Two novel ternary albendazole-cyclodextrin-polymer systems: dissolution, bioavailability and efficacy against Taenia crassiceps cysts

Evaluation of β-lapachone-methyl-β-cyclodextrin inclusion complex prepared by spray drying and its application against different developmental stages of Schistosoma mansoni in murine model

BACKGROUND

β-lapachone (β-lap) is a naphthoquinone widely found in species of vegetables. However, its poor aqueous solubility limits its systemic administration and clinical applications in vivo. To overcome this limitation, several studies have been carried out in order to investigate techniques that can enhance the solubility and dissolution rate of β-lap, such as the use of inclusion complexes with cyclodextrin.

PURPOSE

To evaluate the in vivo effect of β-lap complexed in methyl-β-cyclodextrin (MβCD) on the evolutionary stages of Schistosoma mansoni in a murine model.

METHODS

The development and characterization of the physicochemical properties of the inclusion complex of β-lap in β-lap:MβCD was prepared by solubility and dissolution tests, FTIR, DSC, X-RD and SEM. The mice were infected and subsequently treated with β-lap:MβCD orally with 50 mg/kg/day and 100 mg/kg/day for 5 consecutive days, starting therapy on the 1^st (skin schistosomula), 14^th (pulmonary schistosomula), 28^th (young worms) and 45^th (adult worms) days after infection. Control groups were also formed; one infected untreated, treated with MβCD, and the other treated with PZQ.

RESULTS

The loss of the crystalline form of β-lap in the β-lap:MβCD complex obtained by spray drying was proven through physical-chemical characterization analyses. β-lap:MβCD caused reduction in the number of worms of the 33.56%, 35.7%, 35.45% and 36.45%, when the dose was at 50 mg/kg, and 65.00%, 60.34%, 52.72% and 65.01%, in the dose 100 mg/kg; when treatment was started in the 1^st, 14^th, 28^th and 45^th days after infection, respectively. It was also possible to observe a significant reduction in the number of immature eggs and an increase in the number of ripe and dead eggs and, consequently, a reduction in the damage caused by the egg antigens to the host tissue, where we attributed the reduction in the average diameter of the granulomas to the β-lap.

CONCLUSION

The dissolved content of β-lap:MβCD by spray drying reached almost 100%, serving for future formulations and delineation of the mechanisms of action of β-lap against S. mansoni.

Albendazole-loaded cubosomes interrupt the ERK1/2-HIF-1α-p300/CREB axis in mice intoxicated with diethylnitrosamine: A new paradigm in drug repurposing for the inhibition of hepatocellular carcinoma progression

Hepatocellular carcinoma (HCC) is a leading cause of cancer related deaths worldwide. It was suggested that albendazole (ABZ) is a powerful inhibitor of several carcinoma types. However, the bioavailability of ABZ is very poor. Additionally, the mechanisms underlying the antitumor effects of ABZ may go beyond its tubulin-inhibiting activity. Therefore, we aimed to examine the effects of ABZ suspension (i.p. and p.o.) and ABZ-loaded cubosomes (LC) on the diethylnitrosamine-induced HCC in mice. ABZ-loaded nanoparticles exhibited a mean particle size of 48.17 ± 0.65 nm and entrapped 93.26 ± 2.48% of ABZ. The in vivo absorption study confirmed a two-fold improvement in the relative bioavailability compared with aqueous ABZ suspension. Furthermore, the oral administration of ABZ cubosomal dispersion demonstrated regression of tumor production rates that was comparable with ABZ (i.p.). ABZ relieved oxidative stress, improved liver function, and decreased necroinflammation score. The antiangiogenic activity was evident as ABZ effectively downregulated tissue expression of CD34, mRNA expression of CD309 and VEGF at the protein expression level. Besides, lower levels of MMP-9 and CXCR4 indicated antimetastatic activity. ABZ showed a considerable level of apoptotic activity as indicated by increased mRNA expression level of p53 and the increased Bax/BCL-2 ratio and active caspase-3. Additionally, Ki-67 expression levels were downregulated showing an antiproliferative potential. These protective effects contributed to increasing survival rate of diethylnitrosamine-treated mice. These effects found to be mediated via interrupting ERK1/2-HIF-1α-p300/CREB interactions. Therefore, our findings revealed that disrupting ERK1/2-HIF-1α-p300/CREB interplay might create a novel therapeutic target for the management of HCC.

