasma,uterine tissue,lochial fluid,and milk of postpartum dairy cattle

The objective of this study was to determine the disposition of ampicillin in plasma, uterine tissue, lochial fluid, and milk of postpartum dairy cattle. Ampicillin trihydrate was administered by intramuscular (i.m.) injection at a dose of 11 mg/kg of body weight every 24 h (n = 6, total of 3 doses) or every 12 h (n = 6, total of 5 doses) for 3 days. Concentrations of ampicillin were measured in plasma, uterine tissue, lochial fluid, and milk using HPLC with ultraviolet absorption. Quantifiable ampicillin concentrations were found in plasma, milk, and lochial fluid of all cattle within 30 min, 4 h, and 4 h of administration of ampicillin trihydrate, respectively. There was no significant effect of dosing interval (every 12 vs. every 24 h) and no significant interactions between dosing interval and sampling site on the pharmacokinetic variable measured or calculated. Median peak ampicillin concentration at steady‐state was significantly higher in lochial fluid (5.27 μg/mL after q 24 h dosing) than other body fluids or tissues and significantly higher in plasma (3.11 μg/mL) compared to milk (0.49 μg/mL) or endometrial tissue (1.55 μg/mL). Ampicillin trihydrate administered once daily by the i.m. route at the label dose of 11 mg/kg of body weight achieves therapeutic concentrations in the milk, lochial fluid, and endometrial tissue of healthy postpartum dairy cattle.     

硫酸头孢喹肟乳房注入剂在牛奶中的药代动力学研究

选取8头健康黑白花奶牛,每头牛随机选择两个乳区,以每个乳区1支(8g:75mg/支)的剂量进行单次乳房灌注给予硫酸头孢喹肟乳房注入剂。采用超高效液相色谱-串联质谱(UPLC-MS/MS)方法检测乳中头孢喹肟的浓度。结果表明,该制剂采用单次乳房灌注给药后,乳中药物能发挥较好抑菌效果的时间约为24～30小时,因此建议该制剂治疗奶牛临床型乳房炎的用药方案为：1支(8g:75mg)/(乳区.次),每天给药1次。     

Determination of milk/plasma ratio and milk and plasma pharmacokinetics of amoxicillin after intramuscular administration in lactating cows

This study was conducted to determine the passage ratio of amoxicillin into milk and its pharmacokinetics in milk and plasma after intramuscular administration. Five healthy dairy cows (Holstein, weighing 450–500 kg, aged 2–4 years) were used in this study. They received single intramuscular amoxicillin at a dose of 14 mg/kg body weight. Blood and milk samples were collected prior to drug administration (0); after 15, 30, 45, 60, and 90 min; and 2, 3, 4, 6, 8, 10, and 12 hr after administration. The plasma and milk concentrations of amoxicillin were determined using high‐performance liquid chromatography with ultraviolet detection. The passage ratio of amoxicillin into milk and plasma was determined using both AUC‐based calculation and milk and plasma concentrations at sampling times; it was calculated 0.46 and 0.52, respectively. The terminal half‐life and mean residence time of amoxicillin were 6.05 and 8.60 hr in plasma and 2.62 and 5.35 hr in milk, respectively. The C_max2 levels of amoxicillin in plasma and milk were measured as 1,096 and 457 ng/ml, respectively. It was observed that amoxicillin exhibited a secondary peak in plasma and milk. This study was the first to report on the passage ratio of amoxicillin into milk in lactating cows.     

Pharmacokinetics of toltrazuril and its metabolites in pregnant and nonpregnant ewes and determination of their concentrations in milk,allantoic fluid,and newborn plasma

The objectives of this study were to determine the pharmacokinetics of toltrazuril and its metabolites in pregnant and nonpregnant ewes following a single oral dose and to determine the plasma concentrations of these compounds in milk, allantoic fluid, and newborn plasma. Eighteen healthy ewes were randomly divided into three groups (n = 6 each): pregnant ewes at 12–13 weeks of gestation (group A), nonpregnant ewes (group B), and pregnant ewes at 1–2 weeks before expected lambing date (group C). Ewes in all groups received a single oral dose of toltrazuril at 20 mg/kg body weight. In groups A and B, blood samples were collected at 1, 3, 5, 7, 9, 12, 15, 18 hr, every 6 hr to day 3, every 12 hr to day 7 and thereafter every 24 hr to day 14 post-toltrazuril administration. In group C, parturition was induced 24–36 hr after toltrazuril administration then milk, allantoic fluid, and newborn plasma samples were collected immediately after birth. Drug metabolites were assayed using ultra high-performance liquid chromatography–ultraviolet detection method (UHPLC-UV). The maximum concentration (C_max), area under the plasma concentration-time curve (AUC_0–t), AUC to 24 and 48 hr (AUC_0–24), and (AUC_0–48) were significantly higher in pregnant ewes. Longer apparent half-life (T_1/2), significantly higher apparent volume of distribution (Vd/F) and total clearance (Cl/F) were observed in nonpregnant ewes. The time to maximum plasma concentration (T_max), mean residence time (MRT) and elimination rate constant (K_el) were similar in both groups. The AUC_0–24 and AUC_0–48 were significantly higher in nonpregnant ewes. The AUC_0–t was significantly higher in pregnant ones. The ratio of plasma toltrazuril concentrations in ewes and toltrazuril concentrations in newborn lambs' plasma, allantoic fluid, and milk were 68%, 2.3%, and 5.3%, respectively. Results of this study showed that toltrazuril is well absorbed after a single oral dose in ewes with widespread distribution in different body tissues.     

