Doramectin

Doramectin (Dectomax) is a veterinary drug approved by the Food and Drug Administration (FDA) for the treatment of parasites such as gastrointestinal roundworms, lungworms, eyeworms, grubs, sucking lice and mange mites in cattle. Mutational biosynthetic antiparasitic antibiotic structurally related to the avermectins.

Critical points in the evaluation of analytical methods based on liquid chromatography separation for the determination of doramectin in different environmental samples.[Pubmed:24815899]

Chemosphere. 2015 Jan;119 Suppl:S9-15.

In recent years, the number of analytical methods of target compound residues (such as pharmaceuticals) has grown rapidly. Most of them are based on high performance liquid chromatography (HPLC). From the economic point of view, it is usual to apply the conditions of available HPLC methods or to design extraction and chromatographic separation conditions using HPLC and transfer them subsequently to a more sensitive technique like liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). However, if such a transfer is planned, it is important to assess the quality of the newly-designed LC-MS/MS method. The determination of parameters like matrix effects (ME), extraction efficiency (EE) and absolute recovery (AR) is mandatory. These parameters can visualise the weakest step in the analytical method and enable methods based on different techniques to be compared. The aim of this work was to show how quality assessment should be carried out in order to transfer an optimised method from one technique to another. The representative compound used in our investigation was Doramectin (DOR), an anthelmintic drug used in veterinary medicine. The quality of the suggested methods for determining this drug in three environmental matrices (water, sediment and fish tissue) using HPLC-UV and LC-MS/MS was evaluated on the basis of known values of absolute recovery (HPLC-UV) and matrix effect, extraction efficiency and absolute recovery (all LC-MS/MS). Finally, the suggested methods for determining DOR in water, sediment and fish tissue based on LC-MS/MS measurements were validated and applied to the analysis of real environmental samples.

Anthelmintic efficiency of doramectin, fenbendazole, and nitroxynil, in combination or individually, in sheep worm control.[Pubmed:27096532]

Rev Bras Parasitol Vet. 2016 Jul-Sep;25(3):353-8.

The anthelmintic efficiency of Doramectin, fenbendazole, and nitroxynil, used individually or in combination, was determined by the Fecal Egg Count Reduction (FECR) test and cultivation of larvae of anthelminthic-treated sheep grouped as follows: G1 (Doramectin), G2 (fenbendazole), G3 (nitroxynil), G4 (Doramectin + fenbendazole), G5 (Doramectin + nitroxynil), G6 (fenbendazole + nitroxynil), G7 (Doramectin + nitroxynil + fenbendazole), G8 (untreated). In addition to individually used Doramectin and fenbendazole, the helminths were also resistant to the combination of Doramectin + fenbendazole; nitroxynil + fenbendazole; and Doramectin + nitroxynil + fenbendazole, with their FECR rates ranging from 62-83%. The helminths showed possible nitroxynil-resistance, but had low resistance when the drug was administered in combination with Doramectin. The evaluation of individual helminth species revealed that fenbendazole was fully effective against Cooperia; Doramectin (G1), moderately effective against Haemonchus and insufficiently active against Cooperia; nitroxynil, effective against Haemonchus and insufficiently active against Cooperia. It was concluded from the results that herd nematodes are resistant to Doramectin, fenbendazole, and nitroxynil, and that the combined use of the drugs not only fails to significantly improve the anthelmintic efficiency against Haemonchus and Cooperia, but is also cost-ineffective.

Lernaea cyprinacea infection in a new host Puntius pulchellus in intensive culture system and its control by doramectin.[Pubmed:28316399]

J Parasit Dis. 2017 Mar;41(1):120-127.

The present study explored the susceptibility of Puntius pulchellus subadults to Lernaea cyprinacea infection subsequent upon their first introduction to an intensive culture system that had a previous history of Lernaea infection and evaluated the efficacy of Doramectin against the parasite. All the P. pulchellus introduced to the culture pond got infected demonstrating 100 % susceptibility of this species to Lernaea infection. Pathological changes caused by the parasite as evidenced by the extensive hemorrhage and tissue necrosis of the host at the point of parasite attachment was most severe in P. pulchellus. On the contrary, among the fish species already present in the pond and were previously exposed to the infection before the start of the present study, only Labeo fimbriatus developed mild to moderate infection. Cirrhinus mrigala, Ctenopharyngodon idella and Cyprinus carpio from the same culture pond did not develop Lernaea infection. Doramectin administration at 1 mg/kg b.wt. of fish incorporated in feed and given orally for 10 days or by a single intramuscular injection at 200 mug/kg b.wt. was found to be effective in controlling L. cyprinacea adult parasite infection in P. pulchellus. Doramectin hastened healing of the wounds caused by L. cyprinacea and did not cause any noticeable adverse reactions or toxicity to the fish host during the present study. In conclusion, P. pulchellus was observed to be highly susceptible to L. cyprinacea upon its first exposure to the infective stages of the parasite and a single intramuscular injection of Doramectin at 200 mug/kg b.wt. was more effective than oral administration of the drug in controlling L. cyprinacea infection.

Treatment of canine generalized demodicosis using weekly injections of doramectin: 232 cases in the USA (2002-2012).[Pubmed:26190685]

Vet Dermatol. 2015 Oct;26(5):345-9, e73.

BACKGROUND: Generalized demodicosis is a severe skin disease in the dog, with limited treatment options. HYPOTHESIS/OBJECTIVES: To demonstrate that Doramectin, when given at a dose rate of 0.6 mg/kg body weight, is a safe and effective treatment for generalized demodicosis in the dog. ANIMALS: Four hundred client-owned dogs diagnosed with generalized demodicosis at one general small-animal practice. Of these, 232 completed their treatment and were included in the study. METHODS: A retrospective study was carried out by searching the computerised medical records of dogs seen at one general small-animal practice in Tennessee, USA. The records of each dog with a diagnosis of generalized demodicosis, who underwent treatment using weekly injections of Doramectin at a dose rate of 0.6 mg/kg body weight, were analysed. RESULTS: Remission was achieved in 94.8% of dogs treated with weekly subcutaneous injections of Doramectin at a dose rate of 0.6 mg/kg body weight. Adverse events were rare with two suspected instances (0.5%) being recorded. The mean duration of treatment was 7.1 weeks. CONCLUSIONS AND CLINICAL IMPORTANCE: Doramectin given at a dose rate of 0.6 mg/kg body weight by subcutaneous injection at weekly intervals is a useful and well-tolerated treatment for generalized demodicosis in the dog.