Polyethylene Sebacate-Silymarin Nanoparticles with Enhanced Hepatoprotective Activity.

The present study evaluates role of pullulan as hepatic targeting agent. Nanoparticles of silymarin (SIM) a hepatoprotective drug were prepared using polyethylene sebacate (PES) as biodegradable polymer and surface modified with pullulan. PES-SIM nanoparticles (PES-SIM NP) and PES-SIM nanoparticles surface modified with pullulan (PES-SIM-PUL) were prepared by nanoprecipitation. Nanoparticles were evaluated for hepatoprotective activity in a model of carbon-tetrachloride (CCl4) induced hepatotoxicity in rats. Pretreatment of rats with PES-SIM-NP and PES-SIM-PUL revealed reduced levels of SGOT, SGPT and ALKP compared to CCl4 treated group (p < 0.01) whereas levels of LPO and catalase were comparable to vehicle control suggesting enhanced hepatoprotection with nanoparticles. Histopathological evaluation of liver tissues also revealed better hepatoprotection with nanoparticles. Further significant decrease (p < 0.01) in levels of SGOT, SGPT and ALKP with difference PES-SIM-PUL than PES-SIM NP confirms the role of pullulan as hepatic targeting agent.

Evaluation of pullulan-functionalized doxorubicin nanoparticles for asialoglycoprotein receptor-mediated uptake in Hep G2 cell line.

The present study discusses evaluation of pullulan-functionalized doxorubicin nanoparticles for asialoglycoprotein receptor-mediated uptake in the Hep G2 cell line. Doxorubicin hydrochloride (DOX) nanoparticles using polymers of different hydrophobic character, polyethylene sebacate (hydrophobic) and poly (lactic-co-glycolic acid) (intermediate hydrophobicity) with high entrapment efficiency and particle size were prepared by modified nanoprecipitation, using Gantrez AN 119 as complexing agent. Nanoparticles of Gantrez AN 119 were also prepared to represent a hydrophilic polymer. Cell uptake of DOX nanoparticles was found to be comparable to DOX solution irrespective of DOX concentration, nanoparticles size, and pullulan concentration. Furthermore, uptake of nanoparticles functionalized with or without pullulan prepared with polymers of different hydrophobic character revealed comparable uptake. Comparable uptake of DOX solution and DOX nanoparticles functionalized with or without pullulan suggest extracellular release of DOX as the mechanism of uptake from the nanoparticles. In vivo evaluation in hepatic cancer model is therefore essential to confirm the role of pullulan as asialoglycoprotein receptors ligand.

Polyethylene sebacate-doxorubicin nanoparticles for hepatic targeting.

The present study discusses polyethylene sebacate (PES)-doxorubicin (DOX) nanoparticles (PES-DOX NP) using pullulan as asialoglycoprotein receptor (ASGPR) ligand for hepatic targeting. Pullulan, a hydrophilic polymer served as ligand and as stealth agent. PES-DOX NP were prepared by modified nanoprecipitation using PES and Gantrez AN 119 (Gantrez), as complexing agent in the organic phase, while DOX was dissolved in the aqueous phase. Pullulan was adsorbed on the formed nanoparticles (PES-DOX-PUL). Intimate association of PES and Gantrez, and ionic complexation of DOX with Gantrez (confirmed by FTIR), coupled with rapidity of nanoprecipitation resulted in nanoparticles with high entrapment efficiency and high drug loading. Nanoparticles were successfully freeze dried. Drug release from PES NP followed zero order kinetics. PES-DOX NP and PES-DOX-PUL exhibited low hemolytic potential and good serum stability. Comparative biodistribution study in rats using (99m)Tc labeled formulations revealed higher blood concentration and lower liver concentration of PES-DOX-PUL, confirming the long circulating nature of PES-DOX-PUL, and thereby the possibility of improved targeting to hepatocytes. Nanoparticles revealed lower DOX concentration in the heart suggestive of low cardiotoxicity. Our study presents a radically different yet simple approach for the design of PES-DOX nanoparticles with high drug loading for improved therapy in hepatic cancer.

Nanoparticles of polyethylene sebacate: a new biodegradable polymer.

The present study demonstrates feasibility of preparation of nanoparticles using a novel polymer, polyethylene sebacate (PES), and its application in the design of drug-loaded nanocarriers. Silymarin was selected as a model hydrophobic drug for the present study. Two methods of preparation, viz., nanoprecipitation and emulsion solvent diffusion, were evaluated for preparation of nanoparticles. Effect of surfactants polyvinyl alcohol (PVA), lutrol F 68, and Tween 80 on the preparation of blank and silymarin-loaded PES nanoparticles was evaluated. Nanoprecipitation resulted in the formation of nanoparticles with all the surfactants (<450 nm). Increase in surfactant concentration resulted in decrease in entrapment efficiency and particle size except with PVA. The type and concentration of surfactant was critical to achieve low size and adequate drug entrapment. While increase in concentration of PES resulted in larger nanoparticles, inclusion of acetone in the organic phase resulted in particles of smaller size. In case of emulsion solvent diffusion, nanoparticles were obtained only with lutrol F 68 as surfactant and high surfactant concentration. The study revealed nanoprecipitation as a more versatile method for preparation of PES nanoparticles. Scanning electron microscopy studies revealed spherical shape of nanoparticles. Freeze-dried nanoparticles exhibited ease of redispersion, with a marginal increase in size. Differential scanning calorimetry and X-ray diffraction analysis revealed amorphous nature of the drug. The study demonstrates successful design of PES nanoparticles as drug carriers.

Engineered nanocarriers of doxorubicin: a current update.

Doxorubicin remains the first line of treatment for various cancers ever since its discovery in 1971. Cardiotoxicity and nephrotoxicity associated with unformulated doxorubicin triggered the development of doxorubicin nanocarriers. Although the therapeutic profile of doxorubicin is appreciably improved by entrapping in nanocarriers, they are largely taken up by organs of the reticuloendothelial system. Engineered nanocarriers of doxorubicin refer to carriers modified to escape recognition by reticuloendothelial system and/or functionalized with target specific ligands for selective accumulation at the target site. The first developments in engineered nanocarriers were the stealth carriers. These effectively bypassed the reticuloendothelial system and enhanced the therapeutic profile of doxorubicin by enabling passive accumulation in tumors. Stealth nanocarriers of doxorubicin revealed significant decrease in cardiotoxicity and nephrotoxicity, which led to the approval of liposomal doxorubicin for clinical applications. Success of liposomal doxorubicin was soon dulled by the appearance of newer toxicities like palmar-plantar erythrodysesthesia commonly referred as hand foot syndrome. The search for the magic bullet of doxorubicin has further intensified and resulted in design of engineered nanocarriers with high specificity for cancer cells. This review charts the progress from nanocarriers to engineered nanocarriers of doxorubicin, and highlights the current status of engineered nanocarriers of doxorubicin in clinical trials.