Albendazole treatment in cystic echinococcosis: pharmacokinetics and clinical efficacy of two different aqueous formulations

Albendazole solid dispersions against alveolar echinococcosis: a pharmacotechnical strategy to improve the efficacy of the drug

Alveolar echinococcosis is a neglected parasitic zoonosis caused by Echinococcus multilocularis. The pharmacological treatment is based on albendazole (ABZ). However, the low water solubility of the drug produces a limited dissolution rate, with the consequent failure in the treatment of the disease. Solid dispersions are a successful pharmacotechnical strategy to improve the dissolution profile of poorly water-soluble drugs. The aim of this work was to determine the in vivo efficacy of ABZ solid dispersions using poloxamer 407 as a carrier (ABZ:P407 solid dispersions (SDs)) in the murine intraperitoneal infection model for secondary alveolar echinococcosis. In the chemoprophylactic efficacy study, the ABZ suspension, the ABZ:P407 SDs and the physical mixture of ABZ and poloxamer 407 showed a tendency to decrease the development of murine cysts, causing damage to the germinal layer. In the clinical efficacy study, the ABZ:P407 SDs produced a significant decrease in the weight of murine cysts. In addition, the SDs produced extensive damage to the germinal layer. The increase in the efficacy of ABZ could be due to the improvement of water solubility and wettability of the drug due to the surfactant nature of poloxamer 407. In conclusion, this study is the basis for further research. This pharmacotechnical strategy might in the future offer novel treatment alternatives for human alveolar echinococcosis.

Do albendazole-loaded lipid nanocapsules enhance the bioavailability of albendazole in the brain of healthy mice?

Neurocysticercosis is a neglected tropical disease that affects the central nervous system and is the most common cause of human epilepsy acquired in developing countries. Therapeutic failures attributed to medical management of neurocysticercosis with albendazole (ABZ) have been primarily linked to the poor drug absorption rate resulting in low drug level in plasma and brain tissue. The aim of the current work was to characterize and compare the brain pharmacokinetic behavior of ABZ formulated as a suspension or lipid nanocapsules (ABZ-LNCs) in healthy mice. The relative availability in brain tissue of the active metabolite ABZ sulphoxide increased 183% when ABZ was administered as LNCs, in relation to ABZ suspension. The parent drug was also detected for a short period of time. The bioavailability of ABZ in ABZ-LNCs treated mice increased more than 2 fold compared with ABZ suspension group. The enhanced drug brain exposure observed after administration of ABZ-LNCs to healthy mice has potential usefulness for the treatment of human neurocysticercosis.

Identification of Functional MKK3/6 and MEK1/2 Homologs from Echinococcus granulosus and Investigation of Protoscolecidal Activity of Mitogen-Activated Protein Kinase Signaling Pathway Inhibitors In Vitro and In Vivo

Cystic echinococcosis is a zoonosis caused by the larval stage of Echinococcus granulosus sensu lato There is an urgent need to develop new drugs for the treatment of this disease. In this study, we identified two new members of mitogen-activated protein kinase (MAPK) cascades, MKK3/6 and MEK1/2 homologs (termed EgMKK1 and EgMKK2, respectively), from E. granulosus sensu stricto Both EgMKK1 and EgMKK2 were expressed at the larval stages. As shown by yeast two-hybrid and coimmunoprecipitation analyses, EgMKK1 interacted with the previously identified Egp38 protein but not with EgERK. EgMKK2, on the other hand, interacted with EgERK. In addition, EgMKK1 and EgMKK2 displayed kinase activity toward the substrate myelin basic protein. When sorafenib tosylate, PD184352, or U0126-ethanol (EtOH) was added to the medium for in vitro culture of E. granulosus protoscoleces (PSCs) or cysts, an inhibitory and cytolytic effect was observed via suppressed phosphorylation of EgMKKs and EgERK. Nonviability of PSCs treated with sorafenib tosylate or U0126-EtOH, and not with PD184352, was confirmed through bioassays, i.e., inoculation of treated and untreated protoscoleces into mice. In vivo treatment of E. granulosus sensu stricto-infected mice with sorafenib tosylate or U0126-EtOH for 4 weeks demonstrated a reduction in parasite weight, but the results did not show a significant difference. In conclusion, the MAPK cascades were identified as new targets for drug development, and E. granulosus was efficiently inhibited by their inhibitors in vitro The translation of these findings into in vivo efficacy requires further adjustment of treatment regimens using sorafenib tosylate or, possibly, other kinase inhibitors.

