On-line version ISSN 2224-9435
Print version ISSN 1019-9128
J. S. Afr. Vet. Assoc. vol.84 n.1 Pretoria Jan. 2013
Gabriela A. AlbarellosI; Laura MontoyaI; Graciela A.A. DenamielI; Sabrina M. PassiniI; María F. LandoniII
ICátedra de Farmacología, Universidad de Buenos Aires, Argentina
IICátedra de Farmacología, Universidad Nacional de La Plata, Argentina
The aim of the present study was to describe the plasma pharmacokinetic profile and skin concentrations of lincomycin after intravenous administration of a 15% solution and oral administration of 300 mg tablets at a dosing rate of 15 mg/kg to cats. Susceptibility of staphylococci (n = 31) and streptococci (n = 23) strains isolated from clinical cases was also determined. Lincomycin plasma and skin concentrations were determined by microbiological assay using Kocuria rhizophila ATCC 9341 as test microorganism. Susceptibility was established by the antimicrobial disc diffusion test. Individual lincomycin plasma concentration-time curves were analysed by a non-compartmental approach. After intravenous administration, volume of distribution, body clearance and elimination half-life were 0.97 L/kg ± 0.15 L/kg, 0.17 L/kg ± 0.06 L/h.kg and 4.20 h ± 1.12 h, respectively. After oral administration, peak plasma concentration, time of maximum plasma concentration and bioavailability were 22.52 µg/mL ± 10.97 µg/mL, 0.80 h ± 0.11 h and 81.78% ± 24.05%, respectively. Two hours after lincomycin administration, skin concentrations were 17.26 µg/mL ± 1.32 µg/mL (intravenous) and 16.58 µg/mL ± 0.90 µg/mL (oral). The corresponding skin: plasma ratios were 2.08 ± 0.47 (intravenous) and 1.84 ± 0.97 (oral). The majority of staphylococci and streptococci tested in this study were susceptible to lincosamides (87.09% and 69.56%, respectively). In conclusion, lincomycin administered orally at the assayed dose showed a good pharmacokinetic profile, with a long elimination half-life and effective skin concentration. Therefore, it could be a good first option for treating skin infections in cats.
Lincomycin is, as clindamycin, a lincosamide antibiotic mainly active against staphylococci, streptococci and anaerobic bacteria (Giguère 2006). It is recommended for treating skin and other soft tissue infections produced by susceptible bacteria in dogs and cats (Papich & Riviere 2009). Lincosamides are antibiotics classified as 'important' (instead of 'critically important' or 'highly important') based on their importance in human medicine (WHO 2005, cited by Collignon, Courvalin & Aidara-Kane 2008) and would therefore be a better alternative to other antibiotics for the treatment of bacterial infections in animals (Collignon et al. 2008).
Lincomycin achieves therapeutic concentrations in most body tissues (Giguère 2006) and is widely metabolised in the liver to inactive metabolites that are eliminated through bile and urine (Brown et al. 1975; Hornish, Gosline & Nappier 1987).
Lincomycin pharmacokinetics have been studied in calves (Burrows, Barto & Weeks 1986), pigs (Kuroha, Son & Shimoda 2001; Nielsen & Gyrd-Hansen 1998), sheep (Ziv & Sulman 1973), goats (Abo El-Sooud, Goudah & Abd El-Aty 2004), chickens (Soback et al. 1987) and cats (Albarellos et al. 2012). However, to the authors' knowledge there is no published information on lincomycin pharmacokinetic behaviour after oral administration in cats.
The aim of this study was to characterise the plasma pharmacokinetic profile and skin concentrations of lincomycin after intravenous and oral administration in domestic cats.
Materials and methods
Experimental animals were five adult (5-year-olds) mixed-breed cats, with an average weight of 4.95 kg ± 0.55 kg. All cats were healthy, as determined by clinical examination, complete blood and plasma biochemical analysis and urinalysis. Animals were housed in facilities at the Faculty of Veterinary Medicine, University of Buenos Aires and allowed to acclimatise for two months before the experiment. Access to a high-quality commercial dry food (Royal Canin®, Argentina) and water was available ad libitum before the study. All animal procedures were approved by the Institutional Animal Care and Use Committee, School of Veterinary Science, University of Buenos Aires, Argentina.
A 15% lincomycin aqueous solution (Tritonyl inyectable®, Triton Vet S.R.L., Argentina) was used for intravenous administration. The dose (15 mg/kg) was half diluted with saline (NaCl 0.9%) before administration and infused over a 3 min period. For the oral administration, marked 300 mg lincomycin tablets (Tritonyl 300®, Triton Vet S.R.L, Argentina) were used. Each animal received 75 mg (each tablet was divided into quarters).
