Thiadiazole chitosan conjugates as a novel cosmetic ingredient for rinse-off hair conditioners: design, formulation, characterization and in silico-molecular docking studies.

Recently, chitosan derivatives, as eco-sustainable and renewable products, have been recorded to be highly effective toward cosmetics with potent biological activity. The main core of this research is to develop an organic hair conditioner (OHC) based on two chitosan-thiadiazole conjugates, chitosan-(ethylthio‑thiadiazole) (CH-ETD) and chitosan-(benzylthio‑thiadiazole) (CH-BTD), with natural fragrances. A series of nine OHC formulae were prepared (CH1-CH3 for chitosan based OHC, E1-E3 for CH-ETD based OHC, and B1-B3 for CH-BTD based OHC) and characterized based on their visual examination, pH, thermal stability, dirt dispersion, moisturizing time, percentage of solid content, hair irritation, rinsing, combing, and the luster. The results showed that the pH values of all OHC formulae were 4.2-4.7 which is considered acceptable to avoid skin irritation. A distinctive film surrounds each individual hair shaft in the CH-ETD and CH-BTD treated groups when compared to control hair without the application of hair conditioner under a scanning electron microscope SEM with a magnification power of 100 μm. Additionally, every single hair shaft is clearly covered, and the control group exhibited noticeable hair issues that were not observed in the treated groups, which showed no signs of tangling. Due to the end-use performance properties of the formulated hair conditioner products, it can be concluded that the formulas of (CH, E2, and B2) were the best efficacy; hair easier to style, detangle the hair, retain moisture, not be very thick, not cause irritation or inflammation, minimize frizz, and create a protective barrier on the hair. These findings collectively validate the potential of CH-ETD and CH-BTD based formulations coupled with natural perfumery as a transformative approach to hair care, aligning with consumer preferences for both efficacy and environmental sustainability. Furthermore, in this work, docking studies have been conducted to provide theoretical proof about the significant roles of chitosan and keratin in hair growth and cosmetic applications (skin).