Inbreeding depression on production and reproduction traits of buffaloes from Brazil

The objective of this study was to evaluate the influence of inbreeding depression on traits of buffaloes from Brazil. Specifically, the traits studied were body weight at 205 and 365 days of age, average daily gain from birth to 205 days (ADG_205), average daily gain between 205 and 365 days (ADG205_365) in Mediterranean buffaloes, and milk yield, lactation length, age of first calving and calving intervals in Murrah buffaloes. Inbreeding effects on the traits were determined by fitting four regression models (linear, quadratic, exponential and Michaelis‐Menten) about the errors generated by the animal model. The linear model was only significant (P < 0.05) for growth traits (exception of ADG205_365). The exponential and Michaelis‐Menten models were significant (P < 0.01) for all the studied traits while the quadratic model was not significant (P > 0.05) for any of the traits. Weight at 205 and 365 days of age decreased 0.25 kg and 0.39 kg per 1% of increase in inbreeding, respectively. The inbred animals (F = 0.25) produced less milk than non‐inbred individuals: 50.4 kg of milk. Moreover, calving interval increased 0.164 days per 1% of increase in inbreeding. Interestingly, inbreeding had a positive effect on age at first calving and lactation length, decreasing age of first calving and increasing lactation length.     

高效液相色谱荧光检测法同时检测鸡血浆中阿莫西林和氨苄西林残留

建立高效液相色谱荧光法同时检测鸡血浆中阿莫西林和氨苄西林的残留量。鸡血浆经乙腈提取,饱和二氯甲烷萃取,酸性条件下水杨醛沸水浴衍生化后,以0.01mol/L的磷酸二氢钾溶液（A）和乙腈溶液（B）为流动相,梯度洗脱,流速为1.0mL/min,荧光检测激发波长为354nm,发射波长为445nm。阿莫西林和氨苄西林线性范围均为5.0~5 000.0μg/L,线性关系良好（r=0.999 9,0.999 6）。当阿莫西林和氨苄西林添加水平均为5.0~125.0mg/L时,鸡血浆样品平均回收率均高于74.72%,相对标准偏差（RSD）均低于8.65%,日内相对标准偏差分别低于4.99%和10.60%,日间相对标准偏差分别低于7.98%和11.29%。测定鸡血浆样品中AMO的检测限（LODs）为2.0μg/L（S/N=3）、定量限（LOQs）为5.0μg/L（S/N=10）,AMP的检测限为1.0μg/L（S/N=3）、定量限为2.5μg/L（S/N=10）。该方法操作简便、快速,且结果精确、灵敏、可靠,可适用于鸡血浆中阿莫西林、氨苄西林同时提取和检测。     

恩诺沙星及其代谢产物在奶山羊的药动学及乳中药物浓度

本试验研究单剂量静脉注射、肌肉注射和乳房灌注恩诺沙星（2.5mg/kg)在健康奶山羊的药动学及乳中药物浓度。采用HPLC法测定血浆和乳中恩诺沙星及其代谢产物环丙沙星的浓度，用统计矩原理处理血浆中药物浓度－时间数据，计算非房室模型的药动学参数。静脉注射、肌肉注射和乳房灌注恩诺沙星的t1/2β分别为1.32、1．55、0．99h;AUC为1．06、3．04、2．66mghL^-1；恩诺沙星的代谢分数为35．01％、44．06％、45．73％；环丙沙星的t1/2β为1．81、2．94、2．32h。乳中的药物浓度高于同期血中药物浓度，且乳中环丙沙星浓度高于恩诺沙星浓度并维持更长的时间。     

Plasma Concentrations,Pharmacokinetics and Urinary Excretion of Gatifloxacin after Single Intravenous Injection in Buffalo Calves