The study was carried out in a randomised cross-over design with a two week washout period.
Lincomycin was administered intravenously (15 mg/kg) through a 24G catheter (Abbocath-T®, Venisystems™, Abbott, Ireland) placed into the cephalic vein. For oral administration, a quarter tablet was administered per cat (actual dose of 15.19 mg/kg ± 1.65 mg/kg). Cats were deprived of access to food for 12 h prior to the study and up to 6 h post administration.
For blood collection, a jugular vein was catheterised 24 h before each study according to a technique described previously (Albarellos et al. 2003).
The same blood sampling schedule was used for both phases of the study. Blood samples (0.7 mL) were collected through the jugular catheter prior to antibiotic administration and at the following post-administration times: 5 min, 10 min, 20 min, 30 min, 45 min, 1 h, 1 h 30 min, 2 h, 3 h, 4 h, 6 h, 8 h, 10 h and 12 h.
Samples were collected into heparinised tubes, mixed and placed on ice until plasma separation 30 min later. Plasma was separated after centrifugation (1500 g, 15 min) and stored at -20 °C until analysis. All samples were assayed in the week after collection.
Skin samples (1 cm2) were collected under general anaesthesia (tiletamine/zolazepam 10 mg/kg, Zelazol, Fort Dodge, Pfizer S.R.L., Argentina) from the loose skin over the shoulders two hours after lincomycin was administered (either intravenously or orally). Samples were rinsed briefly with saline solution, dried with sterile gauze, weighed and stored at -20 °C.
To avoid heat inactivation of the antibiotic, skin samples were carefully and slowly cut to small pieces (≈1 mm3). Lincomycin was eluted using the technique described by Bamberger et al. (2005). Briefly, samples were incubated in 0.1 m phosphate buffer pH 7.8 (in a ratio 1:2 w/v) for 24 h at 4 °C, applying agitation during the first 40 min of incubation. Samples were subsequently centrifuged (1500 g, 15 min) and the supernatant fluid was collected.
Lincomycin plasma and skin concentrations were determined by microbiological assay (Bennet et al. 1966) using Kocuria rhizophila (formerly Micrococcus luteus) ATCC 9341 as test microorganism. This method was selected because of its sensitivity, simplicity and good correlation with high-performance liquid chromatography (HPLC) determination (Strachunskii et al. 1993). Standard curves were prepared, depending on the sample matrix to be quantified, on normal cat plasma or phosphate buffer pH 7.8. Each sample was seeded in triplicate and each standard dilution in quintuplicate. The limits of detection and quantification of the method for plasma and phosphate buffer were 0.78 µg/mL and 1.56 µg/mL, respectively. The method was linear between 0.78 µg/mL and 50 µg/mL (r = 0.9965). Inter-and intra-assay coefficients of variation were less than 10%.
Individual lincomycin plasma concentration-time curves were analysed by a non-compartmental approach with a software programme (PCNONLIN 4.0, SCI Software, Lexington, KY, USA). Major pharmacokinetic parameters were calculated according to classical equations (Gibaldi & Perrier 1982). The observed maximum plasma concentration (Cmax) and time of maximum plasma concentration (Tmax) were recorded directly from the data. The apparent terminal rate constant, kz, was determined by linear regression of the last five or six points on the terminal phase of the logarithmic plasma concentration-time curves.
The means and standard deviations of pharmacokinetic parameters are expressed. Main pharmacokinetic parameters (area under the curve [AUC (0-∞) ], elimination half-life [T½] and mean residence time [MRT]), skin concentrations and skin: plasma concentration ratios were compared statistically for the two administration routes, applying a nonparametric paired test (Wilcoxon test). Differences were considered statistically significant at p < 0.05.
Susceptibility test on Staphylococcus spp. and Streptococcus spp.
A total of 31 Staphylococcus strains and 23 Streptococcus strains were isolated from skin and mucosal infections from clinical cases attending the Small Animals Hospital, Faculty of Veterinary Science, University of Buenos Aires.
Bacterial susceptibility to lincomycin was established by an antimicrobial disc diffusion test, using 2 ug clindamycin discs in accordance with CLSI (2008) recommendations. Staphylococcus aureus ATCC 25923 and Streptococcus pneumoniae ATCC 49619 were used as quality controls.
No adverse effects were observed during or following administration (either route) of lincomycin in any of the cats.
