Development and Pharmacokinetic Evaluation of Two Parenteral Formulations of Albendazole Using Prodrug and Cosolvent Approaches.

Albendazole is a broad-spectrum anthelmintic drug used for parasitic infections. In addition, due to its mechanism of action, it has been studied as an anticancer agent. However, poor and highly variable bioavailability are limiting factors for its use in systemic illnesses. The present study aimed to develop two parenteral formulations of albendazole and to compare its pharmacokinetic profile with the conventional oral administration. Parenteral formulations were developed using two different approaches: a phosphonooxymethylated prodrug and cosolvents. For the albendazole prodrug, once synthetized, its solubility and hydrolysis with alkaline phosphatase were evaluated. A factorial design of experiments was used for the cosolvent formulation. Stability and hemolytic activity were assessed. A pharmacokinetic study was performed on New Zealand rabbits. Both formulations were administered intravenously, and the prodrug was also administered intramuscularly. Results were compared with those obtained after the oral administration of albendazole. A 20,000-fold and 6000-fold increase in albendazole solubility was found with the prodrug and cosolvent formulations, respectively. Both parenteral formulations displayed higher albendazole plasma concentrations for the first 2 h compared with oral administration, even when the oral dose was doubled. The absolute bioavailability of oral albendazole was 15.5% while for the intramuscular administration of the prodrug was 102.6%. Both parenteral formulations showed a significant decrease in the formation of albendazole sulfoxide (ANOVA p<0.05) and allowed greater exposure to albendazole. Albendazole cosolvent parenteral formulation could be a promising option in systemic illnesses considering its ease of preparation and superb pharmacokinetic performance.

Analysis of the effect of in vitro dissolution on the pharmacokinetics of albendazole

Abstract Albendazole is an anthelmintic drug commonly used in parenchymal neurocysticercosis and cystic echinococcosis. The aim of this study was to explore whether disparities in the dissolution profiles of albendazole products lead to significant differences in pharmacokinetic parameters. Three generic products and the innovator were evaluated in vitro. Quality control tests were performed, and dissolution profiles were obtained according to the Mexican Pharmacopeia. Although all products passed the quality control tests, none of the generic products complied with the similarity factor (f 2). The product with the lowest f 2 value in respect to the reference was chosen for in vivo evaluation. The study was carried out in 12 healthy volunteers who received 400 mg of the generic or reference product according to a crossover design. No significant differences were found in Cmax and AUC for albendazole and its main metabolite, albendazole sulfoxide, between products. Two absorption peaks were observed in the pharmacokinetic profile, and a population (22%) with different absorption rates and delay time for the the second peak was found. Based on the results, due to the high variability in the absorption process the differences observed in vitro could not be observed in vivo.

Giardia duodenalis: Flavohemoglobin is involved in drug biotransformation and resistance to albendazole.

Giardia duodenalis causes giardiasis, a major diarrheal disease in humans worldwide whose treatment relies mainly on metronidazole (MTZ) and albendazole (ABZ). The emergence of ABZ resistance in this parasite has prompted studies to elucidate the molecular mechanisms underlying this phenomenon. G. duodenalis trophozoites convert ABZ into its sulfoxide (ABZSO) and sulfone (ABZSOO) forms, despite lacking canonical enzymes involved in these processes, such as cytochrome P450s (CYP450s) and flavin-containing monooxygenases (FMOs). This study aims to identify the enzyme responsible for ABZ metabolism and its role in ABZ resistance in G. duodenalis. We first determined that the iron-containing cofactor heme induces higher mRNA expression levels of flavohemoglobin (gFlHb) in Giardia trophozoites. Molecular docking analyses predict favorable interactions of gFlHb with ABZ, ABZSO and ABZSOO. Spectral analyses of recombinant gFlHb in the presence of ABZ, ABZSO and ABZSOO showed high affinities for each of these compounds with Kd values of 22.7, 19.1 and 23.8 nM respectively. ABZ and ABZSO enhanced gFlHb NADH oxidase activity (turnover number 14.5 min-1), whereas LC-MS/MS analyses of the reaction products showed that gFlHb slowly oxygenates ABZ into ABZSO at a much lower rate (turnover number 0.01 min-1). Further spectroscopic analyses showed that ABZ is indirectly oxidized to ABZSO by superoxide generated from the NADH oxidase activity of gFlHb. In a similar manner, the superoxide-generating enzyme xanthine oxidase was able to produce ABZSO in the presence of xanthine and ABZ. Interestingly, we find that gFlHb mRNA expression is lower in albendazole-resistant clones compared to those that are sensitive to this drug. Furthermore, all albendazole-resistant clones transfected to overexpress gFlHb displayed higher susceptibility to the drug than the parent clones. Collectively these findings indicate a role for gFlHb in ABZ conversion to its sulfoxide and that gFlHb down-regulation acts as a passive pharmacokinetic mechanism of resistance in this parasite.

