Formulation Design and Optimization of Toners for Various Skin Conditions

Toners are much more than just basic astringents. Toners are now versatile skincare products that were first created to restore the pH equilibrium of the skin after cleaning, particularly in an era when harsh, high-pH face washes were popular (1). The components used in today's formulas are enhanced to perform far more functions than simple cleansing. They soothe inflammation, tighten pores, moisturize the face, and even combat acne by reducing excess oil (2). For example, oily skin is frequently characterized by increased pores as well as a glossy look because of an excess of sebum. Common issues like acne, clogged pores, and trouble putting makeup might result from this. Modern toners incorporate essential oils, vitamins, herbal extracts, and antioxidants as crucial ingredients to address these issues and enhance the texture and general health of the skin (3). The science underlying these formulas is examined Within this article, emphasizing the ways in which balancing ingredients, soothing botanicals, and moisturizing agents can combine to produce potent toners. Combinations of ingredients that address various skin types, such as sensitive, dry, oily, and acne-prone skin, are given particular consideration (4).

Types of Skin and Their Characteristics

Understanding your skin type is essential for choosing the right skincare products and developing effective formulations. Below are the major skin types and their features:

1. Normal Skin

This skin type is well-balanced not too oily or too dry. It usually has a smooth texture, fine pores, and minimal imperfections. People with normal skin can typically tolerate a wide variety of skincare ingredients without irritation or reactions.

2. Dry Skin

Dry skin often feels tight, especially after washing. It may appear dull, flaky, or rough and is more prone to fine lines and irritation. This type benefits from deeply moisturizing products that help restore and lock in hydration.

3. Oily Skin

Characterized by excess sebum production, oily skin tends to look shiny and may have enlarged pores. It is more likely to experience acne, blackheads, and congestion. Genetics, hormones, and climate can all influence oiliness.

4. Combination Skin

This type includes both oily and dry areas typically, the T-zone (forehead, nose, chin) is oily, while the cheeks may be dry or normal. Managing combination skin often involves using targeted products for different areas of the face. (5)

5. Sensitive Skin

Easily irritated by skincare products, environmental changes, or allergens, sensitive skin may react with redness, burning, itching, or stinging. It requires gentle, fragrance-free formulations designed to soothe and protect.

6. Acne-Prone Skin

Prone to frequent breakouts, this type may experience whiteheads, blackheads, and inflamed pimples. Acne-prone skin needs specialized, non-comedogenic formulations that control oil without over-drying.

7. Dehydrated Skin

Often mistaken for dry skin, dehydrated skin lacks water, not oil. It can feel tight, dull, and uncomfortable and may occur with any skin type even oily. Hydrating ingredients like hyaluronic acid help replenish moisture levels.

8. Mature Skin

With age, skin tends to lose elasticity and moisture, leading to wrinkles, sagging, and dryness. Mature skin benefits from nourishing, firming, and antioxidant-rich products that support skin regeneration (6).

Figure 1: Types of skin

 Method of extraction

• Preparation: Powdered green tea leaves are measured and mixed with hot distilled water in a 1:10 ratio.
• Heating: The mixture is maintained at 80–90°C for 15–30 minutes with occasional stirring.
• Cooling: After heating, the mixture is allowed to cool to room temperature.
• Filtration: The cooled mixture is filtered using muslin cloth or Whatman filter paper to separate the extract.
• Concentration: The filtrate (green tea extract) can be concentrated using a water bath or rotary evaporator if required. (7)

MATERIALS AND METHODOLOGY

Materials required for the formulation

Table 1: Materials required for the formulation

Sr. No	NAME OF THE INGREDIENT	SCIENTIFIC NAME	USES
01	Aloe vera	Aloe barbadense	Anti-acne
02	Green tea extract	Camellia sinensis	Moisturizer
03	Rose water	Rosa damascene	Reduce excess of oil
04	Glycerin	Propane-1,2,3-triol	Antiinflammation
05	Methylparaben	Methyl 4- hydroxybenzoate	Preservative
06	Distilled water	-	Solvent

