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At least 19 recordsLinked to original sources
PubMed1975

Simultaneous high-speed liquid chromatographic determination of tetracycline and rolitetracycline in rolitetracycline formulations.

A rapid, precise high-speed liquid chromatographic procedure for the simultaneous determination of tetracycline and rolitetracycline in rolitetracycline formulations is described. Samples are dissolved in water, chilled to 0 degrees, and chromatographed on a pellicular cation-exchange resin, The specificity of this method represents a significant improvement over present analytical procedures, which fail to differentiate between rolitetracycline and its hydrolysis product, tetracycline, in these formulations.

Biological Assay↗
PubMed1976

[Combination of bacteriostatic and bactericidal drugs: lack of significant in vitro antagonism between penicillin, cephalothin, and rolitetracycline].

Although it is generally believed that bactericidal and bacteriostatic drugs should not be combined in vivo, in vitro experiments using the checkerboard dilution technique revealed no antagonism between penicillin/cephalothin and rolitetracycline but rather additive or synergistic activity of either drug combination in 40 to 50% of 20 Escherichia coli, and 14 Staphylococcus aureus strains. Slight antagonism occurred only between 3 and 8 h after combining penicillin/cephalothin and rolitetracycline in either bacteriostatic or bactericidal concentrations, but not after 24 h of incubation, nor was antagonism found with combinations of these drugs in bacteriostatic concentrations. Neither bacteriostatic nor bactericidal activity of penicillin/cephalothin and rolitetracycline was inhibited by pretreatment of one E. coli strain with bacteriostatic rolitetracycline or bacteriostatic penicillin/cephalothin concentrations. Penicillin and cephalothin could exert a bactericidal effect after 2-h exposure of the E. coli strain to bacteriostatic rolitetracycline concentrations. Combined action of subinhibitory penicillin and rolitetracycline concentrations resulted in more pronounced inhibition of growth than either drug alone. The higher activity of penicillin/cephalothin in combination with rolitetracycline on some E. coli and S. aureus strains might be due to a better access of rolitetracycline into bacterial cells whose cell walls have been weakened by cell wall-active, bactericidal drugs. Thus, growth of penicillin-induced spheroplasts of E. coli and stable staphylococcal L-forms was inhibited by much lower concentrations of rolitetracycline than were the corresponding parent cells with intact cell walls.

Cephalothin↗
PubMed1976

The site of the neuromuscular block produced by polymyxin B and rolitetracycline.

The site of neuromuscular blockade induced by polymyxin B and rolitetracycline was studied on isolated nerve and nerve-muscle preparations. Polymyxin B (1.8 X 10(-4) M) was equipotent to lidocaine as a local anaesthetic on a frog desheathed nerve preparation, while rolitetracycline (up to 3.6 X 10(-3)M) had no local anaesthetic effect. Polymyxin B (6 X 10(-5) M) and rolitetracycline (7 X 10(-4) M) blocked by 50% the response of rat diaphragm induced by phrenic nerve stimulation, but did not decrease the amount of acetylcholine (ACh) released from this preparation during nerve stimulation. Both antibiotics depressed the response of the rat diaphragm to inject ACh, and this response was more sensitive to inhibition by the drugs than was the response to nerve stimulation. With rolitetracycline, a concentration that blocked the response to nerve stimulation by 50% inhibited the response to injected ACh by 85%, and this relationship was similar to that with d-tubocurarine; however, polymyxin B was relatively more effective than d-tubocurarine in inhibiting the effect of ACh. Polymyxin B (1-1.5 X 10(-4) M) but not rolitetracycline (1 X 10(-3) M) depressed the response of the diaphragm to direct muscle stimulation. It is concluded that polymyxin B and rolitetracycline block neuromuscular transmission predominatly by an effect to depress the muscle's sensitivity to ACh; polymyxin B probably acts by an effect similar to that of local anaesthetics, while rolitetracycline probably acts by an effect similar to that of d-tubocurarine.

Acetylcholine↗
PubMed1990

[The of effect of rolitetracycline on oxygen consumption in a suspension of E. coli].

Authors studied the oxygen demand by E. coli suspensions (serotypes 023 and 026) modifying it with various concentration of Rolitetracyclin, and proceeded by comparison of both serotypes. Time dependence of oxygen demand has been determined using the direct Warburg's manometric method. The obtained results are summerized as following four points: 1. Tested Rolitetracyclin doses caused the decrease in oxygen demand of E. coli suspensions significantly for the majority of time intervals. Rolitetracyclin actioned similarly in both serotypes. 2. Rolitetracyclin 0.5 microgram concentration actioned bacteriostatically on both serotypes, and showed more pronounced action on E. coli 026 serotypes with higher metabolic activity. 3. Rolitetracyclin 5 and 50 micrograms bactericidal concentrations inhibited markedly the oxygen demand in both serotypes. 4. Using this method allowed to determine the difference in metabolic activity of both E. coli serotypes tested.

Escherichia coli↗
PubMed1981

Effect of unilateral nephrectomy on the pharmacokinetics of rolitetracycline in rabbits.

