Fabrication of an Herbal Patch for Fast Guard Joint Pain Relief

Joint pain is one of the most common musculoskeletal disorders affecting millions of people worldwide. It is characterized by discomfort, stiffness, inflammation, swelling, and reduced mobility in one or more joints of the body. Joint pain can occur due to several conditions including arthritis, osteoarthritis, rheumatoid arthritis, gout, sports injuries, aging, obesity, and autoimmune disorders. The increasing prevalence of joint pain among both elderly and young populations has become a major public health concern because it affects the quality of life, daily activities, productivity, and physical well-being of individuals. Modern lifestyles, lack of physical activity, unhealthy dietary habits, prolonged working hours, stress, and obesity are significant contributing factors responsible for the rising incidence of joint disorders.[1]

The skeletal system plays an important role in maintaining the structure and movement of the human body. Joints act as connecting points between bones and facilitate smooth movement and flexibility. Healthy joints contain cartilage, synovial fluid, ligaments, and tendons that work together to reduce friction and absorb shock during movement. Damage to any of these structures can lead to inflammation and severe pain. Joint pain may vary from mild discomfort to severe chronic pain that interferes with walking, standing, sleeping, and routine activities. Chronic joint pain can also lead to depression, anxiety, fatigue, and social isolation in affected individuals.[2]

Arthritis is considered one of the leading causes of joint pain globally. Osteoarthritis is a degenerative joint disease caused by the gradual breakdown of cartilage, while rheumatoid arthritis is an autoimmune disorder in which the immune system attacks healthy joint tissues. These conditions cause inflammation, swelling, redness, and reduced joint mobility. According to various health reports, arthritis and related musculoskeletal disorders are rapidly increasing due to aging populations and sedentary lifestyles. Therefore, there is a growing need for effective, safe, affordable, and patient-friendly therapies for the management of joint pain.[3]

Conventional treatment options for joint pain include oral analgesics, non-steroidal anti-inflammatory drugs, corticosteroids, opioid medications, physiotherapy, and surgery. Although these therapies provide symptomatic relief, long-term use of oral medications is associated with several adverse effects such as gastric irritation, ulcers, kidney damage, liver toxicity, cardiovascular complications, and drug dependency. Many patients also experience poor compliance due to frequent dosing and systemic side effects. Hence, researchers are increasingly focusing on alternative approaches that can provide localized action with fewer adverse effects.

Transdermal drug delivery systems have emerged as an innovative and effective method for delivering therapeutic agents through the skin directly into systemic circulation or targeted tissues. A transdermal patch is a medicated adhesive preparation designed to release active ingredients at a controlled rate through the skin. The skin is the largest organ of the human body and serves as an effective route for drug administration because it provides a large surface area, easy accessibility, and non-invasive application. Transdermal patches improve patient compliance, avoid first-pass metabolism, reduce gastrointestinal side effects, and maintain sustained drug release.[4]

Herbal medicine has been used since ancient times for the treatment of pain, inflammation, and various chronic diseases. Medicinal plants contain several bioactive compounds such as alkaloids, flavonoids, terpenoids, tannins, glycosides, and phenolic compounds that possess analgesic, anti-inflammatory, antioxidant, antimicrobial, and healing properties. Herbal therapies are widely accepted because they are considered safer, economical, natural, and associated with fewer side effects compared to synthetic drugs. Traditional systems of medicine including Ayurveda, Siddha, Unani, and Traditional Chinese Medicine have described numerous medicinal herbs useful for relieving joint pain and improving musculoskeletal health.

The development of herbal transdermal patches combines the advantages of herbal medicine and transdermal drug delivery systems. Herbal patches provide localized therapeutic action at the site of pain and help in sustained release of herbal constituents. They are easy to apply, convenient to use, non-invasive, and suitable for long-term therapy. Herbal patches can improve drug bioavailability and reduce systemic exposure, thereby minimizing adverse effects associated with oral administration.[5]

Several medicinal herbs have shown promising effects in the management of joint pain and inflammation. Ginger is widely used due to its anti-inflammatory and analgesic activities. It contains active constituents such as gingerols and shogaols that inhibit inflammatory mediators and reduce pain. Turmeric is another important medicinal herb containing curcumin, which exhibits potent anti-inflammatory, antioxidant, and wound-healing properties. Eucalyptus oil is commonly used in topical formulations because of its cooling and soothing effects. Menthol and camphor produce a sensation of cooling and improve blood circulation, thereby reducing muscle stiffness and pain.

