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

Albendazole (ABZ) and mebendazole (MBZ) are the 2 most commonly used drugs in the treatment of soil-transmitted helminth infections in humans, but their performance is hampered by low solubility and physicochemical properties. We developed different formulations (β-cyclodextrin inclusion complexes, chitosan-based microcrystals (CH), and polyvinyl alcohol and polysorbate 80-based nanoparticles [P80]) of ABZ and MBZ with an improved in vitro solubility profile and tested their activities in vitro and in vivo against the hookworm Heligmosomoides polygyrus. We found that all formulations tested showed a faster and higher dissolution level and were more active than the standard drugs. When compared to ABZ, ABZ-P80 revealed the highest improvement in terms of solubility increase (4-fold increase) and in vivo activity (an ED 50 of 7.0 mg/kg for ABZ and of 4.1 mg/kg for ABZ-P80). Although the activity of MBZ was in all cases lower than ABZ, the improved formulations of MBZ performed better than standard MBZ, where MBZ-CH showed a significantly higher in vivo activity (ED 50 of 8.02 mg/kg vs. an ED 50 of 203 mg/kg for MBZ). In this work, we identified MBZ-CH and ABZ-P80 formulations as lead formulations hence further studies should be conducted., (Copyright © 2020 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.)

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

Succinyl-β-CD derivatives were obtained by green synthesis with degrees of substitution (DS) 1.3 and 2.9. The spray-drying technique was used to obtain albendazole (ABZ):succinyl-β-CD inclusion complexes. Phase solubility diagrams indicated that both succinyl-β-CD derivatives formed 1:1 molar ratio ABZ complexes, but the complex with DS 2.9 has a lower formation constant. The presence of stable inclusion complexes in aqueous solution was confirmed by NMR. For both complexes the aromatic moiety is encapsulated into the host cavity. In the solid-state, 13 C and 15 N NMR spectral differences between ABZ and ABZ included in spray-dried systems showed that strong structural changes occurred in the systems. At least two different ABZ amorphous species were identified based on DS. ABZ species were stable over more than six months based on spectral data. Finally, the influence of DS in the number and type of the inclusion complexes was elucidated., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Albendazole (ABZ) and ricobendazole (RBZ) are referred to as class II compounds in the Biopharmaceutical Classification System. These drugs exhibit poor solubility, which profoundly affects their oral bioavailability. Micellar systems are excellent pharmaceutical tools to enhance solubilization and absorption of poorly soluble compounds. Polysorbate 80 (P80), poloxamer 407 (P407), sodium cholate (Na-C), and sodium deoxycholate (Na-DC) have been selected as surfactants to study the solubilization process of these drugs. Fluorescence emission was applied in order to obtain surfactant/fluorophore (S/F) ratio, critical micellar concentration, protection efficiency of micelles, and thermodynamic parameters. Systems were characterized by their size and zeta potential. A blue shift from 350 to 345 nm was observed when ABZ was included in P80, Na-DC, and Na-C micelles, while RBZ showed a slight change in the fluorescence band. P80 showed a significant solubilization capacity: S/F values were 688 for ABZ at pH 4 and 656 for RBZ at pH 6. Additionally, P80 micellar systems presented the smallest size (10 nm) and their size was not affected by pH change. S/F ratio for bile salts was tenfold higher than for the other surfactants. Quenching plots were linear and their constant values (2.17/M for ABZ and 2.29/M for RBZ) decreased with the addition of the surfactants, indicating a protective effect of the micelles. Na-DC showed better protective efficacy for ABZ and RBZ than the other surfactants (constant values 0.54 and 1.57/M, respectively), showing the drug inclusion into the micelles. Entropic parameters were negative in agreement with micelle formation.

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

An efficient and green method has been developed for the synthesis of succinyl-β-cyclodextrin in aqueous media obtaining very good yield. Acidic groups have been introduced in the synthesized carrier molecule to improve the guest-host affinity. To evaluate the suitability of the novel excipient focused to develop oral dosage forms, albendazole, a BSC class II compound, was chosen as a model drug. The β-cyclodextrin derivative and the inclusion complex were thoroughly characterized in solution and solid state by phase solubility studies, FT-IR spectroscopy, SEM, XRD, ESI-MS, DSC, 1D (1)H NMR, 1D (13)C NMR, selective 1D TOCSY, 2D COSY, 2D HSQC, 2D HMBC and ROESY NMR spectroscopy. Phase solubility studies indicated that both of them β-cyclodextrin and succinyl-β-cyclodextrin formed 1:1 inclusion complexes with albendazole, and the stability constants were 68M(-1) (β-cyclodextrin), 437M(-1) (succinyl-β-cyclodextrin), respectively. Water solubility and dissolution rate of albendazole were significantly improved in complex forms. Thus, the succinyl-β-cyclodextrin derivative could be a promising excipient to design oral dosage forms., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

