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.

The therapeutic efficacy of perorally administered drug is often concealed by their poor oral bioavailability (BA) and low metabolic stability in the gastrointestinal tract (GIT). Most of the newly discovered drug molecules are of high molecular weight and belong to biopharmaceutical classification system (BCS) – II. Poor aqueous solubility and high membrane permeability characteristics of BCS – II drugs limit BA after oral administration. Recently, lipid-based drug delivery (LBDD) systems have gained much importance due to their ability to improve the solubility and BA of poorly soluble drugs. Oral delivery of drugs incorporated in solid lipid nanoparticles (SLNs) has gained considerable interest since the last two decades. SLNs have advantages above the others, as compared to polymer toxicity which is low, as inexpensive excipients and organic solvents are not used. SLNs offer the possibility to develop new therapeutics due to their unique size-dependent properties. An attempt to incorporate drugs into SLNs offers a new prototype in drug delivery system which can be utilized for drug targeting to specific tissue. This review presents elaborate information of SLNs with their aim, advantages, challenges and limitations, the principle of formulation, routes of administration and their biodistribution. It also describes the gastrointestinal absorption and the factors affecting absorption of SLNs from GIT along with its application.

Mixed micellar systems have been tried with the aim of achieving higher solubility of drugs compared to single micellar systems. Hydrophobic-hydrophilic mixed micellar systems have been used for the above purpose for the drug ciprofloxacin in the past. In the present study, a hydrophilic-hydrophilic binary micellar system comprising of pluronic copolymers pluronic F127 and pluronic L64 has been studied for its effect on solubilization of the drug Ciprofloxacin. The solutions of the two individual pluronic and their mixed micellar system with drugs were subjected to characterizations viz. UV-spectrophotometry, fluorimetry, FT-IR, dynamic light scattering (DLS), rheology, and partition coefficient. The mixed pluronic–drug system displayed greater solubility of the drug compared with the neat pluronic-drug systems in most of the characterizations. New C–OH bond formation was evidenced by FT-IR spectra due to drug micelle interaction. The values of free energy changes of micellization were found to be −25 kJ mol−1 for pluronic F127, −74.5kJmol−1 for L-64, and −170.4 kJ mol−1 for the mixed pluronic. This is suggestive of spontaneous and stronger binding of drug ciprofloxacin with mixed pluronic in comparison with that in single micellar systems. Graphic abstract

No abstract

No abstract