development of nanoemulsion-based patch formulations containing plantago lanceolata and althaea officinalis extracts for the treatment of cough and sore throat

In recent years, plant-based extracts have garnered considerable attention for their applications in healthcare, with a corresponding increase in the number of related studies. plantago lanceolata, which possesses anti-inflammatory, antibacterial, and antitussive properties, has long been used to treat coughs and the common cold. althaea officinalis is also traditionally used as an emollient and a protective agent against respiratory tract irritation caused by chronic cough. nevertheless, the limited stability and poor solubility of these plant extracts frequently limit their therapeutic application. nanoemulsions (nes) offer a promising approach to overcome these limitations by enhancing solubility, stability, and bioactivity while protecting active compounds from environmental degradation. moreover, formulating nanoemulsion-based mucoadhesive patches (ne-mps) can prolong the residence time at the site of action, form a protective barrier on mucosal surfaces, and alleviate local symptoms such as pain and irritation. the objective of this study was to develop an ne-mp incorporating extracts of p. lanceolata and a. officinalis for the treatment of cough and sore throat. the extract-loaded nanoemulsion (e-ne) was prepared using ethyl oleate, labrasol, kolliphor rh40, pluronic f68, span 80, and ultrapure water. meanwhile, nacmc, gelatin, and glycerin were employed to prepare the mucoadhesive patch form. in vitro characterization studies were performed for ne and ne-mp formulations. the average droplet sizes of blank and extract-loaded nes were found as 112.63 ± 2.62 nm and 115.96 ± 3.90 nm, respectively, with pdi values <0.3, confirming monodisperse distribution. also, nes exhibited newtonian flow behavior. ft-ir analysis demonstrated that molecular- level dispersion of extracts within the formulations. the ph values of both ne and ne-mp formulations were suitable for mucosal application. overall, ne and ne-mp systems containing p. lanceolata and a. officinalis extracts were successfully prepared, highlighting their potential as innovative dosage forms for the symptomatic treatment of cough and sore throat