An analysis of the single-dose pharmacokinetics of rolitetracycline in rabbits after unilateral nephrectomy is presented. Rolitetracycline was injected i.v. 3.5 mg/kg before operation and after 2 weeks, 3 months and 6 months from unilateral nephroctomy. The concentration of the antibiotic in plasma was estimated by the fluorimetric method of Kohn. The two-compartment open model was applied to calculate rolitetracycline concentration changes. The calculations of pharmacokinetic parameters were performed using the Hewlett-Packard 9830B computer and fitting the concentrations of the antibiotic in blood to the general biexponential equation. AUC of rolitetracycline was increased in operated animals by 130% after 6 months. The mean kel at this time decreased, while t0.5 beta was prolonged from 1.0 h to 3.0 h. It is assumed that the dosage regimen of rolitetracycline should be changed in subjects possessing one kidney.

Animals↗
PubMed1983

Investigation into the combined hepatotoxicity of rolitetracycline and ethinyloestradiol.

The effect of rolitetracycline (50 micrograms/g i.v.) alone or in combination with ethinylestradiol (0.1 and 1.0 micrograms/g s.c. once daily for 4 days) on liver function (BSP retention, serum GPT and SDH) and histomorphology was investigated in mice. Rolitetracycline alone increased liver weight, BSP-retention and serum GPT levels. Ethinylestradiol at the lower dose tended to enhance the BSP retention and the morphological changes of the liver produced by rolitetracycline but had no additional effect on the serum GPT and on liver weight. In contrast, hepatotoxic effects of the higher dose of ethinylestradiol were not further enhanced by rolitetracycline.

Animals↗
PubMed1981

Age dependency of rolitetracycline-induced hepatic steatosis.

A comparative study on the effect of rolitetracycline (50 micrograms/g i.v.) on the hepatic content of triglycerides and the release of esterified fatty acids from the liver into the blood was performed in young and adult NMRI mice of both sexes. Rolitetracycline caused an accumulation of triglycerides only in the livers of adult animals, the effect being much more pronounced in females than in males. In agreement with this a very strong inhibition of lipid release from the liver and a significant decrease of the esterified fatty acids of the serum was produced only in adult females. The results suggest that the livers of young animals of both sexes are relatively resistant to the steatotic effect of rolitetracycline.

Age Factors↗
PubMed1991

[The effect of age on pharmacokinetic parameters of oxytetracycline and rolitetracycline in rabbits].

The effect of rabbit age in the Californian White breed was investigated on oxytetracycline and rolitetracycline concentrations in the blood serum and soft tissues, and on the biological half-life of the given antibiotics. The animals were at the age shortly before sexual maturity or they had reached sexual maturity. Oxytetracycline was administered in form of the preparation Oxymykoin inj. a. u. v. Spofa and roliteracycline nitrate in form of the preparation Rolitetracycline inj. Spofa. These tetracyclines were administered intramuscularly at a single dose of 20 mg per kg liveweight. In comparison with adult animals, in young rabbits the starting concentrations of the two tetracyclines in the blood (first hour) were statistically insignificantly higher; they were resorbed in the systemic circulation in a shorter time and were excreted faster from the blood (mainly oxytetracycline). The significantly lower serum concentrations were recorded in the 6th, 12th and 24th hour after oxytetracycline administration, and in the 12th and 24th hour after rolitetracycline administration. At the same time a decrease was observed in the concentrations of the two oxytetracyclines in the organs and muscles of young animals.

Aging↗
PubMed1978

[On the circulation compatibility of doxycycline and rolitetracycline in conscious minipigs (author's transl)].

The effect of large doses of doxycycline (Vibravenös) and rolitetracycline on blood pressure, heart rate and ECG was investigated in 36 conscious minipigs. The antibiotics were infused into the v. tibialis at doses of 16, 24 and 32 mg/kg at injection periods of 4, 6 and 8 min. The dosage applied was about 10-20 times higher than the therapeutical single dose of doxycycline and about 4-8 times higher than the single dose of rolitetracycline. 16 mg doxycycline or rolitetracycline/kg resulted in a minor short-lasting increase of blood pressure and extension of the P-Q interval in the ECG. The definitely pathological P-Q value of 160 ms was not observed in any of the cases treated with doxycycline, whereas rotitetracycline led to clearly pathological P-Q values in 2/6 of the cases, and to AV block in 4/6 of the cases. Neither after doxycycline nor after rolitetracycline did the increased dose of 24 and 32 mg/kg result in an enhanced effect on circulation. However, both the blood pressure and the P-Q values following 32 mg rolitetracycline/kg significantly exceeded those following 32 mg doxycycline/kg. These trials suggest that with regard to circulatory tolerance there are no objections to increasing the usual therapeutical dose of intravenous doxycycline if the injection time is adequately extended.

Animals↗
PubMed1987

[Antimicrobial action of rolitetracycline in gelatin sponge packs (Marbagelan) in tympanoplasty].

Gelatine sponge packs (Marbagelan) saturated in rolitetracycline (Reverin) were evaluated. The antimicrobiotic efficacy of the substance was determined in 26 packs before insertion and in 20 packs removed from the external ear meatus after varying periods. High concentrations of rolitetracycline were found independent of saturation grade in the packs before insertion. In the packs removed from the external meatus acceptable antimicrobial activity was found independent of the time the packs remained in the ear. An efficient prophylaxis against infection in ear surgery is guaranteed.

