Formulation, Optimization and Evaluation of Herbal Face Pack Containing Multani Mitti, Beetroot, Neem, Turmeric, Cinnamon and Sandalwood

The skin is the largest organ of the human body, constituting approximately 15% of total body weight. It serves as the primary physical barrier against mechanical, chemical, biological, and environmental stressors, while also playing essential roles in thermoregulation, sensory perception, and vitamin D synthesis [1,2]. Maintaining healthy skin is therefore not merely a cosmetic concern but a matter of overall physiological wellbeing.

Contemporary lifestyles characterized by increased exposure to environmental pollutants, UV radiation, stress, and chemically laden personal care products have heightened the prevalence of dermatological conditions including acne vulgaris, hyperpigmentation, premature ageing, and contact dermatitis [3,4]. The global cosmeceutical market has responded with an array of synthetic formulations; however, prolonged use of such products has been associated with allergic reactions, hormonal disruption, and skin sensitization due to the presence of parabens, sulfates, synthetic fragrances, and artificial colourants [5].

In this context, herbal cosmetics formulated from plant-derived bioactive compounds represent a compelling and scientifically supported alternative. Ethnobotanical and Ayurvedic traditions have long employed natural ingredients for skincare, and contemporary pharmacognostic research has validated many of these traditional claims through systematic phytochemical and pharmacological studies [6,7].

Face packs are topical semi-solid or powder formulations intended to cleanse, nourish, and revitalise facial skin by exfoliating dead cells, controlling excess sebum secretion, improving microcirculation, and imparting a soothing effect [8]. Herbal face packs, in particular, leverage the synergistic activity of multiple plant-based actives to deliver broad-spectrum skincare benefits without the risks associated with synthetic formulations [9].

The present formulation incorporates six strategically selected herbal and mineral ingredients: neem (Azadirachta indica) for its potent antibacterial, antifungal, and anti-inflammatory activity; turmeric (Curcuma longa) for its curcumin-rich antioxidant and antiseptic profile; sandalwood (Santalum album) for its skin-brightening and cooling properties; beetroot (Beta vulgaris) as a rich source of betalains, Vitamin C, and folic acid; cinnamon (Cinnamomum verum) for its astringent and antimicrobial properties; and multani mitti (Fuller's Earth) as a natural absorbent clay that deep-cleanses pores and controls oiliness [10–15].

The aim of the present study was to develop three formulations (F1, F2, F3) of this herbal face pack with varying ingredient concentrations and to systematically evaluate them for morphological, physicochemical, and physical characteristics, ultimately identifying the optimized batch for safe and effective topical application.

2. MATERIALS AND METHODS

2.1 Collection and Procurement of Materials

All herbal raw materials — neem leaf powder, sandalwood powder, turmeric powder, cinnamon powder, and beetroot powder — were procured from a certified herbal supplier in Pune, Maharashtra, India. Multani mitti (Fuller's Earth) was obtained from a pharmaceutical-grade supplier. Rose water (distilled) was used as the wetting agent for application. All materials were verified for identity, purity, and quality prior to use. The study was conducted in compliance with standard laboratory practices.

2.2 Formulation Design

Three formulations (F1, F2, F3) were designed with varying concentrations of ingredients to evaluate the effect of compositional changes on physicochemical and sensory properties. The composition of all three formulations is presented in Table 1.

Table 1: Composition of herbal face pack formulations (F1, F2, F3) — quantities in mg per 100 mg batch

2.3 Method of Preparation

The herbal face pack was prepared as a dry powder blend following the steps outlined below:

1. Individual ingredients were accurately weighed using a calibrated electronic balance.
2. Each ingredient was separately dried, ground using a mortar and pestle, and passed through sieve no. 120 to obtain a uniform fine powder.
3. All powdered ingredients were geometrically mixed in a clean mortar and pestle to achieve a homogeneous blend, beginning with the smallest quantity and progressively adding larger quantities.
4. The blended powder was again passed through sieve no. 120 to ensure uniform particle size distribution.
5. The final dry blend was stored in a sealed, airtight glass container away from heat and moisture.
6. For application, approximately 1–2 teaspoons of the powder were mixed with sufficient rose water or distilled water to form a smooth, spreadable paste. The paste was applied uniformly on cleansed facial skin, left to dry for 15–20 minutes, and rinsed off with lukewarm or cold water.

3. EVALUATION PARAMETERS

3.1 Morphological Evaluation

All three formulations were visually assessed and organoleptically evaluated for colour, odour, appearance, texture, and smoothness under standard laboratory lighting conditions by three trained evaluators. Observations were recorded as the consensus of all evaluators (Table 2).

