Formulation and Evaluation of Herbal Sunscreen Lotion

Sunscreens are topical agents used to protect the skin from the harmful effects of ultraviolet (UV) radiation. These formulations work by either reflecting, scattering, or absorbing UV-A and UV-B rays, which are known to cause photoaging, sunburn, and an increased risk of skin cancer. Regular use of sunscreen helps prevent premature skin aging and reduces the incidence of various UV-induced dermatological disorders. UV radiation is typically divided into three types: UV-A (320–400 nm), UV-B (290–320 nm), and UV-C (100–290 nm). While UV-C is mostly absorbed by the Earth’s atmosphere, UV-A and UV-B reach the skin and contribute to different forms of damage. UV-A penetrates deeper, causing long-term effects like aging and DNA damage, whereas UV-B is responsible for more acute issues such as sunburn and blistering.To address this, sunscreens are formulated using active ingredients that function as either physical blockers or chemical absorbers. Physical blockers, like zinc oxide and titanium dioxide, remain on the surface of the skin and reflect UV rays. Chemical absorbers, on the other hand, penetrate the skin and absorb UV radiation, converting it into less harmful energy. Many modern sunscreen products combine both types to achieve broad-spectrum protection. The effectiveness of a sunscreen is typically measured by its Sun Protection Factor (SPF), which indicates the level of protection it offers against UV-B rays. A higher SPF value corresponds to greater protection. However, SPF does not directly correlate with the time a person can spend in the sun without burning; rather, it measures the comparative increase in exposure time required to cause sunburn when using the sunscreen versus without it. In recent years, there has been growing concern over the safety and environmental impact of synthetic sunscreen agents. Compounds like oxybenzone and avobenzone, although effective, have been associated with skin irritation and potential hormonal effects. Furthermore, their accumulation in water bodies has raised environmental alarms, particularly concerning coral reef damage. As a result, the focus has shifted towards naturally derived, plant-based alternatives. Herbal and botanical ingredients offer a safer and more sustainable approach to photoprotection. Many medicinal plants are rich in flavonoids, phenolic acids, and antioxidants that absorb UV radiation and neutralize free radicals. These phytoconstituents are not only effective in minimizing sun damage but also contribute to overall skin health through anti-inflammatory and moisturizing actions. Polyherbal formulations, which combine multiple herbal extracts, are widely used in traditional medicine systems for their synergistic effects. In the context of sunscreens, combining extracts such as Aloe vera, Green tea, Tulsi, Neem, Sandalwood, Litchi, Cucumber, and Liquorice allows for broader protective coverage while enhancing the formulation’s stability and cosmetic acceptability. This project is aimed at formulating and evaluating a herbal sunscreen lotion using a combination of plant-based extracts known for their UV-absorbing and antioxidant properties. The study includes preparation of the formulation, analysis of physicochemical properties (such as pH, viscosity, spreadability), and SPF evaluation using UV spectrophotometry. The goal is to develop a safe, effective, and eco-friendly alternative to chemical sunscreens that meets current demands for natural skincare solutions

MATERIALS AND METHODS

List of Materials, Chemicals and Equipments

Table no:1 Plant materials used for the development of formulation

Table no: 2 Chemical ingredients used for the development of formulation

Table no: 3 Equipments used for the formulation

METHODS

PHYSICOCHEMICAL STUDY OF THE PLANT MATERIALS

Determination of ash value 

The ash value is an important parameter for the evaluation of the crude drugs. The following different methods are adopted.

• Total ash
• Acid insoluble ash
• Water soluble ash

Determination of moisture content 

Weigh accurately 3g of powdered drug and transfer it into a tared Petri dish. Then the crude drugs were heated at 105c in an oven till constant weight was obtained. Percentage moisture content of the sample was calculated with the reference to the air-dried drug.

Moisture content (%) = Initial weight of sample-Final weight of sample/Initial weight of sample ? 100

PREPARATION OF PLANT EXTRACT

Aqueous extraction of collected material is done by Maceration.