Assessment of serum pharmacokinetics and urinary excretion of albendazole and its metabolites in human volunteers

Background

Soil Transmitted Helminth (STH) infections negatively impact physical and mental development in human populations. Current WHO guidelines recommend morbidity control of these infections through mass drug administration (MDA) using albendazole (ABZ) or mebendazole. Despite major reductions in STH associated morbidity globally, not all programs have demonstrated the expected impact on prevalence of parasite infections. These therapeutic failures may be related to poor programmatic coverage, suboptimal adherence or the exposure of parasites to sub-therapeutic drug concentrations. As part of the DeWorm3 project, we sought to characterize the serum disposition kinetics and pattern of urinary excretion of ABZ and its main metabolites ABZ sulphoxide (ABZSO) and ABZ sulphone (ABZSO₂) in humans, and the assessment of the duration and optimal time point where ABZ and/or its metabolites can be measured in urine as an indirect assessment of an individual’s adherence to treatment.

Methodology/Principal findings

Consecutive venous blood and urine samples were collected from eight (8) human volunteers up to 72 h post-ABZ oral administration. ABZ/metabolites were quantified by HPLC. The ABZSO metabolite was the main analyte recovered both in serum and urine. ABZSO Cmax in serum was 1.20 ± 0.44 μg/mL, reached at 4.75 h post-treatment. In urine, ABZSO Cmax was 3.24 ± 1.51 μg/mL reached at 6.50 h post-ABZ administration.

Conclusion/Significance

Pharmacokinetic data obtained for ABZ metabolites in serum and urine, including the recovery of the ABZ sulphoxide derivative up to 72 h in both matrixes and the recovery of the amino-ABZ sulphone metabolite in urine samples, are suggesting the possibility of developing a urine based method to assess compliance to ABZ treatment. Such an assay may be useful to optimize ABZ use in human patients.

Trial registration

ClinicalTrials.gov NCT03192449.

The soil-transmitted-helminths (STH) infections are produced by four species of parasites: Ascaris lumbricoides, Trichuris trichiura, and hookworm (Necator americanus and Ancylostoma duodenale). These parasites are transmitted by eggs present in human faeces, which contaminate the environment in areas where sanitation is poor. These diseases negatively impact health and development. Current STH control is based on mass drug administration (MDA) programs, mainly through the use of albendazole (ABZ) and mebendazole. However, although MDA programs have been shown to reduce the prevalence of STH infection and to control morbidity in school-age children, rapid reinfection is common among treated children and many programs fail to reach coverage targets. Optimizing methods to assess treatment coverage may allow programs to more effectively deliver MDA to populations requiring treatment. We conducted a controlled trial to evaluate the serum pharmacokinetic behaviour and urinary excretion of ABZ and its metabolites in human volunteers. The study focused also on to evaluate, by mean of non-invasively measures, ABZ treatment coverage and adherence. The measurement of ABZSO concentrations both in serum and urine may be useful methods to monitor adherence to ABZ treatment and serve as a more objective measurement of program coverage.

Albendazole nanocrystals in experimental alveolar echinococcosis: Enhanced chemoprophylactic and clinical efficacy in infected mice

Human alveolar echinococcosis is caused by the fox tapeworm Echinococcus multilocularis and is usually fatal if left untreated. Medical treatment with albendazole (ABZ) remains an effective option. However, due to its low aqueous solubility, ABZ is poorly and erratically absorbed following oral administration resulting in low drug levels in plasma and liver distribution. Thus, there arises the need to find a simple, efficient and scalable method to produce new ABZ formulations with increased bioavailability. Bearing this in mind, ABZ nanocrystals (ABZ-NCs) appears to be a useful tool to achieve this goal. The aim of the current study was to investigate the chemoprophylactic and clinical efficacy of an ABZ-NC formulation on mice infected with E. multilocularis. In the chemoprophylactic efficacy study, mean weight of the cysts recovered from the ABZ-NC group was 50% lower than that recorded from untreated mice, whereas the treatment with ABZ suspension did not show preventive effect. The viability of protoscoleces isolated from ABZ-NC treated mice was significantly lower than control groups. In the clinical efficacy studies, both ABZ formulations resulted in a reduction in the mean weight of the cysts obtained from mice, however only the treatment with the nanosuspension revealed significant differences (P < 0.05) compared to the control groups. Treatment with ABZ-NCs reduced the weight of the cysts by 77% and the viability of their protoscoleces to 34%. All these results coincided with the tissue damage determined at the ultrastructural level. The enhanced chemoprophylactic and clinical efficacy of ABZ-NCs observed in this study could be attributed to an increase in the oral bioavailability of the drug. In a next step, we will characterize the cyst concentration profile after the administration of ABZ-NCs in mice infected with E. multilocularis.

