The transport of the antiparasitic agents, ivermectin, selamectin and moxidectin was studied in human intestinal epithelial cell monolayers (Caco-2) and canine peripheral blood lymphocytes (PBL). Both models expressed the mdr1-coded 170 kDa ATP-binding cassette (ABC) transporter P-glycoprotein (P-gp). Fluxes of the P-gp substrate rhodamine-123 (Rh-123) across Caco-2 monolayers showed that ivermectin and selamectin acted as potent P-gp inhibitors with IC50 values of 0.1 microm. The transport of radiolabelled ivermectin, selamectin and moxidectin through Caco-2 monolayers showed that ivermectin, selamectin and moxidectin were P-gp substrates with secretory/absorptive ratios of 7.5, 4.7 and 2.6 respectively. Secretory transport of [3H]-ivermectin and [3H]-selamectin was blocked by the P-gp inhibitor, verapamil. Ivermectin and selamectin inhibited the efflux of Rh-123 from PBL and the concentration of inhibition was similar to that of verapamil. In contrast, moxidectin did not have a significant effect on Rh-123 efflux from PBL. The data suggest that ivermectin and selamectin are potent P-gp substrates, while moxidectin is a weak one.[2]

To assess chemotherapeutic efficacy of topical selamectin, eight Brugia malayi and six Brugia pahangi microfilaremic cats were treated with a single administration of topical selamectin. For chemoprophylactic efficacy assessment, a single application of topical selamectin was administrated to 9 healthy, uninfected cats. The cats in both groups were subjected to a monthly blood testing for microfilariae and filarial DNA for 1 year. Topical selamectin treatment in B. malayi and B. pahangi microfilaremic cats showed 100% effectivity in eradicating microfilaremia but only 78.5% effectivity in eliminating filarial DNA. In the chemoprophylactic group, selamectin demonstrated 66.7% efficacy in preventing B. malayi infection. Our findings suggest that a single administration of 6 mg/kg topical selamectin given every two months could effectively prevent B. malayi infection. Application of topical selamectin twice a year could block circulating microfilariae. [1]

[1]. First study of topical selamectin efficacy for treating cats naturally infected with Brugia malayi and Brugia pahangi under field conditions. Parasitol Res. 2019 Apr;118(4):1289-1297.

[2]. Selamectin is a potent substrate and inhibitor of human and canine P-glycoprotein. J Vet Pharmacol Ther. 2005 Jun;28(3):257-65.

Selamectin is a milbemycin.
Selamectin is a topical parasiticide and antihelminthic used on dogs and cats to treat and prevent infections of heartworms, fleas, ear mites, sarcoptic mange, and certain types of ticks in dogs as well as prevent heartworms, fleas, ear mites, hookworms, and roundworms in cats. It also removes 2 types of lungworm in cats and one type of lungworm in dogs. It is distributed by Zoetis, a former Pfizer subsidiary. It is structurally related to ivermectin and milbemycin. Selamectin is not approved for human use.
See also: Sarolaner; Selamectin (component of).