The mean plasma concentration-time curves for the two administration methods of the antibiotic are shown in Figure 1. Estimated pharmacokinetic parameters for both administration routes are summarised in Table 1.
Oral absorption was rapid (Tmax = 0.80 h ± 0.11 h) although quite variable between animals (Cmax = 22.52 µg/mL ± 10.97 µg/mL). Lincomycin oral bioavailability (F) was almost complete (F = 81.78% ± 24.05%). No statistically significant differences were observed between pharmacokinetic parameters after intravenous or oral administration.
Lincomycin skin concentrations are shown in Table 2. For both administration routes, the lincomycin concentrations were higher than the corresponding plasma concentration; skin: plasma ratio for intravenous and oral administration was 2.08 ± 0.47 and 1.84 ± 0.97, respectively. No statistically significant differences were observed in skin concentrations or skin: plasma ratios between administration routes.
Of the tested staphylococci samples, 87.09% (27/31) were susceptible to lincomycin, whilst 69.56% (16/23) of the tested streptococci samples were susceptible to the antibiotic.
Lincomycin is an antibiotic with long duration in the body owing to its lipid solubility and wide tissue distribution. It has good activity against Gram-positive cocci and anaerobes. Because of these features, lincomycin is recommended for the treatment of a variety of skin, respiratory, gastrointestinal, soft-tissue and bone infections (Greene & Boothe 2012; Patel 2006).
The microbiological assay for measuring lincomycin concentrations in plasma and other biological matrices has been used in many studies (Abo El-Sooud et al. 2004; Albarellos et al. 2011; Brown et al. 1975; Burrows et al. 1986; Marcus, Ziv & Glickman 1995; Nielsen & Gyrd-Hansen 1998; Soback et al. 1987; Ziv & Sulman 1973). This analytical method is appropriate and accurate as lincomycin has no active metabolites (Brown et al. 1975; Brush et al. 1976; Hornish et al. 1987).
It is important to emphasise that animals were anaesthetised for skin sampling for approximately 30 min. Clinical parameters were carefully monitored throughout the procedures and all the cats remained stable, but haemodynamic modifications influencing the pharmacokinetic behaviour of lincomycin cannot be ruled out. However, previous antimicrobial pharmacokinetic studies performed in anaesthetised dogs, although with a different antibiotic, showed no significant changes in pharmacokinetic parameters (Duval & Budsberg 1995).
Lincomycin pharmacokinetic parameters after intravenous administration were similar to those reported in a previous study (Albarellos et al. 2012). However, the dose used in the present study was higher than the one used in the earlier study by Albarellos et al. (2012). This difference is clearly observed in the dose-dependent parameters that varied accordingly.
Lincomycin oral absorption was rapid and almost complete (Tmax = 0.80 h and F = 81.78%). Similar high oral bioavailability was reported by Nielsen and Gyrd-Hansen (1998) after lincomycin administration to fasted pigs.
No statistically significant differences were observed for elimination-related parameters (T½ and MRT) when comparing the two administration routes.
Lincosamides are lipophilic antibiotics and are therefore expected to achieve higher concentrations in most tissues than in plasma (Giguère 2006). In a study analysing clindamycin tissue concentrations in cats, Brown et al. (1990) found tissue: plasma ratios > 1. In the present study we found similar results. Lincomycin skin concentrations were higher than the corresponding plasma concentrations and skin: plasma ratios were also > 1, reflecting lincomycin accumulation in this tissue. However, it was noted that whole tissue concentrations are difficult to interpret because they represent the sum of all concentrations (intracellular, extracellular fluid and also any remaining blood contamination). It is also important to note that in the present study skin samples were taken at a single time point (2 h after antibiotic administration) and a single dose was administered. Therefore, the expected tissue accumulation in an ordinary therapeutic treatment could not be analysed.
Lincomycin skin concentrations and skin: plasma ratios were equivalent for both administration routes assayed. This finding is in accordance with the similar plasma concentration profile of the drug for the two administration routes and its high oral bioavailability.
Plasma lincomycin concentrations after intravenous or oral administration were well above MIC50, values recorded in literature (Albarellos et al. 2012; Giguère 2006) for the entire proposed dosing interval for this antibiotic (8 h - 12 h) (Plumb 2011). According to results of this study, a 15 mg/kg oral dose of lincomycin could allow a 12 h dosing interval in cats.
Similarly, lincomicyn skin concentrations were above an MIC50 of 1 µg/mL, but this refers to a single time point. However, it is possible to assume that lincomycin accumulates in tissues (because of its chemical characteristics) and therefore tissue concentrations will remain above plasma concentrations throughout the dosing interval.
