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.

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 β-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.

No abstract

No abstract

No abstract

Trichinella spiralis (T. spiralis), which is a cosmopolitan nematode that infects humans among other species, presents a complex host-parasite relationship that hinders the development of tools to eradicate the parasitosis. The aim of this research was to analyze the host response during a primary infection with T. spiralis in five genetically different mouse lines of the CBi-IGE stock. Adult males from the CBi+, CBi−, CBi, CBi/L and CBi/C lines were infected with 1, 2 or 4 L1 larvae per g of body weight. In the chronic stage, the number of parasites per g of tissue (relative larval load, rLL) showed a significant host genotype-dose interaction, since it did not increase in the same way in the five genotypes. At the lowest dose, both CBi− and CBi/L mice were resistant while CBi+, CBi/C, and CBi were susceptible. At the highest dose, only CBi/L remained resistant, and CBi+ was the most susceptible. The reproductive capacity index of adult worms (RCI = rLL/infective dose) evinced only a genotype effect, allowing rating each line as resistant or susceptible regardless of dose. Animals receiving 2 L1 larvae were also sacrificed in the intestinal phase (6 and 13 days p-i) to determine the number of adult parasites (nAP) recovered in a small intestine segment, and female fecundity (Ff). No differences in nAP were observed among genotypes on day 6 p-i. nAP decreased between days 6 and 13 p-i, this reduction being different among genotypes and significant only in CBi/L and CBi/C. Ff decreased in CBi/L and CBi/C on day 13 p-i. At the time of infection, serum cytokine baseline values showed a Th1 orientation for genotype CBi/L (high IFN-γ and IL-2) * Corresponding author. and a Th2 for CBi+ (high IL-4 and IL-10).The variability in the response observed in this murine model suggests its potential usefulness to gain insight into the mechanisms that regulate hostparasite relationship.

No abstract

Sir,Entamoeba gingivalis and Trichomonas tenax are human buccal protozoa. They live in dental tartar, in the necrotic mucosa of the cells and the gingival fringes of the gums 6 .The complexity of the oral environment and the multifactorial nature of the caries lesion, with the consequent loss of dental pieces, requires the cooperation of other disciplines such as Microbiology, Chemistry and Dietetics. Both partial and total loss of dental pieces produce modifications in buccal biotic conditions 1 . Some investigators think that E. gingivalis is an agent which causes periodontitis 7 , while others consider it an opportunist capable of survive in the medium induced by periodontal disease 5 .T. tenax, in spite of being considered as a commensal might take part in the first phases of the process of destruction of periodontal tissues 6 owing to the finding of an acid phosphatase 3 , a surface protein similar to fibronectine 6 and an important collagenolytic activity 6 .The objetive was to determine the frequency of these two protozoa and their relation with salivary IgA and with salivary pH in patients with dental prothesis.Fifty adult patients with either fixed or mobile prothesis were selected. Tartar and/or dental plaque samples of the 4 inferior incisors were obtained by means of a scaler, as well as a saliva sample was taken from each of the patients. Both were collected in the morning with no previous brushing or, in other cases, after a period of at last three or four hours after the last buccal hygiene.Tartar, as well as dental plaque were diluted with sterile physiologic solution and was observed through an optical microscope (100x and 400x).There was a previous microscopic observation of saliva followed by another observation after 2000 r.p.m. centrifugation during 5 minutes (100x and 400x) to identify protozoa.Both samples were coloured with Gomori trichromic stain 11 and cultured at 37 °C in the following specific media: Bacto Endamoeba Medium for E. gingivalis and Diamond medium 4 for T. tenax. Cultures were daily observed for 72 hours.In saliva samples, pH was determined by means of strips of indicant paper (V.N.: 6/0-7/5), and secretory IgA concentration was determined by the radial immunodiffusion method 10 (V.N.: 20-40 mg/dl).The statistical analysis was performed by the χ 2 test (signification level 0/05) so as to study the association between pH and IgA with the presence of parasite 2 .Out of the 50 examined patients, 36 (72%) presented parasites, 29 were monoparasitized, 26 presented E. gingivalis and 3 presented T. tenax; the other 7 presented both protozoa.The frequency of E. gingivalis in the population studied was 66% and 20% for T. tenax. Both protozoa were predominant in the tartar sample, and/ or the dental plaque.The cultures performed for the search of T. tenax increased significantly the diagnostic sensitivity, since out of the 10 positive patients, 5 were diagnosed only through the culture. However, for E. gingivalis, neither the culture nor the trichromic coloration increased sensitivi...