Wintergreen oil contains methyl salicylate, which acts as a counterirritant and provides relief from muscle and joint pain. Clove oil possesses analgesic and antimicrobial properties due to the presence of eugenol. Capsaicin obtained from chili peppers is also used in topical pain-relieving formulations because it helps in reducing pain sensation by affecting sensory nerve endings. These herbal ingredients can be effectively incorporated into transdermal patches for enhanced therapeutic activity.[6]

The fabrication of herbal patches involves the selection of suitable polymers, plasticizers, solvents, adhesives, permeation enhancers, and herbal extracts. Polymers are important components because they form the matrix structure of the patch and control drug release. Commonly used polymers include hydroxypropyl methylcellulose, polyvinyl alcohol, ethyl cellulose, and carbopol. Plasticizers such as glycerin and polyethylene glycol improve flexibility and prevent brittleness of the patch. Permeation enhancers facilitate penetration of herbal constituents through the skin barrier.[7-8]

The skin acts as a protective barrier against external substances. The outermost layer of the skin, known as the stratum corneum, limits the penetration of drugs. Therefore, permeation enhancers are added to transdermal formulations to improve drug absorption. Essential oils, alcohols, surfactants, and fatty acids are commonly used as permeation enhancers. These agents alter the structure of the stratum corneum and increase permeability, allowing efficient diffusion of active compounds.[9-10]

The solvent casting method is one of the most widely used techniques for preparing herbal transdermal patches. In this method, polymers are dissolved in suitable solvents to form a homogeneous solution. Herbal extracts and other additives are then incorporated into the polymeric mixture. The resulting solution is poured into molds or petri dishes and dried to form thin films. After drying, the films are cut into desired sizes and packed properly for further evaluation.[11-15]

An ideal herbal patch should possess good flexibility, uniform thickness, proper adhesion, smooth surface, and controlled drug release characteristics. The patch should remain stable during storage and should not cause irritation or discomfort to the skin. Proper packaging and storage conditions are also important for maintaining stability and effectiveness[15-17].

Herbal transdermal patches have gained significant popularity due to increasing consumer preference for natural and non-invasive therapies. The growing awareness regarding the harmful effects of long-term use of synthetic drugs has encouraged the use of herbal formulations. Herbal patches are commonly used for pain relief, stress reduction, motion sickness, smoking cessation, and cosmetic applications. Their commercial success indicates a strong demand for innovative herbal healthcare products.[18-19]

The pharmaceutical industry is continuously exploring advanced technologies to improve transdermal drug delivery systems. Nanotechnology, microencapsulation, and bioadhesive systems are being integrated into herbal formulations to enhance drug penetration and therapeutic efficacy. Nanoparticles improve stability and controlled release of herbal constituents, thereby increasing effectiveness. Such technological advancements can further improve the performance of herbal patches for joint pain management.[20-22]

Inflammation is one of the major causes of joint pain and tissue damage. It is a biological response triggered by injury, infection, or autoimmune reactions. During inflammation, several chemical mediators such as prostaglandins, cytokines, histamines, and leukotrienes are released, causing pain, swelling, redness, and heat. Herbal ingredients possessing anti-inflammatory activity help in reducing the production of these mediators and thereby alleviate pain and inflammation.[23-25]

Pain management is an important aspect of healthcare because chronic pain affects physical, emotional, and psychological well-being. Effective pain relief therapies should provide rapid onset of action, prolonged effect, minimal side effects, and improved quality of life. Herbal patches offer several advantages in this regard because they provide localized therapy and sustained release of active ingredients.[26-28]

Patient compliance is an important factor in successful therapy. Many patients, especially elderly individuals, experience difficulty in swallowing oral tablets or maintaining frequent dosing schedules. Transdermal patches are easy to apply and require less frequent administration, thereby improving compliance. They also eliminate the need for injections and reduce the risk of gastrointestinal irritation.

The market for herbal healthcare products is rapidly expanding due to increased consumer awareness regarding natural medicine and preventive healthcare. Herbal formulations are widely accepted because they are considered eco-friendly and culturally acceptable. Governments and healthcare organizations are also encouraging research on herbal medicine for the development of safe and affordable therapies.

