Department of Pharmacy, Chaitanya (Deemed to be university), Himayatnagar, Hyderabad, Telangana, India.
Herbal cosmetic nanogels represent a novel and promising formulation strategy that combines the therapeutic benefits of herbal ingredients with the advanced delivery capabilities of nanotechnology. The incorporation of fruit-derived bioactives into nanogel systems has garnered significant attention in recent years due to the rich content of vitamins, antioxidants, enzymes, and natural acids found in fruits, which offer a wide range of skin benefits. Herbal nanogels are an advanced drug delivery system that combines the therapeutic benefits of herbal medicines with the technological advantages of nanotechnology. They represent a promising area of research in pharmaceutical sciences and natural product therapy due to their potential to enhance the bioavailability, stability, and targeted delivery of herbal drugs. Nanogels, being nanoscale hydrogel systems, allow for enhanced skin penetration, controlled release, and improved stability of sensitive fruit actives. Fruits such as papaya (Carica papaya), orange (Citrus sinensis), pomegranate (Punica granatum), strawberry (Fragaria ananassa), and grape (Vitis vinifera) are commonly used in cosmetic nanogels for their skin-brightening, anti-aging, exfoliating, and antioxidant properties. These nanogels are typically prepared using natural or synthetic polymers like Carbopol or chitosan, with the fruit extract incorporated via nanoemulsion or ionic gelation techniques. The resulting nanogel formulations are non-greasy, easy to apply, and cosmetically elegant, making them highly suitable for facial care, anti-acne, anti-aging, and skin-rejuvenating products. Preliminary evaluations indicate high consumer acceptability, improved bioactivity of fruit components, and minimal skin irritation. Thus, herbal cosmetic nanogels containing fruit extracts offer a natural, effective, and safe alternative to synthetic cosmetic products, aligning with the rising demand for green and sustainable skin care solutions.
Nanogels are nanoscale, three-dimensional, hydrophilic polymer networks capable of holding large amounts of water or biological fluids. They are typically in the size range of 20–200 nm and are composed of natural or synthetic polymers.
Herbal nanogels are nanogel formulations that incorporate herbal extracts or phytoconstituents (active plant compounds) for therapeutic applications. By combining herbal bioactive with nanotechnology, the formulation improves the solubility, absorption, and efficacy of herbal drugs, which are often limited by poor water solubility and low bioavailability.
Advantages of Herbal Nanogels
Applications of Herbal Nanogels
Nanogels improve the delivery, efficacy, and aesthetic appeal of herbal cosmetics due to:
Use of Fruits in Nanogels:
Fruits are rich in:
Examples of Fruits for Nanogel Formulation
|
Fruit |
Active Compounds |
Benefits |
Use in Nanogels |
|
Papaya |
Papain enzyme, Vit A & C |
Exfoliating, brightening |
Anti-acne, glow gel |
|
Pomegranate |
Punicalagin, antioxidants |
Anti-aging, collagen booster |
Anti-wrinkle gel |
|
Strawberry |
Alpha-hydroxy acids, Vit C |
Skin renewal, lightening |
Peel-off or night gel |
|
Banana |
Potassium, Vit B6, antioxidants |
Moisturizing, softening |
Hydrating day gel |
|
Lemon |
Citric acid, Vit C |
Lightening, antibacterial |
Spot-correction gel |
|
Aloe Vera (herbal) |
Polysaccharides, enzymes |
Soothing, healing |
Base + synergy with fruits |
|
Cucumber |
Flavonoids, water content |
Cooling, anti-puffiness |
Eye gel or face gel |
Mechanism Of Drug Release from Nanogels
a. pH stimulus
b. Degradation of nanogel
c. Ionic exchange with environment
d. Simple diffusion
e. From external energy sources
