Tissue disposition, excretion and metabolism of vinblastine in mice as determined by high-performance liquid chromatography

Transient Hepatotoxicity Induced by Vinblastine in a Young Girl with Chiasmatic Low Grade Glioma

BACKGROUND

Vinblastine (VBL) is a cytostatic drug frequently applied in children with lymphoma and progressive low-grade glioma (LGG), with hematotoxicity as the main side effect.

CASE REPORT

Here, the case of a 7-month-old girl with tumor progression of an LGG during standard chemotherapy with carboplatin and vincristine, is presented. Switching to VBL led to a 20-30- fold increase of transaminases (grade IV CTCAE 5.0), spontaneously resolving after the end of treatment. The toxicity is possibly age-related since it did not re-occur at the restart of VBL at 4 years old. This finding might have consequences for toxicity screening in future protocols, especially when including infants.

Simultaneous quantification of vinblastine and desacetylvinblastine concentrations in canine plasma and urine samples using LC-APCI-MS/MS

A highly sensitive and specific liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC/APCI-MS/MS) method has been developed and validated for simultaneous quantification of vinblastine and its metabolite, desacetylvinblastine, in canine plasma and urine samples. Plasma and urine samples were processed by a solid phase extraction procedure. The optimal chromatographic behavior of these analytes was achieved on pentafluorophenyl (PFP) propyl analytical column (5μm, 50×2.1mm) under isocratic elution of 0.75mL/min with a mobile phase of 5mM ammonium acetate and methanol. The samples were analyzed in positive ion, multiple reaction monitoring mode. The calibration curves were linear over 0.125-2ng/mL (lower calibration curve); 2-100ng/mL (higher calibration curve) and 0.125-5ng/mL for vinblastine and desacetylvinblastine in plasma, and over 1-2000ng/mL and 0.5-100ng/mL for vinblastine and desacetylvinblastine in urine samples, respectively. The limits of quantitation of vinblastine and desacetylvinblastine were 0.125ng/mL in both matrices. The intra and interday accuracy was above 89% and precision below 8.6% for both analytes in both matrices. The developed method was successfully applied to ongoing in vivo vinblastine pharmacokinetic studies in dogs.

Analytical approaches for traditional chinese medicines exhibiting antineoplastic activity

Traditional Chinese medicines have attracted great interest in recent researchers as alternative antineoplastic therapies. This review focuses on analytical approaches to various aspects of the antineoplastic ingredients of traditional Chinese medicines. Emphasis will be put on the processes of biological sample extraction, separation, clean-up steps and the detection. The problems of the extraction solvent selection and different types of column chromatography are also discussed. The instruments considered are gas chromatography, capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) connected with various detectors (ultraviolet, fluorescence, electrochemistry, mass, etc.). In addition, determinations of antineoplastic herbal ingredients, including camptothecin, taxol (paclitaxel), vinblastine. vincristine, podophyllotoxin, colchicine, and their related compounds, such as irinotecan, SN-38, topotecan, 9-aminocamptothecin, docetaxel (taxotere) and etoposide, are briefly summarized. These drugs are structurally based on the herbal ingredients, and some of them are in trials for clinical use. Evaluation of potential antineoplastic herbal ingredients, such as harringtonine, berberine, emodin, genistein, berbamine, daphnoretin, and irisquinone, are currently investigated in laboratories. Other folk medicines are excluded from this paper because their antineoplastic ingredients are unknown.

The importance of drug-transporting P-glycoproteins in toxicology

The importance of specific transport in toxicology is becoming increasingly clear and the work on P-glycoprotein has certainly been a major contribution to these growing insights. P-Glycoproteins were discovered by their ability to confer multidrug resistance in mammalian tumour cells. They are localised in the cell membrane where they actively extrude a wide range of compounds including many anti-cancer drugs from the cell. Besides in tumour cells, drug-transporting P-glycoproteins are also expressed in a polarised fashion in normal tissues that perform an excretory or barrier function, such as the liver, kidneys, intestines, brain endothelial cells. Based on this expression profile, it has been proposed that P-glycoproteins are important in protecting the host by reducing exposure to xenobiotics. Further studies with P-glycoprotein knockout mice have clearly established this protective function. In general, the clearance of substrate drugs is lower in knockout mice due to a diminished hepatobiliary excretion, direct intestinal excretion and/or increased enterohepatic cycling. Moreover, their uptake in sanctuary sites, such as the brain or the foetus, was profoundly higher in P-glycoprotein knockout mice, as was the uptake of drugs from the gastro-intestinal tract into the systemic circulation following oral ingestion. These results clearly highlight the impact that transport proteins can play in toxicology.

