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.

In vitro assessment of acyclovir permeation across cell monolayers in the presence of absorption enhancers.

The aim of the investigation was to establish transepithelial permeation of acyclovir across Caco-2 and Madin-Darby canine kidney (MDCK) cell monolayers and attempt to improve its permeation by employing absorption enhancers (dimethyl beta cyclodextrin, chitosan hydrochloride and sodium lauryl sulfate) and combinations thereof. Caco-2 and MDCK cell monolayers have been widely employed in studying drug transport, mechanisms of drug transport, and screening of absorption enhancers and excipients. Transepithelial electrical resistance and permeation of 99mTc-mannitol were employed as control parameters to assess the tight junction and paracellular integrity. Permeation of acyclovir in the presence of absorption enhancers was found to be significantly higher compared with drug permeation in their absence when assessed as apparent permeability coefficients (Papp). Synergistic improvements in Papp values of acyclovir were obtained in case-selected combinations of absorption enhancers; dimethyl beta cyclodextrin-chitosan hydrochloride, chitosan hydrochloride-sodium lauryl sulfate, and dimethyl beta cyclodextrin-sodium lauryl sulfate, were used. Recovery and viability assessment studies of both cell monolayers suggested reestablishment of paracellular integrity and no damage to cell membranes. Significantly improved permeation of acyclovir in the presence of selected combinations of absorption enhancers may be used as a viable approach in overcoming the problem of limited oral bioavailability of acyclovir.

Role of 99mTc-mannitol and 99mTc-PEG in the assessment of paracellular integrity of cell monolayers.

AIM: To assess the role of 99mTc-mannitol and 99mTc-polyethylene glycol 4000 in the evaluation of paracellular integrity of Caco-2 and Madine-Darby canine kidney (MDCK) cell monolayers, and confirm it in the presence of absorption promoters. METHODS: Radiolabelling of mannitol and polyethylene glycol was performed by a simple reduction method. Transepithelial electrical resistance values were measured to gain information regarding the integrity of tight junctions of Caco-2 and MDCK cell monolayers. Permeabilities of 99mTc-mannitol/99mTc-polyethylene glycol across cell monolayers were studied in the absence and presence of absorption promoters, namely dimethyl-beta-cyclodextrin, chitosan hydrochloride and sodium lauryl sulfate, and during recovery studies to assess paracellular integrity. RESULTS: Values for the apparent permeability coefficient (Papp) of Tc-mannitol were found to be 0.286 x 10 cm x s(-1) and 0.507 x 10 cm x s(-1) in Caco-2 and MDCK cell monolayers, respectively, whereas corresponding values for 99mTc-polyethylene glycol were 0.046 x 10 cm x s(-1) and 0.065 x 10 cm x s(-1). The insignificant Papp values of the marker molecules demonstrated the paracellular integrity of the cell monolayers. Significant increases in the Papp values in the presence of absorption promoters and their combinations due to opening of paracellular pathways and a return of Papp values to almost baseline values during recovery studies confirm the role of these marker molecules in the assessment of paracellular integrity of cell monolayers. CONCLUSION: 99mTc-labelled marker molecules can be attractive, useful and viable alternatives to the conventionally used markers in the assessment of paracellular integrity because of the absence of tissue-damaging corpuscular radiation and the ease of production of radiochemically pure and stable molecules at a reasonable cost.