Analysis of anthracycline antitumour drugs in tissues and body fluids using liquid chromatography

Pre-targeting and direct immunotargeting of liposomal drug carriers to ovarian carcinoma

Background

Epidermal growth factor receptor (EGFR) is overexpressed in many solid tumor types, such as ovarian carcinoma. Immunoliposome based drug targeting has shown promising results in drug delivery to the tumors. However, the ratio of tumor-to-normal tissue concentrations should be increased to minimize the adverse effects of cytostatic drugs.

Methodology/Principal Findings

We studied the EGFR-targeted doxorubicin immunoliposomes using pre-targeting and local intraperitoneal (i.p.) administration of the liposomes. This approach was used to increase drug delivery to tumors as compared to direct intravenous (i.v.) administration of liposomes. EGFR antibodies were attached on the surface of PEG coated liposomes using biotin-neutravidin binding. Receptor mediated cellular uptake and cytotoxic efficacy of EGFR-targeted liposomes were investigated in human ovarian adenocarcinoma (SKOV-3 and SKOV3.ip1) cells. In vivo distribution of the liposomes in mice was explored using direct and pre-targeting approaches and SPECT/CT imaging. Targeted liposomes showed efficient and specific receptor-mediated binding to ovarian carcinoma cells in vitro, but the difference in cytotoxicity between targeted and non-targeted liposomes remained small. The relatively low cytotoxic efficacy is probably due to insufficient doxorubicin release from the liposomes rather than lack of target binding. Tumor uptake of targeted liposomes in vivo was comparable to that of non-targeted liposomes after both direct and pre-targeting administration. For both EGFR-targeted and non-targeted liposomes, the i.p. administration increased liposome accumulation to the tumors compared to i.v. injections.

Conclusions/Significance

Intraperitoneal administration of liposomes may be a beneficial approach to treat the tumors in the abdominal cavity. The i.p. pre-targeting method warrants further studies as a potential approach in cancer therapy.

Direct sampling from human liver tissue cross sections for electrophoretic analysis of doxorubicin

After chemoembolization of the liver with doxorubicin (Dox), this drug and its metabolites are not homogeneously distributed in this organ. The distribution cannot be easily measured making it difficult to assess how the drug performs in different tissue regions. Here we report a technique for sampling tissue cross sections that can analyze the contents of micrometer size regions. The tissue cross sections were from the explanted liver of a hepatocellular carcinoma patient. Samples were directly aspirated from a 5 microm thick tissue cross section into a 50 microm i.d. capillary where the tissue was solubilized with a separation buffer containing sodium dodecyl sulfate. Upon sample dissolution, Dox and natively fluorescent compounds were separated and detected by micellar electrokinetic chromatography with laser-induced fluorescence detection. Sampling reproducibility and recovery were assessed using 10% (w/v) gelatin as tissue mimic. Sampling from gelatin slices containing Dox revealed a relative standard deviation of 13%, which was comparable to that of sampling from solution. Dox recovery was 82% +/- 16% (n = 5). When sampling tumor and nontumor tissue regions, samples could be taken from the same region 100 microm apart. Atomic force microscopy was used to determine that each sample was 8.4 +/- 1.0 pL in volume which made it possible to determine Dox concentrations in the ranges of 0.4-1.3 and 0.3-0.5 microM for the samples taken from tumor and nontumor regions, respectively. The results demonstrated the feasibility of sampling, detection, and quantification of Dox in micrometer size regions, which could be a useful resource for analyzing the Dox concentration and distribution in highly heterogeneous tissues.

Separation methods for anthraquinone related anti-cancer drugs

The quinoid anthracycline-related anti-cancer agents represent an important group of anti-tumour drugs with a wide spectrum of activity. We review here some of the separation techniques used for the analysis of anthracyclines and related compounds. In this review we have covered a range of compounds from the early anthracycline antibiotics such as doxorubicin to the more recent anthracenediones and anthrapyrazoles such as mitoxantrone and losoxantrone, respectively. We also include novel compounds such as AQ4N and C1311, both awaiting clinical trial. Separations of the anthraquinone related anti-cancer agents are predominantly by HPLC. These separation techniques have been used for a variety of applications including drug stability, protein binding and therapeutic drug monitoring as well as detailed pharmacokinetic and metabolic studies. Pharmacokinetics, and therefore drug analysis, plays a central role in both the development of new agents and also leads to a better understanding of clinically established agents in this class. Sample preparation and extraction methods including solid-phase and liquid-liquid extraction have also been highlighted. Many anthraquinone related compounds are highly coloured and fluoresce. They are suitable for a range of detection methods including UV-Vis, electrochemical and fluorescence. The methods described are used for sometimes complex separations that are needed for the evaluation of such compounds in biological samples.

A simple HPLC method using a microbore column for the analysis of doxorubicin

Doxorubicin is one of the most potent anti-tumor agents generally used in the treatment of bone cancer. A simple and sensitive HPLC method was developed and validated for the assay of doxorubicin. The method used a C18 Luna microbore column (50 x 1 mm) with a fluorescent detector (505 nm Ex. and 550 nm Em.). The mobile phase consisted of water-acetonitrile-acetic acid (80:19:1, v/v/v, pH 3.0) and the flow rate was 0.1 ml min(-1). Daunomycin was used as the internal standard. This isocratic system required a 10-min run-time, giving a detection limit of 0.02 ng (0.035 pmol per injection). Standard curves were linear over the concentration range of 0.01-0.1 microg ml(-1). Relative standard deviations (R.S.D.) for the within-day, day-to-day precision, and the accuracy measurement for the assay were less than 4.0, 3.2, and 4.1%, respectively. This HPLC method was used to study the in vitro release characteristics of doxorubicin from implantable drug delivery system.