A.Y.I. El-Gendi

Cairo University, Al Qāhirah, Muḩāfaz̧at al Qāhirah, Egypt

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Publications (13)12.34 Total impact

  • Source
    M Atef · A.Y.I. El-Gendi · Aziza M Amer · A.M. Abd El-Aty ·
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    ABSTRACT: The pharmacokinetic aspects of florfenicol (FLO) were investigated via intravenous (I.V.) and intramuscular (I.M.) injections in five goats at a dose of 20 mg kg(-1) b.wt. Animals were pre-treated with albendazole orally in a dose of 2.5 mg kg(-1) b.wt, ivermectin or rafoxanide subcutaneously in a dose 0.2 and 7.5 mg kg(-1) b.wt, respectively. Florfenicol was injected intramuscularly two hours following anthelmentic administration and blood samples were taken by jugular venapuncture at standardized intervals. The concentrations of florfenicol (FLO) in serum were determined by high performance liquid chromatography (HPLC) method. The obtained results revealed that ivermectin administration did not induce a significant difference in serum florfenicol concentration between anthelmentic-treated and non-treated goats. On the other hand, goats pre-treated with rafoxanide or albendazole showed a significant decrease in serum florfenicol level as compared to non-anthementic treated goats. The absorption half-life (t(½ab)), C(max), AUMC, AUC and systemic bioavailability (F%) are significantly decreased, whereas elimination half-life (t(½el)) and MRT are increased in goats pre-treated by the three tested anthementics.
    Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 12/2010; 48(12):3340-4. DOI:10.1016/j.fct.2010.08.039 · 2.90 Impact Factor
  • A.Y.I. El-Gendi · M Atef · Aziza M.M. Amer · Gehan M Kamel ·
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    ABSTRACT: Following IV injection of doxycycline in a dose of 20 mg kg(-1) b.wt., its serum concentration was best fitted in two-compartment open model in chickens fed either on control or on anticoccidials-containing rations. Diclazuril and halofuginone resulted in a significant short distribution half-life (t(½α)) (7.17±0.39 and 11.88±1.05 min, respectively) and increased total body clearance (Cl(tot)) 0.37±0.024 and 0.295±0.034 L/kg/h, respectively. Following oral dosing the tested drug absorbed with t(½ab) of 41.38±1.6, 17.48±0.86 and 41.83±1.8 min, respectively and their C(max) values (3.18±0.18, 5.425±0.48 and 0.986±0.037 μg/ml) were attained at 2.07±0.097, 1.403±0.074 and 2.55±0.106 h. For doxycycline alone and in presence of diclazuril and halofuginone, respectively. Systemic bioavailability was 22.64±3.46, 86.74±9.23 and 22.38±3.09%, respectively. Following IM injection t(½ab) were 9.096±1.34 for doxycycline alone, 16.24±2.21 and 15.6±1.7 min in the presence of diclazuril and halofuginone, respectively. C(max) was 3.10±0.28, 4.63±0.57 and 0.55±0.07 μg/ml reached at 0.8±0.083, 1.13±0.126 and 1.21±0.105 h. For the antibiotic alone, and in presence of either diclazuril and halofuginone, respectively. Systemic bioavailability was 22.41±3.86, 88.97±12.9 and 12.31±0.99% in chickens fed on anticoccidial-free, diclazuril- and halofuginone-containing rations, respectively. Both the tested anticoccidials induced higher doxycycline tissue residues in all tested tissue samples.
    Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 11/2010; 48(11):3209-14. DOI:10.1016/j.fct.2010.08.024 · 2.90 Impact Factor
  • Source
    M Atef · A Y El-Gendi · Aziza · M.M. Aziza Amer · A M Abd El-Aty ·
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    ABSTRACT: The pharmacokinetics of danofloxacin was determined in five clinically normal adult female goats after intravenous (IV) or intramuscular (IM) doses of 1.25 mg/kg body weight. Blood and urine samples were collected from each animal at precise time intervals. Serum and urine concentrations were determined using microbiological assay methods and the data were subjected to kinetic analysis. After intravenous injection, the serum concentration–time curves of danofloxacin were characteristic of a two-compartment open model. The drug was rapidly distributed and eliminated with half-lives of 17.71±1.38 min and 81.18±3.70 min, respectively. The drug persisted in the central, highly perfused organs with a K 12/K 21 ratio of 0.67±0.25. The mean volume of distribution at a steady state (V dss) was 1.42±0.15 L/kg. After intramuscular administration, the serum concentration peaked after 0.58±0.04 h at approximately 0.33±0.01 μg/ml. While danofloxacin could be detected in serum for 4 and 6 h, it was recovered in urine for up to 24 and 72 h after IV and IM administration, respectively. The systemic bioavailability after IM injection was 65.70%±10.28% and the serum protein-bound fraction was 13.55±1.78%.
    Veterinary Research Communications 08/2001; 25(5):367-77. DOI:10.1023/A:1010642726054 · 1.24 Impact Factor
  • Source
    M Atef · A Y el-Gendi · A. A. M. Amer · A M Abd El-Aty ·
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    ABSTRACT: Florfenicol, a monofluorinated analogue of thiamphenicol, has antibacterial activity against a broad spectrum of bacterial strains, including enteric bacteria that are resistant to chloramphenicol and thiamphenicol. The pharmacokinetics of florfenicol was studied following a single intravenous bolus or intramuscular injections at a dose of 20 mg/kg body weight, in five healthy goats. Serum florfenicol concentrations were determined using two analytical methods: microbiological assay and high-performance liquid chromatography (HPLC). Pharmacokinetic analysis was performed using redundant routine equations and the results derived from each method were compared. While florfenicol was detected for up to 4 and 8 h after administration by the bioassay, the drug was recovered in serum after 12 and 24 h by HPLC following intravenous and intramuscular injections, respectively. Comparison of the concentration profiles obtained by the two methods revealed substantial differences in the resultant kinetic data. Values for the initial serum concentration, elimination half-life, the area under the serum concentration-time curve, the mean residence time, and the systemic bioavailability were significantly (P < 0.01) higher when florfenicol concentrations were determined using HPLC. In conclusion, differences between analytical methodologies should be considered when interpreting the kinetic data for clinical use. However, both the hepatic biotransformations and the interchangeability of enantiomers need further investigation.
    Journal of Veterinary Medicine Series A 04/2001; 48(3):129-36. DOI:10.1046/j.1439-0442.2001.00339.x · 0.93 Impact Factor
  • M Atef · A Y el-Gendi · M M Aziza · A M Abd El-Aty ·
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    ABSTRACT: The single-dose disposition kinetics of florfenicol was determined in healthy, non-lactating Egyptian goats, after its intravenous (i.v.) and intramuscular (i.m.) administration at 20 mg kg-1 b.wt. Drug concentrations in serum and urine were determined using microbiological assay method and data was subjected to a kinetic analysis. Florfenicol concentrations in serum decreased in a bi-exponential manner after intravenous administration with distribution (t1/2 alpha) and elimination (t1/2 beta) half-lives of 10.256 +/- 0.938 and 56.237 +/- 3.102 minute, respectively. The steady-state volume of distribution (Vdss) and total body clearance (Cltot) were 3.413 +/- 0.304 l kg-1 and 3.306 +/- 0.333 l kg h-1. After intramuscular administration, the peak serum concentration (Cmax) was 0.859 +/- 0.025 micrograms ml-1, achieved at (Tmax) 1.220 + 0.045 h. Florfenicol was detected in urine up to 24 and 96 hour after i.v. and i.m. administration, respectively. The extent of the protein binding and systemic bioavailability of florfenicol were 22.45 +/- 1.727% and 65.718 +/- 3.372%, respectively.
