Effect of sex and genotype of the host on the anthelmintic efficacy of albendazole microcrystals, in the CBi-IGE Trichinella infection murine model.

Albendazole (ABZ) is an anthelmintic pharmaceutical commonly used in the treatment of nematode infections. It is a Class II drug poorly water-soluble, with very low bioavailability, a feature particularly limiting to treat the trichinellosis chronic phase. Microcrystals obtained by controlled precipitation using hydroxyethyl cellulose and chitosan have previously been shown to improve ABZ biopharmaceutical properties. This investigation aimed to test the systems' in vivo efficacy in the CBi-IGE murine model of Trichinella spiralis infection in the infection's different phases and parasite' stages. Treatment in the enteral phase led to a 90% decrease in the larval muscle load, probably due to its effect on T. spiralis female fecundity. Both microcrystal systems given in the migratory phase halved muscle load in males, a response not observed in females. The chitosan-based microcrystals proved to be the best when administered in the chronic phase of the infection ­ an increased proportion of L1 dead larvae was found compared to controls, except in CBi+-treated females. Males and females from the highly susceptible CBi+ line presented a significantly different treatment response in this phase. In vivo efficacy depended on the host genotype and sex and was related to the parasite cycle stage in which the formulations were administered.

Effect of Genotype and Sex of the Host on the Bioavailability of Novel Albendazole Microcrystals Based on Chitosan and Cellulose Derivatives.

Albendazole (ABZ), an anthelmintic compound widely used in the treatment of systemic nematode infections, is included in the list of class II drugs based on the Biopharmaceutical Classification System. ABZ has limited effectiveness due to its poor water solubility and consequent low bioavailability. Bioavailability of novel ABZ microcrystals based on hydroxyethylcellulose (S4A) or chitosan (S10A) was studied in male and female mice of two inbred lines, from the murine CBi-IGE model of trichinellosis, differing in susceptibility to this parasitosis (line CBi/L, resistant; line CBi+, susceptible). ABZ microcrystals were administered orally, and albendazole sulfoxide (ABZSO) was quantified in plasma by high-performance liquid chromatography. Mice given the microcrystals showed a significant increase in maximum plasmatic concentration (Cmax) compared with those receiving pure ABZ (P < 0.01). In both genotypes, males and females given S4A had higher Cmax than those receiving S10A (P < 0.05). CBi/L showed a greater Cmax than CBi+ (significantly different only in females treated with S4A (P = 0.001)). CBi/L females attained a higher Cmax than males (P < 0.05). No sex effect was observed for this variable in CBi+ (P > 0.05). The results of the pharmacokinetic analysis indicate that the microcrystalline formulations optimize ABZ bioavailability, both in males and females, S4A being the best system in CBi/L mice and S10A in CBi+. In summary, the microcrystals increased ABZ bioavailability, and under the conditions of this investigation, both host genotype and sex influenced the pharmacokinetic parameters measured.

Synthesis and characterization of a new cyclodextrin derivative with improved properties to design oral dosage forms.

This work aimed to synthesize a novel ß-cyclodextrin derivative, itaconyl-ß-cyclodextrin to evaluate whether albendazole inclusion complexes with the new ß-cyclodextrin derivative-improved albendazole dissolution efficiency and its anthelminthic activity. The new derivative was thoroughly evaluated and characterized, and an average degree of substitution of 1.4 per cyclodextrin molecule was observed. Albendazole:itaconyl-ß-cyclodextrin complexes were prepared by spray drying procedures and investigated using phase solubility diagrams, dissolution efficiency, X-ray diffraction, differential scanning calorimetry, Fourier transform infrared, scanning electronic microscopy, mass spectrometry, and nuclear magnetic resonance spectroscopy. Phase solubility diagrams and mass spectrometry studies showed that the inclusion complex was formed in an equimolar ratio. Stability constant values were 602 M-1 in water, and 149 M-1 in HCl 0.1 N. Nuclear magnetic resonance experiments of the inclusion complex showed correlation signals between the aromatic and propyl protons of albendazole and the itaconyl-ß-cyclodextrin inner protons. The studies indicated solid structure changes of albendazole included in itaconyl-ß-cyclodextrin. The maximum drug release was reached at 15 min, and the inclusion complex solubility was 88-fold higher than that of the pure drug. The in vitro anthelmintic activity assay showed that the complex was significantly more effective than pure albendazole.