The fabrication of herbal patches for joint pain relief represents an interdisciplinary approach involving pharmaceutics, pharmacognosy, medicinal chemistry, polymer science, and dermatology. Proper formulation design and optimization are necessary to achieve desired therapeutic outcomes. Researchers must carefully select herbal ingredients, polymers, and excipients to ensure compatibility and effectiveness.[29-32]

Quality control plays a crucial role in the development of herbal formulations. Standardization of herbal extracts is essential because variations in plant source, cultivation conditions, harvesting methods, and extraction processes can affect the quality and potency of herbal products. Proper authentication and phytochemical analysis are necessary to maintain consistency and safety.

The use of natural polymers in herbal patches has gained attention because of their biodegradability, biocompatibility, and eco-friendly nature. Polymers such as chitosan, gelatin, sodium alginate, and pectin are being investigated for transdermal applications. Natural polymers provide good film-forming properties and improve patient safety.

Bioavailability is another important factor affecting therapeutic efficacy. Oral administration of herbal drugs may result in poor bioavailability due to degradation in the gastrointestinal tract and first-pass metabolism. Transdermal delivery bypasses these limitations and provides better absorption of active compounds.[33-35]

Herbal patches can also be used as adjunct therapy along with physiotherapy, exercise, and lifestyle modifications for comprehensive management of joint disorders. Regular physical activity, balanced diet, weight management, and stress reduction are essential for maintaining healthy joints and preventing musculoskeletal problems.

The safety profile of herbal patches is generally better than synthetic topical formulations because they contain natural ingredients. However, proper evaluation is necessary to rule out allergic reactions, skin sensitization, and toxicity. Clinical studies and stability testing are important for establishing safety and efficacy.[36-38]

The fabrication of herbal patches for fast joint pain relief is a promising area of pharmaceutical research. Such formulations have the potential to provide rapid therapeutic action, prolonged pain relief, improved mobility, and enhanced quality of life. Continued research and development can lead to the commercialization of effective and affordable herbal transdermal products.[39-41]

Herbal transdermal patches represent an innovative approach for the management of joint pain and inflammation. The combination of medicinal herbs and advanced drug delivery systems offers numerous advantages including localized therapy, sustained release, reduced side effects, and improved patient compliance. The increasing demand for herbal healthcare products and advancements in pharmaceutical technology are expected to promote the development of novel herbal patches for musculoskeletal disorders in the future.[42-44]

DRUG PROFILE

Material

Table.1: Materials Used

Equipment’s:

Table.2: Equipment Used

Formulation Table

Table.3: Formulation Batch F1

Tbale.5: Formulation Batch F3

Collection and Authentication of Herbal Materials

The herbal materials including turmeric, ginger, eucalyptus oil, menthol, camphor, and wintergreen oil were collected from authenticated herbal suppliers. The raw materials were identified and authenticated based on their organoleptic and physicochemical characteristics.

Preparation of Herbal Extracts

Turmeric and ginger were washed properly to remove dust and impurities. The materials were shade dried for several days and pulverized into coarse powder using a grinder. The powdered materials were subjected to extraction using ethanol as solvent by maceration method for 48 hours. The extracts were filtered and concentrated using evaporation techniques. The concentrated extracts were stored in airtight containers for further use.

Preparation of Polymeric Solution

Required quantities of HPMC and PVA were weighed accurately and dissolved separately in distilled water with continuous stirring. The polymeric solutions were mixed together to form a uniform viscous solution.

Addition of Plasticizers and Permeation Enhancers

PEG-400 and glycerin were added slowly into the polymeric mixture with continuous stirring to improve flexibility and elasticity of the patch. Eucalyptus oil was added as a permeation enhancer to increase skin penetration of herbal constituents.

Incorporation of Herbal Ingredients

Accurately weighed quantities of turmeric extract, ginger extract, menthol, camphor, and wintergreen oil were added to the polymeric solution. Tween 80 was added to obtain uniform

Casting of Patch

The prepared solution was poured carefully into clean and dry petri plates lined with backing membrane. The solution was spread uniformly to obtain patches of equal thickness.

Drying of Patch

The petri plates containing formulation were dried at room temperature followed by drying in hot air oven at controlled temperature for complete removal of solvents.

Cutting and Storage

After drying, the prepared patches were removed carefully from petri plates and cut into uniform sizes using a sharp cutter. The patches were wrapped in aluminum foil and stored in desiccators until further evaluation.

