4) on a magnetic stirrer at 37 ± 0.5° at 100 rpm. 5 ml

quantity of sample was withdrawn at different time periods and same volume of dissolution medium was replaced in the flask to maintain Ulixertinib datasheet sink condition. The withdrawn samples were filtered and then the filtrate was diluted with phosphate buffer (pH 7.4). The samples were analyzed for drug release by measuring the absorbance at 249 nm using UV–visible spectrophotometer. The in vitro drug release studies were carried out in triplicate for each formulation. The in vitro release data of all the formulation were fitted with various kinetics models such as zero order, first order, Higuchi model and Korsmeyer–Peppas, 9 in order to predict kinetics and mechanism of drug release. The release constant was calculated from the slope of plots and regression

coefficient (r2), diffusion exponent (n) was determined. The stability study of freeze dried nanoparticles was carried out for D1 (1:2) to assess the stability of drug in nanoparticles. For this purpose the samples were taken in borosilicate vials and sealed and the vials were stored in room temperature (25°–30 °C) and refrigerator (3°–5 °C) over a period of 3 months. After specified period 0, 1, 2 and 3 months, the samples were checked for their physical appearance and drug content by UV spectrophotometer, as well as chemical stability by Fourier transform infrared (FTIR) studies. The biodistribution studies8 of ddi loaded albumin PD0332991 mw nanoparticles were carried out on healthy adult Wistar rats weighing 200–250 g and after obtaining approval from the local animal ethics committee and CPCSEA (DSCP/PH.D PHARM/IAEC/49/2010-2011). All animals were provided with proper care, food, water ad libitum

and were maintained under well ventilated in large spacious cages throughout the study. The rats were divided randomly into three groups with three animals per group and they were fasted at least 12 h before experimentation. Group 1 was injected with ddi (which was dispersed in water for injection) into the tail vein of rats, Group 2 was received ddi loaded albumin nanoparticles and Group 3 was administered polysorbate 80 coated albumin nanoparticles. All the formulations were given in a dose level equivalent to 20 mg/kg body weight. 7 One hour after injection, the rats were sacrificed by euthanized and organs such as liver, lung, kidney, through lymph nodes, spleen, brain and blood were isolated. The organs were washed with clean buffer saline and absorbed dry with filter paper and then weighed. Prior to the analysis organs homogenates were prepared and was digested with 10% v/v trichloroacetic acid and was treated with 10 ml of acetonitrile to extract didanosine. Didanosine content in the various organs was estimated by reverse-phase HPLC method. BSA nanoparticles were prepared and loaded with didanosine by desolvation techniques with ethanol as it does not require an increase in temperature.