Absorption, Distribution and Excretion
The results of residue determinations of the growth promotors carbadox, tylosin, & virginiamycin in kidney, liver, & muscle from pigs in feeding experiments are described as well as the analytical methods used. Residues of the carbadox metabolite quinoxaline-2-carboxylic acid were found in liver from pigs fed 20 mg/kg in the diet with a withdrawal time of 30 days. No residues were detected in muscle with zero withdrawal time. The limit of determination was 0.01 mg/kg for both tissues. No residues of virginiamycin & tylosin were found in pigs fed 50 & 40 mg/kg, respectively, in the diet, even with zero withdrawal time. Residues of tylosin of 0.06 mg/kg & below were detected in liver & kidney from pigs fed 200 or 400 mg/kg & slaughtered within 3 h after the last feeding.

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Metabolism / Metabolites
Reduction of virginiamycin S with sodium borohydride produces allo- & normal-dihydro-virginiamycin S. Reduction of the tosylhydrazone of virginiamycin S with sodium cyanoborohydride affords deoxyvirginiamycin S. These compounds are less active than virginiamycin S. Like virginiamycin S they enhance the activity of virginiamycin M1.
Virginiae butanolides (VBs), which are among the butyrolactone autoregulators of Streptomyces species, act as a primary signal in Streptomyces virginiae to trigger virginiamycin biosynthesis & possess a specific binding protein, BarA. To clarify the in vivo function of BarA in the VB-mediated signal pathway that leads to virginiamycin biosynthesis, two barA mutant strains (strains NH1 & NH2) were created by homologous recombination. In strain NH1, an internal 99-bp EcoT14I fragment of barA was deleted, resulting in an in-frame deletion of 33 amino acid residues, including the second helix of the probable helix-turn-helix DNA-binding motif. With the same growth rate as wild-type S. virginiae on both solid & liquid media, strain NH1 showed no apparent changes in its morphological behavior, indicating that the VB-BarA pathway does not participate in morphological control in S. virginiae. In contrast, virginiamycin production started 6 hr earlier in strain NH1 than in the wild-type strain, demonstrating for the first time that BarA is actively engaged in the control of virginiamycin production & implying that BarA acts as a repressor in virginiamycin biosynthesis. In strain NH2, an internal EcoNI-SmaI fragment of barA was replaced with a divergently oriented neomycin resistance gene cassette, resulting in the C-terminally truncated BarA retaining the intact helix-turn-helix motif. In strain NH2 & in a plasmid-integrated strain containing both intact & mutated barA genes, virginiamycin production was abolished irrespective of the presence of VB, suggesting that the mutated BarA retaining the intact DNA-binding motif was dominant over the wild-type BarA. These results further support the hypothesis that BarA works as a repressor in virginiamycin production & suggests that the helix-turn-helix motif is essential to its function. In strain NH1, VB production was also abolished, thus indicating that BarA is a pleiotropic regulatory protein controlling not only virginiamycin production but also autoregulator biosynthesis.
Previous findings suggest the location of the central loop of domain V of 23S rRNA within the peptidyltransferase domain of ribosomes. This enzymatic activity is inhibited by some antibiotics, including type A (virginiamycin M or VM) & type B (virginiamycin S or VS) synergimycins, antibiotics endowed with a synergistic action in vivo. In the present work, the ability of VM & VS to modify the accessibility of 23S rRNA bases within ribosomes to chemical reagents has been explored. VM afforded a protection of rRNA bases A2037, A2042, G2049 & C2050. Moreover, when ribosomes were incubated with the two virginiamycin components, the base A2062, which was protected by VS alone, became accessible to dimethyl sulphate (DMS). Modified reactivity to chemical reagents of different rRNA bases located either in the central loop of domain V or in its proximity furnishes experimental evidence for conformational ribosome alterations induced by VM binding

Appl Environ Microbiol. 2015 Oct;81(19):6621-36.