    DTW. Deutsche tierärztliche Wochenschrift 05/2000; 107(4):147-50. · 0.41 Impact Factor
  • M Atef · A Y el-Gendi · M G el-Sayed · A M Amer ·

    DTW. Deutsche tierärztliche Wochenschrift 04/1986; 93(3):110-2. · 0.41 Impact Factor
  • A.Y.I. El-Gendi · M.G.A. El-Sayed · M Atef · A. Zaki Hussin ·
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    ABSTRACT: Evaluation of the pharmacokinetic properties of 4 antibiotics: penicillin-G (P), streptomycin (S), chloramphenicol (C) and oxytetracycline (O) was performed in groups of camels following a single i.m. injection of therapeutic doses, i.e. 6000 IU, 10, 4 and 3 mg/kg b.wt., respectively. The concentrations of these antibiotics in serum were determined by microbiological assay methods. The highest serum concentrations were reached after 0.42, 1.44, 4.02 and 0.94 hr for P, S, C, and O respectively with corresponding t 1/2 alpha values of 0.12, 0.28, 1.48 and 0.17 hr and t 1/2 beta values of 1.09, 8.28, 6.20 and 7.00 hr.
    03/1983; 261(2):186-95.
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    ABSTRACT: Eight experiments were carried out on eight clinically healthy non-pregnant ewes. Each animal was injected intravenously with either sulphadiazine or sulphadimidine at a dose rate of 100 mg/kg body weight. A two-compartment pharmacokinetic model was developed to describe the disposition of these drugs. The elimination half-lives were 7.15 +/- 0.58 h and 9.51 +/- 0.59 h and the distribution half-lives were 0.56 +/- 0.07 h and 0.42 +/- 0.05 h for sulphadiazine and sulphadimidine, respectively. The apparent specific volumes of distribution were less than 1 litre/kg (0.410 and 0.501 litres/kg for sulphadiazine and sulphadimidine, respectively) which indicates a relatively lower distribution of these drugs to tissues than in plasma in sheep. The degree of plasma protein binding was similar for both drugs (19.15 +/- 0.55% and 23.12 +/- 0.32%) for sulphadiazine and sulphadimidine, respectively). Serum concentrations of ketone bodies, total lipids and calcium were significantly reduced, and blood glucose concentration significantly increased following administration of both of these sulphonamides, whilst serum total protein concentration was unaltered. The serum cholesterol concentration was significantly reduced following sulphadiazine administration, but not after sulphadimidine.
    Journal of Veterinary Pharmacology and Therapeutics 10/1981; 4(3):173-82. DOI:10.1111/j.1365-2885.1981.tb00728.x · 1.19 Impact Factor
  • M.G.A. El-Sayed · M Atef · A.Y.I. El-Gendi · S.A.H. Youssef ·
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    ABSTRACT: In 12 experiments on 6 mongrel dogs, furosemide was given both orally and i.v. in a dose of 20mg/kg. Following i.v. injection, the blood concentration curve followed an open one-compartment model. The elimination half-lives after both oral and i.v. routes were nearly similar, i.e. 1.42 +10.13 and 1.13 +0.06 hours respectively. The apparent volume of distribution corresponded well to the total body water (about 60%), i.e. 69.64 +5.61 and 52.06+4.82% b.wt. after oral and i.v. routes respectively. The body clearance of this drug after i.v. and oral administration showed close values, i.e. 5.27 +0.19 and 5.96 +0.14 mg/kg(-1) min(-1) respectively. The systemic bioavailablity of furosemide after oral administration amounted to 77.13 +5.24% with a maximum blood conc. (Cmax.) of 22.73 +2.03 microgram/ml, 30 min after administration.
    10/1981; 253(1):4-10.
  • A B Hassan · A Y El-Gendi · M A El-Fadaly · M F Mohamed ·

    Mykosen 08/1981; 24(7):421-30.
