High-Precision Quantitation of Biofluid Samples Using Direct Mass Spectrometry Analysis.

The transition of mass spectrometry for clinical analysis is highly desirable, and major progress has been made with direct sampling ionization for operation simplification. High-precision quantitation, however, remains a major challenge in this transition. Herein, a novel method was developed for direct quantitation of biofluid samples, using an extremely simplified procedure for incorporation of internal standards selected against the traditional rules. Slug flow microextraction was used for the development, with conditions predicted by a theoretical model, viz., using internal standards of partition coefficients very different from the analytes and large sample-to-extraction solvent volume ratios. Direct quantitation of drug compounds in urine and blood samples was demonstrated. This development enabled an extremely simplified protocol that is expected to have a significant impact on on-site or clinical analysis.

Soil Behaviour of the Veterinary Drugs Lincomycin, Monensin, and Roxarsone and Their Toxicity on Environmental Organisms.

Lincomycin, monensin, and roxarsone are commonly used veterinary drugs. This study investigated their behaviours in different soils and their toxic effects on environmental organisms. Sorption and mobility analyses were performed to detect the migration capacity of drugs in soils. Toxic effects were evaluated by inhibition or acute toxicity tests on six organism species: algae, plants, daphnia, fish, earthworms and quails. The log Kd values (Freundlich model) of drugs were: lincomycin in laterite soil was 1.82; monensin in laterite soil was 2.76; and roxarsone in black soil was 1.29. The Rf value of lincomycin, roxarsone, monensin were 0.4995, 0.4493 and 0.8348 in laterite soil, and 0.5258, 0.5835 and 0.8033 in black soil, respectively. The EC50 for Scenedesmus obliquus, Arabidopsis thaliana, Daphnia magna and LC50/LD50 for Eisenia fetida, Danio rerio, and Coturnix coturnix were: 13.15 mg/L,32.18 mg/kg dry soil,292.6 mg/L,452.7 mg/L,5.74 g/kg dry soil and 103.9 mg/kg (roxarsone); 1.085 mg/L, 25 mg/kg dry soil, 21.1 mg/L, 4.76 mg/L, 0.346 g/kg dry soil and 672.8 mg/kg (monensin); 0.813 mg/L, 35.40 mg/kg dry soil, >400 mg/L, >2800 mg/L, >15 g/kg dry soil, >2000 mg/kg (lincomycin). These results showed that the environmental effects of veterinary drug residues should not be neglected, due to their mobility in environmental media and potential toxic effects on environmental organisms.

Preparation, biodistribution and scintigraphic evaluation of (99m)Tc-lincomycin.

A complex of lincomycin was synthesized with technetium-99m. The synthesis was carried out by using SnCl2.2H2O as reducing agent and ascorbic acid as stabilizer. The effect of various parameters such as amount of ligand/reducing agent, pH value and reaction time on radio labeling process was studied. The characterization of the (99m)Tc-Lincomycin was performed by HPLC and electrophoresis Biodistribution studies were carried out by analyzing the model of bacterial infectious rats (Sprague-Dawley). The uptake of infectious lesions at different time interval was also studied by using scintigraphic technique. The complex showed effective target to non-target ratio for various inflammatory or infectious lesions. The (99m)Tc-Lincomycin effective binding to living bacteria and could be used successfully as an infection imaging agent.

Pharmacokinetics of lincomycin following single intravenous administration in buffalo calves.

Lincomycin 10 mg kg(-1), IV in buffalo calves followed two-compartment open model with high distribution rate constant α (11.2 ± 0.42 h(-1)) and K 12/K 21 ratio (4.40 ± 0.10). Distribution half-life was 0.06 ± 0.01 h and AUC was 41.6 ± 1.73 µg mL(-1) h. Large Vdarea (1.15 ± 0.03 L kg(-1)) indicated good distribution of lincomycin in various body fluids and tissues. Peak plasma level of lincomycin (71.8 ± 1.83 µg mL(-1)) was observed at 1 min as expected by IV route. The elimination half-life and MRT of lincomycin were short (3.30 ± 0.08 and 4.32 ± 0.11 h, respectively). Lincomycin 10 mg kg(-1) IV at 12-h interval would be sufficient to maintain T > MIC above 60 % for bacteria with minimum inhibitory concentrations (MIC) values ≤1.6 µg mL(-1). Favourable pharmacokinetic profile in buffalo calves and a convenient dosing interval suggest that lincomycin may be an appropriate antibacterial in buffalo species for gram-positive and anaerobic bacterial pathogens susceptible to lincomycin.

