Formulation and Characterization of a Polyherbal Nanogel for Acne Management

Skin diseases constitute a significant burden on global health, particularly among adolescents and young adults. Among these, acne vulgaris is one of the most prevalent chronic inflammatory dermatoses, affecting approximately 85–90% of adolescents globally [1]. This condition is primarily a disorder of the pilosebaceous unit, characterized by comedones, inflammatory papules, pustules, nodules, and in severe cases, cystic lesions and scarring. The etiopathogenesis of acne involves a multifactorial process, including excessive sebum production, hyperkeratinization, colonization by Cutibacterium acnes (formerly Propionibacterium acnes), and subsequent inflammatory responses [2]. Additionally, hormonal fluctuations, especially during puberty, and environmental factors such as pollution and humidity can aggravate the condition. Several synthetic therapeutic agents are currently available for acne management, including benzoyl peroxide, retinoids, antibiotics (clindamycin, erythromycin), salicylic acid, and azelaic acid. While efficacious, prolonged use of these agents often leads to adverse effects such as skin irritation, dryness, photosensitivity, and most critically, the emergence of antibiotic resistance [3]. Given these challenges, there has been a paradigm shift toward herbal and polyherbal formulations for dermatological applications. Herbal remedies are often considered safer and better tolerated due to their biocompatibility and reduced side effects, thereby fostering increased consumer acceptance [4]. The potential of herbal extracts to mitigate acne symptoms lies in their anti-inflammatory, antimicrobial, antioxidant, and sebum-regulating properties. Notable botanicals include:

Turmeric (Curcuma longa): Possesses potent anti-inflammatory and antibacterial activity via its active component curcumin [5].

Neem (Azadirachta indica): Demonstrates broad-spectrum antimicrobial and anti-inflammatory effects [6].

Tea tree oil (Melaleuca alternifolia): Rich in terpinen-4-ol, tea tree oil has been clinically shown to reduce acne lesions due to its bactericidal action [7].

Orange peel (Citrus sinensis) and Lemon juice (Citrus limon): Provide vitamin C, flavonoids, and natural AHAs that contribute to skin exfoliation and oil control [8].

Honey (Apis mellifera): Offers hydrating and antibacterial properties that support skin healing [9].