The influence of P170-glycoprotein modulators on the efficacy and the distribution of vincristine as well as on MDR1 expression in BRO/mdr1.1 human melanoma xenografts

Multidrug resistance modulators may increase the antitumour efficacy of drugs affected by P170-glycoprotein (Pgp) in Pgp-positive tumours in vivo. Inhibition of Pgp function in normal tissues, however, may enhance side-effects. Dexniguldipine-HCl, its analogues B9203-009 and B9303-036, and the dipyridamole derivative BIBW22BS could reverse vincristine (VCR) resistance in BRO/mdr1.1 cells (transfected with full-length MDR1 cDNA) and 2780AD cells (selected for doxorubicin resistance) in vitro. VCR resistance in BRO/mdr1.1 xenografts grown subcutaneously (s.c.) in the nude mouse was not or only slightly affected by the Pgp modulators. VCR concentrations in normal mouse tissues increased with the dose of the Pgp modulator administered and this was most pronounced in liver, kidney, small gut and colon. Dexniguldipine 40 mg/kg intraperitoneally (i.p.) given once 4 h before VCR 1 mg/kg intravenously (i.v.) resulted in increased VCR concentrations in BRO/mdr1.1 xenograft tissue. Surprisingly, when dexniguldipine 40 mg/kg i.p. was administered daily x3 before VCR, tumour VCR concentrations were not affected. This phenomenon was not observed in normal mouse tissues. Upregulation of MDR1 mRNA to 2.7- to 3.8-fold higher levels than control mRNA in BRO/mdr1.1 xenograft tissue occurred after VCR or dexniguldipine at 4-8 h and up to 1.7-fold at 24-28 h after injection. The combination showed 3.6- to 3.7-fold increased levels at 4 h after VCR injection. The lower VCR concentrations measured in BRO/mdr1.1 xenograft tissue after pretreatment with dexniguldipine for 3 days relative to animals treated with dexniguldipine only once will likely be caused by a gradual increase of Pgp expression as a response to the upregulation of MDR1.

Plasma pharmacokinetics, tissue disposition, excretion and metabolism of vinleucinol in mice as determined by high-performance liquid chromatography

We investigated the pharmacokinetics of the experimental semisynthetic vinca alkaloid vinleucinol (VileE; O4-deacetyl-3-de(methoxycarbonyl)-3-[[[1-ethoxycarbonyl-2- methylbutyl]amino]carbonyl]-vincaleukoblastine). The study was performed in male FVB mice receiving 10.5 mg/kg VileE i.v. or p.o. Plasma, urine, faeces and tissue samples were analysed by a selective method based on ion-exchange normal-phase high-performance liquid chromatography (HPLC) with fluorescence detection and liquid-liquid extraction for sample clean-up. Apart from the parent drug, two other metabolic compounds were detected. One of these metabolites is vinleucinol acid (VileA; O4-deacetyl-3-de(methoxycarbonyl)-3-[[[1-carboxyl-2- methylbutyl]amino]carbonyl]-vincaleukoblastine), which possesses no cytotoxic activity. The structure proposed for the second metabolite (VileX) was based on tandem mass spectrometry (MS-MS) and infrared (IR) spectroscopy data. Metabolization of VileE to VileX must occur in the amino acid moiety of the molecule, with a (beta- or gamma-) lactone ring being formed after oxidation of the (beta- or gamma) carbon of the amino acid. VileX is a major metabolite, which is excreted in faeces and urine after i.v. administration and accounting for up to 23% of the administered dose. The activity of VileX against cultured L1210 cells is four times that of the parent drug VileE and comparable with that of vinblastine (VBL). At 48 h after administration of VileE, the concentration of VileX exceeds that of the parent drug in many tissues. These findings indicate that the metabolite VileX may be at least largely responsible for the activity observed against xenografts in mice after administration of the parent drug, VileE.

Disruption of the mouse mdr1a P-glycoprotein gene leads to a deficiency in the blood-brain barrier and to increased sensitivity to drugs

We have generated mice homozygous for a disruption of the mdr1a (also called mdr3) gene, encoding a drug-transporting P-glycoprotein. The mice were viable and fertile and appeared phenotypically normal, but they displayed an increased sensitivity to the centrally neurotoxic pesticide ivermectin (100-fold) and to the carcinostatic drug vinblastine (3-fold). By comparison of mdr1a (+/+) and (-/-) mice, we found that the mdr1a P-glycoprotein is the major P-glycoprotein in the blood-brain barrier and that its absence results in elevated drug levels in many tissues (especially in brain) and in decreased drug elimination. Our findings explain some of the side effects in patients treated with a combination of carcinostatics and P-glycoprotein inhibitors and indicate that these inhibitors might be useful in selectively enhancing the access of a range of drugs to the brain.

Plasma pharmacokinetics, tissue disposition, excretion and metabolism of vinorelbine in mice as determined by high performance liquid chromatography

We have investigated the pharmacokinetics of the investigational semi-synthetic vinca alkaloid vinorelbine (navelbine, NVB). The analyses have been performed by using a sensitive and selective method based on ion-exchange normal phase high-performance liquid chromatography with fluorescence detection combined with liquid-liquid extraction for sample clean-up. Pharmacokinetic studies were performed in male FVB mice receiving 12 mg/kg NVB through intravenous injection. The results have been compared to those obtained for vinblastine (VBL). The plasma pharmacokinetics of NVB can be described by a three compartment model. The elimination half-life is significantly longer and the plasma AUC values higher for NVB compared to VBL. This is reflected in tissues, where, 24 hr after drug administration, the concentration of NVB is 5 to 10-fold higher compared to VBL. Qualitatively, the tissue distribution and retention of the drugs is very similar. The drug concentrations in most tissues decline parallel with the circulating plasma levels, whereas prolonged retention is found in tissues of lymphatic and testicular origin. Deacetylation yielding deacetylnavelbine (DNVB) is the primary metabolic route for NVB. This cytotoxic metabolite accounts for a substantial part of the overall disposition of drug. Only 58% of the administered dose is excreted in the urine (17%) and faeces (41%) as NVB or DNVB. No other metabolites have been detected.