Method of Preparation

1. Take aloe vera and transfer it into a clean beaker.
2. Add green tea extract to the beaker and mix well.
3. Add rose water to the prepared mixture.
4. Add glycerine to enhance the moisturizing effect.
5. Introduce methylparaben into the mixture as a preservative.
6. Stir the mixture thoroughly to ensure even distribution of all ingredients.
7. Finally, add distilled water to bring the formulation to the desired volume and mix until homogeneous. (8)

FORMULATIONS

Table 2: Formulations of toners

Evaluation of Face Toner

To ensure the safety, effectiveness, and overall quality of the formulated face toner, several evaluation tests were conducted. Each test assesses a different property of the toner, providing insights into how it will perform in real-world use.

• pH Measurement

To check the skin compatibility of the toner, its pH was measured using a calibrated pH meter. The measurement was taken after transferring a sample of the toner into a beaker. A balanced pH helps maintain the skin’s natural barrier and ensures the product is gentle enough for regular use.

• Surface Tension Test

The toner’s surface tension was evaluated using a stalagmometer. This helps determine how well the toner can spread across the skin surface, which directly affects ease of application and absorption.

• Drop Counting or Weighing: Either the number of drops of a specific volume of each liquid is counted, or a known number of drops are collected and weighed.
  • • Drop Count Method: γ?/γ? = (d?/d?) * (n?/n?), where γ is the surface tension, d is the density, and n is the number of drops for liquid 1 (toner) and liquid 2 (water). 
    • Drop Weight Method: γ?/γ? = (m?/m?) * (n?/n?), where m is the mass of the drops for liquid 1 (toner) and liquid 2 (water). 

• Skin Irritation Test

A small patch test was performed by applying the toner on the inside of the forearm. After 24 hours, the area was checked for any redness, swelling, itching, or irritation. This simple test helps ensure that the toner is safe for sensitive skin.

• Light Exposure Test

To test stability under light, a sample of the toner was placed in a transparent, container and exposed to indirect sunlight for a few hours. Any changes in colour, scent, or texture were noted. If significant changes occurred, it suggested that the toner should be stored in a dark, opaque bottle. (9)

• Spread ability Test

The toner was applied to clean, dry skin to observe how easily it spread and how quickly it was absorbed. A good toner should apply smoothly without leaving a sticky residue.

• Homogeneity Test

The toner bottle was shaken and visually examined to ensure all ingredients were evenly distributed. The absence of clumping, layer separation, or uneven colour indicated good homogeneity.

• Skin Conditioning Assessment

The toner was gently massaged into the skin to assess its effects on texture and moisture. Improvements in softness and hydration were indicators of effective conditioning.

• Temperature Stability Test

The toner was subjected to alternating warm and cool environments. Observing whether its consistency, appearance, or fragrance changed helped determine the formulation’s thermal stability. (10)

RESULTS AND DISCUSSION

Organoleptic Characteristic

Table 3: Organoleptic evaluation of toner

Physical evaluation

The evaluation of various parameters confirmed the overall suitability of the toner formulations. Formulation 2 was found to be non-irritating to the skin, provided adequate moisturization, and showed excellent spread ability without being overly sticky. Based on these results, Formulation 2 proved to be the best choice for skin application, ensuring comfort, hydration, and ease of use.

Table 4: physical evaluation of formulations

•  pH Evaluation:

Among all, Formulation 2, with a pH of 5.0, is most suitable for skin application as it is closest to the natural skin pH (4.7–5.5). It helps maintain the skin’s acid mantle, reducing the risk of irritation and ensuring better compatibility with various skin types.

Table 5: pH of the formulations

• Surface Tension:

The surface tension of all five toner formulations was measured using a stalagmometer. Among them, Formulation 2 (F2) showed a surface tension of 41.85 dyne/cm², which is considered steady and ideal for skin compatibility. Other formulations ranged from 40.08 to 49.58 dyne/cm², showing varying consistency.

Table 6: surface tension of formulations

• Light exposure test:

There won't be any noticeable toner discolouration.

(a)Formulation before keeping in sunlight       (b) Formulation after exposure to sunlight(48hr)