Systematic approach for the formulation and optimization of atorvastatin loaded solid lipid NANOAPARTICLES using response surface methodology.

Atorvastatin is a lipid lowering agent with poor oral bioavailability (12%) because of poor solubility and extensive first pass hepatic metabolism. In order to overcome these issues, atorvastatin loaded solid lipid nanoparticles (ATOR-SLNs) were prepared by using glyceryl tripalmitate as lipid carrier, poloxamer 407 as surfactant and soya lecithin as emulsifier. The purpose of this work was to optimize the formulation with the application of response surface methodology to improve the physicochemical properties. The central composite rotatable design consisting of three factored factorial design with three levels was used for the optimization of the formulations. The optimized formulation was composed of drug/lipid ratio of 1:3.64, surfactant concentration of 1.5% with 5 min time for sonication. Fourier transforms infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) studies confirmed the compatibility of drug and lipid in the formulation. The optimized ATOR- SLNs showed almost spherical shape with a mean particle size of 338.5 nm, zeta potential of -24.7mV, DL of 17.7% and EE of 81.06% respectively. The in vitro drug release study showed a burst release at the initial stage followed by the prolongation of drug release from lipid matrix. Stability study revealed that ATOR-SLNs were more stable at 4±2˚C when compared with storage at 25±2˚C/60±5% RH during the six months storage period. These results indicated that the developed ATOR-SLNs is a promising approach for increment of bioavailability by improving the physicochemical properties.

Synthesis and evaluation of MePEG-PCL diblock copolymers: surface properties and controlled release behavior.

The amphiphilic block copolymers are composed of various combinations of hydrophilic and hydrophobic block unimers. The variation in unimer ratio alters the surface as well as micelle-forming properties of the block copolymers. These nanoscopic micelles have the ability to encapsulate hydrophobic compounds and act as potential drug carrier. MePEG-PCL copolymers with various block lengths were synthesized by ring-opening polymerization and characterized by 1HNMR, GPC, WXRD and DSC. The number average molecular weight of the block copolymer was found to vary from 7511 to 21,270 as determined by GPC and 1HNMR studies. The surface topology of the polymer films was determined by AFM analysis, which shows a smoother surface with increased MePEG contents in the block copolymers. The protein-binding assay indicates a better biocompatibility of the block copolymers in comparison to MePEG or PCL alone. The CMC of the block copolymer provides the information about micelle formations for encapsulation of hydrophobic materials and affects the in vitro release.

Preparation and characterization of nebivolol nanoparticles using Eudragit® RS100.

Nebivolol, a beta-blocker, has been widely used for the treatment of hypertension and cardiovascular diseases; but has drawbacks like poor solubility and bioavailability requiring frequent dosing. The present study attempts to overcome these issues through nanoparticulate delivery system using widely used carrier Eudragit(®) RS100. The solvent evaporation (single emulsion) technique was used for developing nanoparticles. The impact of formulation and process variables on particle size and entrapment efficiency was studied to optimize the formulation. The physico-chemical characterization confirmed the particle size in nano range with smooth and spherical morphology. Further, Fourier transforms infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) studies confirm compatibility of drug-polymer combination. The in vitro drug release study of the prepared nanoparticles showed prolongation of drug release with reduced burst release in comparison with pure drug powder.

Preparation and evaluation of a new erythromycin derivative -- erythromycin taurate.

Erythromycin taurate, a new derivative of erythromycin, was prepared by reacting erythromycin base with tauric acid and its physico-chemical and biological properties were evaluated. The derivative has reasonably good solubility in organic solvents. The partition coefficient values in chloroform/water 1.17 and octanol/water 1.16 systems indicate its good distribution in various tissues in vivo. The in vitro antimicrobial potency of the derivative (833.33 microg mg(-1)) is higher than that of the existing derivatives such as erythromycin estolate, erythromycin stearate, erythromycin ethyl succinate, erythromycin gluceptate, erythromycin lactobionate. The antimicrobial spectrum is comparable to that of the parent compound. Our results indicate that erythromycin taurate has a high potential for possible clinical application and is more efficient against Escherichia coli and Klebsiella pneumoniae than the parent base.