Most of the staphylococci and streptococci samples tested in this study were susceptible to lincosamides (87.09% and 69.56%, respectively); however, it is important to consider that lincomycin antibacterial activity could be overestimated because antimicrobial susceptibility was evaluated with clindamycin discs (a more potent lincosamide) (CLSI 2008). Nevertheless, bacterial susceptibility rates for lincomycin found in this study suggest that lincomycin could be a good first option for treating the majority of skin infections in cats.
According to the data obtained in this study, lincomycin would be a useful alternative for the treatment of uncomplicated skin infections in cats.
The authors are indebted to Royal Canin, Argentina for the kind provision of the animal food. This work was supported by a grant (Research Project 20020100100745, 2011-2014) of the Secretaría de Ciencia y Técnica, Universidad de Buenos Aires, Argentina.
The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article.
G.A.A. (University of Buenos Aires) and M.F.L. (University of La Plata) were the project leaders and responsible for experimental and project design. L.M. (University of Buenos Aires) and S.M.P. (University of Buenos Aires) performed most of the experimental in vivo work. G.A.A.D. (University of Buenos Aires) performed most of the bacteriological work.
Abo El-Sooud, K., Goudah, A. & Abd El-Aty, A.M., 2004, 'Lack of pharmacokinetic interaction between lincomycin and aspirin in healthy goats', Journal of Veterinary Pharmacology and Therapeutics 27, 389-392. http://dx.doi.org/10.1111/j.1365-2885.2004.00611.x, PMid:15500581 [ Links ]
Albarellos, G.A., Bonafine, R.R., Kreil, V.E., Ambros, L.A., Montoya, L. & Hallu, R.E., 2003, 'A non-surgical jugular catheterization technique for multiple blood sampling in cats', Laboratory Animals 37, 188-192. http://dx.doi.org/10.1258/002367703766453029, PMid:12869280 [ Links ]
Albarellos, G.A., Montoya, L., Denamiel, G.A., Velo, M.C. & Landoni, M.F., 2012, 'Pharmacokinetics and bone tissue concentrations of lincomycin following intravenous and intramuscular administrations to cats', Journal of Veterinary Pharmacology and Therapeutics 35, 534-540. http://dx.doi.org/10.1111/j.1365-2885.2011.01355.x, PMid:22132730 [ Links ]
Bamberger, D.M., Foxworth, J.W., Bridwell, D.L., Shain, C.S. & Gerding, D.N., 2005, 'Extravascular antimicrobial distribution and the respective blood and urine concentrations in humans', in V. Lorian (ed.), Antibiotics in laboratory medicine, 5th edn., pp. 719-814, Lippincott Williams & Wilkins, Philadelphia. [ Links ]
Bennet, J.V., Brodie, J.L., Bennet, E.J. & Kirby, W.M., 1966, 'Simplified accurate method for antibiotic assay of clinical specimens', Applied Microbiology 14, 170-177. [ Links ]
Brown, R.B., Barza, M., Brusch, J.L., Hashimoto, Y. & Weinstein, L., 1975, 'Pharmacokinetics of lincomycin and clindamycin phosphate in a canine model', Journal of Infectious Diseases 131, 252-260. http://dx.doi.org/10.1093/infdis/131.3.252, PMid:1127255 [ Links ]
Brown, S.A., Zaya, M.J., Dieringer, T.M., Hunter, R.P., Nappier, J.L., Hoffman, G.A. et al., 1990, 'Tissue concentrations of clindamycin after multiple oral doses in normal cats', Journal of Veterinary Pharmacology and Therapeutics 13, 270-277. http://dx.doi.org/10.1111/j.1365-2885.1990.tb00776.x, PMid:2231867 [ Links ]
Brush, J.L., Barza, M., Brown, R.B., Bergeron, M.G. & Weinstein, L., 1976, 'Comparative pharmacokinetics of thirteen antibiotics in dogs with especial reference to concentrations in liver, kidney, bile and urine', Infection 4(suppl. 2), 82-90. [ Links ]
Burrows, G.E., Barto, P.B. & Weeks, B.R., 1986, 'Chloramphenicol, lincomycin and oxytetracycline disposition in calves with experimental pneumonic pasteurellosis', Journal of Veterinary Pharmacology and Therapeutics 9, 213-222. http://dx.doi.org/10.1111/j.1365-2885.1986.tb00032.x, PMid:372366CLSI. [ Links ]
