Preparation Of Patches Research Articles

Tert-butylhydroquinone and tert-butylcatechol positivity as warning lights of skin sensitization to tert-butylphenol derivatives in adhesives and diabetes devices.

Tert-butylphenol (TBP) derivatives, antioxidants in adhesives and diabetes devices, may provoke allergic contact dermatitis (ACD). The objective of this study is to report sensitization to TBP derivatives in medical devices and to highlight that tert-butylhydroquinone (BHQ) and tert-butylcatechol (TBC) are potential screeners in this regard. Fifteen patients with ACD from adhesives and diabetes devices were patch tested to different TBPs: BHQ 1% pet., TBC 0.25% pet., BHA 2% pet., BHT 2% pet., 4-tert-butylphenol (TBP) 1% pet. and 2,4-di-tert-butylphenol (di TBP) 1% pet. The culprit devices (medical adhesives, sanitary pads, diabetes devices) and TBP patch preparations were analysed using gas chromatography-mass spectrometry (GC-MS). BHQ (9/13), TBC (7/13), and to a lesser extent BHT (3/15), BHA (2/15) and TBP (2/13) gave positive reactions. Seven patients had developed ACD from adhesives and diabetes devices, respectively, and one patient from sanitary pads. GC-MS analyses of the medical devices and patch test materials confirmed the presence of the patch-test positive TBPs, or chemically related derivatives, or, interestingly, tert-butylbenzoquinones (BBQ) were found, that is, spontaneously formed, highly reactive TBP metabolites, likely (pseudo-) cross reacting with the patch tested TBPs. TBPs might be overlooked sensitizers in medical devices, and BHQ and TBC are potential screeners in this regard.

Current Approaches on Transfersomal Patch: A Noninvasive Innovative Booster for Improved Transdermal Drug Delivery.

Pharmaceutical research is increasingly focusing on transdermal drug delivery due to its potential for improved compliance and bioavailability. However, it is challenging due to the tight intracellular junctions present in the skin. Researchers have developed noninvasive methods, like transfersomes, to overcome these challenges. Transfersomes are ultra-deformable vesicles utilized for improved transdermal applications. They are made up of a phospholipid-rich lipid bilayer, an edge activator, and an ethanol/aqueous core. After topical treatment, transfersomes can penetrate deeper skin regions, delivering larger concentrations of active compounds. A transfersomal patch is applied to the skin and left for an extended period of time to allow a large dose of medication to permeate into the bloodstream. The transfersomal patch offers an advantage over the transfersomal gel because it allows the transfersomes to be applied under occlusive conditions, resulting in greater permeability, a lower amount of active medication, and a steady supply rather than a massive dose. This review represents the preparation and evaluation of transfersomal patches, recent research approaches, and future aspects of transfersomal patches. This study suggests that drug-loaded transfersomal patches could be a unique option to avoid invasive therapy.

Dual cross-linking mechanism of sodium alginate composite hydrogel for adhesive microneedle patch preparation

The introduction of microneedles has revolutionized transdermal drug delivery. However, solid microneedle patches often fail to conform to the epidermis and adapt to changes in skin curvature, limiting their effectiveness. Using sodium alginate hydrogel to create flexible microneedle patches can address this issue, but conventional sodium alginate hydrogels suffer from inhomogeneous structure, dehydration, and poor mechanical properties. These drawbacks result in reduced drug delivery efficacy and insufficient mechanical robustness. To enhance the performance of sodium alginate hydrogels, this study presents a novel sodium alginate composite hydrogel with a dual cross-linking mechanism. The hydrogel, with a gelatin to sodium alginate ratio of 1:1, exhibited optimal surface morphology and mechanical properties suitable for microneedle patch preparation. The resulting microneedle patch demonstrated excellent water adhesion, securely attaching to skin and oral mucosa surfaces. In vitro experiments confirmed the microneedle's ability to puncture and release the drug, dissolving and releasing the drug within 15 minutes. The patch also showed superior piercing and dissolution properties on the mouth palate, highlighting it may serve as a potential delivery location for more efficient microneedle patch drug administration. In the future, this technology will show great potential in expanding the scope of drug administration for transdermal drug delivery and in reducing the work pressure of healthcare professionals.

