Effect of Laser Radiation on Drug Release from Liposomes

Abstract

Liposomes vesicles have drawn attention of researchers as carriers of various drugs that could be used for therapeutic applications. fn the present work liposomes were prepared from a mixh1re of I,2dipalmitoyl-sn-l-phosphatidylcholine (DPPC) as a photosensitive. site in the membrane, L-a-phosphatidylcholine from natural egg yolk (egg PC) and 3-sn-phosphatidylcholine from soybean (Soy PC) and Cholestero1 in the weight ratio of 1: 3: 2: 1.2 respectively. Liposomes were loaded with Methotrexate (MTX) as a model drug. Effect of 30, 60 and 80 joules/ml of 650 nm diode laser irradiation on the drug release of MTX, phase transition,

size distribution, dielectric propetiies and molecular stability of the prepared liposomes were studied. The results indicated that, the drug release percentages of the irradiated samples increased in comparison with the control one as the laser dose was increased. The release was measured every 30 min up to 3 hours using spect •ofluorometric technique at excitation wavel ength of 345 nm and emission wavelength of 450 nm. The phase transition temperature Tc showed a decrease as the laser dose was increased. All of the studied liposomes have a dielectric dispersion in the frequency range from 0.1 - 10 MHz. Liposomes exposed to different laser doses showed an i ncrease in a parameter, decrease in dielectric decrement L\£ and slight changes in the relaxation time. FT-IR spectra showed that the used laser energy did not cause any changes in the stability of the encapsulated drug. Jt was concluded from the results that, laser irradiation of 30, 60 and 80 joules/ml can be used as a powerful technique in order to increase the encapsu lated drug release from liposomes in comparison with the control sample, and consequently reduce the side effects of the encapsulated drug and increase its ability of avoiding diseases.