Factorial design based optimization of the formulation of albumin microspheres containing adriamycin

The use of factorial design in the formulation of adriamycin-associated albumin microspheres, using the heat-stabilization technique, is illustrated. The effect of stabilization temperature, protein concentration and stabilization time on the entrapment and recovery of adriamycin in microspheres have been investigated using a 2 x 4 x 4 factorial design. The associated drug content in unwashed and four times washed microspheres was determined using HPLC. Maximum drug association and drug recovery were obtained from microspheres synthesised using 25 per cent w/v albumin solution and stabilized at 120 degrees C for 2.5 min. Under these conditions, the entrapped and total associated drug content of the microspheres was about 4 per cent and 12 per cent w/w respectively, and the drug recovery was about 75 per cent. The in vitro dissolution study carried out using dynamic dialysis revealed that the release of adriamycin from these particles follows a bi-phasic pattern. The results demonstrate that use of short stabilization time, low protein concentration and low stabilization temperature are required for the formulation of microspheres with high adriamycin content.