Formulation And Evaluation of a Mimosa Pudica Leaf Extract-Based Transdermal Patch Foranti-Inflammatory Activity

Medicinal and aromatic plants form a significant part of global flora, contributing to pharmaceutical and healthcare industries. India, with its rich biodiversity and long-standing traditional medicinal systems such as Ayurveda, Siddha, Unani, and folk practices, has recorded over 9,000 native plant species known for their therapeutic properties. According to a World Health Organization (WHO) study, about 80% of the population in developing countries depends on traditional, plant-based medicines for primary healthcare. [1] Among these plants, Mimosa pudica L., commonly known as the “sensitive plant” or “touch-me-not,” is a creeping perennial herb from the Mimosaceae family. It is particularly noted for its unique response to touch, where its leaves fold inward and droop, then reopen within minutes. This plant has gained popularity in various indigenous and modern medicinal systems due to its diverse bioactive constituents and pharmacological effects.[2] M. pudica has been used traditionally to treat conditions such as insomnia, depression, anxiety, rheumatoid arthritis, diabetes, and wounds. In Siddha medicine, its powdered root (e.g., Thottalvadi Chooranam) exhibits antioxidant and antidiabetic activities in experimental models. Additionally, in Traditional Chinese Medicine (TCM), it is used for tuberculosis, traumatic injuries, and kidney disorders. Phytochemical screening of the plant has revealed compounds such as tannins, flavonoids, terpenoids, alkaloids, phenols, and saponins. These constituents are responsible for its wide range of pharmacological activities including hepatoprotective, antimicrobial, anti-inflammatory, analgesic, neuroprotective, anxiolytic, and anticancer effects.[3]

Fig 1:- Mimosa Pudica

Transdermal Drug Delivery Systems (TDDS): A Modern Drug Delivery Approach

Transdermal patches represent a non-invasive, controlled drug delivery system that allows for the continuous release of therapeutic agents through the skin and into the systemic circulation. Since the first FDA-approved transdermal patch (scopolamine for motion sickness) in 1981, TDDS has been used for various drugs such as fentanyl, clonidine, nitroglycerin, and nicotine.[4]

Anatomy of skin:

The skin, constituting the body’s largest organ, encompasses approximately 16% of the average individual's total body mass and presents a vast surface area of 1.7 m^2. Its fundamental function resides in serving as a protective barrier against various external threats, including pathogens, ultraviolet (UV) radiation, chemical agents, allergens, and excessive water loss, thereby effectively segregating the internal milieu from the external environment. Three primary sections make up skin: (1) the outermost layer, called the epidermis, which contains the stratum corneum; (2) the intermediate layer, called the dermis; and (3) the innermost layer, called the hypodermis.

1.Epidermis- The epidermis, which is the skin's outermost layer, varies in thickness, measuring about 0.8 mm on the soles of the feet and palms of the hands. The viable epidermis, which is made up of multilayered regions of epithelial cells, is frequently referred to as the epidermal layers beneath the stratum corneum. Approximately 95% of the cells in the epidermis are keratinocytes; melanocytes, Langerhans cells, and Merkel cells are among the other cells in the epidermal layers[6]. The majority of the cells in the stratum corneum are made up of 20% lipid and 70% insoluble keratins.[5]

The microscopic section of epidermis shows

-Stratum corneum

-Stratum lucidium

-Stratum granulosum

-Stratum spinosum

-Strarum basal

Fig 2:- Structure Of Skin

2.Dermis- The skin's strength and elasticity are provided by the elastin and collagenous fibers, which make up 70% of the dermis's 2-3 mm thickness [6]. Both the dermis and the epidermis receive nourishment from blood vessels located in the dermis. The dermis layer also contains nerves, lymphatic vessels, and macrophages.

3.Hypodermis- The layer directly beneath the dermis is called the subcutis, or hypodermis in histology. A significant number of fat cells make up the elastic layer known as the subcutis, which acts as a shock absorber for blood vessels and nerve endings. This layer has an average thickness of 4 to 9 mm. The actual thickness, however, varies depending on the body region and from person to person[7]. Drug penetration through the intact skin can occur via the transepidermal and trans appendegeal pathways. The stratum corneum, a multilayered, multicellular barrier with adiverse architectural style, is traversed by molecules as part of the transepidermal pathway. Intercellular or intracellular transepidermal penetration are other names for it[8].

Drug Delivery Routes across Human Skin.

Drug molecules can penetrate by three pathways:

1.Sweat ducts

2.Hair follicles

3.Sebaceous glands

The Main Components of Transdermal Patch Contain as Following:

1.Polymer Matrix- The polymer matrix constitutes the fundamental component of Transdermal Drug Delivery Systems (TDDS), dictating the controlled release of medication. Polymers selected for TDDS applications must adhere to stringent criteria, including Biocompatibility, chemical inertness, cost-effectiveness, and stability over extended storage Periods. Among the polymers commonly employed are natural substances such as waxes, Gums, zein, gelatin, and cellulose derivatives as well as synthetic counterparts like Polyvinylpyrrolidone, polyethylene, polypropylene, polyvinyl alcohol, polyvinyl chloride, And polymethylmethacrylate. Additionally, elastomeric materials find widespread application. These polymers are pivotal in modulating drug release kinetics, thereby ensuring the efficacy, safety, and reliability of transdermal drug delivery systems in pharmaceutical research and development.