  • A B Hassan · A. Y. I. El-Gendi ·
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    ABSTRACT: One dose of 5 mg./kg. b. wt. adenosine triphosphate intravenously in anaesthetised dogs decreased arterial blood pressure and renal blood flow by 58.2 and 15.4 %, respectively after 5 min, with a slow return to near normal levels after 40 min. Infusion of the same substance at rates of 0.25 and 1 mg./ kg./min for 30 min decreased arterial blood pressure by 27.2 and 55.0 % but increased renal blood flow by 14.4 and 18.2 %, respectively. Stopping the infusion was followed by a rapid return to normal levels.Withdrawal of 20 and 30 ml. blood/kg. b. wt. from anaesthetised dogs decreased blood pressure by 43.7 and 63.5 % and renal blood flow by 33.0 and 68.8 %, respectively. Infusion of ATP at the above rates restored both to near the normal lvel.ZusammenfassungEinfluß von Adenosintriphosphat (ATP) auf den arteriellen Blutdruck und die renale Durchblutung von Hunden vor und nach BlutentzugDie einmalige i. V. Verabreichung von ATP in einer Dosis von 5 mg/kg KGW bei narkotisierten Hunden reduzierte innerhalb von 5 Minuten den arteriellen Blutdruck um 58 % und die renale Durchblutung um 15 %, mit einer langsamen Rückkehr zu annähernd normalen Werten innerhalb von 40 min. Die Infusion von ATP während 30 min in einer Menge von 0,25 bzw. 1 mg/kg KGW/min reduzierte den arteriellen Blutdruck um 27 bzw. 55 %, führte jedoch zu einer Steigerung der renalen Durchblutung um 14 % bzw. 18 %. Nach Sistieren der Infusion wurden schnell wieder Normalwerte erreicht.Der Entzug von 20 und 30 ml. Blut/kg KGW bei narkotisierten Hunden reduzierte den Blutdruck um 43,7 und 63,5 % und die renale Durdiblutung um 33 % und 69 %. Die Infusion von ATP in den vorerwähnten Mengen bewirkte eine Normalisierung beider Kriterien.RésuméInfluence de l'adénosine-triphosphate ATP) sur la pression artérielle et l'irrigation sanguine rénale des chiens avant et après une prise de sangL'application unique par voie intraveineuse d'ATP à une dose de 5 mg/kg de poids chez des chiens sous narcose a diminué en 5 minutes la pression artérielle de 58 % et l'irrigation sanguine rénale de 15 %. Un lent retour aux valeurs proches de la normale a suivi dans l'espace de 40 minutes.L'infusion d'ATP durant 30 minutes avec une quantité de 0,25 et 1 mg/kg de poids a diminué la pression artérielle de 27 et 55 % mais a provoqué une augmentation de l'irrigation sanguine rénale de 14 et 18 %. Les valeurs normales sont rapidement réapparues après l'arrêt de l'infusion.La prise de 20 et 30 ml de sang/kg de poids chez des chiens sous narcose a diminué la pression sanguine de 43,7 et 63,5 % et l'irrigation sanguine rénale de 33 et 69 %. L'infusion d'ATP dans les quantités indiquées provoqua une normalisation des deux paramètres.ResumenEl influjo del adenosintrifosfato (ATF)sobre la tensión sanguínea arterial y el flujo sanguíneo renal en perros normales y sangradosLa administración iv. única de ATF en una dosis de 5 mg/kg PC en perros narcotizados reducía en el plazo de 5 minutos la tensión sanguínea arterial en un 58 % y el flujo sanguineo renal en un 15 % con un retorno lento a los valores normales aproximados al cabo de 40 min. La infusión de ATP durante 30 min. en la dosis de 0,25 y 1 mg/kg PC/min, resp., reducía la tensión sanguínea arterial en un 27,2 y 55,0 %, resp., mas conducía a un incremento del flujo sanguíneo renal en un 14 % y 18 %, resp. Tras la interrupción de la infusión se alcanzaron rápidamente de nuevo los valores normales.La extracción de 20 y 30 ml de sangre/kg PC a los perros anestesiados reducía la tensión sanguínea en un 43,7 y 63,5 % y el flujo sanguíneo renal en un 33,0 y 68,8 %. La infusión de ATF en las cantidades citadas arriba ocasionaba la normalización de ambos criterios.