Formulation and In-Vitro Penetration Test of Ketoprofen Patch with Addition Aloe vera Powder (Aloe vera L.) Bioenhancer

Ketoprofen is a non-steroidal anti-inflammatory drug (NSAID) which is generally used to reduce pain and inflammation. The main obstacle in administering drugs via transdermal is the low penetration of drugs through the skin. Aloe vera contains lignin compounds which are thought to be bioenhancer. This research aims to formulate ketoprofen and aloe vera powder in form patch and compare penetration patch with and without the addition of aloe vera powder. Preparation patch 3 formulas were made with different ratios of HPMC E5 and Eudragit E100 polymers F1 (6:2), F2 (8:2), F3 (10:2). Formula 3 is the best formula with a comparison of HPMC E5 and Eudragit E 100 of 10:2. Formula 3 has a thin, dry patch and is easy to remove from the mold. F3 then remade with additions bioenhancer by 5 % and patch without additions bioenhancer. The results of the physical quality test showed that the formula with and without the addition of aloe vera as an enhancer has uniform weight, thickness, pH and folding resistance which meets the requirements for patch preparation. Franz diffusion cell result for patch preparations with the addition of aloe vera showed a better penetration value than without the addition of aloe vera with a cumulative value of 92.5815 μg/cm2 and a total flux of 260.4355 μg/cm2 hour.

Polystyrene-polyisoprene-polystyrene coated Fe3C–C/MXene composite film based flexible, and multifunctional patch for electromagnetic interference shielding and joule heating

Portable and wearable electronics demand flexible, multifunctional films with electromagnetic interference (EMI) shielding and thtaermal management capabilities. However, the preparation of flexible films with suitable performance is still a challenge. Here, we constructed the flexible, stretchable, and multifunctional patch with a multistage structure composed of Fe3C–C (FC) fibrous film, MXene, and polystyrene-polyisoprene-polystyrene (SIS), which exhibited outstanding EMI shielding effectiveness total (SET) of 56 dB. Due to the package of the SIS layer, the EMI SE of the as-prepared patch remains almost unchanged after 3000 cycles of bending test or placing in the air for one month. Furthermore, the multistage structure film shows excellent Joule heating performance and can maintained for a long time. This work provides a simple and effective strategy for the preparation of multifunctional flexible patches, which have great application potential in the fields of EMI shielding and thermal management.

Microneedle delivery system with rapid dissolution and sustained release of bleomycin for the treatment of hemangiomas

Hemangioma of infancy is the most common vascular tumor during infancy and childhood. Despite the proven efficacy of propranolol treatment, certain patients still encounter resistance or face recurrence. The need for frequent daily medication also poses challenges to patient adherence. Bleomycin (BLM) has demonstrated effectiveness against vascular anomalies, yet its use is limited by dose-related complications. Addressing this, this study proposes a novel approach for treating hemangiomas using BLM-loaded hyaluronic acid (HA)-based microneedle (MN) patches. BLM is encapsulated during the synthesis of polylactic acid (PLA) microspheres (MPs). The successful preparation of PLA MPs and MN patches is confirmed through scanning electron microscopy (SEM) images. The HA microneedles dissolve rapidly upon skin insertion, releasing BLM@PLA MPs. These MPs gradually degrade within 28 days, providing a sustained release of BLM. Comprehensive safety assessments, including cell viability, hemolysis ratio, and intradermal reactions in rabbits, validate the safety of MN patches. The BLM@PLA-MNs exhibit an effective inhibitory efficiency against hemangioma formation in a murine hemangioma model. Of significant importance, RNA-seq analysis reveals that BLM@PLA-MNs exert their inhibitory effect on hemangiomas by regulating the P53 pathway. In summary, BLM@PLA-MNs emerge as a promising clinical candidate for the effective treatment of hemangiomas.Graphical

