Using the liquid extrusion method with vibrating nozzle, we made alginate microspheres with salicylic acid. By adding Tween 80 or lactose into the alginate solution for extrusion or by adding chitosan into the CaCl2 solution for crosslinking, we modified the micropsheres' characteristics, aiming to influence the speed of the active ingredient release process. During the drying process, the microspheres' diameter was reduced, while the alginate became more concentrated due to water evaporation. The dried particles were less than 1000 µm in size in all the samples, the chitosan-coated ones having the largest diameter. Those particles were also the most agglomerated after drying. The highest amount of salicylic acid was incorporated into the particles without excipients, due to higher percentage of the alginate solution for extrusion (2,0 %) compared to the particles with added Tween 80 or lactose (1,8 %). By adding chitosan into the calcium chloride solution, the incorporation of salicylic acid in the microparticles did not increase. The active substance release profile showed that most likely not all of the incorporated salicylic acid was released from the microspheres because the alginate matrix did not dissolve completely. After 5 minutes of diluting the microspheres in the water, most of the salicylic acid was released from all of the microspheres, which shows that we were unable to slow down the release process. The highest amount of the salicylic acid was released from the microspheres without excipients, while the lowest amount was released from the microspheres with lactose. Tween 80 did not promote the release of the salicylic acid from the microspheres.
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