Pharmacokinetics and bone tissue concentrations of lincomycin following intravenous and intramuscular administrations to cats.

The pharmacokinetic properties and bone concentrations of lincomycin in cats after single intravenous and intramuscular administrations at a dosage rate of 10 mg/kg were investigated. Lincomycin minimum inhibitory concentration (MIC) for some gram-positive strains isolated from clinical cases was determined. Serum lincomycin disposition was best-fitted to a bicompartmental and a monocompartmental open models with first-order elimination after intravenous and intramuscular dosing, respectively. After intravenous administration, distribution was rapid (T(1/2(d)) = 0.22 ± 0.09 h) and wide as reflected by the volume of distribution (V((d(ss)))) of 1.24 ± 0.08 L/kg. Plasma clearance was 0.28 ± 0.09 L/h · kg and elimination half-life (T(1/2)) 3.56 ± 0.62 h. Peak serum concentration (C(max)), T(max), and bioavailability for the intramuscular administration were 7.97 ± 2.31 µg/mL, 0.12 ± 0.05 h, and 82.55 ± 23.64%, respectively. Thirty to 45 min after intravenous administration, lincomycin bone concentrations were 9.31 ± 1.75 µg/mL. At the same time after intramuscular administration, bone concentrations were 3.53 ± 0.28 µg/mL. The corresponding bone/serum ratios were 0.77 ± 0.04 (intravenous) and 0.69 ± 0.18 (intramuscular). Lincomycin MIC for Staphylococcus spp. ranged from 0.25 to 16 µg/mL and for Streptococcus spp. from 0.25 to 8 µg/mL.

Preparation and properties of polyvinyl alcohol/N-succinyl chitosan/lincomycin composite antibacterial hydrogels for wound dressing.

Hydrogels are three-dimensional polymeric networks capable of absorbing large amounts of water or biological fluids with the properties resembling natural living tissues. Herein, polyvinyl alcohol (PVA)/N-succinyl chitosan (NSCS)/lincomycin hydrogels for wound dressing were prepared by the freezing/thawing method, then characterized by FTIR, SEM, and TGA. The compression strength, swelling behavior, water retention capacity, antibacterial activity, drug release and cytotoxicity were systematically investigated. The results showed that the introduction of NSCS remarkably enhanced the swelling capacity, leading to the maximum swelling ratio of 19.68 g/g in deionized water. The optimal compression strength of 0.75 MPa was achieved with 30 % NSCS content.Additionally, the incorporation of lincomycin brought a remarkable antibacterial activity against both Escherichia coli and Staphylococcus aureus. Specifically, 77.71 % of Staphylococcus aureus was inhibited with 75 µg/mL lincomycin, while the MTT assay demonstrated the nontoxic nature of the composite hydrogels. In summary, this PVA/NSCS/lincomycin hydrogel showed promising potential for wound dressing.

Lincomycin and spectinomycin in the treatment of breeding rams with semen contaminated with ureaplasmas.

Ureaplasma species were isolated from semen samples collected sequentially from one Awassi and three Assaf breeding rams. Each ram was injected subcutaneously with an aqueous solution of lincomycin and spectinomycin for five consecutive days at a dose equivalent to 4.5 mg kg-1 lincomycin and 9.0 mg kg-1 spectinomycin daily. Serum and semen samples were collected at intervals during the treatment and assayed for lincomycin. No Ureaplasma species were isolated from semen samples collected during the course of the treatment and at intervals for 17 days after the last treatment. The concentration of lincomycin in semen ranged from 0.51 microgram ml-1 four hours after treatment to 0.08 microgram ml-1 24 hours after treatment, and these levels were three to nine times higher than the corresponding serum concentrations.

Absorption of lincomycin through the respiratory pathways and its influence on alveolar macrophages after aerosol administration to chickens.

