Polyherbal Anti-Acne Gel of Neem, Tulsi & Aloe Vera: Formulation and Evaluation in a Carbopol 940 Base

This project develops and evaluates a polyherbal anti-acne gel that combines standardised ethanolic extracts of neem (Azadirachta indica) leaf and tulsi (Ocimum sanctum) leaf with aloe vera (Aloe barbadensis) gel in a Carbopol 940 base. Acne vulgaris is one of the most common reasons young Indians walk into a dermatology OPD or a pharmacy, and topical antibiotics such as clindamycin are increasingly limited by bacterial resistance. Herbal gels are widely sold in Indian pharmacies, but many are marketed with little published evaluation data.

The group prepares four gel batches (F1–F4) that differ only in Carbopol concentration, then evaluates them for appearance, homogeneity, pH, viscosity, spreadability, extrudability, marker content (total phenolics by the Folin–Ciocalteu method), in-vitro release through a dialysis membrane in a Franz diffusion cell, and antibacterial activity against Staphylococcus aureus and Staphylococcus epidermidis by agar-well diffusion, compared with a marketed 1% clindamycin gel. The optimised batch is placed on accelerated stability at 40 ± 2 °C / 75 ± 5% RH as per ICH Q1A(R2).

The study is designed for the PCI B.Pharm BP813PW Project Work slot and ties directly to the Semester VIII electives BP809ET Cosmetic Science and BP806ET Quality Control and Standardization of Herbals, as PCI requires. All results are analysed with one-way ANOVA and Tukey's post-hoc test in GraphPad Prism, which gives the group a clear, defensible basis for choosing the optimised formulation.

Abstract

A polyherbal topical gel containing neem and tulsi leaf extracts and aloe vera gel was formulated in Carbopol 940 at four polymer concentrations (0.5, 0.75, 1.0 and 1.5% w/w). The batches were evaluated for physicochemical properties, total phenolic content, in-vitro release and antibacterial activity against acne-associated staphylococci. The optimised batch was subjected to one-month accelerated stability testing. Data were analysed by one-way ANOVA with Tukey's test (p < 0.05).

Introduction

Acne vulgaris affects a large share of adolescents and young adults and has a real psychosocial cost. Bacteria colonising the pilosebaceous unit, together with inflammation, drive the lesions. Topical antibiotics work, but their long-term use selects resistant strains. Neem and tulsi are documented in the Ayurvedic Pharmacopoeia of India and in published literature for antibacterial and anti-inflammatory activity; aloe vera gel is soothing and helps hydration. A gel base is preferred for acne-prone, oily skin because it is non-greasy, easy to spread and washable.

Literature gap

Published studies on herbal anti-acne gels usually evaluate a single extract, or report physical tests without a marker assay or statistical comparison. Few student-level studies compare polymer concentration systematically, and most skip stability data entirely. This project closes that gap with a planned batch series, a quantitative marker, a positive-control comparison and ICH-style stability.

Proposed work

• Authenticate and standardise crude drugs (ash values, extractive values, loss on drying, TLC fingerprint).
• Prepare extracts by Soxhlet extraction and screen them phytochemically.
• Formulate F1–F4 and evaluate each in triplicate.
• Select the optimised batch on viscosity, spreadability, release and zone of inhibition.
• Run accelerated stability on the optimised batch.

Feasibility

• Technical: every instrument (UV spectrophotometer, Brookfield viscometer, pH meter, Franz cells, incubator, stability chamber) is standard in a PCI-approved B.Pharm college.
• Economic: plant material is locally available; Carbopol, excipients and culture media cost well under ₹8,000 for the group.
• Time: extraction and formulation fit in weeks 2–6; evaluation and microbiology in weeks 6–10; stability runs in parallel with report writing.
• Ethical: the study is fully in-vitro, with no human or animal subjects.

Acne is a chronic, visible skin condition for which young people in India frequently self-medicate with over-the-counter herbal products or long courses of topical antibiotics. Long-term topical antibiotic use contributes to resistance in skin staphylococci, while many herbal gels on pharmacy shelves are sold without published data on pH compatibility with skin, viscosity, spreadability, marker content, antibacterial activity or stability.

