Formulation, Characterization, and Evaluation of an Emulsion Containing Apple Cider Vinegar and Clove Extract for Topical Application

Natural products are increasingly favored in skincare due to their therapeutic properties and minimal side effects. Ingredients like apple cider vinegar (ACV) and clove extract are well-known in traditional medicine for their medicinal properties. ACV is rich in acetic acid, known to help balance skin pH, reduce pigmentation, and enhance skin tone.

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 Clove extract contains eugenol, a powerful antioxidant and anti-inflammatory agent that helps combat oxidative stress on the skin. Oxidative stress and the resulting damage caused by free radicals are leading contributors to skin aging, hyperpigmentation, and various dermatological conditions.
       
           
       
Traditional remedies such as ACV and clove extract are believed to protect the skin by neutralizing free radicals and promoting an even skin tone. However, the combination of these two ingredients in an emulsion has not been thoroughly studied, particularly regarding their antioxidant properties and stability in a topical formulation. This research aims to fill this gap by developing a stable emulsion and evaluating its efficacy as an antioxidant and skin-protective agent.

1.1 Background:

In recent years, the cosmetics industry has been shifting towards natural formulations due to consumer demand for cleaner, safer, and sustainable ingredients. Synthetic additives, although effective, often pose risks such as irritation or allergic reactions. By contrast, natural ingredients like ACV and clove extract offer a safer alternative, backed by traditional use and emerging scientific evidence. ACV's acidic properties help exfoliate dead skin cells, while clove extract's antimicrobial and antioxidant activities offer protective benefits. The goal of this study is to optimize their combination in a stable topical emulsion.

2. Literature Review:

The use of ACV in dermatology dates back centuries. Historical texts mention the use of vinegar for treating wounds, infections, and skin conditions. Modern research has shown that ACV can balance the skin's pH, aid in exfoliation, and reduce hyperpigmentation (Sato et al., 2020).

Clove extract, with its high eugenol content, has also been widely studied. Eugenol has been found to inhibit free radicals, reducing oxidative damage to the skin and protecting against environmental stressors (Kim et al., 2021).

Previous studies have focused on ACV and clove oil individually, but research combining both in a topical formulation is sparse. Combining these ingredients in an emulsion allows for the benefits of both to be harnessed, offering a novel approach to skincare. Emulsions, as delivery systems, improve the penetration of active ingredients and enhance skin hydration (Jones & Davis, 2019). This study aims to explore the synergistic effects of ACV and clove extract within an emulsion framework, extending the work of previous studies by focusing on stability and antioxidant properties.

3. MATERIALS AND METHODS:

3.1 Equipment and Chemicals:

The equipment and chemicals used for this study were carefully selected based on their analytical grade. All measurements and formulations were conducted in the Formulation and Development laboratory at Sagar Institute of Research and Technology.

Table 1: Instruments Used

Table 2: Chemicals Used

The pre-formulation studies focused on determining the compatibility of ACV and clove extract with the emulsifying agent (Tween 80) and thickening agent (Xanthan gum). Solubility tests confirmed that ACV is freely soluble in water, while clove extract, due to its oily nature, required the use of an emulsifying agent for stability

3.3 Emulsion Preparation:

The emulsion was prepared using a cold-mix technique. The step-by-step preparation method is as follows:1. Dispersing the Emulsifying Agent and Thickening Agent: Tween 80 (3 ml) was dispersed in 30 ml of distilled water. Xanthan gum (0.5 g) was added gradually with constant stirring to prevent clumping.

   2. Incorporation of Active Ingredients: Apple cider vinegar (5 ml) and clove extract (2 ml) were added to the emulsifier-thickener mixture under constant agitation.

3. Addition of Preservatives: Potassium sorbate (0.1 g) was dissolved in distilled water and added to the emulsion.

4. Homogenization: The emulsion was homogenized using a high-shear mixer for 5 minutes to ensure uniform distribution of active ingredients.

5. Final Adjustment and Storage: The emulsion was adjusted to a final volume of 150 ml and stored at 40°C with 75% relative humidity for stability testing.

4. RESULTS AND DISCUSSION:

4.1 Stability Testing:

The stability of the emulsion was evaluated over 45 days, with measurements taken at 15-day intervals. The parameters measured were pH, viscosity, and spreadability.

4.2 pH Stability:

The pH of the emulsion was measured over the testing period to assess its stability. The results showed that the emulsion maintained a pH between 5.4 and 6.0, which is ideal for topical skincare formulations.

Spreadability is an important factor in topical formulations, as it determines how easily the product can be applied to the skin. F3 showed the

best spreadability, making it ideal for skincare use.

Table 6: Spreadability of Emulsions

Table 8: Viscosity of Emulsions