Absorption, Distribution and Excretion
(14)C-avilamycin was fed to growing pigs at a level of 60-80 ppm (1.5-2 times the recommended dose), and radioactivity (RA) in tissues was measured. During the actual zero-withdrawal period, pigs fed 60 ppm of uniformly labeled (U-14)C-avilamycin for 14 days had RA residues of 0.14, 0.66, 0.34, and 0.55 ppm in muscle, liver, kidney, and fat, respectively. Pigs fed 80 ppm of dichloroisoviramycin-labeled (14)C-avilamycin showed a 3-5 fold reduction in residues, indicating that most residues originated from the oligosaccharide portion of avilamycin. The main metabolite in liver and feces was fluorocyanate. Most of the RA in the fat of pigs fed (U-14)C-avilamycin was found in fatty acids. (14) C-Avilamycin is rapidly and almost quantitatively excreted in pigs; 5% of the dose is excreted in mice, with the remainder excreted in feces. (14) The excretion pattern and metabolic characteristics of C-Avilamycin in rats are similar to those in pigs. Seven female and four to five male growing pigs (weighing 7-12 kg) were fed a standard diet containing 20 mg/kg avilamycin in three different forms (crystalline, micronized, and non-micronized) for six days. Gas chromatography analysis showed that the microbial active residues in the feces of pigs fed crystalline, micronized, and non-micronized avilamycin accounted for 2.0%, 4.5%, and 15.0% of the total residues of avilamycin and its degradation products, respectively. The average microbial active residues in the feces of pigs fed crystalline, micronized, and non-micronized avilamycin were 0.94, 2.28, and 8.45 μg/g, respectively. Gas chromatography was used to determine the total residues of avilamycin and its hydrolysis products (including DIA). The results showed that the fecal avilamycin content in pigs fed crystalline, micronized, and non-micronized avilamycin was 43.3, 40.1, and 43.4 μg/g, respectively. Two crossbred sows weighing approximately 40 kg were fed 0.9 kg of feed containing unlabeled avilamycin (active concentration of 60 mg/kg) twice daily for 7 days. Each pig was given a single dose of 120 mg (14)C-avilamycin (9.3 kBq/mg) mixed in 450 g of feed after being fed the unlabeled drug. After consuming the feed containing (14)C-avilamycin, each pig was then fed 450 g of feed without the drug. Subsequently, throughout the experiment, the sows were fed 0.9 kg of feed without the drug twice daily. Most of the (14)C residues in the two pigs were excreted within the first 4 days, with over 91% excreted on days 2 and 3. The peak excretion of (14)C residues in urine occurred during the first 24 hours of the collection period, with recovery rates of 2.75% and 3.30% for the two pigs, respectively. During the 9-day collection period, the two pigs excreted 96.9% and 99.0% of the total administered dose, respectively. On average, 93.4% of the excreted dose was found in feces and 4.54% in urine. Six male and six female 7-week-old broiler chickens (Hubbard-White Mountain hybrids) were fed a standard broiler fattening diet supplemented with 14.16 mg (14)C-avilamycin/kg (equivalent to 15 mg/kg avilamycin activity in the diet) for 4, 7, or 10 days, respectively. Throughout the administration period, the experimental chickens had free access to the medicated diet. At the end of each administration period, two male and two female chickens were randomly selected, fasted and deprived of water for 6 hours, and then samples were collected from muscle, liver, abdominal fat, kidney, and subcutaneous fat skin for radiochemical analysis. At all sampling time points, the residual radioactivity levels in muscle and kidney were below the detection limits of 0.008 μg/g and 0.024 μg/g, respectively. Seven days after administration, the mean peak concentration in the liver reached 0.039 μg/g. Ten days after administration, the mean total residual radioactivity (expressed as avilamycin equivalent) in skin, liver, and fat were 0.018, 0.022, and 0.024 μg/g, respectively. Steady-state radioactivity concentrations in all tissues were reached within 4–7 days after administration.
For more complete data on absorption, distribution, and excretion of avilamycin (6 items in total), please visit the HSDB record page.

