Macrolide

Cell extracts of Streptomyces antibioticus, an oleandomycin producer, can inactivate oleandomycin in the presence of UDP-glucose. The inactivation can be detected through the loss of biological activity or by alteration in the chromatographic mobility of the antibiotic. This enzyme activity also inactivates other macrolides (rosaramicin, methymycin, and lankamycin) which contain a free 2'-OH group in a monosaccharide linked to the lactone ring (with the exception of erythromycin), but not those which contain a disaccharide (tylosin, spiramycin, carbomycin, josamycin, niddamycin, and relomycin). The culture supernatant contains another enzyme activity capable of reactivating the glycosylated oleandomycin and regenerating the biological activity through the release of a glucose molecule. It is proposed that these two enzyme activities could be an integral part of the oleandomycin biosynthetic pathway.[1]

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Cell extracts of Streptomyces antibioticus (the producer organism of Oleandomycin) can inactivate Oleandomycin in the presence of UDP-glucose. This inactivation is characterized by the loss of the antibiotic's biological activity and changes in its chromatographic mobility [1]
- The enzyme activity in the cell extracts also inactivates other macrolide antibiotics that contain a free 2'-OH group in a monosaccharide linked to the lactone ring, including rosaramicin, methymycin, and lankamycin (erythromycin is an exception). However, it fails to inactivate macrolides with a disaccharide moiety, such as tylosin, spiramycin, carbomycin, josamycin, niddamycin, and relomycin [1]
- The culture supernatant of Streptomyces antibioticus contains another enzyme activity that can reactivate glycosylated Oleandomycin and restore its biological activity by releasing a glucose molecule [1]

Assay for Oleandomycin inactivation by cell extracts: Prepare cell extracts from Streptomyces antibioticus. Mix the cell extracts with Oleandomycin and UDP-glucose in an appropriate reaction buffer. Incubate the reaction mixture under suitable conditions (e.g., optimal temperature and pH for enzyme activity). After incubation, detect the inactivation of Oleandomycin by measuring the loss of its biological activity (using relevant microbial inhibition assays) or changes in its chromatographic mobility [1]
- Assay for reactivation of glycosylated Oleandomycin by culture supernatant: Collect the culture supernatant of Streptomyces antibioticus. Mix the supernatant with glycosylated Oleandomycin (obtained from the previous inactivation reaction) in a suitable buffer. Incubate the mixture under appropriate conditions. After incubation, assess the reactivation of Oleandomycin by detecting the recovery of its biological activity or the release of glucose [1]

In vitro inactivation of oleandomycin.
Oleandomycin (6.6 ,ug/ml; 8.3 ,M) was incubated with 50 1.l of dialyzed cell extract in the presence of 1 mM UDP-glucose at 30°C in a final volume of 150 [lI. Both at zero time and after 6 h of incubation, samples were removed and boiled for 2 min. After cooling, the residual antibiotic activity was determined by bioassay against M. luteus .
In some experiments, UDP-D-[6-3H]glucose (20 ,uCi/ml; 2 mM) was used instead ofthe nonlabelled compound, and the products of the reaction mixture were analyzed by paper chromatography .[1]

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In vitro reactivation of oleandomycin.
For assays of reactivation of oleandomycin, tritiated inactive oleandomycin was used'as a substrate after preparation as follows. An inactivation assay was carried out using UDP-[3H]glucose as a cofactor and the labelled inactive and modified oleandomycin was eluted from the paper strips after paper chromatography by immersion in absolute methanol and incubation at room temperature overnight with gentle shaking. The eluate was lyophilized and dissolved in a small volume of methanol; then aliquots (approximately 8,000 cpm) were incubated with 40 to 50 pI of the ammonium sulfate precipitates from the culture supernatant (without addition of any cofactor) in a final volume of 100 ,u at 30°C for 2 h. The reaction products were analyzed by counting the radioactivity in 1-cm strips after paper chromatography.[1]

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Thin-layer chromatography. Samples of the inactivation assays (50 pul; 15 pug of oleandomycin) were applied to silica gel F254 plates (Merck) and subjected to ascending chromatography with methanol as the solvent. The plates were developed and then stained with a mixture of anisaldehyde concentrated sulfuric acid-ethanol (1:1:9) and heating at 100°C for 2 min (16). Parallel samples (without staining) were assayed by bioautography against M. luteus.[1]