Flow Chart of Fabrication Process

Collection of Herbal Materials

                     ↓

Authentication of Raw Materials

                    ↓

Washing and Shade Drying

                   ↓

Powder Preparation

                  ↓

Extraction by Maceration Method

                 ↓

Filtration and Concentration of Extract

                ↓

Preparation of Polymeric Solution

              ↓

Addition of Plasticizers and Permeation Enhancers

             ↓

Incorporation of Herbal Extracts and Oils

                              ↓

Continuous Stirring to Obtain a Homogeneous Mixture

                             ↓

Casting into Petri Plates

                           ↓

Drying at Room Temperature Followed by Oven Drying

                          ↓

Removal of Dried Patch

                         ↓

Cutting into Uniform-Sized Patches

                        ↓

Packaging in Aluminium Foil

                       ↓

Storage in a Desiccator

                      ↓

Evaluation of Herbal Patch

Organoleptic Evaluation

Organoleptic evaluation of the herbal patch was carried out by visual inspection to determine its physical appearance, color, texture, smoothness, flexibility, and uniformity. The prepared patches were observed for the presence of air bubbles, cracks, brittleness, stickiness, and surface imperfections. A good herbal patch should possess a smooth surface, uniform appearance, proper flexibility, and should be free from visible defects. Organoleptic evaluation is important because it helps in assessing the overall quality, acceptability, and elegance of the formulation. The color and odor of the patch also indicate the proper incorporation of herbal ingredients such as turmeric, ginger, eucalyptus oil, and menthol.

Thickness Determination

Thickness of the herbal patch was determined using a digital vernier caliper at different positions of the patch including center and edges. The average thickness was calculated to ensure uniform distribution of the formulation throughout the patch. Uniform thickness is important for maintaining consistent drug content and uniform release of active constituents. Variations in thickness may lead to unequal drug delivery and reduced therapeutic effectiveness. A properly formulated transdermal patch should have uniform thickness with good flexibility and mechanical stability.

Weight Variation Test

The weight variation test was performed to evaluate the uniformity of prepared patches. Individual patches of equal size were cut and weighed separately using a digital weighing balance. The average weight was calculated, and individual weights were compared with the average value. This test ensures that all patches contain a uniform amount of ingredients and polymers. Uniform weight distribution is essential for obtaining reproducible therapeutic effects and maintaining quality control during formulation development.

Folding Endurance

Folding endurance was determined to evaluate the flexibility and mechanical strength of the herbal patch. In this test, a small strip of the patch was repeatedly folded at the same point until

Tensile Strength

Tensile strength is an important parameter used to evaluate the mechanical properties of the patch. It measures the force required to break the patch when stretched. The prepared patch was fixed between two clamps, and force was applied gradually until the patch broke. Tensile strength indicates the ability of the patch to withstand mechanical handling during packaging, storage, and application. A patch with good tensile strength should not tear easily and should maintain its structural integrity throughout use.

Percentage Elongation

Percentage elongation determines the elasticity of the patch. It measures the extent to which the patch can stretch before breaking. The initial length and final length of the patch after stretching were measured, and percentage elongation was calculated. Higher elongation values indicate better elasticity and flexibility of the formulation. Proper elasticity is important because transdermal patches must adapt comfortably to body movements without breaking or peeling off from the skin.

Surface pH Determination

Surface pH of the herbal patch was determined to ensure compatibility with skin and avoid irritation during application. The patch was slightly moistened with distilled water, and the pH was measured using a pH meter. The pH of the formulation should be close to the normal skin pH range to prevent redness, itching, or irritation. Surface pH evaluation is particularly important in herbal formulations because essential oils and herbal extracts may alter the acidity or alkalinity of the patch.

Moisture content analysis was carried out to determine the amount of water present in the patch. The prepared patches were weighed initially and then kept in a desiccator containing calcium chloride for complete drying. After drying, the patches were reweighed, and percentage moisture content was calculated. Low moisture content helps in preventing microbial growth and maintaining stability of the formulation. Excessive moisture may lead to brittleness, stickiness, or degradation of active ingredients during storage.