ß-cyclodextrin dendritic derivatives as permeation mediators to enhance the in vitro albendazole cysticidal activity by the improvement of the diffusion component.

The improvement of permeation of drugs across parasites' membranes to promote their diffusion component represents a challenge to achieve better therapeutic effects, including the avoidance of drug resistance. In the context of medicinal chemistry, suitable structural modifications can be made, either on a drug or a nanocarrier, to trigger different mechanisms that promote the influx across membranes. This study aimed to demonstrate the potential of a set of dendritic derivatives of ß-cyclodextrin (m2G, h2G, and m3G) as nanocarriers, based on their physicochemical and biological behavior in terms of (i) stability, monitored by 1H NMR at pH 7 for seven days, (ii) ability to complex, and subsequently release around 50-80% of the cargo molecule (albendazole) in a biphasic medium and (iii) the absence of in vitro cysticidal effect in cysticercus cultures. The albendazole/nanocarrier inclusion complexes (ICs) were proved in the T. crassiceps model. According to the EC50 values related to the cysticidal activity of albendazole, either free or complexed, the potency of this drug in the ICs experienced a significant increase, which may be attributed to the enhancement of its solubility but also to a better permeation mediated by the amphiphilic dendritic moieties, which ultimately positively impacts the diffusion of this drug through the tegument of the cysticerci. Additional considerations akin to synthetic ease of the dendritic nanocarriers, and production cost, along with the obtained outcomes, allowed us to place m2G followed by m3G as the best options to be considered for further in vivo assays.

Adherence to self-administering interferon-ß1a using RebiSmart® device in Mexican patients with relapsing multiple sclerosis.

BACKGROUND: Adherence to disease-modifying therapies is determinant to attain maximal clinical benefit in multiple sclerosis (MS). RebiSmart® is an electronic auto-injector for subcutaneous delivery of interferon ß-1a (INF-ß1a) that monitors adherence by featuring a log of each drug administration for objective evaluation. The aim of this study was to assess long-term adherence to INF-ß1a by using the RebiSmart® device in Mexican patients with relapsing MS. METHODS: This is an observational multicenter study on patients with relapsing MS treated with INF-ß1a subcutaneously delivered by the RebiSmart® device. Adherence was computed as the number of injections received during the study period divided by the number of injections scheduled and expressed as percent. RESULTS: A total of 66 patients from 6 specialized MS centers were evaluated (45 females and 21 males, mean age 43.91±13.32 years). Mean adherence was 79.51±18% (median: 85.54%, range: 34.4-100%). During a median follow-up of 27.5 months (mean 33.36±29.39 months) the annualized relapse rate had a mean of 0.50±1.63. Mean initial EDSS was 1.90±1.52, and mean EDSS at the end of follow-up was 1.80±1.74. Compared with their counterparts, the mean number of relapses was significantly lower among patients with high (>80%) adherence (0.25±0.44 vs 0.67±92 relapses, respectively; P = 0.03). The proportion of relapse-free patients was 75.0% among patients with high adherence and 53.3% in low-compliant patients (P = 0.06). High adherence patients presented lower rates of EDSS worsening ≥1.0 at the end of treatment, as compared with low-compliant patients (11.1% vs 43.3%, respectively; P = 0.003). High schooling (>12 years) was the only predictor of a high adherence (OR: 2.97, 05% CI: 1.08-1.18; P = 0.03) and of being relapse-free during follow-up (OR: 3.22, 05% CI: 1.12-9.23; P = 0.03). CONCLUSION: Adherence to INF-ß1a using RebiSmart® in this Mexican cohort with MS was moderate, but associated with low relapse rate and influenced by high schooling.

