M.J. Bernad-Bernad

Preformulation Studies of a Liposomal Formulation Containing Sirolimus for the Treatment of Dry Eye Disease

PURPOSE The aim of this study was to develop and characterize a liposomal product containing sirolimus to be administered subconjunctivally for the treatment of nonresponsive keratoconjunctivitis sicca (KCS) or dry eye. METHODS Formulations were prepared using an ethanol injection method and an adaptation of the heating method in pursuance of the most suitable methodology for future industrial production. Liposomes were loaded with either a high dose of 1 mg/mL of sirolimus or a less toxic dose of 0.4 mg/mL. The effects of critical process and formulation parameters were investigated. Liposomes were characterized in terms of size, zeta potential, polydispersity, differential scanning calorimetry, morphology, entrapment efficiency, phospholipid content, thermal stability, and sterility. The formulation was evaluated clinically in dogs with spontaneous KCS. RESULTS Sterile liposomal dispersions with sizes ranging from 140 to 211 nm, were successfully obtained. High entrapment efficiency of 93%-98% was achieved. The heating method allowed an easier production of liposomes with high entrapment efficiency, to significantly shorten production time and the elimination of the use of alcohol. The poor stability of the obtained liposomes in aqueous dispersion made the inclusion of a lyophilization step necessary to the manufacturing process. In vivo testing of the liposomal sirolimus formulations in the spontaneous KCS dog model have produced promising results, particularly with a sirolimus dose of 1 mg/mL, indicating the need for further development and study of proposed formulations in the treatment of canine KCS. Clinical improvement in tear production in dogs with spontaneous KCS treated with the 1 mg/mL dose product was observed. CONCLUSIONS The heating method allowed easier production of high entrapment efficiency liposomes to significantly shorten production time and the elimination of the use of alcohol. Tear production was increased in dogs administered with the formulation.

Characterization of physical interaction between Casiopeina III-ia and chitosan. Toward a Cas III-ia drug delivery system.

Casiopeínas are a new generation of anticancer drugs that have shown great in vitro and in vivo antineoplastic activities. Information about interaction drug-excipient, for developing a based-nanoparticle drug delivery system, has not been investigated yet. In order to elucidate if chitosan (CS) modifies the copper complex due to its interaction with Cu(2+) ion, different studies in aqueous media between CS and Casiopeina III-ia (Cas III-ia) were carried out. CS-Cas III-ia mixtures were characterized by viscosity curves, UV-vis, EPR, and in vivo activity against HeLa cell line. Rheological behavior showed a decrease of viscosity when the drug was present due to diminished electrostatic interactions of charged amine group. UV-vis results illustrate that Cas III-ia is not stable at low pH as a result of interaction with acetic acid. However, when chitosan is present at the acidic solution Cas III-ia is stable. These results are supported by EPR studies. Finally, activity of the drug against HeLa cell line was not modified. Therefore, the present work presents evidence that there is no breaking of copper complex due to interaction between CS and Cas III-ia in acidic media. In addition, Cas III-ia maintains both its stability and effectiveness against cancer cell line.

Influence of Curcumin (Curcuma Longa) as a Natural Anticoccidial Alternative in Adult Rabbits: First Results

Coccidiosis is one of the most common ailments in rabbits farming and is usually treated with drugs that can produce resistance; therefore, a natural alternative was sought. The objective of the current study was to evaluate the efficacy of the aqueous extract of curcumin (Curcuma longa) on the excretion of oocysts of Eimeria spp. in New Zealand white rabbits. Twenty-four eight-month-old rabbits were divided into four groups of six animals to be C. longa extract administered at 0 (Control), 10, 25 or 40 mg/kg body weight (BW). Rabbit weights were recorded and faeces samples were collected on d 0, 7, 14, 21, 28, 35 and 42. The McMaster technique was used for quantifying Eimeria spp. oocysts. Results were analysed using multivariate analysis of variance for repeated observations. Statistically significant differences (P<0.05) from d 28 were observed among the Control, the group of 25 mg/kg BW and that of 40 mg/kg BW. At d 42, statistically difference (P<0.05) among the Control group and the other three groups was observed. It could be concluded that C. longa decreased Eimeria spp. oocysts excretion efficiently at a dose of 40 mg/kg BW with 80.1, 63.7 and 64.9% for d 28, 35 and 42, respectively, with reducing concentration of eggs per gram of faeces with about 20.1, 15.6 and 17.8 for d 14, 21 and 35, respectively. However, further studies are needed to assess and confirm the antiparasitic activity of C. longa.

Subconjunctivally injected liposome encapsulated sirolimus and topical tacrolimus for the treatment of non-responsive keratoconjunctivitis sicca in the spontaneous dog model

Abstract Objective: The aim of this study was to evaluate the therapeutic utility of sirolimus liposomes (prepared by two different techniques at two different doses) by subconjunctival injection, and tacrolimus

Characterization of hybrid microparticles/Montmorillonite composite with raspberry-like morphology for Atorvastatin controlled release

In this work, we prepared a novel composite based on hybrid gelatin carriers and montmorillonite clay (MMT) to analyze its viability as controlled drug delivery system. The objective of this research involves the characterization of composites formed by structured lipid-gelatin micro-particles (MP) and MMT clay. This analysis included the evaluation of the composite according to its rheological properties, morphology (SEM), particle size, XRD, FT-IR, and in vitro drug release. The effect of pH in the properties of the composite is evaluated. A novel raspberry-like or armor MP/MMT clay composite is reported, in which the pH has an important effect on the final structure of the composite for ad-hoc drug delivery systems. For pH values below the isoelectric point, we obtained defined morphologies with entrapment efficiencies up to 67%. The pH level controls the MP/MMT composite release mechanism, restringing drug release in the stomach-like environment. Intended for oral administration, these results evidence that the MP/MMT composite represents an attractive alternative for intestinal-colonic controlled drug delivery systems.