The pharmacokinetics and urinary excretion of gatifloxacin were investigated after a single intravenous injection of 4 mg/kg body weight in buffalo calves. The therapeutic plasma drug concentration was maintained for up to 12 h. Gatifloxacin rapidly distributed from blood to tissue compartments, which was evident from the high values of the distribution rate constant, α₁ (11.1 ± 1.06 h⁻¹) and the rate constant of transfer of drug from central to peripheral compartment, k ₁₂ (6.29 ± 0.46 h⁻¹). The area under the plasma drug concentration–time curve and apparent volume of distribution were 17.1 ± 0.63 (μg.h)/ml and 3.56 ± 0.95 L/kg, respectively. The elimination half-life (t _{1/2 β}), total body clearance (Cl_B) and the ratio of drug present in tissues and plasma (T/P) were 10.4 ± 2.47 h, 235.1 ± 8.47 ml/(kg.h) and 10.1 ± 2.25, respectively. About 19.7% of the administered drug was excreted in urine within 24 h. A satisfactory intravenous dosage regimen for gatifloxacin in buffalo calves would be 5.3 mg/kg at 24 h intervals. Abbreviations for pharmacokinetic parameters are given in the footnote of Table I     

In vitro phagocytic activity of milk neutrophils during lactation cycle in Murrah buffaloes of different parity

Milk samples were collected from 34 lactating Murrah buffaloes on days 0, 5, 15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 270 and day 300 after calving. Milk somatic cell counts (SCC) were highest in multiparous buffaloes . Milk SCC were significantly lower in buffaloes of third and fourth parity during early lactation and than increased significantly (p < 0.01) by the end of lactation. Milk neutrophils were significantly lower in all the buffaloes during early lactation, but increased significantly (p < 0.01) afterwards. Milk lymphocytes were significantly higher during early lactation, but decreased significantly (p < 0.01) by the end of lactation. Phagocytic activity (PA) was highest in day 1 colostrum and then decreased significantly (p < 0.01) by the fourth milking in buffaloes of second, third and fourth parity . Phagocytic index (PI) was also highest in colostrums of primiparous buffaloes. Irrespective of parity, maximum PA and PI was observed during mid lactation. In terms of in vitro phagocytic activity, early lactation is the most critical period followed by late and mid lactation.     

Modification of the Pharmacokinetics and Dosage of Cefuroxime by Endotoxin-induced Fever in Buffalo Calves

The effect of endotoxin-induced fever on the pharmacokinetics and dosage regimen of cefuroxime was investigated in buffalo calves following a single intravenous dose of 10 mg/kg body weight. The fever was induced by intravenous administration of E. coli endotoxin at a dose of 1 g/kg body weight. The distribution and elimination half-lives were 0.100 h and 1.82 h, respectively, in healthy and 0.109 h and 2.28 h, respectively, in febrile buffalo calves. About 91% of the administered dose was excreted in the urine within 24 h. There was no effect of fever on the plasma protein binding of cefuroxime. The dosage regimen for intravenous administration of cefuroxime may be reduced in febrile conditions but the probability of this was only 0.3.     

Pharmacokinetics in pulmonary epithelial lining fluid and plasma of ampicillin and pivampicillin administered to horses

Ampicillin concentrations in pulmonary epithelial lining fluid (PELF) and plasma was studied after single intravenous ampicillin administration (15mg/kg) or single intragastric administration of its prodrug, pivampicillin (19.9mg/kg) to horses and discussed in relation to minimum inhibitory concentrations (MIC) of common equine respiratory pathogens. After intravenous administration, elimination of ampicillin was fast and not detectable in plasma after 12h in three out of six horses. Pivampicillin was absorbed well in non-fasted horses with an oral bioavailability of 36%. The degree of penetration of ampicillin into PELF, as described by the AUC(PELF)/AUC(plasma) ratio from 0 to 12h was 0.40 after intravenous administration and 1.00 after pivampicillin administration. In horses, ampicillin administered either intravenously or orally, in the form of pivampicillin, can provide clinically relevant drug concentrations in PELF for at least 12h, when treating susceptible equine respiratory pathogens (e.g. streptococci). Treatment of other bacterial pathogens requires susceptibility testing and possibly more frequent dosing, depending of minimum inhibitory concentrations (MIC) values.     

Evaluation of direct and indirect measures of quarter milk from crossbred buffaloes

Somatic cell count (SCC), bacteriological findings and electrical conductivity (EC) were measured in milk from 216 quarters of 54 Murrah crossbred buffaloes for characterization of buffalo milk. Mean SCC in normal, subclinical and clinical mastitic milk was 171, 799 and 6039 × 10³/mL, respectively. Coagulase negative Staphylococci (CNS) were the major organisms associated with subclinical mastitis, whereas CNS and coliforms were the predominant organisms in clinical mastitis. EC values were found to be significantly higher in buffalo milk with mammary infection. The best trade-off between sensitivity and specificity for diagnosing mastitis in buffaloes by EC score was found at the cut-off value of 3.7 mS/cm. The direct measures such as SCC, EC, bacteriological findings, and appearance of milk were found to be useful for the evaluation of udder health of buffaloes and categorization of milk.