Ekstrakt talusa Usnea barbata (L.) Weber ex F. H. Wigg., Parameliaceae u emulzionim nosačima stabilizovanim biorazgradivim emulgatorima: preformulaciona i formulaciona istraživanja

Abstract

Uvod Lokalna terapija antibiotskim preparatima predstavlja pogodan način prevencije i/ili lečenja određenih infekcija kože, ali ima i niz ograničenja koja su vezana kako za lekovite supstance sa antimikrobnim delovanjem, tako i za podloge koje se koriste kao njihovi nosači. Pored porasta rezistencije bakterija, nedostatak dermalne primene antibiotika je i njihova slaba penetracija u kožu, ali i toksičnost nekih od njih prema humanim ćelijama. Usled toga, nameće se potreba za pronalaženjem novih supstanci sa antimikrobnom aktivnošću širokog spektra dejstva i poboljšanom dermalnom raspoloživošću/bezbednosnim profilom. Kao potencijalni izvori ovakvih supstanci sve više se istražuju lišajevi, među kojima se naročito istakla Usnea barbata (L.) Weber ex F.H. Wigg., Parmeliaceae (jevrejska ili lišaj brada). Iako se brojna biološka svojstva lišaj brade pripisuju usninskoj kiselini, novija istraživanja ukazala su na neke prednosti upotrebe njenog ekstrakta dobijenog primenom natkritičnog ugljen-dioksida (CO2) u odnosu na ovu supstancu per se. Sa druge strane, poznato je da su emulzioni sistemi (naročito kremovi), kao najpopularniji nosači lekovitih supstanci u dermatološkim preparatima, često stabilizovani tradicionalnim anjonskim/nejonskim mešanim emulgatorima, koji mogu izazvati neželjene reakcije, posebno na oboleloj koži. Pored toga, značajan uticaj kozmetičke industrije na dermofarmaciju je, uz porast zabrinutosti za zaštitu životne sredine, stavio u fokus istraživanja savremenih emulgatora povoljnijeg ekološkog i dermatološkog profila, koji istovremeno mogu da obezbede poboljšane senzorne osobine kremova za primenu na koži. Cilj istraživanja Cilj istraživanja ove doktorske disertacije bio je razvoj emulzionog sistema tipa hidrofilnog krema sa biorazgradivim alkil poligukozidnim (APG) emulgatorima prirodnog porekla, kao nosača za ekstrakt talusa U. barbata sa kvantifikovanom usninskom kiselinom, kroz procenu koloidne strukture, fizičke stabilnosti i biofarmaceutskih karakteristika, te ispitivanja efikasnosti i bezbednosti prototip formulacije gotovog proizvoda, koji bi našao potencijalnu primenu kao alternativa antibiotskim preparatima u lokalnoj terapiji infekcija kože...

Introduction Local therapy with antibiotic preparations represents the preferable way of prevention and/or treatment of some skin infections but also has a number of limitations connected to antimicrobial agents on one the hand and vehicles used as their carriers, on the other. Aside from bacterial resistance growth, a major problem regarding dermal application of antibiotics is their poor penetration into the skin, and also toxicity to human cells, documented for some of them. Therefore, there is a growing interest in the research concerning new substances with broad-spectrum antimicrobial activity and improved dermal availability/safety profile. Lately, various lichens are being intensively investigated as potential sources of such substances, among which Usnea barbata (L.) Weber ex F. H. Wigg., Parmeliaceae (old man’s beard) has been singled out, as one of the most frequently investigated. Although various biological properties of old man’s beard have been attributed to usnic acid, recent research suggested certain benefits of usage of its extract obtained using supercritical carbon dioxide (CO2), compared to this compound per se. On the other hand, it is well established that the emulsion systems (particularly creams), as the most popular carriers in dermatological preparations, are often stabilized using conventional anionic/non-ionic emulsifiers, known to cause adverse effects, especially in the diseased skin. Besides that, a major impact of the cosmetic industry on dermopharmacy, alongside with the growing environmental concerns, has put in the focus research of contemporary emulsifiers with favorable dermatological and ecological profile, which are also able to provide enhanced sensory properties of creams for skin application. Aim The aim of this doctoral dissertation was the development of an emulsion system of hydrophilic cream type based on biodegradable alkyl polyglucoside (APG) emulsifiers, as a potential carrier for the extract of the talus of U. barbata with quantified usnic acid, throughout the assessment of colloidal structure, physical stability and biopharmaceutical characteristics and also evaluation of efficacy and safety of the prototype formulation of the final product, which could potentially serve as an alternative to the antibiotic preparations in the local treatment of skin infections...