FORMULATION OF SOY LECITHIN-BASED LIPOSOMES AS A CONTROLLED DELIVERY VEHICLE FOR METHOTREXATE

Liposomes are spherical vesicles composed of phospholipids that spontaneously self-assemble in aqueous media to form a lipid bilayer with an internal aqueous core. These nanocarriers can successfully encapsulate drugs with low bioavailability and high toxicity, such as methotrexate, which is widely recognized for its potent antiproliferative and anti-inflammatory effects. This research work aimed to evaluate the encapsulation efficiency of methotrexate in soy lecithin-based liposomes to develop an optimized controlled delivery vehicle. The experimental design involved formulating liposomes with drug-to-lipid weight ratios of 1:1 and 1:5 using the Mozafari method. Encapsulation efficiency was determined via UV-Vis spectrophotometry, applying the Beer-Lambert law to quantify the unencapsulated drug from the absorbance at 302 nm. Following sample centrifugation, the 1:1 ratio yielded an outstanding encapsulation efficiency of 99.80% and a drug loading capacity of 59.82%, while the 1:5 ratio achieved 99.01% efficiency and 11.87% loading capacity. Controlled release tests were systematically conducted, collecting samples over time to quantify drug concentration. The Korsmeyer-Peppas model revealed that both formulations exhibited an anomalous transport release mechanism; the 1:1 formulation showed a higher release constant (3.36 min-1) than the 1:5 system (2.20 min-1). Similarly, the Higuchi kinetic constant was higher in the 1:1 formulation (6.45%  min-0.5) than in the 1:5 blend (4.24% min-0.5), indicating that the 1:5 formulation provided a significantly more controlled drug release profile.