Metabolic effects of anthelminthic drugs in the larval stage of the cestode Taenia crassiceps, cysticercosis experimental model - A review

Taenia crassiceps is an experimental model used for cysticercosis studies and has suffered metabolic analyzes regarding the effect of anthelminthic drugs. The metabolic analyses are useful tools to determine the drugs mode of action and the parasite`s survival mechanisms. The energetic pathways are good candidates for this kind of approach as they are essential for the parasite`s survival and adaptation to the environment. In this review we discuss the anthelminthic drugs mode of action and its metabolic impact on Taenia crassiceps cysticerci.

Cysticidal activity of praziquantel-mebendazole combination: In vitro and in vivo studies

The current pharmacological treatment of neurocysticercosis is based on two drugs, praziquantel (PZQ) and albendazole; however, suboptimal efficacy has been documented. Previous studies, have documented the activity of mebendazole (MBZ) against Taenia sp, and its capability to cross the blood-brain barrier. Considering this information and in an effort to search other options for neurocysticercosis treatment, the present study was designed to assess the in vitro and in vivo activity of the PZQ-MBZ combination against Taenia crassiceps metacestodes. For the in vitro studies T. crassiceps cysticerci (ORF strain) were used and the analysis of the combinations was performed using the Surface of Synergistic Interaction (SSI). For the in vivo evaluation the experimental infection model of T. crassiceps ORF in Balb-C mice was used. In vitro results showed that the combination of PZQ 121.6 nM-MBZ 5.1 nM exhibited the highest synergic cysticidal effect. In vivo, the PZQ-MBZ combination (25 mg/kg - 50 mg/kg, respectively) was more effective than each drug alone. The findings indicate that PZQ in combination with MBZ could be a promising alternative for the treatment of neurocysticercosis. Complementary studies are required to confirm its clinical applicability.

Chitosan coated nanostructured lipid carriers for enhanced in vivo efficacy of albendazole against Trichinella spiralis

The study investigated chitosan coated nanostructured lipid carriers (NLCs) for oral delivery of albendazole in treatment of trichinellosis. NLCs comprised precirol and oleic acid with Tween and Span 80. Dicetylphosphate was used as charging agent to allow chitosan coating. Trichinella spiralis infected mice were used and albendazole suspension, coated or uncoated NLCs were orally administered at different stages of infection. NLCs were spherical with size of 188 and 200 nm for coated and uncoated NLC, respectively. Treatment during intestinal phase reduced worm count with NLCs showing better rank. This was reflected further by reduced larvae count and improved histopathological features. Starting treatment in the migrating phase reduced larval count by 62.9, 99.6 and 89.5 % after administration of suspension, coated and uncoated NLCs, respectively. The same rank was recorded for the encysted phase. NLCs enhanced the efficacy of albendazole against Trichinella spiralis compared with suspension with chitosan coated NLCs being superior.

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.

Synthesis and characterization of mesoporous SBA-15 and SBA-16 as carriers to improve albendazole dissolution rate

Albendazole (ABZ, anti-parasitic active pharmaceutical ingredient) is a crystalline low water-soluble drug, thus the dissolution rate in gastrointestinal fluids is limited. Consequently, the improvement of the water solubility and dissolution rate of ABZ implies a great challenge for a more efficient treatment of hydatidosis. In this context, SBA-15 and SBA-16 ordered mesoporous silica materials were synthetized and loaded with ABZ. X-ray diffraction, FT-IR spectroscopy, nitrogen physisorption manometry, particle size distribution and scanning electronic microscopy were used to characterize unloaded and loaded materials (ABZ/SBA-15 and ABZ/SBA-16). The loaded ABZ amount in the carriers was estimated by elemental analysis. For the loaded materials, the drug solubility and release profile were evaluated. In addition, mathematical models were compared to explain the dissolution kinetics of ABZ from mesoporous solids. ABZ was successfully loaded into the mesopores. The amorphous state of the adsorbed ABZ was confirmed by differential scanning calorimetry that resulted in a notable increment in the dissolution rate compared to crystalline ABZ. Drug release behaviors were well simulated by the Weibull model for ABZ/SBA-15 and by the Gompertz function for pure ABZ and ABZ/SBA-16. The SBA-15 carrier exhibited the highest drug loading and dissolution rate becoming a promising material to improve ABZ bioavailability.

