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.

Effect of the treatment with Achyrocline satureioides (free and nanocapsules essential oil) and diminazene aceturate on hematological and biochemical parameters in rats infected by Trypanosoma evansi.

This study aimed to verify the effect of the treatment with A. satureioides essential oil (free and nanoencapsulated forms) and diminazene aceturate on hematological and biochemical variables in rats infected by Trypanosoma evansi. The 56 rats were divided into seven groups with eight rats each. Groups A, C and D were composed by uninfected animals, and groups B, E, F and G were formed by infected rats with T. evansi. Rats from groups A and B were used as negative and positive control, respectively. Rats from the groups C and E were treated with A. satureioides essential oil, and groups D and F were treated with A. satureioides nanoencapsulated essential oil. Groups C, D, E and F received one dose of oil (1.5 mL kg(-1)) during five consecutive days orally. Group G was treated with diminazene aceturate (D.A.) in therapeutic dose (3.5 mg kg(-1)) in an only dose. The blood samples were collected on day 5 PI for analyses of hematological (erythrocytes and leukocytes count, hemoglobin concentration, hematocrit, mean corpuscular and mean corpuscular hemoglobin concentration) and biochemical (glucose, triglycerides, cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin, urea and creatinine) variables. A. satureioides administered was able to maintain low parasitemia, mainly the nanoencapsulated form, on 5 days post infection. On the infected animals with T. evansi treated with A. satureioides essential oil (free and nanocapsules) the number of total leucocytes, lymphocytes and monocytes present was similar to uninfected rats, and different from infected and not-treated animals (leukocytosis). Treatment with A. satureioides in free form elevated levels of ALT and AST, demonstrating liver damage; however, treatment with nanoencapsulated form did not cause elevation of these enzymes. Finally, treatments inhibited the increase in creatinine levels caused by infection for T. evansi. In summary, the nanoencapsulated form showed better activity on the trypanosome; it did not cause liver toxicity and prevented renal damage.

Clinical management of babesiosis in dogs with homeopathic Crotalus horridus 200C.

Homeopathic Crotalus horridus 200C was evaluated in 13 clinical cases of babesiosis in dogs, compared with another 20 clinical cases treated with diminazine. Babesiosis is an important tropical tick-borne haemoprotozoan disease in dogs clinically manifested by anorexia, dehydration, temperature, dullness/depression, diarrhoea/constipation, pale mucosa, hepatomegaly, vomiting/nausea, splenomegaly, distended abdomen/ascites, yellow coloured urine, emaciation/weight loss, and occular discharge. The diagnosis of babesiosis was based on cytological evidence of Babesia gibsoni in freshly prepared blood smears. The dogs were treated with oral C. horridus 200C, 4 pills four times daily for 14 days (n=13) or diminazine aceturate 5 mg/kg single intramuscularly dose (n=20). All the dogs were administered 5% Dextrose normal saline at 60 ml/kg intravenously for 4 days. Initial clinical scores were similar in both groups and showed similar progressive improvement with the two treatments over 14 days. Parasitaemia also improved in both groups, but haematological values showed no change. No untoward reactions were observed. It appears that C. horridus is as effective in causing clinical recovery in moderate cases of canine babesiosis caused by Babesia gibsoni as the standard drug diminazine. Large scale randomized trials are indicated for more conclusive results.

Long-term occurrence of Trypanosoma congolense resistant to diminazene, isometamidium and homidium in cattle at Ghibe, Ethiopia.

Ten trypanosome isolates were collected at random from cattle at Ghibe, Ethiopia, in February 1993 and all shown to be savannah-type Trypanosoma congolense. When inoculated into naïve Boran (Bos indicus) calves, all 10 isolates were resistant to diminazene aceturate (Berenil), isometamidium chloride (Samorin) and homidium chloride (Novidium) at doses of 7.0 mg/kg body weight (b.w.), 0.5 mg/kg b.w. and 1.0 mg/kg b.w., respectively. In order to determine whether this multiple-drug resistance was expressed by individual trypanosomes, clones were derived from two of the isolates and characterised in mice for their sensitivity to the three compounds; by comparison to drug-sensitive populations, the two clones expressed high levels of resistance to all 3 trypanocides. In experiments to characterise the uptake kinetics of [14C]-Samorin, the maximal rates of uptake (Vmax) for 4 Ghibe isolates ranged from 9.2 to 15.0 ng/10(8) trypanosomes/min. In contrast, Vmax for the isometamidium-sensitive clone T. congolense IL 1180 was 86.7 +/- 8.6 ng/10(8) trypanosomes/min. Lastly, molecular karyotypes were determined for eight isolates: seven different chromosome profiles were observed. These data indicate that in February 1993 there was a high prevalence of drug-resistant trypanosome populations with different chromosome profiles in cattle at Ghibe. Since a similar situation existed at the same site in July 1989, this suggests that the drug-resistance phenotype of trypanosomes at Ghibe had not altered over a 4 year period.

The Bo-RBC-SCID mouse model for evaluating the efficacy of anti-theilerial drugs.

We have previously developed a mouse model which allowed the proliferation of Theileria sergenti in severe combined immunodeficiency (SCID) mice with circulating bovine erythrocytes (Bo-RBC). In the present study, this model was utilized to test the efficacy of anti-theilerial drugs. Bo-RBC-SCID mice were created by giving periodic transfusions of T. sergenti-free Bo-RBC, and subsequently infecting with T. sergenti. Three anti-protozoal compounds, Pamaquine (Yamanouchi Pharmaceutical Co. Ltd), Ganaseg (Japan CIBA-GEIGY Ltd) and Buparvaquone (Coopers Animal Health Ltd), were subcutaneously administered into the mice at doses recommended for cattle therapy. Blood examinations demonstrated that all three drugs significantly reduced the level of parasitemia although Ganaseg was effective only at a dose five times higher than that recommended for cattle therapy. Administration of the drugs neither caused any sign of acute toxicity nor changed the rate of Bo-RBC in the SCID mice's circulating blood cells. The results indicate that the Bo-RBC-SCID mouse model may offer a useful in vivo system for evaluating the efficacy of anti-protozoal drugs against T. sergenti.