Absorption, Distribution and Excretion
Macrolides are widely distributed in tissues, reaching concentrations roughly the same as, or even higher than, plasma concentrations in some cases. They actually accumulate in many cells, including macrophages, at concentrations up to 20 times or more of plasma concentrations. This accumulation is partly why some macrolides (e.g., tilmicosin) require longer dosing intervals. … Macrolides tend to accumulate in the spleen, liver, kidneys, and especially the lungs. They enter pleural fluid and ascites, but not cerebrospinal fluid (unless the meninges are inflamed, in which case the drug concentration is only 2-13% of the plasma concentration). They accumulate in bile and breast milk. Up to 75% of the dose is bound to plasma proteins, and they bind to α1-acid glycoproteins rather than albumin. /Macrolides/
Macrolides are readily absorbed from the gastrointestinal tract if not inactivated by gastric acid. In most cases, plasma concentrations peak within 1–2 hours, but the absorption pattern can be unstable due to the presence of food and may depend on the salt or ester used. Absorption by rumen reticulocytes is typically delayed and unstable. /Macrolides/
Macrolide antibiotics and their metabolites are primarily excreted via bile (>60%) and frequently undergo enterohepatic circulation. Urinary clearance can be slow and variable (typically <10%), but may be the more important clearance route after parenteral administration. Macrolide concentrations in milk are typically several times higher than plasma concentrations, especially in mastitis. /Macrolides/
This study investigated the pharmacokinetics of orlistat (OLD) after intravenous and oral administration alone in healthy dogs, as well as the pharmacokinetics following pretreatment with intramuscular methylaminopyrine or dexamethasone. Following intravenous administration of oliquiromycin (10 mg/kg, bolus), its elimination half-life (t_1/2β), volume of distribution (V_d, area), systemic clearance (Cl_B), and area under the concentration-time curve (AUC) were 1.60 h, 1.11 L/kg, 7.36 (ml/kg)/min, and 21.66 μg·h/ml, respectively. No statistically significant differences were observed after prior administration of methylaminopyrine or dexamethasone. Following oral administration of oliquiromycin, its t_1/2β, peak plasma concentration (C_max), time to peak concentration (t_max), mean absorption time, and absolute bioavailability (Fabs) were 1.6 h, 5.34 μg/ml, 1.5 h, 1.34 h, and 84.29%, respectively. Pretreatment with methylaminopyrine resulted in a significant decrease in C_max (2.93 μg/ml), but a significant prolongation of the mean absorption time (2.23 h). Pretreatment with dexamethasone following oral orthomycin also showed statistically significant changes in pharmacokinetic parameters. C_max increased (8.24 μg/ml), while t_max (0.5 h) and mean absorption time (0.45 h) decreased. Understanding the distribution of macrolides in a single animal species is insufficient to predict their pharmacokinetics in humans. To better understand species-specific differences in the pharmacokinetics of macrolide antibiotics, we investigated the distribution of erythromycin, orthomycin, and tylosin in several mammals. Typically, the serum concentration-time curves following intravenous administration of these drugs can be described by a two-compartment kinetic model and are similar across species. These drugs are rapidly cleared, resulting in a terminal half-life of less than 2 h. Pharmacokinetic comparisons showed that the differences in antibiotic distribution between animal species were greater than those within the same species. When pharmacokinetic data were fitted to an allometric growth model, the logarithms of distribution volume, clearance, and half-life showed a linear relationship with the logarithm of body weight. Based on these relationships, the human pharmacokinetics of erythromycin and orlistatine were inferred, and found to be approximately similar to observed human pharmacokinetics.

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Metabolism/Metabolites
The metabolic inactivation of macrolide drugs is generally extensive, but the relative proportions depend on the route of administration and the specific antibiotic. ……/Macrolides/

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Biological Half-Life
The plasma half-life of macrolide drugs is typically 1–3 hours, ……/Macrolides/

Interactions
Macrolide antibiotics should probably not be used in combination with chloramphenicol or lincosamide antibiotics, as they may compete for the same 50S ribosome binding site, although the in vivo significance of this potential interaction is unclear. Macrolide antibiotics exhibit reduced activity in acidic environments. Parenteral macrolide formulations are incompatible with many other drug formulations. .../Macrolides/
.../Ability to induce phase III migratory electromyography complex (MMC) activity and enhance smooth muscle contractility in dogs... Some macrolide antibiotics, including orlistatine, also possess this ability to varying degrees.../Motilin: Macrolides and Erythromycin/
The effects of tetracycline (TC) and orlistatine (OM) combination therapy on acute infection with four Staphylococcus aureus strains (including TC- or OM-resistant strains) in mice were investigated by quantitative determination of the protective efficacy of single and combination therapy. The degree of synergy is expressed as the synergy ratio (SR), which is the ratio of the experimentally determined efficacy of the combined drug to the theoretical efficacy hypothesized to have an additive effect between the two drugs. In three out of four Staphylococcus aureus strains, synergy between TC and OM or triacetyl-Olimycin (TAO) was confirmed by determining the 50% effective dose and statistically analyzing SR. The degree of synergistic protection varied with the infecting strain and was independent of antibiotic sensitivity or the degree of in vitro synergy. In mice, no synergistic enhancement of acute toxicity was observed with co-administration of TC and OM.