2.Drug- with proper pharmacology and physical chemistry, the transdermal route is a very attractive choice. Transdermal patches provide a lot of benefits for

Medications with Short half- lives, limited therapeutic windows, or high first pass metabolism such as Nitroglycerine, fenatyl, etc.

3.Permeation Enhancers- are compounds utilized to augment the permeability of the Stratum corneum, facilitating higher concentrations of therapeutic medications. They are Categorized into three types: two-component systems, lipophilic solvents, and surface-active Agents. For instance, dimethyl sulfoxide (DMSO) is a widely used permeation enhancer.

4.Adhesive Layer- This layer is responsible for adhering the patch to the skin. It should Have proper adhesive properties to ensure the patch stays in place during wear but can be Easily removed without causing skin irritation.

5.Backing Laminates- in transdermal patches serve as the outermost layer and play a crucial role in providing structural integrity and flexibility to the patch. These backing crucial role in providing structural integrity and flexibility to the patch. These backing materials should possess high adaptability or low modulus to conform to the contours of the skin and ensure comfortable wear. Common materials used for backing laminates include polyethylene and vinyl, which exhibit the desired properties of flexibility.

6.Other excipients like plasticizers and solvents [9]- TDD is a painless systemic drug Delivery technique that involves putting a drug formulation to healthy, undamaged solvents [10,11]. The medication enters the body through the stratum corneum at first, and then Moves through the deeper layers of the epidermis and dermis without building up in the Dermal layer. The dermal microcirculation allows the medication to be absorbed systemically Once it reaches the dermal layer [12,13]. TDD is superior to other traditional drug delivery Methods in several ways [14,15]. It can offer a non-invasive substitute for parenteral methods, hence Avoiding problems like needle fear. Drug pharmacokinetic profiles are less peaks and more homogeneous, which reduces the possibility of harmful side effects. Because TDD Circumvents pre-systemic metabolism, bioavailability is enhanced [5]. A transdermal patch for the prolonged, three-day administration of scopolamine to treat Motion sickness was the first to be licensed for systemic distribution in 1979[16,17]. The Nitroglycerin patch was another transdermal patch created in 1985. A membrane that Regulates the rate of ethylene vinyl acetate is used in the patch created by Gale and Berggren (1985). When it comes to helping people stop smoking, the nicotine patch is arguably the Most popular and well- known transdermal patch. Numerous further uses have been Researched during the last 30 years. These days, medications applied by transdermal patches Include scopolamine, estrogen (to prevent osteoporosis after menopause and to ease Undesirable menopausal symptoms), nitroglycerin (to treat angina), lidocaine (to treat herpes Zoster pain), and other medications [18]. Since TDDS have far more readily regulated and targeted effects than oral administration, they are a more effective drug delivery method. Since its inception, transdermal drug delivery Has provided numerous advantages, such as noninvasiveness, extended therapeutic effect, Decreased side effects, fewer dose frequency, enhanced bioavailability due to bypassing Hepatic first-pass metabolism, and increased patient compliance. Since the skin is the largest Organ in the body, transdermal distribution is a more targeted and selective delivery approach Because medicinal chemicals that are difficult to administer orally can more easily be Absorbed through the broad exposed surface of the tissue[19]. Transdermal patches come in Three primary varieties: the single-layer/multi-layer drug-in- adhesive transdermal patch, Where the medication is integrated into the adhesive; the second form, known as matrix Transdermal patches, includes a separate drug-containing layer that is thought of as a drug Reservoir; and the third type has a drug layer that consists of a semi-solid matrix that contains A drug solution or suspension [18].

Advantages –

• It is convenient method and requires only once weekly application. Such a simple Dosing regimen can aid in patient adherence to drug therapy.
• Transdermal drug delivery can be used as an alternative route of administration To accommodate patients who cannot tolerate oral dosage forms.
• It is of great advantage in patients who are nauseated or unconscious.
• Drugs that cause gastrointestinal upset can be good candidates for transdermal Delivery because this method avoids direct effects on the stomach and intestine.
• Drugs that are degraded by the enzymes and acids in the gastrointestinal system may also Be good targets.
• First pass metabolism, an additional limitation to oral drug delivery, can be avoided With transdermal administration.
• Drugs that require relatively consistent plasma levels are very good candidates for Transdermal drug delivery.

Fig3: - Representation Of Different Types of Patches

Limitation-

• TDDS cannot deliver ionic drugs.
• It cannot develop for drugs of large molecular size.
• TDDS cannot deliver drugs in a pulsatile fashion
• TDDS cannot develop if the drug or formulation irritates the skin.

