Surface-modified Epirubicin-HCl liposomes and its in vitro assessment in breast cancer cell-line: MCF-7.

BACKGROUND: Epirubicin-HCl is highly efficient for breast cancer management at a concentration of 60-90 mg/m(2). However, its application is limited due to cumulative dose-dependent cardio-toxicity. PURPOSE: The main aim of this study was to formulate breast cancer-targeted liposomal carrier by surface conjugation of transferrin to minimize cardio-toxicity of drug along with improved pharmacokinetic profile. METHOD: Liposomes were formulated by ethanol injection method using HSPC, cholesterol and DSPG and later loaded with drug by the ammonium sulfate gradient method. The formulation was characterized for physicochemical properties like size, zeta potential, entrapment efficiency, TEM; in vitro tests like electro-flocculation, hemolysis and drug release; cell line study (MCF-7 cells); in vivo studies including LD50 determination, pharmacokinetic analysis, myocardial toxicity determination and stability. RESULTS AND DISCUSSION: Optimized formulation had molar ratio of 60:30:8:2 (HSPC:Chol:DSPG:mPEG-DSPE) with entrapment efficiency ∼83%, particle size below 200 nm and zeta potential about -20 mV. In vitro studies proved non-interfering property and drug release character of formulation while cell line studies demonstrated improvement in cell uptake and thereby increased cytotoxicity of targeted formulation. The IC50 value obtained for epirubicin solution, non-targeted and targeted liposomes was 0.675, 0.532 and 0.192 µg/ml, respectively. Furthermore, in vivo tests validated safety and distribution profile of prepared formulations. CONCLUSION: Apt properties of prepared Epirubicin-HCl liposomal formulation warrant its clinical application in breast cancer treatment after further studies.

Stability, Pharmacokinetics, Biodistribution and Safety Assessment of Folate-Conjugated Pullulan Acetate Nanoparticles as Cervical Cancer Targeted Drug Carriers.

It is recognized that the stability and journey in the body of nanoparticles are important issues for drug formulations. In this study, we prepared folate-conjugated pullulan acetate nanoparticles (FPANs) and epirubicin loaded FPANs (FPA/EPI) using dialysis method. The storage stability of FPANs and FPA/EPI at 4 degrees C could be up to 3 months. Using folate receptor overexpressed Hela cells, dose dependent cellular uptake and receptor-mediated endocytosis of FPA/EPI were confirmed. From the in vivo pharmacokinetics test, compared to free EPI, half-life time (t½) of FPA/EPI was extended 1.57 times and the area under-the-curve (AUC) increased 3.95 times as well. In addition, biodistribution data showed that, EPI concentration in tumor in FPA/EPI group was 2.01 times higher than that in free EPI group after 96 h; The concentration of drug in liver treated by FPA/EPI was 5.7-11.6 times, while in heart, kidney, especially in stomach and intestine were much lower than those in free EPI group from 24 to 96 h. Furthermore, blank FPANs showed no apparent acute toxicity at dose up to 125 mg/kg. All results suggested that FPA/EPI showed a promising potential on treating cervical carcinoma and its metastatic hepatocellular carcinoma in future because of the high stability, less toxicity and tumor targeting.

Assessment of the validity of a population pharmacokinetic model for epirubicin.

AIMS: The aim of this study was to evaluate a population model for epirubicin clearance using internal and external validation techniques. METHODS: Jackknife samples were used to identify outliers in the population dataset and individuals influencing covariate selection. Sensitivity analyses were performed in which serum aspartate transaminase (AST) values (a covariate in the population model) or epirubicin concentrations were randomly changed by +/-10%. Cross-validation was performed five times, on each occasion using 80% of the data for model development and 20% to assess the performance of the model. External validation was conducted by assessing the ability of the population model to predict concentrations and clearances in a separate group of 79 patients. RESULTS: Structural parameter estimates from all jackknife samples were within 7.5% of the final population estimates and examination of log likelihood values indicated that the selection of AST in the final model was not due to the presence of outliers. Alteration of AST or epirubicin concentrations by +/-10% had a negligible effect on population parameter estimates and their precision. In the cross-validation analysis, the precision of clearance estimates was better in patients with AST concentrations>150 U l-1. In the external validation, epirubicin concentrations were over-predicted by 81.4% using the population model and clearance values were also poorly predicted (imprecision 43%). CONCLUSIONS: The results of internal validation of population pharmacokinetic models should be interpreted with caution, especially when the dataset is relatively small.

Direct assessment of drug penetration into tissue using a novel application of three-dimensional cell culture.

The failure of many anticancer drugs to control growth of solid cancers may stem in part from inadequate delivery to tumor regions distant from vasculature. Although the identification of new anticancer drug targets has led to the development of many new drug candidates, there is a lack of methodology for identifying drugs that adequately penetrate tumor tissue. We have developed a novel multilayered cell culture-based assay, which detects the penetration of anticancer drugs based on their effect within tissue. Drug exposures are made over 1 hour to one side of a disk of tissue approximately 150-microm thick, with the other side temporarily closed off, and penetration is then assessed 1-3 days later via bromodeoxyuridine-based detection of S-phase cells. Using this assay, the tissue distribution of a selection of anthracycline analogues was assessed. At clinically relevant exposures, none of the agents were able to affect cells on the far side of the culture at levels approaching that seen on the near (exposed) side. Doxorubicin and epirubicin exhibited approximately 10-fold decreases in the drug exposure seen by the cells on the far side relative to those on the near side of the cultures, whereas for daunorubicin and mitoxantrone, approximately 30-fold and >30-fold decreases were observed respectively. Results were consistent with the observed gradients in drug-derived fluorescence of doxorubicin, epirubicin, and daunorubicin. This model could be applied as a simple anticancer drug development screen to discover drugs that exhibit desirable penetration properties.

A functional assessment of the relative cardiotoxicity of adriamycin and epirubicin in the rat.

The cardiotoxicity of the two anthracyclines, adriamycin and epirubicin, were studied in 14-week-old Sprague-Dawley rats after the intravenous administration of single doses of 1-4 mg/kg of adriamycin and 2-6 mg/kg of epirubicin. These doses of the two drugs were well tolerated with little acute toxicity. Acute toxicity was characterised by a transient reduction in body weight with recovery within 14 days. The cardiac output of the rats was measured at 4-weekly intervals, for up to 20 weeks, using an external counting technique with the radioactive tracer, 99mTc. The time-related changes in cardiac function in the rat after adriamycin and epirubicin were similar. The time course of the changes in cardiac output were biphasic. There was an initial phase of rapid decline in cardiac output in the first 12 weeks (phase I) and a second phase of persistent depression in cardiac function (phase II) after 12 weeks. The late progression of anthracycline-induced cardiotoxicity could be predicted from the measurements of cardiac output at 12 weeks. The relative cardiotoxicity of adriamycin and epirubicin was evaluated from the reductions in cardiac output and from the incidence of deaths related to cardiotoxicity. Both methods of evaluation showed that adriamycin was approximately twice as cardiotoxic as epirubicin. This relationship was independent both of the dose level of drugs used and of the damage level used for the evaluation. Dose-response curves were steeper for adriamycin than for epirubicin. The present findings agree with the somewhat limited clinical data suggesting that the present rat model is highly predictive and clinically relevant.