[1]. Role of glycosylation and deglycosylation in biosynthesis of and resistance to oleandomycin in the producer organism, Streptomyces antibioticus. J Bacteriol. 1992 Jan;174(1):161-5.

Orionamycin is a macrolide antibiotic, but its antibacterial activity is less than that of erythromycin. It is synthesized by antibiotic strains of the genus Streptomyces. Orionamycin is a macrolide antibiotic with antibacterial activity similar to erythromycin. Orionamycin targets and reversibly binds to the 50S subunit of the bacterial ribosome. This prevents the translocation of peptidyl-tRNA, thereby inhibiting protein synthesis. Macrolide antibiotics produced by antibiotic strains of the genus Streptomyces. See also: Orionamycin (note moved to). Mechanism of Action: The antibacterial mechanism of all macrolide antibiotics appears to be the same. They interfere with protein synthesis by reversibly binding to the 50S subunit of the ribosome. They appear to bind to donor sites, thereby preventing the translocation required for peptide chain growth. This action is primarily limited to rapidly dividing bacteria and mycoplasma. Macrolides are considered bacteriostatic agents… Macrolides exhibit significantly enhanced activity in a higher pH range (7.8–8). /Macrolides/

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Therapeutic Use
MeSH Title: Antibacterial Agents

Drugs: ...for oral or intravenous use to treat pyoderma, sepsis, meningitis, surgical and abdominal infections, respiratory and urinary tract infections, and other infections caused by Staphylococcus, Streptococcus, Corynebacterium, Neisseria, and Mycoplasma.
Drugs (Veterinary): Macrolide antibiotics.
Therapeutic Category: Antibacterial Agents
For more complete therapeutic use data on the macrolide antibiotics oriolanomycin (6 in total), please visit the HSDB record page.

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Drug Warnings
Veterinary Use: Toxicity and side effects of most macrolides are uncommon..., but pain and swelling may occur at the injection site. Allergic reactions are rare. Horses are highly susceptible to cytotoxic disorders caused by macrolide antibiotics, which can be severe and even fatal. ...

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Orionamic acid is a macrolide antibiotic produced by Streptomyces antibioticus [1]
- Glycosylation and deglycosylation processes are involved in the biosynthesis of orionamic acid and the resistance mechanism of the producing bacteria. The activities of these two enzymes (inactivation through glycosylation and reactivation through deglycosylation) are considered to be components of the orionamic acid biosynthetic pathway [1]

C35H61NO12.C22H24N2O8.O4P-3

1227.2643

687.419

C, 61.11; H, 8.94; N, 2.04; O, 27.91

3922-90-5

5284598

White, amorphous powder

1.2±0.1 g/cm3

802.6±65.0 °C at 760 mmHg

439.2±34.3 °C

0.0±6.4 mmHg at 25°C

1.533

1.23

3

13

6

48

1090

18

O=C1[C@H](C)[C@@H](O)[C@@H](C)[C@@H](C)OC([C@H](C)[C@@H](O[C@]2([H])O[C@@H](C)[C@H](O)[C@@H](OC)C2)[C@H](C)[C@@H](O[C@@]3([H])[C@H](O)[C@@H](N(C)C)C[C@@H](C)O3)[C@@H](C)C[C@@]14CO4)=O

RZPAKFUAFGMUPI-DDSISPHDSA-N

InChI=1S/C35H61NO12/c1-16-14-35(15-43-35)32(40)19(4)27(37)18(3)22(7)46-33(41)21(6)31(47-26-13-25(42-11)28(38)23(8)45-26)20(5)30(16)48-34-29(39)24(36(9)10)12-17(2)44-34/h16-31,34,37-39H,12-15H2,1-11H3/t16-,17-,18-,19+,20+,21+,22+,23-,24+,25-,26+,27-,28-,29+,30-,31-,34+,35-/m0/s1

Oleandomycin(3S,5R,6S,7R,8R,11R,12S,13R,14S,15S)-14-(((2R,3R,4R,6S)-4-(dimethylamino)-3-hydroxy-6-methyltetrahydro-2H-pyran-2-yl)oxy)-6-hydroxy-12-(((2S,4S,5S,6S)-5-hydroxy-4-methoxy-6-methyltetrahydro-2H-pyran-2-yl)oxy)-5,7,8,11,13,15-hexamethyl-1,9-dioxaspiro[2.13]hexadecane-4,10-dione

PA 775; PA-775; PA775

2934.99.03.00

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~100 mg/mL (~145.38 mM)
H2O : ≥ 12.5 mg/mL (~18.17 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (3.63 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (3.63 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (3.63 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.5 mg/mL (3.63 mM)

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 (Please use freshly prepared in vivo formulations for optimal results.)