A nanocrystal-based formulation improves the pharmacokinetic performance and therapeutic response of albendazole in dogs

OBJECTIVES

Here, we aimed to assess the pharmacokinetic performance and therapeutic response (anthelmintic efficacy) of an albendazole (ABZ) nano-sized formulation in dogs.

METHODS

In the pharmacokinetic study, ABZ self-dispersible nanocrystals (SDNCS) and a control formulation were administered orally to healthy dogs (n = 6). The concentrations of the sulphoxide metabolite in plasma were determined by high-performance liquid chromatography. For the anthelmintic efficacy trial, SDNCS and a commercially available formulation of ABZ were given to naturally parasitised dogs. The number of Ancylostoma caninum eggs in the faeces was determined using the McMaster technique.

KEY FINDINGS

The area under the curve, Tmax and Cmax for the SDNCS were improved compared to the control. The efficacy study showed no statistical differences between the SDNCS and the commercial formulation at the doses of 25 and 12.5 mg/kg. However, significant differences (P < 0.05) between the treatments were found at 6.25 mg/kg (a quarter of the reference dose) with a reduction in the faecal nematode egg counts of 62.0 ± 21.1% and 100 ± 0% for the control and SDNCS, respectively.

CONCLUSIONS

The improved pharmacokinetic performance observed for the novel formulation of ABZ correlated with an improved in vivo therapeutic response against a model intestinal nematode parasite in dogs.

Robust phase-retrieval-based X-ray tomography for morphological assessment of early hepatic echinococcosis infection in rats

Propagation-based phase-contrast computed micro-tomography (PPCT) dominates the non-destructive, three-dimensional inner-structure measurement in synchrotron-based biomedical research due to its simple experimental setup. To quantitatively visualize tiny density variations in soft tissues and organs closely related to early pathological morphology, an experimental study of synchrotron-based X-ray PPCT combined with generalized phase and attenuation duality (PAD) phase retrieval was implemented with the hepatic echinococcosis (HE) infection rat model at different stages. We quantitatively analyzed and evaluated the different pathological characterizations of hepatic echinococcosis during the development of this disease via our PAD-based PPCT and especially provided evidence that hepatic alveolar echinococcosis invades the liver tissue and spreads through blood flow systems with abundant blood supply in the early stage. Additionally, the infiltration of tiny vesicles in HE lesions can be clearly observed by our PAD-PPCT technique due to the striking contrast-to-noise ratio (CNR) and mass density resolution, which cannot be found by the medical imaging techniques, such as magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound, in hospitals. The results demonstrated that our PAD-PPCT technique has a great potential for indicating the subtle structural information of pathological changes in soft biomedical specimens, especially helpful for the research of early micro-morphology of diseases.

Metformin exhibits preventive and therapeutic efficacy against experimental cystic echinococcosis

Metformin (Met) is an anti-hyperglycemic and potential anti-cancer agent which may exert its anti-proliferative effects via the induction of energetic stress. In this study we investigated the in vitro and in vivo efficacy of Met against the larval stage of Echinococcus granulosus. Metformin showed significant dose- and time-dependent killing effects on in vitro cultured protoscoleces and metacestodes. Notably, the combination of Met together with the minimum effective concentration of ABZSO had a synergistic effect after days 3 and 12 on metacestodes and protoscoleces, respectively. Oral administration of Met (50 mg/kg/day) in E. granulosus-infected mice was highly effective in reducing the weight and number of parasite cysts, yet its combination with the lowest recommended dose of ABZ (5 mg/kg/day) was even more effective. Coincidentally, intracystic Met accumulation was higher in animals treated with both drugs compared to those administered Met alone. Furthermore, the safe plant-derived drug Met exhibited remarkable chemopreventive properties against secondary hydatidosis in mice. In conclusion, based on our experimental data, Met emerges as a promising anti-echinococcal drug as it has proven to efficiently inhibit the development and growth of the E. granulosus larval stage and its combination with ABZ may improve the current anti-parasitic therapy.