Clinical and Laboratory Standards Institute, 2008, Performance standards for antimicrobial disk and dilution susceptibility test for bacteria isolated from animals: Approved Standard, 3rd edn., CLSI, Wayne. [ Links ]
Collignon, P., Courvalin, P. & Aidara-Kane, A., 2008, 'Clinical importance of antimicrobial drugs in human health', in L. Guardabassi, L.B. Jensen & H. Kruse (eds.), Guide to antimicrobial use in animals, pp. 44-58, Blackwell, Oxford. [ Links ]
Duval, J.M. & Budsberg, S.C., 1995, 'Cortical bone concentrations of enrofloxacin in dogs', American Journal of Veterinary Research 56, 188-192. PMid:7717584 [ Links ]
Gibaldi, M. & Perrier, D., 1982, Pharmacokinetics, 2nd edn., Marcel Dekker, New York. [ Links ]
Giguère, S., 2006, 'Lincosamides, pleuromutilins, and streptogramins', in S. Giguère, J.F. Prescott, J.D. Baggot, R.D. Walker & P.M. Dowling (eds.), Antimicrobial therapy in veterinary medicine, 4th edn., pp. 179-184, Blackwell, Ames. [ Links ]
Greene, C.E. & Boothe, D.M., 2012, 'Antibacterial chemotherapy', in C.E. Greene (ed.), Infectious diseases of the dog and cat, 4th edn., pp. 283-309, Elsevier Saunders, St. Louis. [ Links ]
Hornish, R.E., Gosline, R.E. & Nappier, J.M., 1987, 'Comparative metabolism of lincomycin in the swine, chicken and rat', Drug Metabolism Reviews 18, 177-214. http://dx.doi.org/10.3109/03602538708998305, PMid:3330515 [ Links ]
Kuroha, M., Son, D-S. & Shimoda, M., 2001, 'Effects of altered plasma α-1-acid glycoprotein levels on pharmacokinetics of some basic antibiotics in pigs: Simulation analysis', Journal of Veterinary Pharmacology and Therapeutics 24, 423-431. http://dx.doi.org/10.1046/j.1365-2885.2001.00367.x, PMid:11903873 [ Links ]
Marcus, S., Ziv, G. & Glickman, A., 1995, 'Passage of lincomycin from blood into the semen of bulls after multiple subcutaneous administration of a lincomycin-spectinomycin combination', Journal of Veterinary Pharmacology and Therapeutics 18, 75-76. http://dx.doi.org/10.1111/j.1365-2885.1995.tb00555.x, PMid:7752312 [ Links ]
Nielsen, P. & Gyrd-Hansen, N., 1998, 'Bioavailability of spiramycin and lincomycin after oral administration to fed and fasted pigs', Journal of Veterinary Pharmacology and Therapeutics 21, 251-256. http://dx.doi.org/10.1046/j.1365-2885.1998.00131.x, PMid:9731946 [ Links ]
Papich, M.G. & Riviere, J.E., 2009, 'Chloramphenicol and derivatives, macrolides, lincosamides, and miscellaneous antimicrobials', in J.E. Riviere & M.G. Papich (eds.), Veterinary pharmacology and therapeutics, 9th edn., pp. 963-965, Wiley-Blackwell, Ames. [ Links ]
Patel, A., 2006, 'Bacterial pyoderma', in J.R. August (ed.), Consultations in feline internal medicine, vol. 5, pp. 251-259, Elsevier Saunders, St. Louis. http://dx.doi.org/10.1016/B0-72-160423-4/50031-7, PMid:17670561 [ Links ]
Plumb, D.C., 2011, Plumb's veterinary drug handbook, 7th edn., Wiley-Blackwell, Ames. [ Links ]
Soback, S., Ziv, G., Bogin, E., Cohen, Z. & Earon, Y., 1987, 'Pharmacokinetic changes of several antibiotics in chickens during induced fatty liver', Research in Veterinary Science 43, 49-54. PMid:3628983 [ Links ]
Strachunskii, L.S., Gagaeva, E.V., Kuleshova, E.É., Dombrovskii, V.S., Suina, Z.M., Kuleshov, S.E. et al., 1993, 'Evaluation of the bioavailability of preparations subjected to hepato-intestinal circulation: Lincomycin', Pharmaceutical Chemistry Journal 27, 814-818. http://dx.doi.org/10.1007/BF00780570 [ Links ]
Ziv, G. & Sulman, G., 1973, 'Penetration of lincomycin and clindamycin into milk in ewes', British Veterinary Journal 129, 83-91. PMid:4727800 [ Links ]
Buenos Aires 1427, Argentina
Received: 11 Dec. 2012
Accepted: 02 July 2013
Published: 31 Oct. 2013