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Metabolism/Metabolites
Six rats (three males and three females) were fed a diet containing uniformly radiolabeled ¹⁴C-avilamycin at a concentration of 550 mg/kg feed for 4.5 days. Urine and feces were collected during administration, and liver samples were collected upon discontinuation of administration. Avilamycin A accounted for approximately 19% of the fecal radioactivity. Three major metabolites were present in the fecal samples, all derived from the oligosaccharide and eurylic acid fractions of avilamycin. The most abundant metabolite in the feces was flavonoids (metabolite B). Flavonoids are relatively unstable and readily convert to flavonolactones (metabolite A).
Minimum inhibitory concentrations (MICs) of eight antibiotics and two anticoccidial drugs were determined for Clostridium perfringens strains isolated from 26 commercial broiler farms and 22 commercial turkey farms. Isolates were obtained from the intestines of poultry in farms or processing plants using standard culture and identification techniques. The minimum inhibitory concentration (MIC) for each compound was determined using the microbroth dilution method. Most chicken isolates had MICs ranging from 2 to 16 mg/L for tilmicosin, tylosin, and virginiamycin, while MICs for avilamycin, avopatin, monensin, nalaxyl, and penicillin were ≤1 mg/L. Most chicken isolates had higher MICs (≥64 mg/L) and appeared resistant to bacitracin and lincomycin. Most turkey isolates had MICs ranging from 2 to 16 mg/L for bacitracin, tilmicosin, tylosin, and virginiamycin, with some strains having MICs ≤1 mg/L for avilamycin, avopatin, monensin, nalaxyl, and penicillin. Some turkey isolates had MICs ≥64 mg/L for lincomycin. No attempt was made to correlate farm-specific antibiotics with antibiotic susceptibility test results.
...Nine hybrid pigs (five boars and four sows), each weighing approximately 44 kg, were fed a diet containing 76.19 mg/kg of 14C-avilamycin (equivalent to 80 mg/kg of avilamycin activity in the diet), fed every 12 hours for 4, 7, or 10 days. ...A major metabolite observed in liver and fecal extracts was fluorocyanate, a product of the cleavage of the ortho-ester bond between the C and D rings of avilamycin. Fluorocyanate accounted for 40-50% of the total radioactive residues in urine and feces, and 15-20% of the total radioactive residues in the liver.
Avilamycin is poorly absorbed in pigs and extensively metabolized in the intestines. Only about 8% of the total radioactivity in pig feces is attributed to maternal avilamycin. The metabolite was present in the liver but not detected in other tissues. The main metabolite is fluorobenzoic acid, accounting for 40-50% of total radioactive residues in urine and feces, and 15-20% in the liver. No microbially active residues were detected in the liver. Because avilamycin is highly metabolized or degraded in animals, it is unlikely to persist in the environment after excretion in treated animals.