Steps Involved

• 20g of powder is mixed with 200ml water in a glass jar.
• Cover the jar with a lid and let it sit in cool & dark room.
• Shake the jar to facilitate extraction.
• After maceration, strain the mixture through cheese cloth or a clean cotton cloth into a collection container. Discard the solids.
• Filter the liquid extract through a filter paper to remove any impurities.
• Collect the aqueous extract.

PRELIMINARY PHYTOCHEMICAL STUDY 

The extracts were subjected to preliminary phytochemical screening to detect the various phytoconstituents such as Alkaloids, Flavonoids, Tannins, Saponin, Phenol, Glycosides, Proteins and Carbohydrates

FORMULATION OF THE HERBAL SUNSCREEN LOTION  

Table no: 4 Formulation of herbal sunscreen

 Procedure

• Distilled water was heated to approximately 70^o C and measured quantities of herbal extracts were added and stirred until fully dissolved.
• Beeswax, cetostearyl alcohol and sunflower oil were melted together by heating to 70^o C with continuous stirring.
• The hot aqueous phase was slowly added to the oil phase with constant stirring.
• The lotion was allowed to cool to room temperature and a small quantity of perfume was added.
• Distilled water was added to make up the weight.

EVALUATION OF HERBAL SUNSCREEN LOTION 

Organoleptic Evaluation

Formulation prepared was evaluated for the clarity, colour, odour, and foam producing ability.

Determination of pH

The pH of sunscreens was determined using a digital pH meter. pH was measured after 1 g of the formulation was dissolved in 100 ml of newly prepared distilled water for 2 hours. The purpose of this study was to guarantee that the pH of the produced herbal sunscreens is similar to the pH of the skin after 24 hours of use.

Test for homogeneity

A small amount of the sunscreen lotion is placed on a glass slide. The lotion is carefully spread into a thin, even layer on the slide. A cover glass is placed on top. The slide is then observed under a microscope. The lotion is visually examined for any visible particles, clumps, or uneven distribution. If the lotion appears uniform with no visible coarse particles, it's considered homogeneous.

Washability test

Apply a small amount of the sunscreen lotion to the fingertip. Gently rub the lotion-covered fingertip with water. Note how easily the lotion washes off and if any residue remains.

Spreadabilty test

A known weight of the sunscreen lotion is placed on a glass surface. Another glass surface is placed on top, and a weight is added. After a specific time, the diameter of the spread is measured.

Determination of SPF 

SPF value is determined in vitro using a spectrophotometer. 0.0125 grams of each preparation sample was taken and then diluted with 70% ethanol to 50 ml. The 70% ethanol solution was used as a blank. The absorbance results of the sample at a wavelength of 290 - 320 and an interval of 5 nm were recorded, and then the SPF value was calculated. The SPF value was calculated using the Mansur method;

SPF = CF x ∑EE(λ) x I(λ) x Abs(λ)

Description:

CF: Correction Factor (10)

EE: Spectrum of effects of erythema

I: Solar intensity spectrum

Abs: Sample absorbance

RESULTS AND DISCUSSION

Table no:5 Results of physicochemical study

Figure 9: Determination of ash value

Figure 10 &11: Extraction of plant materials

PRELIMINARY PHYTOCHEMICAL STUDY

Table no:6 Results of Preliminary phytochemical study of aqueous extract

[ +: mild, ++: moderate, +++: intense, -: negative]

Table no: 7 Results of preliminary phytochemical study of alcoholic extract

[ +: mild, ++: moderate, +++: intense, -: negative]

Table no: 8 Results of preliminary phytochemical study of chloroform extract

[ +: mild, ++: moderate, +++: intense, -: negative]

EVALUATION OF HERBAL SUNSCREEN LOTION

Table no:9 Evaluation of herbal sunscreen lotion

Table no: 10 Results of determination of SPF