In vivo evaluation of the efficacy of combined albedazole-IFN-α treatment for cystic echinococcosis in mice

Cystic echinococcosis (CE) is a serious helminthic zoonosis caused by Echinococcus granulosus metacestode worldwide. The current chemotherapy of CE is mainly based on albendazole (ABZ). However, more than 20% CE cases failed to such chemotherapy. Thus, novel and more efficient treatment options are urgently needed. This study was to evaluate the in vivo efficacy of combined ABZ-interferon (IFN)-α treatment for CE in mice. After 5 months of secondary infection with protoscoleces, mice were randomly allocated into four groups: ABZ-treated group, IFN-α-treated group, ABZ+IFN-α group, and untreated control group. Drugs in diverse treated groups were respectively administered for 2 months. Mice were then euthanized and associated indications were investigated to evaluate the therapeutic efficacy. ABZ+IFN-α induced a significant reduction of the number, size, as well as weight of cysts, compared with that in the ABZ (p < 0.05) or untreated group (p < 0.01), respectively. This effect was associated with ultrastructural modification of the cyst in the ABZ+IFN-α group. Interestingly, significant decrease of IL (interleukin)-10 in serum and in vitro production by spleen cells with ABZ+IFN-α treatment was observed in comparison with untreated control (p < 0.01). Serum IgE, IgG, and subsets were respectively decreased in ABZ+IFN-α treatment, compared with that in the control group (p < 0.01). In conclusion, our findings demonstrated that combination of ABZ with IFN-α may contribute to an efficient therapeutic regimen of human and animal CE.

Visualization and Pathological Characteristics of Hepatic Alveolar Echinococcosis with Synchrotron-based X-ray Phase Sensitive Micro-tomography

Propagation-based phase-contrast computed tomography (PPCT) utilizes highly sensitive phase-contrast technology applied to X-ray micro-tomography, especially with the extensive use of synchrotron radiation (SR). Performing phase retrieval (PR) on the acquired angular projections can enhance image contrast and enable quantitative imaging. We employed the combination of SR-PPCT and PR for the histopathological evaluation of hepatic alveolar echinococcosis (HAE) disease and demonstrated the validity and superiority of PR-based SR-PPCT. A high-resolution angular projection data set of a human postoperative specimen of HAE disease was acquired, which was processed by graded ethanol concentration fixation (GECF). The reconstructed images from both approaches, with the projection data directly used and preprocessed by PR for tomographic reconstruction, were compared in terms of the tissue contrast-to-noise ratio and density spatial resolution. The PR-based SR-PPCT was selected for microscale measurement and the 3D visualization of HAE disease. Our experimental results demonstrated that the PR-based SR-PPCT technique is greatly suitable for the discrimination of pathological tissues and the characterization of HAE. In addition, this new technique is superior to conventional hospital CT and microscopy for the three-dimensional, non-destructive microscale measurement of HAE. This PR-based SR-PPCT technique has great potential for in situmicroscale histopathological analysis and diagnosis, especially for applications involving soft tissues and organs.

Cystic echinococcosis therapy: Albendazole-loaded lipid nanocapsules enhance the oral bioavailability and efficacy in experimentally infected mice