The release by stimulation of pH from the gel is the result of side group ionization. Nanogel polymers are composed of anionic or cationic side groups. In an aqueous environment, these groups will ionize at the appropriate pH and ionic strength. This creates a fixed charge on the polymer, causing electrostatic repulsion, which enlarges the pores of the gel. As a result, the flow of water into the gel increases, leading to swelling of the nanogel and drug release. The degradable nature of the nanogel ensures low toxicity and prevents unnecessary accumulation after repeated administration. Easily cleavable bonds can be introduced into the polymer backbone. Degradation is for specific reducing compounds, pH or even enzymatic activity. The lowest critical solution temperature (LCST) of the thermosensitive nanogel poly(N-isopropylacrylamide) in an aqueous medium is 32°C. At a temperature lower than the LCST, the amide group of the polymer interacts with the hydrogen of water, so the polymer is hydrated. When the temperature increases, the hydrophobic interaction of the polymer becomes obvious. The hydrogen bond with water is broken, the water phase separates and nanogel aggregation occurs; thereby releasing the captured drug into the environment. The diffusion release of the drug from the gel is the result of the difference in environmental concentration. The drug moves from the higher concentration area (inside the gel) to the lower concentration area (around). Another method is displacement by ions which is present in environment. A lot of research work is developing nanogels that can release biological agents in response to environmental cues at specific sites of action. When a cationic nanogel containing a negatively charged drug interacts with negatively charged particles in the environment/cell surface, the drug will be exchanged for negatively charged particles3.
Image 1: Mechanism of drug release from Nanogels
MATERIALS AND METHODS
Preparation Methods of Herbal Cosmetic Nanogels
Preparation of Herbal Cosmetic Nanogels
The preparation of herbal cosmetic nanogels involves two major steps:
The methods and steps involved in preparing herbal cosmetic nanogels.
Selection of Materials
a. Herbal Extract / Phytoconstituent
b. Polymers / Gelling Agents
c. Solvents
d. Surfactants / Stabilizers (for nanoemulsions)
Formulation:
A. Nanoemulsion - Based Nanogels
Formulation of Nanoemulsion:
Incorporation into Gel Base:
B. Ionic Gelation Method (for nanoparticle-based nanogels)
Synthesize Nanoparticles:
Disperse Nanoparticles into Gel Base:
C. Sol-Gel Technique (Simple Herbal Nanogel Preparation)
Evaluation Parameters
After formulation, the herbal cosmetic nanogel should be evaluated for:
Evaluation Of Nanogel:
a) Appearance: The prepared nanogel were inspected visually for clarity, colour and the presence of any particles.
b) pH: The pH of the all nanogel was determined using digital pH meter. about 1 gm of nanogel was stirred in distilled water till a uniform suspension effected. The volume was made upto 50 ml and pH of the solution was measured.
c) Homogeneity: All developed nanogels were tested for homogeneity by visual inspection after the nanogels have been set in the container. They were tested for their appearance and presence of any aggregates9.
d) Rheological properties: Rheological properties (study of deformation and flow of matter) are required in various pharmaceutical areas. some of the reasons for determining these properties are. · It helps in understanding the physicochemical nature of vehicle and quality control of ingredients, test formulations and final products, together with the manufacturing process such as mixing, pumping and filling. · It reflects the effects such as temperature and storage time on the products. · It helps to acess a topical formulation with respect to the patient usage e.g. removal of the preparation from a jar or tube without spillage or spreadability and adherence to skin10.
· Finally, it helps to monitor the effects of vehicles consistency on the release of drug from the preparation and its subsequent percutaneous absorption11.
e) Spreadability: Spreadibility is determined by apparatus suggested by Mutimer. It consists of wooden block, which is provided by a pulley at one end. By this method, spreadibility is measured on the basis of “Slip” and “Drag”. A ground glass slide is fixed on this block. A sample of 0.1 g of nanogel under study is placed on this ground slide. The gel is fixed on the beach formula was pressed between two slides and a 1 kg weight is placed on the top of two slides and left for about 5 min to expel air and to provide a uniform film of the nanogel between two slides. Excess of the gel is scrapped from edges. The top plate is then subjected to pull the weight. With help of string attaches to the hook and the time required by top slide to cover the distance is noted. A shorter interval indicates better spreadability12.
