Sistema de liberação contendo ciclosporina para o tratamento de ceratoconjuntivite seca: estudo preliminar

OBJETIVO: Este trabalho objetivou o desenvolvimento de um sistema mucoadesivo de liberação de ciclosporina A (CsA) para o tratamento de ceratoconjuntivite seca (CCS). MÉTODOS: O sistema mucoadesivo foi preparado na forma de filme utilizando o polímero quitosana e CsA (25%p/v). Foram administrados no saco conjuntival do olho direito de coelhos normais (n=6) e a aferição da produção de lágrimas foi realizada diariamente antes e após a aplicação, de forma bilateral, durante sete dias, por meio do teste lacrimal de Schirmer. Avaliação oftalmológica foi realizada diariamente durante todo o estudo e seguido da análise histológica. RESULTADOS: Os valores médios de produção de lágrimas foram alterados de 9,88 ± 0,37 mm/min para 16,02 ± 0,38 mm/min antes e após a administração do sistema respectivamente, significando um aumento de aproximadamente 60%. Todos os coelhos apresentaram hiperemia da conjuntiva palpebral e lacrimejamento. A hiperemia permaneceu durante 48 h após administração dos sistemas com resolução espontânea e o lacrimejamento foi diagnosticado até o final do experimento. Não foram observados outros sinais de reações indesejáveis. Nenhuma alteração histológica foi observada na mucosa conjuntival bulbar e palpebral à histopatologia. CONCLUSÃO: Os sistemas desenvolvidos são aparentemente seguros e eficientes criando expectativa para o tratamento da CCS. Novos estudos são necessários para avaliar a concentração de CsA liberada, assim como aceitabilidade e toxicidade dos sistemas em tratamentos mais prolongados

Relationship between clinical and pathological signs and severity of canine leishmaniasis

Canine visceral leishmaniasis (CVL) is a zoonotic disease that presents variable clinical and laboratory aspects. The aims of this study were to identify the main biochemical/hematological status of dogs naturally infected with Leishmania (Leishmania) infantum and to associate theses parameters with clinical forms of CVL. Blood samples were analyzed from 51 dogs, 15 uninfected (control group) and 36 infected, which were classified clinically in three groups: asymptomatic (n=12), oligosymptomatic (n=12) and symptomatic (n=12). All the infected dogs showed lower albumin/globulin ratios (A-G ratio) than the limit of reference. The mean values of total protein, urea, α-globulin 2, globulin and A-G ratio of infected dogs were outside the reference interval and differed significantly from those of the controls. Anemia was detected only in groups that showed clinical signs of the disease, and a statistical analysis indicated a significantly higher frequency of lower eritrogram in these groups than in the asymptomatic group. In addition, a significant association was observed between anemia and the presence of the symptoms, with dogs displaying higher erythrogram values showing better clinical conditions. These results provide additional evidence that the clinical forms of CVL may reflect on the erythrogram status

Ocular Inserts for Sustained Release of the Angiotensin-Converting Enzyme 2 Activator, Diminazene Aceturate, to Treat Glaucoma in Rats.

The aim of this study was to develop and evaluate the effects of chitosan inserts for sustained release of the angiotensin-converting enzyme 2 (ACE2) activator, diminazene aceturate (DIZE), in experimental glaucoma. Monolayer DIZE loaded inserts (D+I) were prepared and characterized through swelling, attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and in vitro drug release. Functionally, the effects of D+I were tested in glaucomatous rats. Glaucoma was induced by weekly injections of hyaluronic acid (HA) into the anterior chamber and intraocular pressure (IOP) measurements were performed. Retinal ganglion cells (RGC) and optic nerve head cupping were evaluated in histological sections. Biodistribution of the drug was accessed by scintigraphic images and ex vivo radiation counting. We found that DIZE increased the swelling index of the inserts. Also, it was molecularly dispersed and interspersed in the polymeric matrix as a freebase. DIZE did not lose its chemical integrity and activity when loaded in the inserts. The functional evaluation demonstrated that D+I decreased the IOP and maintained the IOP lowered for up to one month (last week: 11.0 ± 0.7 mmHg). This effect of D+I prevented the loss of RGC and degeneration of the optic nerve. No toxic effects in the eyes related to application of the inserts were observed. Moreover, biodistribution studies showed that D+I prolonged the retention of DIZE in the corneal site. We concluded that D+I provided sustained DIZE delivery in vivo, thereby evidencing the potential application of polymeric-based DIZE inserts for glaucoma management

<i>In vitro</i> release of DIZE.

