Evaluation of a single-administration ototopical treatment for canine otitis externa: a randomised trial

Long-lasting otic solution containing mometasone furoate can influence intradermal testing in dogs with healthy ears and otitis externa

BACKGROUND

Topical therapy is preferred for otitis externa (OE) in dogs. Otic products commonly contain glucocorticoids that can be systemically absorbed and possibly interfere with diagnostic tests such as intradermal testing (IDT).

HYPOTHESIS/OBJECTIVES

To determine the effect of a long-lasting otic solution containing mometasone furoate (MF) on IDT immediate reactions and to determine withdrawal time before IDT.

ANIMALS

Seventeen dogs with healthy ears (Group 1) and 12 with OE (Group 2).

MATERIALS AND METHODS

Intradermal injections of histamine, anticanine-immunoglobulin (Ig)E and saline were subjectively and objectively evaluated before treatment and weekly for 6 weeks, after a single application of a long-lasting otic solution containing MF.

RESULTS

Statistically significant reductions in the mean subjective histamine scores after application of MF were observed at Weeks 1 (p = 0.012) and 2 (p = 0.028) in Group 1, and Weeks 1 (p = 0.00066), 2 (p = 0.02) and 4 (p = 0.034) in Group 2. Mean histamine objective scores were significantly reduced in Weeks 1 (p = 0.042), 2 (p = 0.0009), 3 (p = 0.001) and 5 (p = 0.018) in Group 1 only. The mean subjective anticanine-IgE scores were significantly reduced in Week 1 in both groups (p = 0.003, p = 0.0066), respectively. There were no significant changes in the mean anticanine-IgE objective score in either group.

CONCLUSIONS AND CLINICAL RELEVANCE

Application of a long-lasting otic solution containing MF can interfere with IDT immediate reactions in healthy and OE dogs. Based on the subjective evaluation, IDT can be performed ≥2 weeks after application of the otic solution in healthy dogs, and ≥4 weeks in dogs with OE.

Stability Studies of a Tetraethyl Orthosilicate-Based Thixotropic Drug Delivery System

Background/Objectives: This study assessed the effects of formulation components on the long-term stability of a previously described tetraethyl orthosilicate-based drug delivery system. Early stability studies of a product concept are crucial not only to provide information on the overall system stability and individual components' contributions to it, but also to identify opportunities for dosage form optimization and to define its use case. Methods: We assessed the time-dependent thixogel properties-specifically, mechanical strength, thixotropy, release of model drug, and dry substance-in both real-time and accelerated shelf-life determination set-ups. Results: Our findings indicate that the concentration and molecular weight of hyaluronic acid, one of the main constituents of the investigated thixotropic systems, are key determinants of formulation stability. We further showed that changes in both of these parameters reflect on the drug release properties and stiffness of the formulation and could inform subsequent product development based on several use cases. Conclusions: Overall, this study provides an understanding of some key factors that would need to be considered prior to and in the final product development process of thixogels in preparation for commercialization.

Clinical safety and efficacy of a single-dose gentamicin, posaconazole and mometasone furoate otic suspension for treatment of canine otitis externa

BACKGROUND

A single-dose, in-clinic, veterinary professional-administered treatment for canine otitis externa was developed to improve compliance and canine welfare.

METHODS

This multicentre, controlled, examiner-masked, randomised field trial was conducted in 316 dogs over 42 days. Dogs were treated once, on day 0, with the investigational product containing gentamicin, posaconazole and mometasone furoate (Mometamax Ultra [MU]) or twice (days 0 and 7) with a control product containing florfenicol, terbinafine and betamethasone acetate (CP). The primary endpoint was a composite otitis index score of 4 or less (of 12) on day 14 and 3 or less (of 12) on day 28.

RESULTS

On day 28, treatment success was recorded in 128 of 143 MU-treated dogs (89.5%), significantly non-inferior to 116 of 133 (87.2%) CP-treated dogs (Farrington-Manning test, Z = 4.1351, p < 0.0001). For mixed cultures of Staphylococcus pseudintermedius and Malassezia pachydermatis, there was 100% treatment success in MU-treated dogs (n = 33), significantly non-inferior to 90.2% (37 of 41) in CP-treated dogs (Farrington-Manning test, Z = 3.1954, p = 0.0007).

