Incorporation of salicylic acid into alginate microspheres by liquid extrusion

Z metodo ekstruzije curka tekočine z vibrirajočo membrano smo pripravili alginatne mikrosfere s salicilno kislino. Z dodatkom Tweena 80 ali laktoze v alginatno raztopino za iztiskanje ali dodatkom hitosana v raztopino za premreževanje s CaCl2 smo spreminjali lastnosti mikrosfer in s tem želeli vplivati na hitrost sproščanja aktivne kozmetične sestavine. Med sušenjem se je premer izdelanih mikrosfer bistveno zmanjšal. Posušeni delci so bili v vseh primerih manjši od 1000 µm. Največji premer so imeli delci s hitosanom, ki so se med sušenjem tudi najbolj sprijeli. Največ salicilne kisline se je vgradilo v delce brez dodatkov, pri katerih je bil delež raztopine alginata za injiciranje višji (2,0 %) kot pri serijah s Tweenom 80 in z laktozo (1,8 %). Z dodatkom hitosana v raztopino za premreževanje se vgrajevanje salicilne kisline v mikrodelce ni povečalo. Profil sproščanja aktivne kozmetične sestavine je pokazal, da se iz mikrosfer ni sprostila vsa vgrajena salicilna kislina, najverjetneje, ker se alginatno ogrodje ni v celoti raztopilo. Po 5 minutah raztapljanja mikrosfer v vodi se je sprostila večina salicilne kisline iz vseh mikrosfer, kar pomeni, da nismo uspeli upočasniti njenega sproščanja. Največ salicilne kisline se je sprostilo iz mikrosfer brez dodatkov, najmanj pa iz mikrosfer z laktozo. Tween 80 ni pospešil sproščanja salicilne kisline iz mikrosfer.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\u27 characteristics, aiming to influence the speed of the active ingredient release process. During the drying process, the microspheres\u27 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