Improvement of albendazole efficacy against enteral, but not against parenteral stages of Trichinella spiralis by preparing solid dispersions in polyvinylpyrrolidone

The Use of Cyclodextrin Inclusion Complexes to Increase the Solubility and Pharmacokinetic Profile of Albendazole

Albendazole is the preferred deworming drug and has strong insecticidal effects on human and animal helminth parasites, showing remarkable activity against hepatocellular carcinoma and colorectal cancer cells. However, it is classified as being in class II in the Biopharmaceutics Classification System due to its poor water solubility (0.2 mg/L) and high permeability, which make the clinical application of albendazole impractical. Through complexation with methyl-β-cyclodextrin, as the best result so far, albendazole's water solubility was increased by 150,000 times, and albendazole could be 90% released during the first 10 min. In an in vivo pharmacokinetic study, the Cmax and Tmax of the active metabolized sulfoxide were changed from 2.81 µg/mL at 3 h to 10.2 µg/mL at 6 h and the AUC0-48 was increased from 50.72 h⁎μg/mL to 119.95 h⁎μg/mL, indicating that the inclusion complex obtained can be used as a new oral therapeutic anti-anthelmintic and anti-tumor agent formulation.

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.

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 and oral bioavailability assessment of a supersaturated self-microemulsifying drug delivery system (SMEDDS) of albendazole

OBJECTIVES

Albendazole's (ABZ) poor aqueous solubility is a major determinant of its variable therapeutic response (20-50%). The purpose of this study was to develop and optimize the composition of a self-microemulsifying drug delivery system (SMEDDS) of ABZ and assess its oral pharmacokinetics in rabbits.

METHODS

A D-optimal mixture design of experiments was used to select the levels of constraints of the formulation variables. The predicted composition was optimized using four responses: dispersion performance, droplet sizes, dissolution efficiency (DE) and time for 85% drug release (t(85%)).

KEY FINDINGS

The optimal composition of the ABZ-SMEDDS formulation, with approximately 5 mg/g drug loading of ABZ, was predicted to be Cremophor EL (30% w/w), Tween 80 (15% w/w), Capmul PG-8 (10% w/w) and acidified PEG 400 (45% w/w). An increase of 63% in the relative bioavailability compared with the commercial suspension was obtained with ABZ-SMEDDS as measured by albendazole sulfoxide (ABZSO) plasma levels. The area under the curve (AUC(0-->24h)) and the peak plasma concentration (C(max)) of ABZ-SMEDDS was higher than those obtained with the commercial suspension by 56% and 52%, respectively.

CONCLUSIONS

This study demonstrates a strategy for the development of a supersaturated SMEDDS formulation of a drug with low aqueous solubility.

The effect of solubilization on the oral bioavailability of three benzimidazole carbamate drugs

The effect of solubilization by complexation with povidone on the oral bioavailability of three anthelmintic benzimidazole carbamate drugs: mebendazole (MBZ), albendazole (ABZ) and ricobendazole (RBZ), was studied in mice. The following in vitro characteristics of the initial raw materials and the drug-povidone complexes were evaluated: melting point (MP); mean dissolution time (MDT); solubility constants (Cs) in n-octanol, acid (pH 1.2) and neutral (pH 7.4) aqueous media; apparent partition coefficients (P) and capacity factors (k'W) determined by HPLC. The following in vivo parameters were also evaluated: AUC(0-infinity), C(max), T(max) and MRT. The possible relationship between in vitro characteristics and in vivo parameters was explored and it was found that an increase in solubility, especially in acidic medium, leads to an increase in AUC and C(max) and a decrease in T(max). Therefore, dissolution seems to be the absorption limiting step for these drugs. For the in vivo parameters related to the amount of absorbed drug (AUC and C(max)), the best correlation was obtained with the in vitro characteristics related to solubility which are Cs, MP and MDT. On the other hand, there were good linear correlations between T(max) which is an in vivo parameter related to the rate of drug absorption, and the lipophilia/hydrophilia (logP and log k'W) relation-parameters.

Bioavailability and efficacy characteristics of two different oral liquid formulations of albendazole

The oral bioavailability and anthelmintic efficacy in mice of a new formulation of albendazole (ABZ) dissolved in a solution of hydroxypropyl-beta-cyclodextrin (HPCD) are compared with a conventional ABZ suspension of carboxymethylcellulose. Plasma concentrations of ABZ and albendazole sulphoxide (ABZ-SO), its active and main metabolite, were assayed by HPLC. The AUC(0- infinity ) and C(max) values obtained for both ABZ and ABZ-SO, after administration of the ABZ-HPCD solution were significantly higher (P<0.01) than those obtained from the ABZ suspension. Although, the differences between the ABZ and ABZ-SO-T(max) values were found not to be significant, regardless of the formulation. The anthelmintic activities against enteral (pre-adult) and parenteral (migrating and encysted larvae) stages of Trichinella spiralis were studied in mice. The ABZ solution was more efficient against pre-adult and encysted larvae than the ABZ suspension. The efficacy differences between both formulations against the migrating larvae, were found to be not significant (P<0.05). For the migrating parasite stage, there was a linear correlation between the anthelmintic activity and pharmacokinetical parameters with respect to the ABZ-AUC(0- infinity ) value. Meanwhile, for the muscular encysted parasite stage, better relationships were obtained for AUC(0- infinity ) and C(max) values from ABZ-SO, which had correlation coefficients of 0.996 and 0.987, respectively.