Pharmacokinetic comparison of intravenous carbendazim and remote loaded carbendazim liposomes in nude mice
Introduction
Carbendazim, classified as a representative benzimidazolic compound, was initially found to be a bioactive metabolite of the fungicide benomyl, and is widely used in crop protection as a fungicide to protect crops from decay caused by various fungal pathogens [1]. It is also used as a pesticide and herbicide for the protection of flowers and flower bulbs. Recently it has been found that subchronic administration of carbendazim induced testicular alterations, spermatogenic inactivity and embryotoxicity [2], [3], [4]. The molecular basis of reproductive toxicity appears to be related to the inhibition of microtubule assembly [5], [6], [7]. While the exact mechanism is unclear, recent findings further revealed that carbendazim induced apoptosis in a variety of cells. The apoptosis phenomena of the compound led us to our most recent findings that carbendazim inhibits both in vitro tumor cell growth and in vivo human tumor xenograft models [8]. Consequently, this agent is presently undergoing Phase 1 clinical trials in adults with advanced malignancies. However, the drug has limited aqueous solubility and low bioavailability due to the first-pass effect of liver metabolism. It has been reported that more than 95% of carbendazim was eliminated during the early phase of i.v. administration [9]. Even though carbendazim continues to be important to achieve an effective chemotherapy for the treatment of a variety of tumor models, its formulation has not been completely satisfactory. The purpose of this study was to develop a liposome formulation that has the following characteristics: (a) a high level potency of carbendazim; (b) a high encapsulation efficiency; and (c) small particle diameter (less than 0.2 μm) that can be filter-sterilized. This report describes an approach to encapsulate carbendazim into unilamellar vesicles based upon a remote loading procedure. The influence of liposome encapsulation on the pharmacokinetic properties was evaluated in a murine model in order to provide inference as to the anticipated pharmacokinetics of the formulation in humans.
Section snippets
Materials
Carbendazim (F.W. 191.18) and the internal standard 2-benzimidazolyl-acetonitrile (Fig. 1) were purchased from Aldrich (Milwaukee, WI, USA). Acetonitrile, methanol and KH2PO4 were purchased from EM Science (Gibbstown, NJ, USA). N,N-dimethylformamide solution was bought from Allied Signal (Muskegon, MI, USA).
Stock solution of carbendazim (1 mg ml−1) was prepared in N,N-dimethylformamide. Stock solution of internal standard (2 mg ml−1) was prepared in acetonitrile (HPLC grade). The stock
Liposome characterization
The formulation appears opaque yellow liquid. The vesicle size determined by light scattering was 148±57 nm. The level of carbendazim encapsulation was related to the interior/external pH gradient. For example, at a fixed drug/lipid molar ratio of 0.8, more than 96% of carbendazim is encapsulated using 300 mM H2SO4 (pH 0.5), whereas only 84% encapsulation was achieved at 50 mM H2SO4 (internal pH 1.33). The external pH was raised to 4.0 to achieve an initial transmembrane pH gradient about 3.5
Discussion
The developed HPLC method proves to be useful and reliable for the determination of serum concentrations of carbendazim. The sample clean-up procedure, involving a direct deproteinization with methanol, is simple and rapid, thus avoiding degradation of the drug. This method, validated for carbendazim concentrations in serum ranging from 20 to 20,000 ng ml−1, has a good reproducibility and accuracy and low limits of quantitation and detection compared to the most published methods detecting the
Conclusions
A unilamellar liposome formulation (sphingomyelin–cholesterol, 3:1, w/w) of carbendazim could be prepared by remote loading at drug/lipid molar ratios of 0.2 and 0.8. An initial transmembrane pH gradient (pH 0.5 in/pH 4.0 out) across the vesicles increased the encapsulation efficiency. A reversed-phase HPLC method was developed and validated to detect serum carbendazim concentration as low as 20 ng ml−1. Liposomal carbendazim significantly improved the pharmacokinetic profile of the drug
References (17)
- et al.
Fundam. Appl. Toxicol.
(1990) - et al.
Toxicology
(1989) - et al.
Toxicol. Appl. Pharmacol.
(1989) - et al.
Fundam. Appl. Toxicol.
(1997) - et al.
Biochim. Biophys. Acta
(1978) - et al.
Chem. Phys. Lipids
(1990) - et al.
J. Chromatogr. B
(1993) - et al.
J. Chromatogr. A
(1998)
Cited by (38)
New drug candidates for liposomal delivery identified by computer modeling of liposomes' remote loading and leakage
2017, Journal of Controlled ReleaseCitation Excerpt :We therefore assumed that in these cases slow leaking in the presence of plasma will show slow leaking also upon storage. The final leakage dataset consisted of 27 molecules from the literature [24,36,37,45–47,52,54,57,60,61,65,70,73,75,76,84–87] and from in-house data. Of these, 15 molecules were classified as slow leaking (positives) and 12 were classified as rapid leaking (negatives).
Characterization of insulin-loaded liposome using column-switching HPLC
2015, International Journal of PharmaceuticsNanotechnology-based intelligent drug design for cancer metastasis treatment
2014, Biotechnology AdvancesDrug enterohepatic circulation and disposition: Constituents of systems pharmacokinetics
2014, Drug Discovery TodayCitation Excerpt :If the drug is rapidly eliminated, resulting in a rapid drop in concentration of the free drug, the drug will permeate back from tissues into the bloodstream. To interpret the pharmacological and toxicological profiles of a drug, it is important to have a comprehensive knowledge of the ADME of the drug [1,8,9]. Tissue distribution is an essential procedure in the preclinical drug discovery process.
Determination of platinum drug release and liposome stability in human plasma by CE-ICP-MS
2013, International Journal of PharmaceuticsIntracellular distribution and mechanisms of actions of photosensitizer Zinc(II)-phthalocyanine solubilized in Cremophor EL against human hepatocellular carcinoma HepG2 cells
2013, Cancer LettersCitation Excerpt :Its major component is the material in which the hydroxyl groups of the castor oil triglyceride have ethoxylated with ethylene oxide to form polyethylene glycol ethers. This surfactant has been used to enhance solubility of those poorly-soluble materials including phthalocyanine [21] by stabilizing emulsions of nonpolar materials in aqueous systems [22]. In the present study, we used Cremophor EL to increase solubility of ZnPc.