If you expect reasonable help from people in this forum you need to provide details. What is the drug? What is zeta potential of the particles? What were the conditions used for loading and release? Etc.
Poonam,There are wide spectrum of reasons for slower drug release. you need to provide more information. Along with it, i dont know how the slow the drug release is but slower drug release is only appealing for better pharmacokinetics of the drug-cell interaction
I have used doxorubicin, drug loading was performed in water at RT with overnight stirring and till 24 h only 37% drug was released from uncoated SPION (-ve), where uncoated nanoparticles may should show fast release?