Albendazole Microcrystal Formulations Based on Chitosan and Cellulose Derivatives: Physicochemical Characterization and In Vitro Parasiticidal Activity in Trichinella spiralis Adult Worms.

The oral route has notable advantages to administering dosage forms. One of the most important questions to solve is the poor solubility of most drugs which produces low bioavailability and delivery problems, a major challenge for the pharmaceutical industry. Albendazole is a benzimidazole carbamate extensively used in oral chemotherapy against intestinal parasites, due to its extended spectrum activity and low cost. Nevertheless, the main disadvantage is the poor bioavailability due to its very low solubility in water. The main objective of this study was to prepare microcrystal formulations by the bottom-up technology to increase albendazole dissolution rate, in order to enhance its antiparasitic activity. Thus, 20 novel microstructures based on chitosan, cellulose derivatives, and poloxamer as a surfactant were produced and characterized by their physicochemical properties and in vitro biological activity. To determine the significance of type and concentration of polymer, and presence or absence of surfactant in the crystals, the variables area under the curve, albendazole microcrystal solubility, and drug released (%) at 30 min were analyzed with a three-way ANOVA. This analysis indicated that the microcrystals made with hydroxyethylcellulose or chitosan appear to be the best options to optimize oral absorption of the active pharmaceutical ingredient. The in vitro evaluation of anthelmintic activity on adult forms of Trichinella spiralis identified system S10A as the most effective, of choice for testing therapeutic efficacy in vivo.

Efficacy of albendazole:ß-cyclodextrin citrate in the parenteral stage of Trichinella spiralis infection.

Albendazole-ß-cyclodextrin citrate (ABZ:C-ß-CD) inclusion complex in vivo antiparasitic activity was evaluated in the parenteral phase of Trichinella spiralis infection in mice. An equimolar complex of ABZ:C-ß-CD was prepared by spray-drying and tested in CBi-IGE male mice orally infected with L1 infective larvae. Infected animals were treated with 50 or 30mg/kg albendazole, (ABZ) equivalent amounts of the ABZ:C-ß-CD complex and non treated (controls). Mice received a daily dose on days 28, 29 and 30 post-infection. A week later, larval burden and percentage of encysted dead larvae were assessed in the host by counting viable and non-viable larvae in the tongue. Complexation of ABZ with C-ß-CD increased the drug dissolution efficiency nearly eightfold. At 37 days p-i, the reduction percentage in muscle larval load was 35% in mice treated with 50mg/kg/day ABZ and 68% in those given the complex. Treatment with the lower dose showed a similar decrease in parasite burden. Treated animals showed a high percentage of nonviable larvae, the proportion being significantly higher in mice receiving the complex than in control animals (72-88% vs. 11%, P=0.0032). These data indicate that ABZ:C-ß-CD increases bioavailability and effectiveness of ABZ against encapsulated Trichinella larvae, thus allowing the use of small doses.

Characterization of albendazole-randomly methylated-ß-cyclodextrin inclusion complex and in vivo evaluation of its antihelmitic activity in a murine model of Trichinellosis.

Albendazole is a benzimidazole carbamate extensively used in oral chemotherapy against intestinal parasites, due to its broad spectrum activity, good tolerance and low cost. However, the drug has the disadvantage of poor bioavailability due to its very low solubility in water; as a consequence, a very active area of research focuses on the development of new pharmaceutical formulations to increase its solubility, dissolution rate, and bioavailability. The primary objective of this study was to prepare randomly methylated ß-cyclodextrins inclusion complexes to increase albendazole dissolution rate, in order to enhance its antiparasitic activity. This formulation therapeutic efficacy was contrasted with that of the pure drug by treating Trichinella spiralis infected mice during the intestinal phase of the parasite cycle, on days five and six post-infection. This protocol significantly decreased muscle larval burden measured in the parenteral stage on day 30 post-infection, when compared with the untreated control. Thus, it could be demonstrated that the inclusion complexes improve the in vivo therapeutic activity of albendazole.

