Controlled drug release from interpolymeric complexes

Controlled drug release is a technique used to provide the therapeutic effect in the desired time and drug delivery to the targeted area. Controlled drug release systems have many advantages, such as reducing possible side effects compared to traditional release systems, increasing patient comfort by extending the time intervals in drug intake. The basic requirement in this technique is that the materials used in drug delivery systems must have high drug carrying capacity and do not contain harmful chemicals for biological systems. In the thesis study, expanded perlite particles due to their high adsorption capacities were utilized as drug carrier material. Doxorubicin, an anti-cancer drug that is frequently used in cancer treatment and is easily quantified with simple techniques (UV-visible spectroscopy), was chosen as a model drug for the study. Interpolymeric complexes were used to adjust drug release profiles from drug loaded expanded perlite particles. In this context, interpolymeric complexes by using two amino acid based polymers (poly-L-histidine and poly-L-lysine) with different charges were coated the expanded perlite. Drug release studies of both drug loaded and interpolymeric complex formed expanded perlite samples were analyzed comparatively. The drug delivery systems prepared were characterized by Raman spectroscopy, zeta-potential analysis, thermal gravimetric analysis and scanning electron microscopy. As a result of the characterization process, the effects of parameters such as pH, time, temperature and concentration on drug release profiles were investigated. Optimum release conditions were determined as 5.5, up to 21 days, and 37oC for pH, time, and temperature, respectively. As expected, the amount of drug released increased by the increase in the particle concentration. For the mathematical analyses of release profiles, Korsmeyer-Peppas, zeroth and first order models were applied to the data. It has been determined that the Korsmeyer-Peppas model is more suitable for both systems, however the system has a profile close to the zeroth order releasing profile. The presence of the interpolymeric complex has been determined to positively affect the drug release profile and resulted in more controlled, pH sensitive and suitable for prolonged sustained release.