Spreadability was calculated by using the formula,
S = M.L/T,
Where,
S = Spreadability,
L = Length of glass slide,
M = Weight tied to upper slide,
T = Time taken to separate the slides13.
f) Extrudability: It is a usual empirical test to measure the force required to extrude the material from tube. The method applied for determination of applied shear in the region of the rheogram corresponding to a shear rate exceeding the yield value and exhibiting plug flow. The method adopted for evaluating nanogel formulation for extrudability is based upon the quantity in percentage of nanogel and nanogel extruded from lacquered aluminium collapsible tube on application of weight in grams required at least 0.5cm ribbon of nanogel in 10 sec. The measurement of extrudability of each formulation shows the triplicate and averages value is presented.
Extrudability = Applied weight to extrude the nanogel from tube (in gm)/ Area (in cm2)14.
g) Rheological Studies (viscosity): Brookfield viscometer was used for the studies. First, the spindle was dipped into the nanogel till the notch on the spindle touched the nanogel surface15.
h) Extract content: For the estimation of the extract in nanogel, extract was extracted from 1 gm of nanogel formulation with 50 ml of phosphate buffer 6.8 and mixture was filtered through membrane filter (pore size 0.45 µm). From this, 2 ml was pipette out and made upto 10 ml. The absorbance of the sample was determined spectrophotometrically at 276 nm. The concentration of extract was estimated from the calibration curve16.
i) In vitro Release studies: The drug release from the formulation was determined by using the apparatus known as Franz Diffusion Cell, which consist of a cylindrical glass tube which was opened at both the ends. 1 gm of nanogel equivalent to 10 mg of extract was spread uniformly on the surface of cellulose nitrate membrane (previously soaked in medium for 24 hrs) and was fixed to the one end of tube. The whole assembly was fixed in such a way that the lower end of tube containing nanogel was just touches (1-2 mm deep) the surface of diffusion medium i.e. 100 ml of pH 6.8 phosphate buffer contained in 100 ml beaker. The assembly was placed on thermostatic hot plate with magnetic stirrer and maintained at temperature 37°C ± 2°C, the contents were stirred using magnetic bar at 100 rpm for a period of 24 hrs, 1 ml of samples were withdrawn at different time intervals. This 1ml was diluted upto 10 ml of fresh phosphate buffer (pH 6.8) and sample were analyze at suitable nm in UV-Visible spectrometer for extract17,18.
j) Skin irritation test:
No irritation -0
Slight irritation -1
Irritation -2
Test for irritation was performed on human volunteers. For each nanogel, 12 volunteers were selected and 1.0 g of formulated nanogel was applied on an area of 2 square inch to the back of hand. The volunteers were observed for lesions or irritation.
k) Microbial Assay: All the nanogel formulations were assayed for their antibacterial activity against gram positive (staphylococcus aureus) and gram negative (Escherichia coli). the assay was carried out by cup and plate method. Zone of inhibition indicates the formulation that give better effect to cure antimicrobial activity19.
l) Stability: Batches evaluation the stability studies were carried out on optimized formulation. The samples were stored at 40°C ± 2°C and 75% ± 5% relative humidity for three months as per ICH guidelines. After 1, 2 and 3 months samples were withdrawn and tested for appearance, pH, particle size, drug content, spreadability, extrudability, viscosity20.
REFERENCES
Dronamraju Nirmala Kumari*, Dr. Lalitha Repudi, A Complete Assessment on Herbal Antiaging Nanogels Using Different Fruits, Int. J. of Pharm. Sci., 2025, Vol 3, Issue 11, 1265-1273 https://doi.org/10.5281/zenodo.17562482
10.5281/zenodo.17562482