Albendazole nanocrystals with improved pharmacokinetic performance in mice

AIM

Albendazole (ABZ) is a broad-spectrum antiparasitic agent with poor aqueous solubility, which leads to poor/erratic bioavailability and therapeutic failures. Here, we aimed to produce a novel formulation of ABZ nanocrystals (ABZNC) and assess its pharmacokinetic performance in mice. Results/methodology: ABZNC were prepared by high-pressure homogenization and spray-drying processes. Redispersion capacity and solid yield were measured in order to obtain an optimized product. The final particle size was 415.69±7.40 nm and the solid yield was 72.32%. The pharmacokinetic parameters obtained in a mice model for ABZNC were enhanced (p < 0.05) with respect to the control formulation.

CONCLUSION

ABZNC with improved pharmacokinetic behavior were produced by a simple, inexpensive and potentially scalable methodology.

Inclusion complex and nanoclusters of cyclodextrin to increase the solubility and efficacy of albendazole

Albendazole (ABZ), a benzimidazole widely used to control gastrointestinal parasites, is poorly soluble in water, resulting in variable and incomplete bioavailability. This has favored the appearance ABZ-resistant nematodes and, consequently, an increase in its clinical ineffectiveness. Among the pharmaceutical techniques developed to increase drug efficacy, cyclodextrins (CDs) and other polymers have been extensively used with water-insoluble pharmaceutical drugs to increase their solubility and availability. Our objective was to prepare ABZ formulations, including β-cyclodextrin (βCD) or hydroxypropyl-β-cyclodextrin (HPβCD), associated or not to the water-soluble polymer polyvinylpyrrolidone (PVP). These formulations had their solubility and anthelmintic effect both evaluated in vitro. Also, their anthelmintic efficacy was evaluated in lambs naturally infected with gastrointestinal nematodes (GIN) through the fecal egg count (FEC) reduction test. In vitro, the complex ABZ/HPβCD had higher solubility than ABZ/βCD. The addition of PVP to the complexes increased solubility and dissolution rates more effectively for ABZ/HPβCD than for ABZ/βCD. In vivo, 48 lambs naturally infected with GIN were divided into six experimental groups: control, ABZ, ABZ/βCD, ABZ/βCD-PVP, ABZ/HPβCD, and ABZ/HPβCD-PVP. Each treated animal received 10 mg/kg of body weight (based on the ABZ dose) for three consecutive days. After 10 days of the last administered dose, treatment efficacy was calculated. The efficacy values were as follows: ABZ (70.33%), ABZ/βCD (85.33%), ABZ/βCD-PVP (82.86%), ABZ/HPβCD (78.37%), and ABZ/HPβCD-PVP (43.79%). In vitro, ABZ/HPβCD and ABZ/HPβCD-PVP had high solubility and dissolution rates. In vivo, although the efficacies of ABZ/βCD, ABZ/βCD-PVP, and ABZ/HPβCD increased slightly when compared to pure ABZ, this increase was not significant (P > 0.05).

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.

Super Aqueous Solubility of Albendazole in β-Cyclodextrin for Parenteral Application in Cancer therapy

Poor aqueous solubility of anticancer drug, albendazole (ABZ), prevents parenteral application. Here, we demonstrate how to increase the aqueous solubility of ABZ to 6- 8 mg/ml using sulfobutylether - β-cyclodextrin (SBE-β-CD) or Hydroxypropyl- β-cyclodextrin (HP- β-CD) by manipulation of complexation parameters such as the physical state of ABZ (ionized in acetic acid), the concentration of ionised ABZ, agitation time and temperature. Solubility was first examined with suspension of excess ABZ powder in cyclodextrin (CD) solutions at pH (2.3, 4.0 & 7.0), subsequently with excess ionised ABZ [ABZ] at pH. 2.3 with the determination of optimal quantity of [ABZ] use for maximal complexation. Complexation time, temperature effect, stability of formulation, with in vitro and in vivo cytotoxicity of [ABZ]-SBE-β-CD was assessed. Suspended ABZ formulation at pH 2.3 showed maximum solubilisation of 2.29 & 1.72 mg/ml, whilst excess addition of [ABZ] showed poor complexation (1.26 & 1.20 mg/ml) in SBE-β-CD & HP- β-CD, respectively. The addition of 8.0 mg/ml and 7.0 mg/ml of [ABZ] to 40% CD solutions at 25ºC showed maximum complexation with SBE-β-CD & HP- β-CD, respectively, at three days, with 2 weeks stability. [ABZ] complexed with SBE-β-CD showed potent cytotoxicity (in vitro & in vivo) in ovarian tumour cells. Hence, the current method may be used for solubilising ABZ for parenteral use.

