Determination of sun protection factor and physical remanence of dermocosmetic emulgels formulated with Manilkara zapota (L.) fruit extract

Purpose: To develop a stable emulgel formulation from Manilkara zapota fruit extract (MZFE) and evaluate its sun-protective factor (SPF) and its physical retention on facial skin. Methods: Active test formulations containing MZFE and placebo (containing no active ingredients) were prepared by dispersing the primary emulsion into a gel phase. Both test and placebo emulgel formulations were subjected to physicochemical evaluation, stability studies, and assessment of possible photo-protective properties. The sun-protective factor (SPF) was determined in vitro by spectrophotometric analysis. Non-invasive in vivo skin bioengineering technique was used to assess the UV-quenching effects of the test and placebo emulgel formulations. Results: A stable and cosmetically acceptable emulgel formulation loaded with MZFE was obtained. The formulation and control exhibited optimum physicochemical stability in stress stability tests. The formulation exhibited promising photo-protective effects both in vitro (SPF = 14.215 ± 0.140) and in vivo (lasted for approximately 120 min). Conclusion: The developed MZFE-loaded test emulgel formulation possesses suitable photoprotection capability in vitro, and displays quenching effects against specific wavelengths of UV light, indicating a UV-filtering property