Evaluation of New Benzimidazole Derivatives as Cysticidal Agents: In Vitro, in Vivo and Docking Studies.

Based on our previous research on cysticidal drugs, we report the synthesis and evaluation of three new benzimidazole derivatives. In these compounds, the amido group was used as a bioisosteric replacement of the ester group. The molecular docking on ß-tubulin revealed that the derivatives interacted through hydrogen bonding with N165, E198 and V236. All compounds showed in vitro activity against Taenia crassiceps cysts. Among them, benzimidazole 3 was found to be the most potent of the series (EC50 0.86 µM). This compound also exhibited the highest probability of binding and the lowest binding free energy score and was therefore selected for in vivo evaluation. Results indicated that the efficacy of compound 3 was comparable to that of the reference drug, albendazole (50.39 vs. 47.16% parasite reduction). Animals treated with compound 3 seemed to tolerate this benzimidazole well, with no changes in behavior, or food and water consumption. These findings are consistent with the in silico prediction results, which indicated low toxicity risks. The pharmacokinetic study showed that the half-life and mean residence time (6.06 and 11.9 h, respectively) were long after oral administration. Together, these results indicate that this new benzimidazole derivative represents a promising structure with cysticidal activity.

Factors Associated With Cysticidal Treatment Response in Extraparenchymal Neurocysticercosis.

Extraparenchymal neurocysticercosis is the most severe form of cysticercosis, and response to treatment is suboptimal. We sought to determine how demographic and clinical characteristics and albendazole sulfoxide concentrations were related to cysticidal treatment response. We conducted a longitudinal study of 31 participants with extraparenchymal vesicular parasites who received the same treatment, albendazole 30 mg/kg/day for 10 days with dexamethasone 0.4 mg/kg/day for 13 days, followed by a prednisone taper. Response to treatment was determined by parasite volumes before and 6 months after treatment. Eight participants (25.8%) had a complete treatment response, 16 (51.6%) had a treatment response > 50% but < 100%, and 7 (22.6%) had a treatment response < 50%. Complete treatment response was significantly associated with higher concentrations of albendazole sulfoxide (P = .032), younger age (P = .032), fewer cysts (P = .049) and lower pretreatment parasite volume (P = .037). Higher number of previous cysticidal treatment courses was associated with a noncomplete treatment response (P = .023). Although the large proportion of participants with less than a complete response emphasizes the need to develop more efficacious pharmacologic regimens, the association of albendazole sulfoxide concentrations with treatment response highlights the importance of optimizing existing therapeutic regimens. In addition, the association of treatment response with parasite volume emphasizes the importance of early diagnosis.

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.

In vitro and in vivo cysticidal activity of extracts and isolated flavanone from the bark of Prunus serotina: A bio-guided study.