Characterizations and bioactivities of abendazole sulfoxide-loaded thermo-sensitive hydrogel

Albendazole (ABZ), a widely used anthelmintic, attributes its primary metabolite-albendazole sulfoxide (ABZSO)-as an effective agent against helminthes. For a purpose of long-lasting releasing ABZSO in a special lesion, the present study successfully manufactured ABZSO-loaded thermo-sensitive hydrogel, which was proved by FTIR and ¹H NMR, in the interim; in vitro and in vivo behaviors of the thermo-sensitive hydrogel containing ABZSO were studied too. The in vivo pharmacokinetics parameters indicated ABZSO-loaded hydrogel as a better choice for sustained release compared with simple ABZSO. Additionally, the effect of the prepared hydrogels against helminth was investigated by the lethality of Caenorhabditis elegans, the results indicated that the lethality of ABZSO-loaded hydrogel (1, 2, and 4 mg/ml, respectively) on C. elegans was higher than that of PLGA-PEG-PLGA group (P < 0.05). It suggested that the hydrogels loaded with albendazole sulfoxide could be considered highly effective against the nematode C. elegans.

Effect of nitazoxanide on albendazole pharmacokinetics in cerebrospinal fluid and plasma in rats

Background: Although albendazole is the drug-of-choice for the treatment of neurocysticercosis, its efficacy is limited due to its low bioavailability. An alternative for optimizing pharmacological treatment is through drug combinations. In vitro studies have shown that nitazoxanide and tizoxanide (the active metabolite of nitazoxanide) exhibit cysticidal activity and that the combination of tizoxanide with albendazole sulfoxide (the active metabolite of albendazole) produced an additive effect. Objectives: (1) To assess the concentration profile of tizoxanide in plasma and in cerebrospinal fluid; and (2) to evaluate the influence of nitazoxanide on the pharmacokinetics of albendazole in plasma and in cerebrospinal fluid. Methods: Two different studies were conducted. In study 1, 10 male Sprague-Dawley rats received a single oral dose of 7.5 mg/kg of nitazoxanide and serial blood and cerebrospinal fluid samples were collected over a period of 4 h. In study 2, 38 healthy male Sprague-Dawley rats were randomly divided into two groups: one of these received a single dose of albendazole (15 mg/kg) and, in the other group, albendazole (15 mg/kg) was co-administered with nitazoxanide (7.5 mg/kg). Plasma and cerebrospinal fluid samples were collected from 0 to 16 h after administration. Albendazole sulfoxide and tizoxanide levels were assayed by using HPLC or LC/MS techniques. Results: In study 1, tizoxanide reached a maximum plasma concentration of 244.42 ± 31.98 ng/mL at 0.25 h; however, in cerebrospinal fluid, this could be detected only at 0.5 h, and levels were below the quantification limit (10 ng/mL). These data indicate low permeation of tizoxanide into the blood brain barrier. In study 2, Cmax, the area under the curve, and the mean residence time of albendazole sulfoxide in plasma and cerebrospinal fluid were not affected by co-administration with nitazoxanide. Conclusion: The results of the present study indicate that in rats at the applied doses, tizoxanide does not permeate into the cerebrospinal fluid. Furthermore, nitazoxanide does not appear to alter significantly the pharmacokinetics of albendazole in plasma or in cerebrospinal fluid.

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.

Abnormalities in the WFU strain ofTaenia crassiceps(Cyclophyllidea: Taeniidae) following years of propagation in mice

Asexually proliferatingTaenia crassiceps(Zeder, 1800) metacestodes isolated within past decades have been successfully sub-cultured under experimental conditions usingMus musculusLinnaeus, 1758 mice. However, during their development, morphological irregularities of scolex structures have been reported in two of the three strains of this cestode species maintained in mice – ORF and KBS. The main goal of this work is to describe the abnormalities observed in a sample of 118 cysticerci of the thirdT.crassicepsstrain used at present – WFU. Morphological abnormalities were detected in 39.8% of the evaginated scoleces; they consisted of supernumerary suckers (n= 2), duplicated (n= 2) or absent rostellum (n= 1), as well as absent or aberrant (n= 29) hooks, which were significantly shorter when compared to the large and short hook lengths referred to in the literature.