<p>In vitro release of DIZE from DIZE inserts (D+I) showing that approximately 80% of the drug was controlled released in four hours (n = 3).</p

DIZE inserts (D+I) promoted neuroprotection in retinas of glaucomatous rats.

<p>Representative photomicrographs of excavation of the optic nerve (arrows). Note the optic nerve head cupping in control glaucomatous animals treated or not with placebo inserts (P+I) when compared to all other groups; n = 5 per group. Treatment with D+I was able to reverse this effect. In detail are representative photomicrographs of longitudinal sections of the optic nerve. A large reduction in the neural fibers was observed in control glaucomatous rats treated or not with P+I. CTRL: control non-treated group; CTRL+P+I: control group that received placebo inserts; CTRL+D+I: control group that received DIZE inserts; GLAU: glaucoma non-treated group; GLAU+P+I: glaucoma group that received placebo inserts; and GLAU+D+I: glaucoma group that received DIZE inserts.</p

Differential scanning calorimetry (DSC) curves of DIZE, placebo inserts (P+I) and DIZE inserts (D+I).

<p>Peaks at 64.3°C <b>(A)</b> and 314.9°C <b>(B)</b> on P+I curve are attributed to evaporation of residual water and degradation of the main polymeric chain, respectively. On DIZE curves, peaks at 98.3°C <b>(A)</b> and 137.0°C <b>(B)</b> are attributed to loss of water from the salt and peaks at 175.1°C <b>(A)</b> and 214.0°C <b>(B)</b> indicates the decomposition of DIZE. Peaks of decomposition of DIZE were not detected in D+I curves; n = 3 per group.</p

<i>In vivo</i> drug biodistribution.

<p><b>(A)</b> Representative images after 30 min, 2, 4, 6 and 18 hours of administration of the radiolabeled formulations; n = 5 per group. Note that ^99mTc-DIZE eye drops began to clear from the corneal region reaching the gastrointestinal tract via the nasolacrimal drainage system after 18 hours; while ^99mTc-D+I remained in the eye. Ey: eye; Ab. Cv.: abdominal cavity. <b>(B)</b> Percentage of administered dose per gram after 18 hours in spleen, heart, stomach, liver, small intestine, large intestine, kidneys, right eye, left eye and blood. *p<0.05 vs. the same organ from rats treated with ^99mTc-D+I (Unpaired Student’s <i>t</i>-test).</p

Representative scanning electron micrograph of DIZE inserts (D+I).

<p><b>(A)</b> Micrograph of the lateral side of the insert (n = 3). <b>(B)</b> Micrograph of the surface of the insert (n = 3). D+I are uniform without granular particles in the middle or in the surface and measuring approximately 40 μm of thickness.</p

Characterization of chitosan inserts containing DIZE by swelling analysis and ATR-FTIR spectra.

<p><b>(A)</b> Swelling index of placebo inserts (P+I: chitosan only) and DIZE inserts (D+I: Dize + chitosan) in PBS; n = 3 per group. D+I swelled more quickly and reached higher swelling indexes than P+I (*p < 0.001). Two-way ANOVA followed by the Bonferroni post test. <b>(B)</b> ATR-FTIR spectra of powdery DIZE (DIZE), P+I (chitosan only) and D+I (Dize + chitosan). D+I spectra showed characteristic bands both of P+I and DIZE. No new bands were identified in D+I.</p