Currently, neurocysticercosis treatment involves two drugs: albendazole and praziquantel; however, their efficacy is suboptimal and new cysticidal drugs are needed. The present paper reports the cysticidal activity of extracts of the bark from Prunus serotina against Taenia crassiceps cysts and the isolation and identification of the main components of the most active extract. Results showed that all extracts displayed in vitro cysticidal activity (EC50=17.9-88.5µg/mL), being the methanolic the most active and selective. Also, methanolic extract exhibited in vivo efficacy at 300mg/kg which was similar to that obtained with albendazole. Bio-guided fractionation of methanolic extract led the isolation of 2,3-dihydro-5,7-dihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one (naringenin, NGN), 3,4,5-trimethoxybenzoic acid and 1,3,5-trimethoxybenzene. NGN exhibited in vitro activity, in a time-concentration-dependent manner (EC50=89.3µM]. Furthermore, NGN at a dose of 376.1µmol/kg displayed similar in vivo efficacy than those obtained with albendazole at 188.4µmol/kg. NGN also caused a high level of damage in all parasite tissue in a similar manner than that observed with the methanolic extract. This study represents the first report of the cysticidal properties of the bark of P. serotina. NGN was identified as the main active compound of this specie and other studies are required to explore the potential of this flavanone as cysticidal agent.

Cysticidal activity of extracts and isolated compounds from Teloxys graveolens: In vitro and in vivo studies.

In the search of new alternatives for neurocysticercosis treatment, the cysticidal activity of organic extracts of Teloxys graveolens was evaluated. The in vitro activity of hexane, ethyl acetate and methanol extracts against Taenia crassiceps cysts was tested and the selectivity index relative to human fibroblasts was determined. Subsequently, the in vivo efficacy of the methanolic extract at doses of 200 and 500 mg/kg in the murine cysticercosis model was evaluated. The ultrastructural effects in vitro and in vivo of the methanolic extract were also investigated using scanning electron microscopy. Additionally, a bioassay-guided fractionation for the isolation of the cysticidal components was performed. Our in vitro findings revealed that all extracts exhibited good cysticidal activity with EC50 values from 44.8 to 67.1 µg/mL. Although the ethyl acetate and methanolic extracts displayed low cytotoxicity, the methanolic extract was the most selective. The methanolic extract also showed in vivo efficacy which was similar to that obtained with ABZ. Significant alterations were found on the germinal layer of the cysts, with a high accumulation of granules of glycogen and vacuoles. The bioguided fractionation of methanolic extract led to the isolation of three flavonoids: chrysin, pinocembrin and pinostrobin; among them, pinocembrin was the compound that displayed cysticidal activity. This is the first study which reveals that T. graveolens could be a potential source for cysticidal and non-toxic compounds.

Utility of electrocorticography in the surgical treatment of cavernomas presenting with pharmacoresistant epilepsy.

AIM: To describe the general aspects of cavernomas and epilepsy and review the available literature on the utility of electrocorticography (ECoG) in cerebral cavernoma surgery. METHODS: We searched studies in PubMed, MedLine, Scopus, Web of Science, and Google Scholar (from January 1969 to December 2013) using the keywords "electrocorticography" or "ECoG" or "prognosis" or "outcome" and "cavernomas". Original articles that reported utility of ECoG in epilepsy surgery were included. Four review authors independently selected the studies, extracted data, and assessed the methodological quality of the studies using the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions, PRISMA guidelines, and Jadad Scale. A meta-analysis was not possible due to methodological, clinical, and statistical heterogeneity of included studies. We analysed six articles with a total of 219 patients. RESULTS: The most common surgical approach was lesionectomy using ECoG in the temporal lobe with Engel I outcome range from 72.7 to 100%. CONCLUSIONS: Small controlled studies suggest that ECoG-guided resection offers the best functional results in seizure control for subjects undergoing cavernoma surgery, especially in the temporal lobe.

Distribution of hydroxychloroquine in lymphoid tissue in a rabbit model for HIV infection.

Hydroxychloroquine has been proposed for HIV treatment; however, little is known about its disposition in the lymphatic system, where replication takes place. Therefore, its distribution in lymphoid tissues (Peyer's patches and popliteal, submandibular, femoral, splenic, and prescapular lymph nodes) was evaluated and compared with that in blood. Results showed a high affinity of hydroxychloroquine for all of these tissues, with higher affinity for the splenic and submandibular lymph nodes, suggesting its potential use as a coadjuvant in HIV therapy.