There is therefore a need to design a polyherbal gel with standardised extracts, to show through systematic batch-wise evaluation which polymer concentration gives acceptable physical properties and release, to compare its antibacterial activity against a marketed clindamycin gel, and to generate preliminary stability data under ICH conditions — so that the formulation choice rests on measured evidence rather than on label claims.

In scope

• Collection, authentication and standardisation of neem and tulsi leaves; fresh aloe vera gel.
• Soxhlet extraction, phytochemical screening and total phenolic content.
• Four gel batches differing only in Carbopol 940 concentration.
• Physicochemical evaluation, in-vitro release, antibacterial activity against two standard staphylococcal strains, and one-month accelerated stability.
• Statistical comparison of batches with one-way ANOVA.

Out of scope

• Clinical efficacy on acne patients or human patch testing (would need Institutional Ethics Committee approval and informed consent).
• Animal skin-irritation studies (would need IAEC approval under CPCSEA).
• Anaerobic culture of Cutibacterium acnes, full six-month ICH stability and commercial scale-up.

Study design: laboratory-based experimental formulation and evaluation study with a one-factor, four-level batch series (Carbopol concentration) and a positive control (marketed clindamycin 1% gel). All measurements are made in triplicate and reported as mean ± SD.

Setting: Department of Pharmaceutics and Pharmaceutical Microbiology laboratory of the college; plant material authenticated by the Department of Botany of a nearby university, with a voucher specimen deposited.

Sample size justification: the unit of analysis is the batch replicate. Three independent replicates per batch (n = 3) is the accepted minimum for formulation studies and gives enough degrees of freedom for one-way ANOVA across four batches (df = 3, 8).

Inclusion / exclusion (materials): leaves free of fungal spots and insect damage; extracts with loss on drying within the pharmacopoeial limit; batches showing phase separation or grittiness are excluded from release and microbiology tests and recorded as failures.

Procedure

1. Shade-dry leaves, powder (sieve no. 40), determine total ash, acid-insoluble ash, alcohol- and water-soluble extractive values and loss on drying.
2. Soxhlet-extract with 90% ethanol, concentrate under reduced pressure, record percentage yield, run phytochemical tests and TLC.
3. Disperse Carbopol 940 in water with propylene glycol, add aloe gel and extracts (each 2% w/w), preservatives (methylparaben 0.18%, propylparaben 0.02%), neutralise with triethanolamine to pH 5.5–6.5.
4. Evaluate physical parameters; estimate total phenolics (gallic-acid equivalents) at 760 nm.
5. Release study: dialysis membrane in Franz cell, phosphate buffer pH 5.5 at 32 ± 0.5 °C, samples at 0.5–8 h; fit zero-order, first-order, Higuchi and Korsmeyer–Peppas models.
6. Agar-well diffusion on Mueller–Hinton agar; measure zones after 24 h at 37 °C.
7. Stability of the optimised batch: 0, 15 and 30 days at 40 ± 2 °C / 75 ± 5% RH.

Statistical analysis: one-way ANOVA followed by Tukey's multiple-comparison test in GraphPad Prism (Excel for data entry and release-kinetic fitting); significance at p < 0.05. Stability data compared with initial values by paired t-test.

Ethics: in-vitro study; no human or animal participants, so IEC/IAEC approval is not required. Microbiology work follows biosafety level-2 practice and the college's biomedical-waste procedure; a declaration to this effect is signed by the guide and HOD.

• Human repeat-insult patch test on volunteers after Institutional Ethics Committee approval and written informed consent, following the ICMR National Ethical Guidelines (2017).
• Activity against Cutibacterium acnes under anaerobic culture, and MIC determination of each extract.
• Full six-month ICH stability at accelerated and long-term conditions.
• Design of experiments (3² factorial with Design-Expert) varying polymer and extract load together.
• Emulgel or nanoemulgel version to improve penetration of lipophilic neem constituents.
• HPTLC quantification of a single marker such as ursolic acid or eugenol instead of total phenolics.