The objective of present study was to develop controlled release lamivudine microspheres using spray drying encapsulation technique to increase the efficacy of anti retroviral drug, lamivudine against HIV infections and decrease its gastric unwanted effects. Low and high molecular weight chitosan and hydroxypropyl methylcellulose (HPMC) in different drug-polymer ratios were used for the preparation of microspheres. A 32 factorial experimental design was employed to explore the effect of polymer type (X1) and drug percentage (X2) on the release rate of the drug from the microspheres. The yield value (Y1), encapsulation efficiency (Y2), particle size (Y3) and the release efficiency percentage (Y4) were selected as the dependent variables. Drug release from microspheres was compared with the release behavior of commercially available formulation Lamidine®. The best encapsulation efficiencies were obtained when chitosan of low molecular weight (CL) or HPMC were used for microencapsulation. Tissue Culture Infective Dose that causes CPE for 50 % of cells (TCID50) was calculated using Reed-Muench formula. TCID50 of the prepared formulae was higher than TCID50 of Control after 5 hours. Marked retardation of lamivudine release from its prepared microspheres indicates the success of controlling drug release over 5 hours.
Preparation and in-vitro Evaluation of Poly--Caprolactone Nanoparticles Containing Atorvastatin Calcium
Preparation and evaluation of poly--caprolactone nanoparticles containing atorvastatin calcium (AC), a drug with poor solubility and poor bioavailability, is presented. The drug loaded nanoparticles were prepared by solvent displacement method using different experimental conditions. The influence of different formulation variables, such as type and concentration of stabilizers in the aqueous phase, concentration of polymer and surfactant in the organic phase, addition of an anti-oxidant, pH of the aqueous phase and others, on particle size, drug entrapment efficiency, in-vitro drug release along with other physico-chemical properties of the nanoparticles was investigated using several full factorial designs. The optimized AC nanoparticles showed an average particle size of less than 200 nm, a drug loading capacity of more than 70% and released the drug in a controlled fashion over 24 hour. Transmission electron microscope (TEM) revealed that the prepared AC nanoparticles were nearly spherical. Short-term stability results of selected formulae were satisfactory.