A concentration of 250 mg m-3 lincomycin was administered by aerosol to 40 chickens, weighing between 1900 and 2200 g. The birds were killed in groups of five at different intervals after dosing, and the trachea, lungs and blood serum were examined for antibiotic content by bioassay. The antibiotic was present at high levels in the trachea for one to 24 hours, and significant levels were present in the lungs and serum. Respiratory macrophages were obtained from the lungs and air sacs of the chickens by lavaging through the surgically prepared trachea with a paediatric urinary catheter. The macrophages were identified by morphology as round or slightly amorphous, refractile, frequently grannular cells; they phagocytosed Staphylococcus aureus 6538.

Tetracyclines, macrolides, lincosamides & chloramphenicol.

Macrolides, lincosamides, tetracyclines and chloramphenicol are structurally unrelated antibiotics which share protein synthesis inhibition as their common mechanism of action. Despite their individual differences, they can all be considered broad spectrum antibiotics with practical use for a wide variety of infections. Due to their similarities in function, however, concurrent or sequential administration of these agents must be undertaken with caution in order to prevent antagonism and induction of bacterial resistance. Full understanding of their function and potential interactions are, therefore, important. Indications, interactions, mechanisms of function, side effects and contraindications are fully discussed.

[Immobilization of antibiotics on a titanium surface]. / Immobilizatsiia antibiotikov na poverkhnosti titana.

Immobilization of antibiotics on the surface of electrolytically oxidated titanium was tried. Transfer of the immobilized ampicillin into hardly soluble calcium ampicillate resulted in providing the coating with antimicrobial activity for 5 days. The quantity of the immobilized antibiotic determined polarographically amounted to 6.4.10(-3) mol per 1 m2 of the surface.

[Experimental therapy of a local infectious-inflammatory process in rats using a lincomycin film]. / Eksperimental'naia terapiia lokal'nogo infektsionno-vospalitel'nogo protsessa u krys s pomoshch'iu linkomitsinovoi plenki.

Implantation of a lincomycin film in granulomotomy resulted in an intensified therapeutical process of a pyo-inflammatory proliferative focus caused by subcutaneous administration of pathogenic Staphylococci, Streptococci, and Pneumococci to albino rats. As compared to the routine surgical tools, this technique provided a two-fold reduction in the periods of healing of wounds and their dissemination. At the same time there was a decrease in the manifestation rate of the pyo-necrotic component of inflammation and an improvement of the general status of the experimental animals.

[Excretion of erythromycin, clindamycin and lincomycin into the saliva]. / Erythromycin, clindamycin és lincomycin nyálba történö kiválasztódásának vizsgálata.

In rabbit experiments (n = 10) the salivary and serum levels of several antibiotics were studied after per os (clindamycin, erythromycin and lincomycin) and iv. (erythromycin) administration. Erythromycin was excreted into the saliva in a considerable degree (in 60-75% of the serum level) and displayed therapeutical levels for 5-6 hrs, whereas clindamycin and lincomycin reached in the saliva only 25-30% of the serum level and therapeutic levels were maintained only for 3 hours.

[The pharmacokinetics of lincomycin when used as a component of a drug combination with ultrahighly dispersed hydroxyapatite]. / Farmakokinetika linkomitsina pri ispol'zovanii v kachestve komponenta lekarstvennoi kompozitsii s gidroksiapatitom ul'travysokoi dispersnosti.

A drug composition LINCOGAP is assessed, consisting of lincomycin hydrochloride (33%), ultrahighly dispersed hydroxyapatite (HA) (33%), gelatin (7%), and water (27%). Distribution of tritium-labeled lincomycin in organs and tissues of experimental animals was studied by the radiometric method after implantation of the composition into a standard rat mandibular defect. Lincomycin concentration surpassing by orders of magnitude the minimal inhibitory concentration for the main lincomycin-sensitive microorganisms persisted at the site of implantation of the composition for at least 7 days, while the concentration in internal organs and tissues was the minimum. Microbiological findings indicate active diffusion of lincomycin from the site of injection into the adjacent bone. Thus, LINCOGAP exerts an antibacterial effect in the pathological focus while its general toxic effect is low and, therefore, side effects are minimized. Combination of the antibiotic with ultrahighly dispersed HA helps regulate the process of bone repair, stimulating the proliferative and functional activity of osteoblasts. Hence, combined drug LINCOGAP is a promising agent for the treatment of inflammatory destructive diseases of osseous tissue.

[Pharmacokinetic research on Pharmachem's lincomycin hydrochloride in pigs]. / Farmakokinetichni prouchvaniia na linkomitsinov khidrokhlorid "Farmakhim" pri praseta.