Despite the promising therapeutic potential of herbal agents, their clinical efficacy is often hampered by poor skin permeability, instability, and inconsistent bioavailability. Nanotechnology, particularly nanogel systems, has emerged as an effective strategy to overcome these limitations. Nanogels are hydrogel particles in the nanometer size range, offering controlled drug release, enhanced skin penetration, targeted delivery, and stability of phytoconstituents [10]. They also improve patient compliance due to their non-greasy, transparent, and spreadable nature. This study aims to develop a polyherbal anti-acne nanogel combining the synergistic effects of five botanicals—turmeric, neem, tea tree oil, orange peel extract, and honey—embedded in a guar gum-based gel matrix. Guar gum, a natural polysaccharide, was selected for its biocompatibility, film-forming, and gelling properties [11]. The rationale behind polyherbalism is multitargeted therapy, where various herbs contribute complementary actions, enhancing the overall therapeutic effect while minimizing side effects. Moreover, the use of ethanol as a solvent in the extraction process facilitates the solubilization of bioactive components, improving stability and dispersion in the gel matrix [6]. This research seeks to bridge a critical gap in acne therapeutics by formulating and evaluating a novel polyherbal anti-acne nanogel that is both safe and effective. The study focuses on a thorough physicochemical evaluation of the developed nanogel, aiming to ensure its functionality, stability, and therapeutic efficiency. To achieve this, the formulation undergoes a comprehensive assessment of its organoleptic properties, which includes careful observation and analysis of its color, odor, and greasiness. These characteristics are vital not only for quality control but also for user acceptability, as they directly influence consumer preference and compliance. A formulation that is visually appealing, non-greasy, and pleasantly scented stands a better chance of being adopted in both clinical and commercial settings [12]. In addition to sensory characteristics, the nanogel is evaluated for its pH and viscosity. The pH of the formulation must align closely with the natural pH of human skin to avoid irritation or disruption of the skin barrier. Viscosity is another crucial parameter that affects the application, spreadability, and retention of the gel on the skin’s surface. A product that is too fluid may not remain on the target site long enough to be effective, whereas one that is too thick may hinder absorption and be uncomfortable for the user [13]. The spreadability and washability of the nanogel are also rigorously examined. Spreadability reflects how easily the gel can be applied across the skin without requiring excessive force, thus enhancing user experience and ensuring uniform distribution of active ingredients. Washability pertains to how easily the formulation can be removed from the skin, which is particularly important for products intended for repeated daily use. A formulation that is easy to rinse off without leaving residue enhances user satisfaction and hygiene [14]. Beyond these physical attributes, the study places significant emphasis on the biological performance of the nanogel, particularly its antimicrobial and anti-inflammatory activities. These pharmacodynamic parameters are central to the therapeutic efficacy of the formulation. The inclusion of potent herbal agents—known for their antibacterial, antiseptic, and soothing properties—aims to target acne at its root causes by inhibiting the growth of Cutibacterium acnes and reducing the inflammation associated with acne lesions [15]. Through this multifaceted evaluation, the final polyherbal nanogel formulation is envisioned as a promising alternative to conventional synthetic acne treatments. It is designed to offer superior skin tolerability, minimize potential side effects, and deliver sustained therapeutic benefits. By combining the strengths of traditional herbal medicine with modern nanotechnology, this research aims to contribute a clinically viable, consumer-friendly, and environmentally safe solution to the ongoing challenge of acne management [16]. The development of this polyherbal nanogel presents a transformative approach to acne treatment, particularly in the context of increasing antibiotic resistance and the side effects associated with conventional synthetic therapies. Unlike traditional formulations that rely heavily on antibiotics, this nanogel offers a resistance-free therapeutic solution, minimizing the risk of microbial adaptation and long-term inefficacy. Rooted in the principles of natural medicine, the formulation embodies a scientifically validated herbal therapy, combining multiple botanicals with proven anti-inflammatory and antimicrobial properties. Its composition ensures not only efficacy but also safety and skin compatibility, making it an ideal candidate for both chronic management and preventive care of acne [17]. Beyond its immediate dermatological applications, this nanogel formulation demonstrates significant promise for scalability and commercialization. Its foundation in natural, well-tolerated ingredients aligns with the growing global demand for herbal-based cosmetic and therapeutic products, positioning it favorably in the burgeoning cosmeceutical market. Importantly, in light of the rising concerns regarding synthetic agents, drug resistance, and adverse dermatological reactions, this research initiative serves as a meaningful step toward the integration of traditional Ayurvedic wisdom with the technological advancements of modern pharmaceutics. It highlights the potential of harmonizing time-tested herbal practices with contemporary drug delivery innovations, opening new avenues for safe, effective, and sustainable dermatological solutions [18].

MATERIALS AND METHODS

Ingredients

1. Orange Peel Extract

Table 1. Phytochemical profile and therapeutic attributes of Orange Peel Extract (Citrus × sinensis) used in polyherbal anti-acne nanogel formulation.

Orange peel extract, derived from the outer rind of Citrus × sinensis, belongs to the family Rutaceae and is a hybrid between Citrus maxima (pomelo) and Citrus reticulata (mandarin orange). The fruit is indigenous to Southeast Asia but is now cultivated globally due to its widespread applications in food, cosmetics, and medicine. Phytochemically, orange peel is rich in essential oils (notably limonene), flavonoids, polyphenols, sugars, and dietary fiber. These bioactive compounds contribute significantly to its antimicrobial, antioxidant, and anti-inflammatory properties—making it a viable therapeutic agent in dermatological applications, particularly for acne. The antibacterial activity of orange peel extract is primarily attributed to limonene and hesperidin, which disrupt bacterial membranes and inhibit the growth of acne-associated pathogens like Staphylococcus aureus and C. acnes. Additionally, the antioxidant profile of the peel helps neutralize reactive oxygen species (ROS), which play a role in inflammation and lesion formation in acne vulgaris [19]. From a dermal application standpoint, orange peel extract also contributes to sebostatic regulation, reducing excess oiliness—a key concern in acne-prone skin. Furthermore, its natural citrus acids support mild exfoliation, promoting skin renewal and preventing comedone formation. In the current study, 1 gram of orange peel extract was incorporated into the nanogel formulation, where it acted synergistically with other botanicals like turmeric and neem to provide a comprehensive anti-acne action. Its compatibility with other components and stability in the gel matrix make it an essential component of the polyherbal formulation [20].