Toxicity Summary
Identification and Uses: Avilamycin is an antibiotic primarily effective against Gram-positive bacteria, including Bacillus spp., Clostridium spp., Corynebacterium bovis, Enterococcus spp., Lactobacillus spp., Listeria monocytogenes, Micrococcus luteus, Staphylococcus aureus, and Streptococcus spp. Avilamycin is intended for use as a veterinary drug in chickens, turkeys, pigs, and rabbits to control bacterial intestinal infections. Human Exposure and Toxicity: Avilamycin may irritate the eyes and may cause anaphylactic reactions in individuals hypersensitive to avianamycin. Animal Studies: Acute toxicity of avianamycin has been evaluated in mice, rats, and rabbits using various routes of administration. Acute intraperitoneal toxicity of avianamycin is more severe than its oral or dermal toxicity. However, deaths observed after intraperitoneal administration are primarily attributable to inflammatory responses caused by unabsorbed avianamycin in the peritoneum, rather than the toxicity of avianamycin itself. Mice were fed pelleted diets supplemented with avilamycin for 28 consecutive days at doses of 0, 30, 300, or 3000 mg/kg (based on avilamycin activity)/kg of feed. Results showed that male mice fed 450 mg/kg body weight daily (based on avilamycin activity) experienced a slight increase in feed intake and body weight. In another study, rats were fed diets supplemented with 0%, 4%, 6%, or 10% (based on avilamycin activity) of dried fermented product for two consecutive weeks. The only treatment-related finding was that urine caused the fecal tray to turn brown to black, although urine in the bladder or freshly excreted urine was yellow. Avilamycin (mycelial cake, 7.83% activity) was added to the diets of pigs at doses of 0, 30, 300, and 3000 mg/kg for 21 weeks, followed by a 4-week withdrawal period. Some blood biochemical parameters, such as gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), sodium, and inorganic phosphorus, showed changes compared to control values, but these changes were small and all within the normal range. In a two-year study, male and female rat pups were fed different doses of avilamycin (derived from 7% active mycelial cake) at doses of 0, 30, 300, or 3000 mg/kg (based on activity), and pure avilamycin at a dose of 3000 mg/kg (based on activity), respectively, throughout the study period. The mothers of these pups were fed the same dose of avilamycin (0, 30, 300, or 3000 mg/kg) one week before the experiment, then mated, and continued to receive the above treatment during pregnancy and lactation. Mortality rates ranged from 58% to 78%, with no significant differences between treatment groups. At weeks 13, 26, 52, and 78, male rats receiving daily intakes of avilamycin (derived from mycelial cake) at doses of 15 and 150 mg/kg body weight showed significantly shortened clotting times in a dose-dependent manner. However, clotting times returned to normal at the last two sampling time points (weeks 104 and 112). The incidence of pancreatic exocrine adenomas was slightly increased in male rats receiving daily intakes of avilamycin (derived from mycelial cake) at doses of 15 and 150 mg/kg body weight, but the difference was not statistically significant. Furthermore, the incidence of parafollicular cell carcinoma of the thyroid gland was also slightly increased in male rats receiving daily intakes of avilamycin (derived from mycelial cake) at doses of 15 and 150 mg/kg body weight, but the difference was not statistically significant. No parafollicular cell carcinoma of the thyroid gland was observed at mycelial cake doses of 1.5 mg/kg body weight/day or at pure avilamycin doses of 150 mg/kg body weight/day. Pregnant rabbits were administered dried avilamycin fermentation product (17.8% activity) via gavage at doses of 0, 250, 716, and 2000 mg/kg body weight. Two rabbits in the low-dose group experienced abortion, while one rabbit each in the medium- and high-dose groups did. All but one of the aborted rabbits exhibited diarrhea or anorexia prior to abortion. The low abortion rate in all treatment groups was considered a secondary consequence of maternal toxicity. In reverse mutagenesis assays of Salmonella TA98, TA100, TA1535, TA1537, TA1538, G46, C3076, and D3052 strains, and Escherichia coli WP2 and WP2uvrA strains, avilamycin did not exhibit mutagenicity regardless of S9 protein activation. Furthermore, in DNA repair assays using primary adult rat hepatocytes, forward mutation assays using L5178Y mouse lymphoma cells, and chromosomal aberration assays using Chinese hamster ovary cells, avilamycin showed no genotoxicity regardless of whether the S9 protein was activated. In sister chromatid exchange assays using bone marrow from Chinese hamsters orally administered avilamycin, and in micronucleus assays using bone marrow from mice treated with avilamycin, avilamycin did not show mutagenicity.

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Non-human toxicity values
Mice (female) intraperitoneal LD50: 1798.9 mg/kg body weight
Mice (male) intraperitoneal LD50: 3435.1 mg/kg body weight
Rat (female) intraperitoneal LD50: 3114.5 mg/kg body weight
Rat (male) intraperitoneal LD50: 2319.3 mg/kg body weight
For more complete non-human toxicity data for avilamycin (6 in total), please visit the HSDB record page.

[1].Novel avilamycin derivatives with improved polarity generated by targeted gene disruption. Chem Biol. 2004 Oct;11(10):1403-11.

See also: Avicramycin; Monensin (component); Avicramycin; Nalacin (component); Avicramycin; Salinomycin Sodium (component)... See more...

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Mechanism of Action
The antibiotic growth promoter avilamycin inhibits protein synthesis by binding to bacterial ribosomes. This article further characterizes its binding site on E. coli ribosomes. The drug interacts with the V domain of 23S rRNA, leaving chemical markers at nucleotides A2482 and A2534. Screening for avilamycin-resistant Halobacterium halobium cells revealed a mutation at helix 89 of its 23S rRNA. Furthermore, mutations at helix 89 and 91, previously shown to confer resistance to ivermectin, also lead to cross-resistance to avilamycin. These data suggest that the binding site of avilamycin is located on the 23S rRNA, near the elbow of the A site tRNA. It is speculated that avilamycin interacts with ribosomes at the ribosomal A site, interfering with the binding of initiation factor IF2 and tRNA, similar to its mechanism of action as ivermectin.