4.MATERIALS AND METHODS: -

Materials used are as following:

API- Rutin, Quercetin, Mimosin

1.Ethanol/ methanol/alcohol (for extraction)

2.Propylene glycol (plasticizer)

3.Glycerol

4.Polymers (polyvinyl alcohol, polyvinylpyrrolidone)

5.Permeation enhancer (dimethyl sulphoxide)

Equipment’s needed are as following:

1.Soxhlet apparatus (round bottom flask, Soxhlet tube, condenser) or maciration

2.Weighing balance

3.Hot air oven

4.Desiccator

5.Verniercaliper/micrometer

Method of preparation: -

1.Collection of Plant: -

The fully matured, fresh and healthy leaves of Mimosa pudica were Collected from area of washim Leaves Were thoroughly cleaned and good leaves were picked and dried under shade. Sufficient Quantity of leaves were powdered in an electric grinder, sieved from 60# to obtain fine and coarse powder.

2.Solubility Analysis: -

After testing solubility of leaf powder in various solvents such as Acetone, chloroform, water, alcohol and petroleum ether, it came to know that Mimosa pudica leaf powder was more soluble in alcohol.

Fig.4- Solubility Analysis

3.Preparation of Herbal Extract: -

50gm of coarse leaf powder was weighed and filled in thimble packet for Soxhlet extraction. In ethanol 95% as solvent. Extraction process was continued for 6hrs. Another method used For extraction was cold maceration. The leaf powder was macerated in petroleum ether by Shaking for one time initially and keeping for 24hrs without disturbing it.

Fig 5: - Extraction Of Mimosa Pudica

4.Phytochemical Screening: -

Fig 6:- Phytochemicals screening

Formulation of Herbal Transdermal Patch: -

Method used for patch formulation is solvent casting method. Firstly, 1gm of PVA & PVP (both are polymers) were weighed individually, then it was collected in beaker along with 10ml of dist. Water, dissolve it completely on hot water bath and avoid bubble formation with the help of glass Rod. After complete dissolution of polymer, remove it from water bath and allow it to reach 25oC or to attain room temperature. Then add extract of leaf powder (drug). Continuous stirring is important in patch formulation to obtain homogenous mixture. Now we Have to add propylene glycol(0.3ml) as plasticizer, glycerol(1ml). Next step for this to pour Above solution into petri- plate with is covered with small quantity of glycerine as lubricant. Keep the petri-plate in hot air oven for 2-4hrs to remove air bubble and the keep it for 20hrs at room temperature by covering in with funnel to avoid rapid evaporation. Now we can Remove patch from petri-plate with help of blade or any sharp and pointed substance.

5. Evaluation Parameters for Transdermal Patches: -

1.Organoleptic Evaluation-

The physical appearance of developed patch was evaluated By using a naked-eye examination as follows:

Appearance- formulated in circular shape and cutted into desire shape and size Colour brown, green and greenish brown.

Clarity- transparent Flexibility-yes(flexible)Smoothness- yes (smooth in texture).

Thickness of Patch- A vernier caliper was used to measure the transdermal patches’ Thickness three times at different site of patch, and the mean value was calculated. It was Found to be 0.5 mm[21]

Fig 7.: - Formulated transdermal patch of Mimosa pudica

2.pH of Patch-

Before using, the patch is swollen in 1ml of distilled water and allowed to sit at room temperature for two hours. By using pH paper, it was came to know that pH of Patch ranges from 5-6.5 (similar to that of skin). It can also analyzed by digital electrode [22,24 ]

Fig 8: - pH Paper Dipped into Solution

3.Percentage Moisture Content-

After the patches were dried for 24 hours in a Desiccator, their percent moisture content was calculated by weighing them.

The formula for This calculation is as follows: % moisture content= (initial weight – final weight)/initial Weight 100% moisture content of our patch was 7.14% [23].

Fig. 9:- Desiccator used to remove moisture

4.Thumb Tack Test: -

This test is used to determine an adhesive’s tack properties. The Relative tack property is simply detected by pressing the thumb on the adhesive. It took Around 2-2.5 sec to release from thumb [22].

5.Skin irritability test:-

The Skin Irritability Test is an essential part of the evaluation of transdermal patches. This test assesses whether the patch causes any skin irritation, redness, swelling, or other allergic reactions upon application. Apply the Mimosa pudica transdermal patch on the shaved area. Secure the patch with surgical tape. Keep it in contact with the skin for 24 hours. Skin irritability test was found to be no irration on skin [24,25].

6.RESULT

Based on phytochemical screening, terpenoids, flavanoids, tannins, polysaccharides, steroids, Alkaloids, and phenols were shown to be present in ethyl alcohol extract. The primary mechanism by which anti-inflammatory drugs work is by inhibiting the cyclooxygenase enzyme, which is in charge of converting arachidonic acid into prostaglandins (PG). Inhibiting these lysosomal enzymes (Cyclooxygenase) or stabilizing the lysosomal membrane are the two ways that non- steroidal anti-inflammatory medications (NSAIDs) work. Moreover, the anti- inflammatory properties of the leaf extract’s lupeone, lupeol, quercetin, and rutin content work as API. Based on a number of review papers and research articles, we may therefore conclude that leaf extract of the mimosa pudica may prevent certain processes that either stimulate or improve the efflux of these intracellular components and act as anti-inflammatory agent.