Novel albendazole formulations given during the intestinal phase of Trichinella spiralis infection reduce effectively parasitic muscle burden in mice.

Trichinellosis is a zoonotic disease affecting people all over the world, for which there is no speedy and reliable treatment. Albendazole (ABZ), an inexpensive benzimidazole used in oral chemotherapy against helminthic diseases, has a broad spectrum activity and is well tolerated. However, the low absorption and variable bioavailability of the drug due to its low aqueous solubility are serious disadvantages for a successful therapy. In this study, we evaluated the in vivo antiparasitic activity of three novel solid microencapsulated formulations, designed to improve ABZ dissolution rate, in a murine model of trichinellosis. Both ABZ and the microparticulate formulations were administered during the intestinal phase of the parasite cycle, on days 5 and 6 post-infection. This protocol significantly decreased muscle larval burden measured in the parenteral phase, on day 30 post-infection, when compared with the untreated control. Moreover, two of the three microencapsulated formulations both strongly and consistently reduced worm burden.

Lovastatin enhances the antitumoral and apoptotic activity of doxorubicin in murine tumor models.

Despite its effectiveness as an antineoplastic drug, doxorubicin (DOX) is usually associated with cardiotoxicity. Lovastatin (LOV), a hypolipidemic agent used in the clinic, has been demonstrated to have antitumoral and antimetastatic effects in murine models. Since the two agents arrest tumor cells in different phases of the cell cycle and induce apoptosis, the goal of this study was to examine the efficacy of a combination therapy with LOV and low doses of DOX, in an attempt to obtain an improved antitumoral effect devoid of toxicity, by using a rat B-cell lymphoma and a mouse mammary tumor. In the two models, the combined treatment showed a synergistic antitumoral effect, which is mainly ascribed to an increased apoptotic response elicited by a LOV/DOX combination than either agent alone. The therapeutic benefit demonstrated by the combination treatment is further emphasized by the lack of toxicity.

Efecto de la ciclosfosfamida sobre el crecimiento de un sarcoma transplantable de rata S-E 100 / Effect of cyclophosphamide on a transplantable rat sarcoma S-E 100

La ciclosfosfamida (Cy) se utiliza en el tratamiento del cáncer como droga citotóxica, produciendo grados variables de inmunodepresión. En trabajos experimentales se ha observado que al administrarse en dosis bajas aumenta la respuesta inmune, preferentemente la mediada por células. Este efecto se debería a una acción selectiva sobre los linfocitos T supresores. Con el objeto de investigar la Cy como moduladora de la respuesta inmune antitumoral se estudió el efecto de una dosis única (20 mg/Kg de peso) sobre el crecimiento de un sarcoma transplantable de rata (S-E100). La droga se administró a distintos días del desafío tumoral. Previamente, se evaluó el efecto de la droga sobre el peso del bazo, el número de células esplénicas y la viabilidad de las células S-E100 in vivo ]cámaras de difusión) con el objeto de determinar una dosis que no ejerciera una acción citotóxica inmediata sobre las células esplénicas ni sobre las células tumorales. Los resultados mostraron que una dosis única de 20mg/Kg de peso no modificó el peso del bazo, el número de células esplénicas ni la viabilidad de las células neoplásicas. Esta misma dosis produjó, en cambio, distintos efectos sobre el crcimiento del S-E100 dependidendo del día de su administración. Cuando se administró la Cy a los 7, 14 o 21 días del crcimiento tumoral se obtuvo la regresión del 100% de los tumores. la histopatología de los tumoes en regresión mostró alteraciones compatibles con un rechazo mediado por células