Moisture Uptake Study

Moisture uptake study was performed to evaluate the hygroscopic nature of the herbal patch. The patches were weighed and exposed to humid conditions in a desiccator containing saturated potassium chloride solution. After a specified period, the patches were reweighed to determine the percentage increase in weight due to moisture absorption. This test helps in predicting the stability of the formulation under humid environmental conditions. Low moisture uptake is desirable for maintaining physical stability and preventing microbial contamination.

Drug Content Uniformity

Drug content uniformity test was performed to determine the uniform distribution of herbal active constituents within the patch. A specific area of the patch was dissolved in a suitable solvent, filtered, and analyzed using a UV spectrophotometer. Uniform drug content ensures that each patch delivers the desired therapeutic dose consistently. Variations in drug content may affect efficacy and reproducibility of treatment. Proper mixing during formulation preparation is essential for achieving uniform distribution of herbal extracts and oils.

In-Vitro Drug Diffusion Study

In-vitro drug diffusion study was conducted using a Franz diffusion cell to evaluate the release pattern of herbal constituents from the patch through a membrane. The patch was placed on the membrane, and receptor medium was maintained at controlled temperature with continuous stirring. Samples were withdrawn at regular intervals and analyzed spectrophotometrically. This study helps in determining the rate and extent of drug release from the formulation.Sustained and controlled release is important for prolonged therapeutic action and effective pain relief.

Adhesion Test

Adhesion test was carried out to evaluate the ability of the patch to remain attached to the skin for a prolonged period. Good adhesion is essential for effective drug delivery because the patch should not peel off during movement or sweating. The adhesive strength of the patch was assessed by applying it to a suitable surface and observing its ability to remain attached under different conditions. Proper adhesion improves patient compliance and therapeutic effectiveness.

Skin Irritation Test

Skin irritation study was performed to evaluate the safety and compatibility of the herbal patch on the skin. The patch was applied to the skin surface and observed for redness, itching, swelling, or allergic reactions over a specified period. Herbal ingredients and essential oils may sometimes produce sensitivity reactions; therefore, irritation testing is important to ensure safe application. An ideal herbal patch should be non-irritant, non-toxic, and comfortable during prolonged use.

Stability Study

Stability studies were carried out to evaluate the physical and chemical stability of the prepared patches during storage. The patches were stored under different temperature and humidity conditions for a specified period and evaluated periodically for appearance, flexibility, drug content, and diffusion characteristics. Stability testing helps in determining the shelf life and storage conditions of the formulation. A stable patch should maintain its physical integrity, therapeutic activity, and drug release profile throughout the storage period.

Percentage Moisture Loss

Percentage moisture loss was evaluated by placing the prepared patches in a desiccator containing anhydrous calcium chloride for a specified period. The patches were weighed before and after storage, and percentage moisture loss was calculated. This parameter helps in assessing the stability and brittleness of the formulation. Excessive moisture loss may cause the patch to become dry and brittle, thereby affecting flexibility and performance.

Flatness Test

Flatness study was conducted to determine whether the patch undergoes constriction or deformation after drying. Strips were cut from different portions of the patch, and changes in length were measured. A flat patch ensures uniform contact with the skin and consistent drug delivery. The absence of constriction indicates good film-forming properties and stability of the formulation.

Swelling Index

Swelling index was determined to evaluate the hydration behavior of the patch. The prepared patches were weighed and immersed in distilled water for a specified period. After swelling, the patches were removed, surface water was wiped off, and the patches were reweighed. The swelling index indicates the ability of polymers to absorb moisture and swell. Proper swelling characteristics help in controlled release of herbal constituents from the transdermal system.

Uniformity of Folding

Uniformity of folding was assessed to determine whether all prepared patches possess similar flexibility and mechanical strength. Multiple patches from different batches were folded repeatedly and observed for cracking or breakage. Uniform folding characteristics indicate consistency in formulation preparation and polymer distribution.

Percentage Yield

Percentage yield was calculated to determine the efficiency of the patch preparation process. The practical yield obtained after formulation was compared with the theoretical yield. High percentage yield indicates efficient formulation methodology with minimal material loss during preparation and drying processes.

RESULT & DISCUSSION:

The present study was carried out to fabricate and evaluate an herbal transdermal patch for fast and effective joint pain relief using natural herbal ingredients such as turmeric, ginger, eucalyptus oil, menthol, camphor, and wintergreen oil. The prepared formulations were evaluated for various physicochemical, mechanical, and diffusion parameters to determine their suitability as transdermal drug delivery systems. Three formulations, namely F1, F2, and F3, were prepared using different concentrations of polymers and herbal ingredients. The obtained results demonstrated that the formulated herbal patches possessed satisfactory physical appearance, flexibility, stability, and drug release characteristics.