LIMITATIONS

Efficacy in chronic otitis externa cases was not investigated. Cytology was not used to aid in diagnosis or for identification of secondary pathogens.

CONCLUSION

This unique combination, single-dose product is safe and effective in dogs with otitis externa. It offers enhanced compliance, canine welfare and quality of life by eliminating the owner burden of treating this painful condition.

Evaluation of hypochlorous acid as an ear flush in dogs with chronic otitis externa

BACKGROUND

Chronic otitis externa (OE) in dogs frequently requires anaesthetised ear flushing.

OBJECTIVES

To evaluate hypochlorous acid as an ear flushing and antimicrobial agent in dogs with chronic OE.

ANIMALS

Twenty dogs with chronic OE caused by the same organisms bilaterally.

MATERIALS AND METHODS

One ear was flushed under anaesthesia with hypochlorous acid, the other with saline solution. Subsequently, the ear flushed with hypochlorous acid was cleaned with the same solution twice daily for 2 weeks, the other ear with a commercial ear cleaner. An ear medication containing miconazole, polymyxin B and prednisolone was used once daily in both ears. Clinical scores were determined before the flush. Ear cytological results were obtained, a hearing test was conducted before and after the ear flush, and a culture was taken directly after flushing. Ears were evaluated after 2 weeks of therapy.

RESULTS

Yeast was present in the ears of 11, cocci in one and a mixed infection in eight dogs. Five ears were negative on culture after flushing with hypochlorous acid, one after the saline flush. Clinical and cytological scores decreased significantly with both solutions after 2 weeks of treatment. There was no difference between treatments in any of the scores at any time point between treatments and in the results of the hearing test before and after the flushing procedure. Adverse effects were not seen.

CONCLUSIONS AND CLINICAL RELEVANCE

Hypochlorous acid is a suitable cleaning solution for canine OE.

Manufacturability of a Tetraethyl Orthosilicate-Based Hydrogel for Use as a Single Application Otitis Externa Therapeutic

Otitis externa, also known as outer ear infection, is a frequent affliction in both humans and animals. The most prevalent treatment for otitis externa is ear drops, but it is difficult to adhere properly to this treatment, causing poor patient compliance and the potential for complications. As a result, we have developed a tetraethyl orthosilicate-based hydrogel for use as single application treatment for otitis externa to increase ease of use and improve patient outcomes. Herein, we investigated the manufacturability of the hydrogel, focusing on several key aspects: formulation repeatability and reproducibility, material source and tolerances, release of a variety of model drugs, and impact of application-specific physiological factors, specifically local pH and enzymatic activity on drug release. Overall, our results indicate that these hydrogels are well suited for production and scalability, as they have a robust manufacturing process, have a wide tolerance for pH level, release a variety of model drugs, and are not impacted by outer ear canal-specific physiological factors.

Malassezia otitis unresponsive to primary care: outcome in 59 dogs

BACKGROUND

Otitis externa (OE) is a common disorder in dogs. Infection by the commensal yeast, Malassezia pachydermatis, may result in chronic disease that does not respond to standard primary care. Chronic infectious OE may be associated with otitis media (OM).

HYPOTHESIS/OBJECTIVE

To report medical management, clinical outcomes and frequency of middle ear involvement, in dogs with Malassezia otitis unresponsive to primary care.

ANIMALS

Fifty-nine dogs from one referral veterinary hospital from January 2007 to September 2018.

METHODS AND MATERIALS

Retrospective analysis of medical records of dogs referred with chronic otitis and treated for Malassezia otitis at a referral veterinary hospital.

RESULTS

Chronic Malassezia OE was treated successfully in 91% of ears, in 87% of these cases with one ear flush intervention. Median time-to-resolution was 27 days after ear flush intervention. Neither duration of otitis, presence of neutrophils in aural discharge nor administration of oral itraconazole affected clinical outcome. Malassezia OM occurred concurrently in 17% of ears.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings assist clinicians and carers of affected dogs in decision-making, by documenting that most cases of canine Malassezia otitis that have not resolved with standard primary care, can be treated successfully with a well-staged and intense medical treatment plan. Malassezia OM should be suspected to occur concurrently in around a fifth of affected ears.