Virginiamycin is a streptogramin antibiotic similar to pristinamycin and quinupristin/dalfopristin. It is a combination of pristinamycin IIA and virginiamycin S1. Virginiamycin is used in the fuel ethanol industry to prevent microbial contamination and in livestock to prevent and treat infections. According to a USDA study, antibiotics can save as much as 30% in feed costs among young swine.
Virginiamycin is a class of streptogramin-related depsipeptides isolated from the bacterium Streptomyces virginiae and other Streptomyces bacterial species. The virginiamycins consist of two major components, virginiamycin M1 and virginiamycin S1. These agents bind to and inhibit ribosome assembly, thereby preventing protein synthesis. Active against Gram-positive bacteria, these antibiotics are primarily used in veterinary practice. (NCI04)
An antibiotic mixture originally isolated from Streptomyces pristinaspiralis. It is a mixture of compounds from STREPTOGRAMIN GROUP A: pristinamycin IIA and IIB and from STREPTOGRAMIN GROUP B: pristinamycin IA, pristinamycin IB, pristinamycin IC.
See also: Virginiamycin (annotation moved to).

C71H84N10O17

1349.5

1348.601

11006-76-1

11006-76-1; 21411-53-0; 23152-29-6;

11979535

Reddish-yellow powder

170-178ºC

4.992

6

19

7

98

2640

0

CCC1C(=O)N2CCCC2C(=O)N(C(C(=O)N3CCC(=O)CC3C(=O)NC(C(=O)OC(C(C(=O)N1)NC(=O)C4=C(C=CC=N4)O)C)C5=CC=CC=C5)CC6=CC=CC=C6)C.CC1/C=C\C(=O)NC/C=C\C(=C/C(CC(=O)CC2=NC(=CO2)C(=O)N3CCC=C3C(=O)OC1C(C)C)O)\C

MVTQIFVKRXBCHS-YWAQVZITSA-N

InChI=1S/C43H49N7O10.C28H35N3O7/c1-4-29-40(56)49-21-12-17-30(49)41(57)48(3)32(23-26-13-7-5-8-14-26)42(58)50-22-19-28(51)24-31(50)37(53)47-35(27-15-9-6-10-16-27)43(59)60-25(2)34(38(54)45-29)46-39(55)36-33(52)18-11-20-44-36;1-17(2)26-19(4)9-10-24(34)29-11-5-7-18(3)13-20(32)14-21(33)15-25-30-22(16-37-25)27(35)31-12-6-8-23(31)28(36)38-26/h5-11,13-16,18,20,25,29-32,34-35,52H,4,12,17,19,21-24H2,1-3H3,(H,45,54)(H,46,55)(H,47,53);5,7-10,13,16-17,19-20,26,32H,6,11-12,14-15H2,1-4H3,(H,29,34)/b;7-5-,10-9+,18-13+/t25-,29-,30+,31+,32+,34+,35+;19-,20-,26-/m11/s1

N-((6R,9S,10R,13S,15aS,22S,24aS)-22-benzyl-6-ethyl-10,23-dimethyl-5,8,12,15,17,21,24-heptaoxo-13-phenyldocosahydro-12H-pyrido[2,1-f]pyrrolo[2,1-l][1]oxa[4,7,10,13,16]pentaazacyclononadecin-9-yl)-3-hydroxypicolinamide compound with (12Z,6R,7R,8E,13Z,15E,17S)-17-hydroxy-6-isopropyl-7,15-dimethyl-32,33-dihydro-31H-5-oxa-11-aza-1(4,2)-oxazola-3(1,5)-pyrrolacycloicosaphane-8,13,15-triene-2,4,10,19-tetraone (1:1)

RP-7293; NSC-246121; RP7293; NSC246121; Virginiamycin antibiotic complex;RP 7293; NSC 246121; Antibiotic 899; Founderguard; Mikamycin; RP 7293; Stapyocine; Streptogramin;Virginiamycin Complex

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)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

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.)