(13)C and (15)N solid-state nuclear magnetic resonance (NMR) spectra were recorded from albendazole (ABZ) and from ABZ:β-cyclodextrin, ABZ:methyl-β-cyclodextrin, ABZ:hydroxypropyl-β-cyclodextrin and ABZ:citrate-β-cyclodextrin, which were prepared by the spray-drying technique. ABZ signals were typical of a crystalline solid for the pure drug and of an amorphous compound obtained from ABZ:cyclodextrin samples. Relevant spectral differences were correlated with chemical interaction between ABZ and cyclodextrins. The number and type of complexes revealed a strong dependence on the cyclodextrin group substituent. Solid-state NMR data were consistent with the presence of stable inclusion complexes., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Both an experimental design and optimization techniques were carried out for the development of chitosan-pectin-carboxymethylcellulose microspheres to improve the oral absorption of albendazole as a model drug. The effect of three different factors (chitosan, pectin and carboxy methyl cellulose concentrations) was studied on five responses: yield, morphology, dissolution rate at 30 and 60 min, and encapsulation efficiency of the microspheres. During the screening phase, the factors were evaluated in order to identify those which exert a significant effect. Simultaneous multiple response optimizations were then used to find out experimental conditions where the system shows the most adequate results. The optimal conditions were found to be: chitosan concentration, 1.00% w/v, pectin concentration 0.10% w/v and carboxymethylcellulose concentration 0.20% w/v. The bioavailability of the loaded drug in the optimized microspheres was evaluated in Wistar rats which showed an area under curve (AUC) almost 10 times higher than the pure drug.

Albendazole-β-cyclodextrin citrate (ABZ:C-β-CD) inclusion complex in vivo antiparasitic activity was evaluated in the parenteral phase of Trichinella spiralis infection in mice. An equimolar complex of ABZ:C-β-CD was prepared by spray-drying and tested in CBi-IGE male mice orally infected with L1 infective larvae. Infected animals were treated with 50 or 30mg/kg albendazole, (ABZ) equivalent amounts of the ABZ:C-β-CD complex and non treated (controls). Mice received a daily dose on days 28, 29 and 30 post-infection. A week later, larval burden and percentage of encysted dead larvae were assessed in the host by counting viable and non-viable larvae in the tongue. Complexation of ABZ with C-β-CD increased the drug dissolution efficiency nearly eightfold. At 37 days p-i, the reduction percentage in muscle larval load was 35% in mice treated with 50mg/kg/day ABZ and 68% in those given the complex. Treatment with the lower dose showed a similar decrease in parasite burden. Treated animals showed a high percentage of nonviable larvae, the proportion being significantly higher in mice receiving the complex than in control animals (72-88% vs. 11%, P=0.0032). These data indicate that ABZ:C-β-CD increases bioavailability and effectiveness of ABZ against encapsulated Trichinella larvae, thus allowing the use of small doses., (Copyright © 2015 Elsevier B.V. All rights reserved.)

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.

Encapsulation of albendazole, a class II compound, into polymeric microparticles based on chitosan-sodium lauryl sulfate was investigated as a strategy to improve drug dissolution and oral bioavailability. The microparticles were prepared by spray drying technique and further characterized by means of X-ray powder diffractometry, infrared spectroscopy and scanning electron microscopy. The formation of a novel polymeric structure between chitosan and sodium lauryl sulfate, after the internal or external gelation process, was observed by infrared spectroscopy. The efficiency of encapsulation was found to be between 60 and 85% depending on the internal or external gelation process. Almost spherically spray dried microparticles were observed using scanning electron microscopy. In vitro dissolution results indicated that the microparticles prepared by internal gelation released 8% of the drug within 30 min, while the microparticles prepared by external gelation released 67% within 30 min. It was observed that the AUC and Cmax values of ABZ from microparticles were greatly improved, in comparison with the non-encapsulated drug. In conclusion, the release properties and oral bioavailability of albendazole were greatly improved by using spraydried chitosan-sodium lauryl sulphate microparticles.

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.