Organoleptic Evaluation

All prepared herbal patches showed smooth surface texture, uniform appearance, and satisfactory flexibility. The patches were free from visible cracks, air bubbles, and particulate matter. The color of the patches ranged from light yellow to pale brown due to the presence of turmeric and ginger extracts. A characteristic aromatic odor was observed because of eucalyptus oil, menthol, camphor, and wintergreen oil. Among all formulations, batch F3 showed the best appearance and flexibility due to the optimum concentration of polymers and plasticizers.

Table.6: Organoleptic evaluation

The organoleptic evaluation confirmed successful incorporation of herbal ingredients into the polymeric matrix without any incompatibility or instability.

Thickness Determination

The thickness of prepared patches was found to be uniform in all formulations, indicating proper casting and even distribution of ingredients. Thickness values slightly increased with increase in polymer concentration.

Table.7: Thickness Determination

Uniform thickness is essential for maintaining consistent drug release and therapeutic efficacy. The obtained results indicated that the solvent casting method produced patches with satisfactory uniformity.

Weight Variation Test

Weight variation studies indicated minimal deviation among individual patches, confirming uniform distribution of herbal constituents and polymers.

Table.8: Weight Variation Test

The increase in patch weight from F1 to F3 was due to increased polymer and herbal extract concentrations. The low standard deviation values indicated good reproducibility of the formulation process.

Folding endurance studies demonstrated good flexibility and mechanical strength of the prepared patches. Higher folding endurance values were observed in formulations containing higher amounts of plasticizers.

Table.9: Folding Endurance

Batch F3 showed maximum folding endurance, indicating excellent flexibility and resistance to cracking during handling and application.

Tensile Strength

Tensile strength evaluation confirmed that the prepared patches possessed sufficient mechanical strength to withstand handling and storage conditions.

Table.10: Tensile strength

The increase in tensile strength with higher polymer concentration indicated better film-forming properties and structural integrity of the patch matrix.

Surface pH

The surface pH of all formulations was found to be within the acceptable skin pH range, indicating compatibility with skin and reduced risk of irritation.

Table.11: Surface PH

The results confirmed that the prepared patches were suitable for topical application without causing redness or discomfort.

Moisture Content

Moisture content studies showed that all formulations possessed low moisture levels, which is beneficial for maintaining physical stability and preventing microbial growth.

Table.12: Moisture content

Slightly higher moisture content in F3 was due to increased polymer concentration and hygroscopic nature of plasticizers.

Moisture Uptake Study

Moisture uptake studies indicated acceptable hygroscopic behavior of the prepared patches under humid conditions.

Table.13: Moisture uptake study

The results demonstrated that the patches remained stable without excessive swelling or deformation during storage.

Drug Content Uniformity

Drug content analysis showed uniform distribution of herbal active constituents throughout the patches.

Table.14: Drug content uniformity

Batch F3 exhibited the highest drug content uniformity due to improved mixing and optimized polymer concentration.

In-Vitro Drug Diffusion Study

In-vitro diffusion studies demonstrated sustained release of herbal constituents from the prepared patches over an extended period. The cumulative drug release increased gradually with time.

Table.15: In-Vitro drug diffusion study

Among all formulations, F3 showed the highest drug release profile, indicating better permeation and sustained release characteristics. The presence of eucalyptus oil acted as a permeation enhancer and improved diffusion of active compounds through the membrane.

Adhesion Test

All prepared patches exhibited satisfactory adhesion properties and remained attached to the application surface for prolonged periods without peeling off.

Table.16: Adhesion test

Good adhesion is necessary for maintaining proper contact between the patch and skin for effective drug delivery.

Skin Irritation Study

Skin irritation studies revealed that none of the formulations produced redness, itching, swelling, or allergic reactions during the study period.

Table.17: Skin irritation study

The results confirmed the safety and compatibility of herbal ingredients for topical application.

Stability Study

The prepared patches were subjected to stability studies under different temperature and humidity conditions. No significant changes were observed in physical appearance, flexibility, drug content, or diffusion characteristics during the storage period.

Table.18: Stability study