Table 2: Morphological (Organoleptic) Evaluation of F1, F2, F3

F1 exhibited a pleasant yellowish-brown colour consistent with the dominant proportion of turmeric and neem, with a fine, smooth texture. F2 appeared slightly darker brown due to higher turmeric content. F3 showed a deep brown hue attributed to higher neem and sandalwood concentrations. All formulations produced a pleasant herbal odour with no off-notes.

3.2 Physicochemical Evaluation

The physicochemical parameters — pH, ash content, and loss on drying — were determined for all three formulations in triplicate. Results are expressed as mean ± standard deviation (Table 3).

3.2.1 pH Determination

A 1% w/v aqueous dispersion of each formulation was prepared in distilled water and the pH was measured using a calibrated digital pH meter (Systronics, India) at room temperature (25 ± 2°C). Three readings were recorded and the mean ± SD calculated. The skin-compatible pH range is 5.5–7.5 for topical cosmetics.

3.2.2 Ash Content

Approximately 2 g of accurately weighed powder was placed in a pre-weighed silica crucible and incinerated at 500–600°C in a muffle furnace until a white or grey, carbon-free ash was obtained. The crucible was cooled in a desiccator and weighed. The ash content (%) was calculated as: Ash content (%) = (W3 − W1) / (W2 − W1) × 100, where W1 = weight of empty crucible, W2 = weight of crucible + sample, W3 = weight of crucible + ash.

3.2.3 Loss on Drying (LOD)

A known weight of powder (2 g) was placed in a pre-weighed petri dish and dried in a hot air oven at 105°C for 3 hours. After cooling in a desiccator, the dish was reweighed. LOD (%) = (W2 − W3) / (W2 − W1) × 100.

Table 3: Physicochemical Evaluation of F1, F2, F3 (Mean ± SD, n=3)

All three formulations exhibited pH values within the acceptable skin-compatible range (5.5–7.5). Formulation F1, with a pH of 7.1 ± 0.05, was most closely aligned with physiological skin pH. Ash content and LOD values were lowest for F1, indicating superior purity and lower moisture content, which is advantageous for powder stability and shelf life.

3.3 Physical Evaluation of Powder Flow Properties

Powder flow characteristics are critical determinants of the uniformity, handling, and dispensability of face pack powder formulations. The following parameters were evaluated for all three batches (Table 4).

3.3.1 Bulk Density

A known weight of powder (10 g) was carefully transferred into a 50 mL graduated measuring cylinder without tapping. The volume occupied was recorded as the bulk volume, and bulk density was calculated as mass/bulk volume.

3.3.2 Tapped Density

The same cylinder was subjected to mechanical tapping (1250 taps) on a tapped density apparatus until no further volume change was observed. Tapped density was calculated as mass/tapped volume.

3.3.3 Angle of Repose

Powder was allowed to flow freely through a fixed-height funnel onto a flat surface. The height (h) and radius (r) of the resultant powder cone were measured. Angle of repose (θ) = tan?¹ (h/r). Values below 30° indicate excellent flow; 30–40° indicates good flow.

3.3.4 Hausner's Ratio and Carr's Index

Hausner's ratio = Tapped density / Bulk density. Values ≤1.25 indicate good flowability. Carr's index (%) = [(Tapped density − Bulk density) / Tapped density] × 100. Values ≤15% indicate excellent powder flow and compressibility.

Table 4: Physical Evaluation of Powder Flow Properties of F1, F2, F3 (Mean ± SD, n=3)

Formulation F1 demonstrated the best powder flow profile among all three batches. The angle of repose (32.62 ± 0.41°) falls within the 'good flow' category. Carr's index of 13.85 ± 0.58% indicates excellent compressibility, while a Hausner's ratio of 1.17 ± 0.01 confirms passable-to-good flowability. F2 showed acceptable but slightly inferior flow properties, and F3 demonstrated moderate flow due to the higher sandalwood content contributing to increased cohesion.

3.4 Skin Irritation (Patch Test)

A patch test was performed on five healthy adult volunteers (age 20–30 years) with informed consent, following ethical guidelines for human skin safety testing. A paste was prepared from each formulation using distilled water and applied to a 2 × 2 cm area on the inner forearm. The area was covered with an occlusive patch for 30 minutes, then inspected at 30 min, 2 hours, and 24 hours for erythema, oedema, itching, and irritation. Results are presented in Table 5.

Table 5: Skin Irritation Patch Test Results for F1, F2, F3