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Therapeutic Use
Antibacterial Agent

Veterinary Drug: Avilamycin is primarily effective against Gram-positive bacteria, including Bacillus spp., Clostridium spp., Corynebacterium bovis, Enterococcus spp., Lactobacillus spp., Listeria monocytogenes, Micrococcus luteus, Staphylococcus aureus, and Streptococcus spp. Avilamycin is a veterinary drug suitable for use in chickens, turkeys, pigs, and rabbits for the control of bacterial intestinal infections.
Drug (Veterinary): Used to reduce the incidence and overall severity of diarrhea caused by pathogenic Escherichia coli in weaned piglets. /US Product Label Contains/

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Drug Warnings
Avilamycin has not been proven effective in pigs with pre-existing clinical symptoms of diarrhea. The safety of avilamycin in breeding pigs has not been established. To ensure the proper use of swine antibiotics, do not administer them to pigs 14 weeks of age or older. Do not feed pigs medicated feed containing avilamycin for more than 42 days throughout their lives.

C61H88CL2O32

1404.24

1402.46

69787-79-7

71674

Colorless, needle-shaped crystals from acetone-ether

188-189.5 °C
Colorless needles from chloroform/petroleum ether; MW: 1404.25; MP: 181-182 °C (1-2.H2O). UV max (methanol): 227, 286 nm (log epsilon 4.12, 3.33) /Avilamycin A/

1.052

6

32

20

95

2660

29

C[C@@H]1[C@H]([C@@H](C[C@@H](O1)O[C@@H]2[C@H](OC3(C[C@H]2O)O[C@@H]4[C@H](O[C@H](C[C@]4(O3)C)O[C@@H]5[C@H]([C@@H](O[C@@H]([C@@H]5OC)C)O[C@@H]6[C@H](O[C@H]([C@H]([C@H]6O)OC)OC7[C@@H]([C@H]8[C@H](CO7)O[C@@]9(O8)[C@H]1[C@H]([C@@]([C@H](O9)C)(C(=O)C)O)OCO1)OC(=O)C(C)C)COC)O)C)C)O)OC(=O)C1=C(C(=C(C(=C1OC)Cl)O)Cl)C

XIRGHRXBGGPPKY-OTPQUNEMSA-N

InChI=1S/C61H88Cl2O32/c1-21(2)53(70)87-49-45-32(92-61(93-45)52-51(78-20-79-52)60(72,27(8)64)28(9)91-61)19-77-56(49)89-57-48(76-14)39(68)44(31(83-57)18-73-11)88-55-40(69)47(43(74-12)24(5)82-55)85-34-17-58(10)50(26(7)81-34)94-59(95-58)16-30(66)42(25(6)90-59)84-33-15-29(65)41(23(4)80-33)86-54(71)35-22(3)36(62)38(67)37(63)46(35)75-13/h21,23-26,28-34,39-45,47-52,55-57,65-69,72H,15-20H2,1-14H3/t23-,24-,25-,26-,28-,29-,30-,31-,32+,33+,34+,39+,40-,41-,42-,43+,44-,45-,47-,48+,49-,50-,51-,52-,55+,56?,57+,58-,59?,60+,61-/m1/s1

[(2R,3S,4R,6S)-6-[(2'R,3'S,3aR,4R,4'R,6S,7aR)-6-[(2S,3R,4R,5S,6R)-2-[(2R,3S,4S,5S,6S)-6-[(2R,3aS,3'aR,6'R,7R,7'S,7aR,7'aR)-7'-acetyl-7'-hydroxy-6'-methyl-7-(2-methylpropanoyloxy)spiro[4,6,7,7a-tetrahydro-3aH-[1,3]dioxolo[4,5-c]pyran-2,4'-6,7a-dihydro-3aH-[1,3]dioxolo[4,5-c]pyran]-6-yl]oxy-4-hydroxy-5-methoxy-2-(methoxymethyl)oxan-3-yl]oxy-3-hydroxy-5-methoxy-6-methyloxan-4-yl]oxy-4'-hydroxy-2',4,7a-trimethylspiro[3a,4,6,7-tetrahydro-[1,3]dioxolo[4,5-c]pyran-2,6'-oxane]-3'-yl]oxy-4-hydroxy-2-methyloxan-3-yl] 3,5-dichloro-4-hydroxy-2-methoxy-6-methylbenzoate

2934.99.9001

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)

Typically soluble in DMSO (e.g. 10 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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