Therapeutic failures attributed to medical management of cystic echinococcosis (CE) with albendazole (ABZ) have been primarily linked to the poor drug absorption rate resulting in low drug level in plasma and hydatid cysts. Lipid nanocapsules (LNCs) represent nanocarriers designed to encapsulate lipophilic drugs, such as ABZ. The goals of the current work were: (i) to characterize the plasma and cyst drug exposure after the administration of ABZ as ABZ-LNCs or ABZ suspension (ABZ-SUSP) in mice infected with Echinococcus granulosus, and ii) to compare the clinical efficacies of both ABZ formulations. Enhanced ABZ sulphoxide (ABZ-SO) concentration profiles were obtained in plasma and cysts from ABZ-LNC treated animals. ABZSO exposure (AUC0-LOQ) was significantly higher in plasma and cyst after the ABZ-LNC treatments, both orally and subcutaneously, compared to that observed after oral administration of ABZ-SUSP. Additionally, ABZSO concentrations measured in cysts from ABZ-LNC treated mice were 1.7-fold higher than those detected in plasma. This enhanced drug availability correlated with an increased efficacy against secondary CE in mice observed for the ABZ-LNCs, while ABZ-SUSP did not reach differences with the untreated control group. This new pharmacotechnically-based strategy could be a potential alternative to improve the treatment of human CE.

Efficacy of Albendazole-Chitosan Microsphere-based Treatment for Alveolar Echinococcosis in Mice

This study aimed to investigate the pharmacology and anti-parasitic efficacy of albendazole–chitosan microspheres (ABZ-CS-MPs) for established intraperitoneal infections of Echinococcus multilocularis metacestodes in an experimental murine model. Male outbred Kunming mice infected with E. multilocularis Metacestodes were administered with three ABZ formulations, namely, ABZ-CS-MPs, Liposome–Albendazole (L-ABZ), and albendazole tablet (ABZ-T). Each of the ABZ formulations was given orally at three different doses of 37.5, 75, and 150mg/kg, three times a week for 12 weeks postinfection. After administering the drugs, we monitored the pharmacological performance and anti-parasitic efficacy of ABZ-CS-MPs compared with L-ABZ, and ABZ-T treated mice. ABZ-CS-MPs reduced the weight of tissues containing E. multilocularis metacestodes most effectively compared with the ABZ-T group and untreated controls. Metacestode grown was Highly suppressed during treatment with ABZ-CS-MPs. Significantly higher plasma levels of ABZ metabolites were measured in mice treated with ABZ-CS-MPs or L-ABZ compared with ABZ-T. In particular, enhanced ABZ-sulfoxide concentration profiles were observed in the mice given 150mg/kg of ABZ-CS-MPs, but not in the mice treated with L-ABZ. Histological examination showed that damages caused disorganization of both the germinal and laminated layers of liver hyatid cysts, demolishing their characteristic structures after treatment with ABZ-CS-MPs or L-ABZ. Over time, ABZ-CS-MPs treatment induced a shift from Th2-dominant to Th1-dominant immune response. CS-MPs As a new carrier exhibited improved absorption and increased bioavailability of ABZ in the treatment of E. multilocularis infections in mice.

Alveolar echinococcosis (AE) is caused by the metacestode stage of Echinococcus multilocularis and is a rare but life-threatening disease. Albendazole is the most frequently used anti-parasitic drugs in patients infected with AE. However, ABZ has only limited water solubility, and small differences in drug solubility may have a major influence on their absorption and resultant pharmacokinetic behavior. Chitosan microspheres as a new carrier increased ABZ absorption and bioavailability. The anti-parasitic efficacy of albendazole–chitosan microspheres (ABZ-CS-MPs) in mice infected with Echinococcus multilocularis was assessed. ABZ-loaded CS-MPs exhibited improved absorption and increased bioavailability in the treatment of E. multilocularis infections in mice compared with those treated with liposome–albendazole and albendazole tablet. ABZ-CS-MPs are in solid form that can be manufactured in capsules or tablets, which can be easily delivered to those in need, particularly those who are nomadic. Therefore, given the merits of low cost, portability, and simple manufacturing, ABZ-CS-MPs are a promising drug to treat alveolar echinococcosis.

In vitro effect of 5-fluorouracil and paclitaxel on Echinococcus granulosus larvae and cells