Murine cysticercosis model: influence of the infection time and the time of treatment on the cysticidal efficacy of albendazole and praziquantel

In the search of new alternatives for neurocysticercosis treatment, Taenia crassiceps ORF strain cysticerci have been used instead of T. solium for in vitro studies. Up to date, the main criteria for the use of the murine cysticercosis model for drug efficacy evaluation have not been assessed. The aim of the present study was to evaluate the influence of two of the main variables related to the in vivo efficacy: the length of drug treatment and the starting time of treatment after experimental infection, using albendazole (ABZ) and praziquantel (PZQ) as test drugs. Additionally, the relationship between the number of cysts and the parasite weight was assessed. For the study, female BALB/c mice were experimentally infected with T. crassiceps cysts. Three different post-infection periods (10, 20 and 30 days) and three different lengths of treatment with ABZ or PZQ (10, 20 and 30 days) were selected. The efficacy of each treatment was evaluated by comparison with a control group. Our results show that for in vivo efficacy studies, the best time to start the drug treatment is 10 days post-infection and that a minimum of 20 days of treatment is required when ABZ or PZQ are used as positive control. Moreover, in this model the parasite weight can be used as a rapid tool to measure the in vivo drug activity.

Characterization of albendazole-randomly methylated-β-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 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.

Modified β-cyclodextrin inclusion complex to improve the physicochemical properties of albendazole. complete in vitro evaluation and characterization

The potential use of natural cyclodextrins and their synthetic derivatives have been studied extensively in pharmaceutical research and development to modify certain properties of hydrophobic drugs. The ability of these host molecules of including guest molecules within their cavities improves notably the physicochemical properties of poorly soluble drugs, such as albendazole, the first chosen drug to treat gastrointestinal helminthic infections. Thus, the aim of this work was to synthesize a beta cyclodextrin citrate derivative, to analyze its ability to form complexes with albendazole and to evaluate its solubility and dissolution rate. The synthesis progress of the cyclodextrin derivative was followed by electrospray mass spectrometry and the acid-base titration of the product. The derivative exhibited an important drug affinity. Nuclear magnetic resonance experiments demonstrated that the tail and the aromatic ring of the drug were inside the cavity of the cyclodextrin derivative. The inclusion complex was prepared by spray drying and full characterized. The drug dissolution rate displayed exceptional results, achieving 100% drug release after 20 minutes. The studies indicated that the inclusion complex with the cyclodextrin derivative improved remarkably the physicochemical properties of albendazole, being a suitable excipient to design oral dosage forms.

Development of the S3Pvac vaccine against murine Taenia crassiceps cysticercosis: a historical review

Our work of the last 25 yr was concerned with the development of a vaccine aimed to prevent porcine Taenia solium cysticercosis and was based on cross-reacting Taenia crassiceps antigens that had proved protective against experimental intraperitoneal murine T. crassiceps cysticercosis (EIMTcC). In recent times the efficacy of the vaccine has been considered in need of confirmation, and the use of EIMTcC has been questioned as a valid tool in screening for vaccine candidates among the many antigens possibly involved. A review of our work divided in 2 parts is presented at this point, the first dealing with EIMTcC and the second with porcine T. solium cysticercosis (presented in this issue). Herein, we revise our results using EIMTcC as a measure of the protective capacity of T. crassiceps complex antigen mixtures, of purified native antigens, and of S3Pvac anti-cysticercosis vaccine composed by 3 protective peptides: GK-1, KETc1, and KETc12 either synthetic or recombinantly expressed and collectively or separately, by diverse delivery systems when administered at different doses and by different routes. Statistical analyses of the data lead confidently to the strong inference that S3Pvac is indeed an effective vaccine against EIMTcC via specific and non-specific mechanisms of protection.

In vitro evaluation of the effects of cysticidal drugs in the Taenia crassiceps cysticerci ORF strain using the fluorescent CellTracker CMFDA

Using a murine model of cysticercosis caused by the Taenia crassiceps ORF strain, we developed a fluorescent quantitative evaluation of the action of two well known anti-helminthic drugs: albendazole sulfoxide and praziquantel. The fluorescence emitted by a biotransformed CellTracker Probe known as CellTracker Green CMFDA in the vesicular fluids of cysticerci was estimated, and the results were compared with macroscopic observations of the parasites. The pharmacological EC(50) value of each drug and changes in the level of biotransformation of the fluorescent tracker caused by the drugs could be easily calculated. These drug-induced changes in biotransformation could be related to changes in the GSH/GSSG ratio of parasites. Both the cysticercosis murine model and the CMFDA biotransformation assay could be used as an in vitro screening method to evaluate potential or well known cysticidal drugs.