    Zentralblatt für Veterinärmedizin. Reihe A 02/1981; 28(2):152-8. DOI:10.1111/j.1439-0442.1981.tb01175.x
  • M Atef · M. G. A. El-Sayed · S. E. A. Youssef · A Y El-Gendi · M Fadali ·
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    ABSTRACT: Following a single i. v. injection of sulphadiazine, sulphadimidine and sulphathiazole in buffaloes (100 mg./kg. b. wt.), it was found that: 1. Sulphathiazole was the most rapidly eliminated, with a half-life value of 198 min, followed by sulphadiazine (230 min); sulphadimidine had the slowest rate (563 min). The volumes of distribution of the 3 sulphonamides were 579, 751 and 452 ml./kg. b. wt., respectively. 2. 24 h after injection no detectable amount of sulphadiazine, but a significant amount of sulphathiazole (10.10 μg./ml.) and sulphadimidine (40.54 μg./ml.), was found in plasma. The protein-bindung tendency of the 3 sulphonamides, as calculated in vitro, showed that values for sulphadiazine and sulphathiazole were very similar (18.01 and 16.62 %, respectively), while that for sulphadimidine (4.31 %), was much lower. 3. Excretion of the 3 sulphonamides in saliva was higher than in milk, with the concentration of sulphadimidine in both higher than that of the other 2 compounds. Very high concentrations of the parent sulphonamides and their acetylated derivatives were found in urine. Pharmakokinetik einiger Sulfonamide bei Büffeln Die einmalige i. v. Injektion von Sulfadiazin, Sulfadimidin oder Sulfa- thiazol bei je 3 Büffeln (100 mg/kg KGW) führte zu folgenden Ergebnissen: Pharmacocinétique de quelques sulfonamides chez des buffles Les résultats suivants ont été obtenus après une injection intraveineuse de Sulfadiazine, de Sulfadimidine ou de Sulfathiazol chez des buffles (100 mg/kg de poids): 1. Le Sulfathiazol fut éliminé le plus rapidement (demi-temps 198 min) suivi par la Sulfadiazine (230 min) et la Sulfadimidine (563 min). Le volume de répartition des 3 sulfonamides fut de 579, 751 et 452 ml/kg de poids. 2. Aucune Sulfadiazine ne fut mise en évidence dans le plasma 24 h après l'injection, mais par contre des concentrations marquées de Sulfathiazol (10,1 μg/ml) et de Sulfadimidine (40,5 μg/ml) ont été constatées. La détermination in vitro de la liaison protéique a donné des valeurs identiques pour la Sulfadiazine (18 %) et le Sulfathiazol (16,6 %), cette valeur étant nettement plus basse pour la Sulfadimidine (4,3 %). 3. L'excrétion des 3 sulfonamides fut plus grande dans la salive que dans le lait. La concentration de Sulfadimidine fut plus forte dans les deux excrétions. Des concentrations élevées des substances de sortie et de leurs métabolites acétiylés ont été mis en évidence dans l'urine. Fármacocinética de algunas sulfonamidas en búfalos La inyección iv. única de sulfadiazina, sulfadimidina o sulfatiazol en 3 búfalos cada vez (100 mg./kg. PC) conducía a los resultados siguientes:
    Zentralblatt für Veterinärmedizin. Reihe A 02/1981; 28(2):122-30. DOI:10.1111/j.1439-0442.1981.tb01171.x
  • A Y El-Gendi · S A Youssef · M Atef · M G El-Sayed · S Abdel Aziz ·
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    ABSTRACT: 1. Three groups of four clinically healthy buffaloes were injected with sulphadiazine, or sulphadimidine, or sulphathiazole in a single dose of 100 mg/kg body weight. 2. Changes in the serum enzyme activities (SGOT, SGPT and alkaline phosphatase) observed with the tested sulphonamides were insignificant, except for increases in SGOT level 6 h after sulphathiazole injection, and in GOT/GPT ratio 30 min and 24 h after sulphadimidine injection. 3. The creatinine level was not affected in sulphonamide-injected animals. All blood samples collected 15 min to 24 h after sulphathiazole injection showed marked increase in glucose and urea levels. Concerning the other two sulphonamides, no significant change was observed in these parameters except for an increased glucose level 24 h after sulphadiazine injection.
    Clinical and Experimental Pharmacology and Physiology 9(2):179-83. · 2.37 Impact Factor

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