Human cystic echinococcosis is a zoonosis caused by the metacestode stage of the tapeworm Echinococcus granulosus. Although benzimidazole compounds such as albendazole and mebendazole have been the cornerstone of chemotherapy for the disease, there is often no complete recovery after treatment. Hence, in searching for novel treatment options, we examined the in vitro efficacies of 5-fluorouracil (5-FU) and paclitaxel (PTX) against E. granulosus germinal cells, protoscoleces and cysts. 5-FU or PTX inhibited the growth of E. granulosus cells in a time dependent manner. Although both treatments had a protoscolicidal effect, 5-FU had a considerably stronger effect than PTX. 5-FU produced a dose- and time-dependent effect, provoking the complete loss of viability after 24 days of incubation. Moreover, cysts did not develop following the inoculation of treated protoscoleces into mice. The loss of viability was slower in PTX treated protoscoleces, reaching to approximately 60% after 30 days. The results of the in vitro treatment with 5-FU and PTX were similar in secondary murine cysts. The employment of SEM and TEM allowed us to examine, at an ultrastructural level, the effects induced by 5-FU and PTX on E. granulosus germinal cells, protoscoleces and murine cysts. In conclusion, the data obtained clearly demonstrated that 5-FU and PTX at clinically achievable concentrations inhibit the survival of larval cells, protoscoleces and metacestodes. In vivo studies to test the antiparasitic activities of 5-FU and PTX are currently being undertaken on the murine model of cystic echinococcosis.

In vivo study of the efficacy of the aromatic water of Zataria multiflora on hydatid cysts

Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) were employed to determine the chemical composition of the essential oil (EO) from aromatic water (AW) of Zataria multiflora. Thymol (66.9%), carvacrol (15.2%), and carvone (7.3%) were found to be the major EO constituents. Eighty laboratory BALB/c mice were infected intraperitoneally by injection of 1,500 viable protoscolices and were divided into prevention (40 mice) and therapeutic (40 mice) groups. To prove the preventive effect of the Z. multiflora AW on development of hydatid cysts, the 40 infected mice were allocated into three treatment groups, including the albendazole group (10 mice that received 150 mg/kg body weight/day for 10 days), the Z. multiflora AW group (15 mice that received 20 ml/liter in drinking water for 8 months), and a control group (15 mice that received no treatment). To estimate the therapeutic effect of the Z. multiflora AW on the hydatid cyst, after 8 months of infection, the 15 remaining mice were allocated into three experimental treatment groups of five animals each, including the albendazole group (300 mg/kg/day for 20 days), Z. multiflora AW group (40 ml/liter in drinking water for 30 days), and control group (no treatment). All mice were then euthanized, and the sizes and weights of the cysts as well as their ultrastructural changes were investigated. The weights and sizes of the hydatid cysts significantly decreased upon treatment with the Z. multiflora AW in both the preventive and therapeutic groups (P < 0.05). The results of scanning electron microscopy also showed considerable damage in the germinal layer of the hydatid cysts recovered from the treated animals.

In vitro and in vivo effects of tamoxifen against larval stage Echinococcus granulosus

Cystic echinococcosis is a zoonotic infection caused by the larval stage of the cestode Echinococcus granulosus. Chemotherapy currently employs benzimidazoles; however, 40% of cases do not respond favorably. With regard to these difficulties, novel therapeutic tools are needed to optimize treatment in humans. The aim of this work was to explore the in vitro and in vivo effects of tamoxifen (TAM) against E. granulosus. In addition, possible mechanisms for the susceptibility of TAM are discussed in relation to calcium homeostasis, P-glycoprotein inhibition, and antagonist effects on a putative steroid receptor. After 24 h of treatment, TAM, at a low micromolar concentration range (10 to 50 μM), inhibited the survival of E. granulosus protoscoleces and metacestodes. Moreover, we demonstrated the chemotherapeutic and chemopreventive pharmacological effects of the drug. At a dose rate of 20 mg/kg of body weight, TAM induced protection against the infection in mice. In the clinical efficacy studies, a reduction in cyst weight was observed after the administration of 20 mg/kg in mice with cysts developed during 3 or 6 months, compared to that of those collected from control mice. Since the collateral effects of high TAM doses have been largely documented in clinical trials, the use of low doses of this drug as a short-term therapy may be a novel alternative approach for human cystic echinococcosis treatment.

