Interestingly, a smaller initial burst (IB, percentage of STRP released after 1 min) IB = 2% for PEI/ALG compared to IB = 22% for PEI/PAC was obtained and also the residual amount (RA) of STRP after 200 min was RA = 70% for PEI/ALG and RA = 17% for PEI/PAC.