Ear, Middle↗
PubMed1986

Combined effects of high doses of rolitetracycline and testosterone on the liver of mice.

The effects of rolitetracycline (50 micrograms/g i.v.) and testosterone proprionate (4 X 1 micrograms/g s.c.) singly and combined on liver weight, serum GPT, SDH and bromsulfophthalein clearance have been measured in young mice. Pretreatment with testosterone tended to enhance the effects of rolitetracycline on the serum enzymes but was otherwise not effective.

Alanine Transaminase↗
PubMed1995

Species specific pharmacokinetics of rolitetracycline.

Comparative studies on some selected pharmacokinetic parameters of rolitetracycline (effective antimicrobial activity levels) in sheep, pigs, rabbits, chickens and pigeons were carried out after intravenous administration of the drug at a dose of 5 mg/kg. The results revealed that a two-compartment open model was usually optimal. Interspecies differences in the rate (alpha) and the volume of distribution (Vda), the area under the serum concentration time curve (AUC) and the total body clearance (ClB) were small. The values of the elimination half-life (t1/2 beta) found in sheep, pigs, rabbits, chickens and pigeons were 1.51, 3.06, 2.18, 4.33 and 2.51 h respectively. These results and data in mice, rabbits and man taken from literature were analysed to determine any correlation to body mass (W). The log of the elimination half-life values (log t1/2 beta) of rolitetetracycline revealed a significant correlation with log values of (W) between animal species. This relationship was described by the equation t1/2 beta = 1.27.W0.29 (r = 0.93, P < 0.01, n = 5) for mammal species and t1/2 beta = 1.81.W0.24 (r = 0.78, P < 0.05, n = 7) for mammal and bird species.

Animals↗
PubMed1976

Pharmacokinetic investigations on diminazene and rolitetracycline in comparison to a combination of both.

Serum level tests were carried out on healthy cows with a combination drug of one part Berenil and two parts Reverin. When compared with the commercial preparations Berenil (Diminazene) and Reverin (Rolitetracycline), the kinetic behaviour of Reverin in the combination preparation was identical. In the case of Berenil, administered in the form of the combination drug, the second slow elimination phase with a 63 hour half-life, as found after the administration of Berenil only, could not be observed. Eight hours after administration of the combination only minimal Berenil serum levels were detectable, after 24 hours the levels were lower than the limit of detection. This has a practical bearing on the question of residues.

Amidines↗
PubMed1999

Common structural features determine the effectiveness of carvedilol, daunomycin and rolitetracycline as inhibitors of Alzheimer beta-amyloid fibril formation.

One of the major pathological features of Alzheimer's disease is the deposition of beta-amyloid peptide (Abeta). Cellular toxicity has been shown to be associated with fibrillar forms of Abeta; preventing this fibril formation is therefore viewed as a possible method of slowing disease progression in Alzheimer's disease. With the use of a series of tetracyclic and carbazole-type compounds as inhibitors of Abeta fibril formation, we here describe a number of common structural features that seem to be associated with the inhibitory properties of these agents. Compounds such as carvedilol, rolitetracycline and daunomycin, which are shown to inhibit Abeta fibril formation, also prevent the formation of species of peptide that demonstrate biological activity in a human neuroblastoma cell line. Molecular modelling data suggest that these compounds have in common the ability to adopt a specific three-dimensional pharmacophore conformation that might be essential for binding to Abeta and preventing it from forming fibrils. Understanding such drug-peptide interactions might aid the development of disease-modifying agents.

Alzheimer Disease↗
PubMedDate not supplied

Kinetics of drug decomposition. Part 45. Logk--pH profile for rolitetracycline degradation.

UV spectrophotometry and fluorometry were applied for an examination of rolitetracycline (RT) degradation at pH's ranged from ca 0-8 to 13-0. It was demonstrated that these methods enable to follow the rate of degradation of tetracycline formed in the course of RT hydrolysis. However, they do not allow to monitor the hydrolysis of RT to tetracycline. Application of the so-called "subtraction technique" permits to calculate the rate constants for the total, reversible epimerization reaction and for the subsequent degradation of the resultant products. A rate equation derived for RT degradation in an alkaline medium beginning at pH 10-5 contains a term second-order in the hydroxide ion. Such a relationship was not yet observed in the course of an antibiotic degradation.

Catalysis↗
PubMedDate not supplied

Kinetics of drug decomposition. Part 48. Specific acid-base hydrolysis of rolitetracycline.

Using chromatographic-spectrophotometric method, the effect of H+ and OH- ions on the rate of hydrolysis of rolitetracycline (RT) to tetracycline (T) at 20degreeC was investigated. The advantage of this analytical procedure over the direct fluorescence or UV absorption measurements of RT solutions during the kinetic investigations in HCl medium was demonstrated. The catalytic rate constants (kH+ and kOH-) for the hydrolytic degradation of RT under oxygen-free conditions are given.

Catalysis↗