Enhanced bioavailability and cysticidal effect of three mebendazole-oil preparations in mice infected with secondary cysts of Echinococcus granulosus

The aim of the present study is to explore the possibility to increase the efficacy of mebendazole (MBZ) against secondary cysts of Echinococcus granulosus harbored in mice by augmenting the solubility and bioavailability of the drug. Firstly, the saturated solubility of MBZ in nine kinds of oil was determined by high performance liquid chromatography (HPLC), and MBZ was found exhibiting the highest, secondary, and lowest solubility in oleic acid (OA), glycerol trioleate (GT), and soybean oil (SB), respectively. Secondly, MBZ-OA suspension, MBZ-GT suspension, MBZ-SB suspension, and MBZ suspended in 1 % tragacanth (MBZ-1 % tragacanth) were selected for further studies on pharmacokinetics and experimental therapy in mice. Four groups of mice were treated orally with one of aforementioned four MBZ preparations at a single dose of 25 mg/kg, and concentrations of MBZ in plasma obtained from each mouse at various intervals within 24 h postadministration were determined by HPLC. The major pharmacokinetic parameters calculated by MBZ plasma concentration-time curve demonstrated that the peak concentration of the drug (C (max) ) values obtained from three MBZ-oil preparation groups was 1.6-2.8 times higher than that of MBZ-1 % tragacanth group. The same was true that the area under the drug concentration-time curve (AUC(0-∞)) values of 19.8 (2.5)-28.2 (2.5) μg/ml × h revealed in the three MBZ-oil preparation groups was significantly higher than that of 11.6 (2.0) μg/ml × h in MBZ-1 % tragacanth group, and the bioavailability of the three MBZ-oil preparation groups was 71-143 % higher than that of MBZ-1 % tragacanth group. In mice infected with secondary cysts of E. granulosus for 8 months treated orally with MBZ-1 % tragacanth at a daily dose of 25 mg/kg for 14 consecutive days, the mean cyst weight was lower than that of untreated control, but the difference was not statistically significant with cyst weight reduction of 48 %. When the infected mice received three MBZ-oil preparations at the same oral dose schedule as aforementioned, the mean cyst weights were significantly lower than those in MBZ-1 % tragacanth group or control group with cyst weight reductions of 71.2-84.7 %. The results indicate that the solubility of MBZ in oils may increase to various degrees according to the kinds of oil used. Meanwhile, three MBZ-oil (OA, GT, and SB) preparations administered orally to mice not only improve the bioavailability of MBZ relative to that of MBZ suspended in 1 % tragacanth, but their effects against hydatid cysts also significantly enhance.

Gene cloning, expression, and localization of antigen 5 in the life cycle of Echinococcus granulosus

Antigen 5 (Ag5) has been identified as a dominant component of cyst fluid of Echinococcus granulosus and is considered as a member of serine proteases family, which in other helminth, plays an important role in the egg hatch and larva invasion. However, whether Ag5 is expressed and secreted in all life stages is unknown. In this study, according to the sequence in GenBank, we cloned and sequenced the open reading frame (ORF) of Ag5 gene from the protoscolices of E. granulosus isolated from the sheep in Qinhai Province of China, and found several substitutions and a base insert and deletion in a short region near the stop code, leading to a frameshift mutation which is conserved with the homologue of other cestode. The ORF is 1,455 bp in length, encoding 484 amino acids with a secretory signal peptide. Bioinformatics analysis predicted several phosphorylation and myristoylation sites and a N-glycosylation site and a species-specific linear B epitope in the protein. The ORF was cloned into the plasmid pET28a(+) vector and expressed in Escherichia coli . The recombinant protein was purified by affinity chromatography. Anti-rEgAg5 antiserum was prepared in rats and used to analyze the localization of Ag5 in protoscolex and adult worm by immunofluorescence technique. Results demonstrated that the Ag5 is strongly expressed in the tegument of protoscolex and the embryonic membrane of egg and surface of oncosphere; meanwhile, it is also weakly expressed in tegument of the adult. This study showed that Ag5 is expressed in all stages of life cycle, secreted from the surface of the worm and may be anchored in membrane by its myristoylation sites; these characteristics make it a candidate antigen for diagnosis and vaccine for both intermediate and definitive hosts.