Trichinellosis is a zoonotic disease affecting people all over the world, for which there is no speedy and reliable treatment. Albendazole (ABZ), an inexpensive benzimidazole used in oral chemotherapy against helminthic diseases, has a broad spectrum activity and is well tolerated. However, the low absorption and variable bioavailability of the drug due to its low aqueous solubility are serious disadvantages for a successful therapy. In this study, we evaluated the in vivo antiparasitic activity of three novel solid microencapsulated formulations, designed to improve ABZ dissolution rate, in a murine model of trichinellosis. Both ABZ and the microparticulate formulations were administered during the intestinal phase of the parasite cycle, on days 5 and 6 post-infection. This protocol significantly decreased muscle larval burden measured in the parenteral phase, on day 30 post-infection, when compared with the untreated control. Moreover, two of the three microencapsulated formulations both strongly and consistently reduced worm burden., (© 2013.)

Albendazole is a benzimidazole derivative with proven efficacy against many parasites such as intestinal helminths. Toxocariasis is one of the important parasitic diseases in humans and animals caused by Toxocara canis. It is well known that T. canis larvae migrate in paratenic hosts, including humans where it may cause visceral larva migrans. Thus, the present research was carried out using in vivo experiments with the aim of finding whether novel albendazole microparticles would be active against migrating larvae of the parasite. Albendazole-chitosan microparticles were prepared by ionotropic gelation with sodium lauryl sulphate or by a liquid-liquid phase separation with sodium hydroxide. Mice were infected with T. canis and then treated with both albendazole-chitosan microparticles. After treatment (28days post-infection), it was examined the anthelmintic effect in mice after oral administration of microparticulate preparations. The number of larvae recovered from mice treated with albendazole formulations were compared with placebo. The results showed that albendazole microparticles were easily prepared in high yield using both aqueous solutions of sodium lauryl sulphate or sodium hydroxide. In vivo evaluation of larva migration showed that albendazole microparticles exhibited a greater anthelmintic effect in the brain (0 larva/mouse). In addition, it was also found that liver and lung showed a significant decrease in the number of larvae. Therefore, these data suggest that albendazole-chitosan microparticles are effective formulations for the treatment of toxocariasis infection by reducing the number of larvae in liver and lung. Particularly, these polymeric preparations were able to totally prevent migration of larvae to the mice brain.

Objectives: In vitro and in vivo experiments were used to determine whether albendazole-PEG 6000 solid dispersions would be effective in the treatment of Toxocara canis larva migrans., Methods: Albendazole-PEG 6000 (1:1, 1:5 and 1:9 ratios) solid dispersions were prepared by the solvent evaporation method. The morphology of the particles was evaluated by scanning electron microsocopy (SEM), and in vitro dissolution assays were also carried out. Mice were infected with T. canis and then treated orally with albendazole-PEG 6000 systems or albendazole suspended in water. The anthelmintic effect was examined at 28 days post-infection (p.i.). The number of larvae recovered from mice treated with albendazole alone and those treated with albendazole-PEG 6000 were compared with the numbers from the placebo group., Results: Dissolution of albendazole from solid dispersions was markedly enhanced by increasing the polymer concentration. At a 1:9 drug:polymer ratio, >90% of the albendazole was dissolved in 10 min. SEM showed microparticles to be of small spherical shape compared with the pure components. In vivo evaluation of larva migration showed that both albendazole-PEG 6000 solutions exhibited a greater anthelmintic effect in the brain (0 larvae/mouse). In addition it was also found that liver and lung showed a significant decrease in the number of larvae. Evaluation of vehicle toxicity (PEG 6000 in water) showed a mice survival rate of 100% at the assayed concentrations., Conclusions: These data suggest that albendazole-PEG 6000 solid dispersions markedly increased the effectiveness of albendazole against the migratory activity of larvae. Particularly, these polymeric solutions were able to totally prevent migration of larvae to the mouse brain.

The loading of albendazole into biodegradable polymeric microparticles provides an attractive alternative to improve the drug dissolution rate. Experimental design and optimization techniques were implemented for the development of albendazole-chitosan microparticles using the ionic interaction method. The effect of seven different factors (chitosan concentration, pH of chitosan solution, stirring rate, stirring time, temperature, ionic agent and pH of ionic solutions) were studied on six responses: the yield, pH, morphology, size, dissolution rate and encapsulation efficiency of the microparticles. During the screening phase, the factors were evaluated at three levels each, in order to identify those which exert a significant effect. Multiple response simultaneous optimization by using the desirability function was then used to find experimental conditions where the system shows the most adequate results. The optimal conditions were found to be: NaOH as ionic agent at a pH value of 13.0, chitosan concentration, 0.50% (w/v) at a pH value of 1.0 and stirring rate, 1,000 rpm.