In the experiments lincomycin hydrochloride LMC "F" with activity 820 UI/mg was used. It was established that in pigs, 5% water solution of LMC "F", applied intramuscularly in doses of 5 and 10 mg/kg m. and internally in doses 50 and 100 mg/kg m., penetrates comparatively quickly in the blood serum, and yet in the first hour established maximal concentrations. Intramuscular injection of LMC "F" of pigs, in doses of 5 and 10 mg/kg m., creates bacteriostatic concentrations in the blood serum for 12 hours, regardless of the quantity of the dose, and applied internally has a longer duration of the retention. The biological half-life of LMC "F" after muscular application in pigs is accordingly 1.7 and 3.5 hours, and after internal application 2.3 and 2.8 hours. Applied a single time intramuscularly in pigs in doses of 5 and 10 mg/kg m., LMC "F" is resorbed from the place of application and after 3 hours is established in most high quantities in the kidney in the lungs, the liver, the bile and in the urine. Mainly it is extracted with the urine in high concentrations--about 190 mg/cm3 (on the 3-rd hour), after intramuscular injection in dose of 10 mg/kg m. The longest time the antibiotic remains in the lungs, the urine and in the bile (up to 96 hours).

[Toxicological and pharmacokinetic research on lincomycin hydrochloride in broiler chickens and layer hens]. / Toksikologichni i farmakokinetichni prouchvaniia na linkomitsinov khidrokhlorid pri pileta broileri i kokoshki.

Tested was the activity of linkomycin hydrochloride at the rate of 820 IU/mg. The LD50 of the preparation was found to exceed 12.0 g/kg body mass at intracrop application to broiler birds. When offered with the drinking water or the feed in amounts that were 3 to 5 times higher than the therapeutic ones for broilers in the course of 45 days it did not cause mortality nor induced changes in the white and red blood cell counts, in the total protein, and in the levels of urea, blood sugar, AlT, and AcT. Neither were there any structural changes in the internal organs. Upon the single intracrop treatment of broilers with linkomycin at 50 and 100 mg/kg most of the amount introduced was established in the blood serum at the second hour and up to the 6th and 8th hour, respectively. Studies on the effect of age on the serum concentrations at this route of introduction revealed that the preparation was absorbed at higher rates in the broilers than in the layers, while with the persistence of the levels there were no essential differences. At the single oral administration with broilers in amounts of 100 mg/kg linkomycin was chiefly retained in the kidneys, liver, and lungs as well in the content of the small and large intestines. At intracrop application to layers in doses of 100 mg/kg in the course of 7 days the antibiotic was excreted with the eggs at the time of treatment and in the course of 4 days later in bacteriostatic concentrations of 0.6-5.9 micrograms/cm3.

Bioavailability of spiramycin and lincomycin after oral administration to fed and fasted pigs.

The disposition of spiramycin and lincomycin was measured after intravenous (i.v.) and oral (p.o.) administration to pigs. Twelve healthy pigs (six for each compound) weighing 16-43 kg received a dose of 10 mg/kg intravenously, and 55 mg/kg (spiramycin) or 33 mg/kg (lincomycin) orally in both a fasted and a fed condition in a three-way cross-over design. Spiramycin was detectable in plasma up to 30 h after intravenous and oral administration to both fasted and fed pigs, whereas lincomycin was detected for only 12 h after intravenous administration and up to 15 h after oral administration. The volume of distribution was 5.6 +/- 1.5 and 1.1 +/- 0.2 L/kg body weight for spiramycin and lincomycin, respectively. For both compounds the bioavailability was strongly dependent on the presence of food in the gastrointestinal tract. For spiramycin the bioavailability was determined to be 60% and 24% in fasted and fed pigs, respectively, whereas the corresponding figures for lincomycin were 73% and 41%. The maximum plasma concentration of spiramycin (Cmax) was estimated to be 5 microg/mL in fasted pigs and 1 microg/mL only in fed pigs. It is concluded that an oral dose of 55 mg/kg body weight is not enough to give a therapeutically effective plasma concentration of spiramycin against species of Mycoplasma, Streptococcus, Staphylococcus and Pasteurella multocida. The maximum plasma concentration of lincomycin was estimated to be 8 microg/mL in fasted pigs and 5 microg/mL in fed pigs, but as the minimum inhibitory concentration for lincomycin against Actinobacillus pleuropneumoniae and P. multocida is higher than 32 microg/mL a therapeutically effective plasma concentration could not be obtained following oral administration of the drug. For Mycoplasma the MIC90 is below 1 microg/mL and a therapeutically effective plasma concentration of lincomycin was thus obtained after oral administration to both fed and fasted pigs.