Comparative performances of flubendazole and albendazole in cystic echinococcosis: ex vivo activity, plasma/cyst disposition, and efficacy in infected mice

The need to identify improved therapy against cystic echinococcosis (CE) has motivated pharmacology-based research. The comparative pharmacological performances of the benzimidazole compounds flubendazole (FLBZ) and albendazole (ABZ) were addressed here. The goals of the work were as follows: (i) to evaluate the ex vivo activities of FLBZ, ABZ, and their respective metabolites against Echinococcus granulosus protoscoleces, (ii) to compare the plasma and cyst disposition kinetics for the two drugs in infected mice, and (iii) to compare the clinical efficacies of FLBZ and ABZ against CE in mice. For the ex vivo study, E. granulosus protoscoleces were incubated with FLBZ, reduced FLBZ (R-FLBZ), ABZ, and ABZ-sulfoxide (ABZSO) (10 nmol/ml). Protoscolex viability was monitored by the methylene blue exclusion test and scanning electron microscopy (SEM). For the pharmacokinetic study, BALB/c mice with CE were allocated to two different groups and orally treated with either FLBZ or ABZ (5 mg/kg of body weight), both formulated as a cyclodextrin-based solution. Blood and cyst samples were taken up to 12 h posttreatment and analyzed by high-performance liquid chromatography (HPLC). For the efficacy study, CE-infected BALB/c mice were divided into three groups: the unmedicated control group and the FLBZ- and ABZ-treated groups. Oral treatments were performed twice a day during 25 days. After treatment, all animals were killed and the weight of the cysts was recorded. Loss of protoscolex viability was observed after drug incubation. FLBZ was detected in plasma (area under the concentration-versus-time curve [AUC] = 1.8 μg · h/ml) and cysts (AUC = 0.3 μg · h/g) collected from treated infected animals. Conversely, ABZSO was the only active molecule measured in plasma (AUC = 4.4 μg·h/ml) and cysts (AUC = 1.5 μg·h/g) after ABZ treatment. FLBZ induced a 90% reduction in cyst weight in comparison to those collected from untreated control mice (P < 0.05). However, no differences in cyst weight were observed between the ABZ-treated (8.2 g) and unmedicated control (10.5 g) groups. Due to these results, we consider flubendazole to have great potential to become a drug of choice in the treatment of cystic echinococcosis.

A patient presenting with abdominal pain to the general practitioner: a case report

Introduction

Right-sided upper abdominal pain is a common cause of presentation to general practitioners.

Case presentation

An otherwise well 46-year-old woman presented to her general practitioner with intermittent abdominal pain that had been present for several months. The only abnormality found at the initial consultation was moderate tenderness in the right upper abdomen. The laboratory tests that were ordered showed elevated parameters of inflammation. Sonography suggested the presence of an echinococcal cyst in segment VIII of the liver. Computed tomography confirmed this finding and showed no other cysts. On the basis of serological tests and the clinical findings, a diagnosis of Echinococcus granulosus infection was made. The patient was therefore admitted to hospital for surgical removal of the cyst. Her postoperative recovery was without complication and she remained free of symptoms.

Conclusion

Echinococcus granulosus infections are rare in Germany, with an incidence of 1:1,000,000. The sonographic appearances are generally characteristic and permit diagnosis. Treatment is pharmacological (albendazole, mebendazole) and surgical. It is curative in the vast majority of cases. The possibility of echinococcal infection should be considered in patients, especially immigrants, with abdominal pain.

Flubendazole in cystic echinococcosis therapy: pharmaco-parasitological evaluation in mice

Cystic echinococcosis (CE) caused by the parasite Echinococcus granulosus is an important public health problem worldwide. Flubendazole has shown poor in vivo efficacy against CE in humans and mice. However, flubendazole causes marked in vitro damage on E. granulosus protoscoleces. The goals of the current work were: a) to compare the plasma pharmacokinetic behaviour of flubendazole formulated as a hydroxipropyl-beta-cyclodextrin aqueous solution or as a carboxymethyl celullose suspension, both given by the oral route to mice, b) to compare flubendazole clinical efficacy in secondary CE in mice after its administration as both formulations, c) to evaluate the flubendazole-induced morphological changes in hydatid cysts recovered from infected mice treated with both drug formulations. Flubendazole administration as a solution resulted in significantly higher plasma maximum concentration (C(max)) and area under the concentration-time curve (AUC) values compared to those obtained after the flubendazole-suspension treatment. This enhanced drug availability correlated with an increased efficacy against secondary CE in mice observed for the flubendazole-solution formulation, while the suspension formulation did not reach differences with the untreated control group. Similar ultrastructural changes were observed in cysts recovered from flubendazole (both formulations) treated mice after 3, 6 and 9months of infection, although the damage extension was greater after treatment with the flubendazole-solution formulation.