Produção e avaliação de compostos vegetais adsorvidos em adjuvantes para o desenvolvimento de novos insumos contra a otite externa canina

Abstract

Canine external otitis is one of the most frequent reasons for dermatological care within veterinary medicine, and difficult to treat as many cases of recurrence and chronicles. In this context, the objective was to evaluate the efficiency of three otological solutions composed of plant extracts and adjuvants in the treatment of canine otitis externa. Three articles were carried out, with the following objectives respectively: Evaluate the antimicrobial activity of otological solutions in vitro; Evaluate the efficiency in the treatment of dogs with otitis externa; Evaluate ceruminolytic activity in vivo and in vitro. For all studies, three different otological solutions were developed and used: LCFO 1003 composed of ethanolic extracts of Triticum aestivum, Bixa orellana and tris-edta; LCFO 1004 composed of ethanolic extracts of Triticum aestivum, Bixa orellana and nacetylcysteine; LCFO 1005 composed of Triticum aestivum, Bixa orellana, nacetylcysteine and tris-edta and as a control group a commercial product based on gentamicin, betamethasone and clotrimazole was used. Article 1: The study of antimicrobial susceptibility was carried out using the disk-diffusion technique, 33 different bacterial strains isolated from dogs with canine external otitis were tested and for the test against the yeast M.pachydermatis, 30 isolates were used and the technique microdilution in broth proposed in the CLSI document M27A3. The results showed that the otological solutions LFC0 1004 and LCFO 1005, presented inhibition halos similar to gentamicin against most of the bacteria tested, mainly from the genus Staphylococcus. As for the yeast M.pachydermatis, all solutions were efficient, demonstrating low MIC values, as well as in the test against bacteria, the LCFO 1005 product demonstrated greater effectiveness. Article 2- For the in vivo study on the target species, 64 dogs with clinical signs of external otitis were used, which were randomly divided into four groups according to the treatment used. All animals were treated once a day for seven days, being evaluated on day “0” (D0), on day 3 (D3) and on day 7 (D7), regarding the presence of otalgia, pruritus, odor, erythema and amount of cerumen. After the evaluation, each clinical sign received a score from 0 to 3, which 0 was considered absent and 3 the most severe form of appearance, from this score a sum was generated per animal and per group during each day of evaluation. On D0 and D7 samples were collected for bacterial and fungal culture and cytology. After seven days of treatment, the compounds LCF0 1003, LCFO 1004 and LCFO 1005 were effective in reducing clinical signs and microorganisms involved in cases of canine external otitis, being similar to the control. Article 3- To evaluate the diffusion activity, artificial canine cerumen was produced, which was deposited in the body of 1ml syringes and added to the otological test solutions with the Oil red marker. Whichwere stored for 24 hours in a water bath and after that the diffusion activity of each solution was measured. For the ceruminolytic test, 500mg of cerumen was deposited in tubes which were added with 2ml of otological solutions, placed in agitation for 20min, drying for 1 hour. After weighing was carried out to quantify the loss of cerumen, this procedure was repeated 5 times. The study demonstrated variability of the products tested in the in vitro diffusion and ceruminolytic analyses. The LCF0 1004 otologic solution behaved closer to the commercial control solution. In the in vivo test, it was possible to observe the effectiveness of all otological solutions in reducing exudate, highlighting the LCFO 1005 solution as the most potent. Thus, it is concluded that the otological solutions LCFO 1003, LCF0 1004 and LCFO 1005 present an efficient therapeutic alternative for the inhibition of otic pathogens in vitro and have an effect on the reduction of clinical signs of external otitis in dogs.