Contribution of alpha 1-acid glycoprotein to species difference in lincosamides-plasma protein binding kinetics.

Protein binding kinetics of lincomycin (LM) and clindamycin (CM) were studied using plasma, albumin and alpha 1-acid glycoprotein (AGP) derived from humans, dogs, cattle and sheep. Based on Rosenthal plots of LM and CM, drug-binding property in plasma presented specific and non-specific binding, except for LM in cattle and sheep and for CM in sheep, where only non-specific binding was demonstrated. Dissociation constant (Kd) and binding capacity (Bmax) for specific binding and proportionality constant (PC) for non-specific binding were as follows: Kd = 3.14 mumol/L, Bmax = 15.28 mumol/L, PC = 0.19 for humans; Kd = 3.84 mumol/L, Bmax = 6.55 mumol/L, PC = 0.14 for dogs; PC = 0.12 for cattle; PC = 0.16 for sheep in LM and Kd = 0.94 mumol/L, Bmax = 12.24 mumol/L, PC = 4.98 for humans; Kd = 1.48 mumol/L, Bmax = 9.52 mumol/L, PC = 2.91 for dogs; Kd = 1.22 mumol/L, Bmax = 4.45 mumol/L, PC = 2.40 for cattle; PC = 1.48 for sheep in CM. The specific binding for each species was different, showing more difference in Bmax compared with Kd. The non-specific binding of LM was similar among species whereas that of CM was different, implying species difference. The drug-binding property of AGP for each species was all specific binding and the Kd was comparable to that obtained from plasma, indicating that AGP is a major specific binder in plasma. The lack of detection of specific binding for LM in cattle and sheep and for CM in sheep plasma could be attributable to a higher Kd and lower plasma AGP concentration compared with other species. The drug-binding property of albumin was characterized as all non-specific, without a great difference among species. Except for CM in sheep, the lower PC in albumin solution compared with that in plasma suggested the presence of another non-specific binder in plasma, i.e. lipoprotein. From the simulation of drug-binding percentage to AGP concentrations, AGP could be a major contributor to drug-plasma protein binding in pathological states. The degree of AGP-drug binding for each species could vary according to the degree of increase of AGP concentrations from a healthy to a pathological state, inducing a decrease in the unbound fraction (fp): 6.1 fold for dogs, 4.6 fold for humans, 1.8 fold for sheep and 1.4 fold for cattle in LM; 5.8 fold for dogs, 5.7 fold for cattle, 4.0 fold for humans and 1.5 fold for sheep in CM. Therefore, the disposition and efficacy of lincosamides affected by fp can be modified differently by the change of fp attributable to the alteration of plasma AGP concentration in each species.

Effects of altered plasma alpha-1-acid glycoprotein levels on pharmacokinetics of some basic antibiotics in pigs: simulation analysis.

Effects of altered plasma alpha-1-acid glycoprotein (AGP) levels on pharmacokinetic parameters of basic antimicrobials, erythromycin (EM), lincomycin (LM) and clindamycin (CM) were evaluated in pigs by simulation analysis. Intravenous (i.v.) injections of EM, LM and CM were performed to obtain pharmacokinetic parameters in healthy conditions. Binding parameters were obtained from an in vitro study using ultrafiltration. Simulation studies indicated that an increase of plasma AGP levels resulted in a decrease of both volume of distribution at steady state (Vdss) and total body clearance (Cltot) for all the drugs. Elimination rate constant for LM was almost unchanged by an increase of plasma AGP levels, whereas those for EM and CM were increased. Plasma concentration-time profiles at a high AGP level (often observed in pathophysiological conditions) were also simulated. All of the total plasma concentration-time profiles were different from those at normal AGP level. The differences were characterized by a higher initial concentration with faster or similar elimination. Unbound plasma concentration-time profile of LM was unaffected by AGP levels, whereas EM and CM were eliminated from plasma more rapidly at high AGP level. These results suggested that adjustment of dosage regimen of EM and CM is required in pathophysiological conditions, but that of LM is not required.