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Drug Indication
Cats and dogs: Treatment and prevention of flea infestations caused by Ctenocephalides spp. for one month following a single administration. This is as a result of the adulticidal, larvicidal and ovicidal properties of the product. The product is ovicidal for 3 weeks after administration. Through a reduction in the flea population, monthly treatment of pregnant and lactating animals will also aid in the prevention of flea infestations in the litter up to seven weeks of age. The product can be used as part of a treatment strategy for flea allergy dermatitis and through its ovicidal and larvicidal action may aid in the control of existing environmental flea infestations in areas to which the animal has access. Prevention of heartworm disease caused by Dirofilaria immitis with monthly administration. The product may be safely administered to animals infected with adult heartworms, however, it is recommended, in accordance with good veterinary practice, that all animals 6 months of age or more living in countries where a vector exists should be tested for existing adult heartworm infections before beginning medication with the product. It is also recommended that dogs should be tested periodically for adult heartworm infections, as an integral part of a heartworm prevention strategy, even when the product has been administered monthly. This product is not effective against adult D. immitis. Treatment of ear mites (Otodectes cynotis). Cats: Treatment of biting lice infestations (Felicola subrostratus)Treatment of adult roundworms (Toxocara cati)Treatment of adult intestinal hookworms (Ancylostoma tubaeforme)Treatment of biting lice infestations (Trichodectes canis)Treatment of sarcoptic mange (caused by Sarcoptes scabiei)
Treatment and prevention of flea infestations caused by Ctenocephalides spp. for one month following a single administration. This is as a result of the adulticidal, larvicidal and ovicidal properties of the product. The product is ovicidal for 3 weeks after administration. Through a reduction in the flea population, monthly treatment of pregnant and lactating animals will also aid in the prevention of flea infestations in the litter up to seven week of age. The product can be used as part of a treatment strategy for flea allergy dermatitis and through its ovicidal and larvicidal action may aid in the control of existing environmental flea infestations in area to which the animal has access. Prevention of heartworm disease caused by Dirofilaria immitis with monthly administration. The product may be safely administered to animals infected with adult heartworms, however, it is recommended, in accordance with good veterinary practice, that all animals 6 months of age or more living in countries where a vector exists should be tested for existing adult heartworm infections before beginning medication with the product. It is also recommended that dogs should be tested periodically for adult heartworm infections, as an integral part of a heartworm prevention strategy, even when the product has been administered monthly. This product is not effective against adult D. immitis. Treatment of ear mites (Otodectes cynotis). Cats: Treatment of biting lice infestations (Felicola subrostratus)Treatment of adult roundworms (Toxocara cati)Treatment of adult intestinal hookworms (Ancylostoma tubaeforme). Dogs: Treatment of biting lice infestations (Trichodectes canis)Treatment of sarcoptic mange (caused by Sarcoptes scabiei)Treatment of adult intestinal roundworms (Toxocara canis).
Cats and dogs: Treatment and prevention of flea infestations caused by Ctenocephalides spp. for one month following a single administration. This is as a result of the adulticidal, larvicidal and ovicidal properties of the product. The product is ovicidal for 3 weeks after administration. Through a reduction in the flea population, monthly treatment of pregnant and lactating animals will also aid in the prevention of flea infestations in the litter up to seven weeks of age. The product can be used as part of a treatment strategy for flea allergy dermatitis and through its ovicidal and larvicidal action may aid in the control of existing environmental flea infestations in areas to which the animal has access. Prevention of heartworm disease caused by Dirofilaria immitis with monthly administration. Stronghold may be safely administered to animals infected with adult heartworms, however, it is recommended, in accordance with good veterinary practice, that all animals 6 months of age or more living in countries where a vector exists should be tested for existing adult heartworm infections before beginning medication with Stronghold. It is also recommended that dogs should be tested periodically for adult heartworm infections, as an integral part of a heartworm prevention strategy, even when Stronghold has been administered monthly. This product is not effective against adult D. immitis. Treatment of ear mites (Otodectes cynotis). Cats: Treatment of biting lice infestations (Felicola subrostratusTreatment of adult roundworms (Toxocara cati)Treatment of adult intestinal hookworms (Ancylostoma tubaeforme). Dogs: Treatment of biting lice infestations (Trichodectes canis)Treatment of sarcoptic mange (caused by Sarcoptes scabiei)Treatment of adult intestinal roundworms (Toxocara canis).

C43H63NO11

769.97

769.44

165108-07-6

9578507

White to off-white solid powder

1.4±0.1 g/cm3

917.0±65.0 °C at 760 mmHg

508.4±34.3 °C

0.0±0.6 mmHg at 25°C

1.618

6.83

3

12

4

55

1550

14

C[C@H]1CC[C@]2(C[C@@H]3C[C@H](O2)C/C=C(/[C@H]([C@H](/C=C/C=C/4\CO[C@H]\5[C@@]4([C@@H](C=C(/C5=N/O)C)C(=O)O3)O)C)O[C@H]6C[C@@H]([C@H]([C@@H](O6)C)O)OC)\C)O[C@@H]1C7CCCCC7

AFJYYKSVHJGXSN-XHKIUTQPSA-N

InChI=1S/C43H63NO11/c1-24-11-10-14-30-23-50-40-36(44-48)27(4)19-33(43(30,40)47)41(46)52-32-20-31(16-15-25(2)38(24)53-35-21-34(49-6)37(45)28(5)51-35)54-42(22-32)18-17-26(3)39(55-42)29-12-8-7-9-13-29/h10-11,14-15,19,24,26,28-29,31-35,37-40,45,47-48H,7-9,12-13,16-18,20-23H2,1-6H3/b11-10+,25-15+,30-14+,44-36-/t24-,26-,28-,31+,32-,33-,34-,35-,37-,38-,39-,40+,42+,43+/m0/s1

(1R,4S,5'S,6R,6'S,8R,10E,12S,13S,14E,16E,20R,21Z,24S)-6'-cyclohexyl-24-hydroxy-21-hydroxyimino-12-[(2R,4S,5S,6S)-5-hydroxy-4-methoxy-6-methyloxan-2-yl]oxy-5',11,13,22-tetramethylspiro[3,7,19-trioxatetracyclo[15.6.1.14,8.020,24]pentacosa-10,14,16,22-tetraene-6,2'-oxane]-2-one

Selamectin , UK-124114 UNII-A2669OWX9N ,

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.)