A simple LC-MS/MS method to determine plasma and cerebrospinal fluid levels of albendazole metabolites (albendazole sulfoxide and albendazole sulfone) in patients with neurocysticercosis.

The development and validation of an LC-MS/MS method for the simultaneous determination of albendazole metabolites (albendazole sulfoxide and albendazole sulfone) in human plasma are described. Samples of 200 µL were extracted with ether-dichloromethane-chloroform (60:30:10, v/v/v). The chromatographic separation was performed using a C(18) column with methanol-formic acid 20 mmol/L (70:30) as the mobile phase. The method was linear in a range of 20-5000 ng/mL for albendazole sulfoxide and 10-1500 ng/mL for albendazole sulfone. For both analytes the method was precise (RSD < 12%) and accurate (RE <7%) with high recovery (>90%). The method was successfully applied to determine the plasma and cerebrospinal fluid levels of albendazole sulfoxide and albendazole sulfone in patients with subarachnoidal neurocysticercosis who received albendazole at 30 mg/kg per day for 7 days. This LC-MS/MS method yielded a quick, simple and reliable protocol for determining albendazole sulfoxide and albendazole sulfone concentrations in plasma and cerebrospinal fluid samples and is applicable to therapeutic monitoring.

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

The effect of two water-soluble polymers: pectin and polyvinylpyrrolidone in combination with beta-cyclodextrin, on the dissolution, bioavailability and cysticidal efficacy of albendazole was evaluated using a commercial suspension as reference product. The dissolution of the albendazole-beta-cyclodextrin-pectin formulation was slow and incomplete (44.7%). No statistical differences in C(max) and AUC were found between this formulation and the reference. Also its cysticidal efficacy (33%) was similar to the reference (38%). The albendazole-beta-cyclodextrin-polyvinylpyrrolidone formulation exhibited the highest dissolution rate (78.5%) and its bioavailability was also significantly increased (2.3-fold). In addition, the cysticidal activity of this formulation (83%) was greater than a commercial suspension. Our results suggest that the ternary system of albendazole-beta-cyclodextrin-polyvinylpyrrolidone could be a potential alternative for the treatment of systemic helmintic diseases and it is worth to continue its preclinical evaluation.

Effect of malnutrition on the pharmacokinetics of cefuroxime axetil in young rats.

PURPOSE: To determine the pharmacokinetics of cefuroxime axetil in malnourished rats using a diet with a restriction in energy and nutrients (group M), a diet with a low quality protein (group K) and a good quality diet (group C) as a control. METHODS: The rats were fed with the corresponding diet during 21 days. After this period a single oral dose of cefuroxime axetil (equivalent to a 2.2 mg dose of cefuroxime) was administered, and plasma samples were taken at 0, 5, 10, 30, 45, 60, 90, 120, 180, 240, 300 and 360 minutes; samples were assayed using an HPLC assay. Biochemical parameters were also measured an a microscopy study of the small intestine was done. After a 21 day period of recovery of the malnourished groups a second pharmacokinetic study was performed using the same sample times as in the first study. RESULTS: In malnourished animals of group K the levels of plasma proteins were low, and showed higher concentrations of fat in the liver. The relative bioavailability of cefuroxime was 78.2% for group M and 64.4% for group K. Groups M and K presented lower values of area under the curve, which means that the amount of antibiotic absorbed was lower than group C. In the second pharmacokinetic study although the animals received a good quality diet, it was observed that the area under the curve of group K was lower, and the relative bioavailability was 54.3%, while group M had similar pharmacokinetic values than control group. CONCLUSIONS: The pharmacokinetics of cefuroxime was affected by malnutrition, suggesting that the absorption process via the transporter was modified in the malnourished groups, specially in the group fed with a low quality protein.