Formulation and Evaluation of Brucine Sulphate Transdermal Patch for Anti-Inflammatory Activity

This study was designed to develop and evaluate a transdermal patch containing brucine sulphate, a herb-based ingredient. Because of its potential to treat a wide range of illnesses with fewer side effects and higher efficacy, herbal medicines are gaining popularity in today’s society. Researchers in the field of phytoformulation have shown that there are a lot of benefits to enhancing the pharmacological activity of herbal drugs by creating nano dosage forms such as nanoparticles, nano-capsules, liposomes, nano-emulsion, and transdermal patches. Drugs can be delivered to patients in a regulated manner through transdermal drug delivery systems. It decreases systemic side effects and, in some cases, provides efficacy compared to other dose forms by enabling a consistent blood level profile. Patch preparation done by using naturally occurring polymers. Thickness, moisture content, folding endurance, and content homogeneity are some of the evaluation measures that are carried out. The transdermal patches evaluated successfully. Average weight of patch was 2.65 g, having folding endurance 94 times and pH of patch was 5.69, moisture content was 7.9%

Formulation and Evaluation of Naringin Loaded Transdermal Patches using 32 Full Factorial Design

The main goal of the current study was to maximize the bioavailability of naringin by prolonging the drug’s release using transdermal patches. Ethyl cellulose (EC) served as the lipophilic component and hydroxy propyl methyl cellulose (HPMC) as the hydrophilic matrix in the preparation of transdermal patches. A 32-complete factorial technique was used to build the optimal design matrix, altering the ratio between the hydrophilic and lipophilic matrices. To create the best optimum formulation, three alternative ratios of EC and HPMC were employed. The patches had pH values ranging from 5.28 ± 0.006 to 5.62 ± 0.015. The transdermal patches had thicknesses ranging from 0.514 ± 0.004 to 0.697 ± 0.004 mm. The average weight of the prepared transdermal patches ranged from 194.67 ± 0.578 to 241.67 ± 1.528 mg. The transdermal patches’ moisture content ranged from 7.23 ± 0.158 to 10.33 ± 0.158%. Tensile strength values of the prepared transdermal patches ranged from 9.59 ± 0.006 to 10.41 ± 0.035 kg/cm2, while the drug content varied from 94.7 ± 0.6 to 97.33 ± 0.208%.

ASSESSING THE SAFETY PROFILE OF POLYMERS IN TRANSDERMAL MICRONEEDLE PATCH FABRICATION: INSIGHTS FROM AN ACUTE TOXICITY STUDY

The acute toxicity study is a crucial component of preclinical toxicology assessments conducted to evaluate the potential adverse effects of a substance or compound on albino rabbits. This study provides key findings and implications of an acute toxicity study of natural and synthetic polymers that are used in the preparation of transdermal microneedle patches (TMNPs) for sustained delivery of doxazocin mesylate. In this study, we divided the albino rabbits into three equal groups (n = 6). Group-I was labeled as a control group and group-II was treated with TMNPs-1 (HPMC, maltose) and group-III was treated with TMNPs-2 (PLGA, polyvinyl acetate). The results obtained from feed consumption, hematology profile, biochemical studies, vital organ weight, and histopathological changes in vital organs were compared with the control group, and proved the safety profile of the polymers involved in the fabrication of microneedle patches. Mechanical strength and dermal safety study established the facts about the safety of microneedle patches and potential risks to health as a carrier system for the delivery of drugs into the systemic circulation directly.

Skin Penetration of Corn Silk (Zea mays L.) Transdermal Patch on Wistar Mice Skin Using Franz Diffusion Cell

Background: Corn silk (Zea mays L.) contains many active compounds, especially the flavonoid quercetin which has pharmacological activity as an antihyperlipidemic agent by reducing cholesterol and triglyceride levels in the body. Antihyperlipidemic treatment by oral route, such as statin drugs, has the disadvantage of experiencing a first-pass effect in the liver, which reduces the bioavailability of the drug. In addition to avoiding the first-pass effect, transdermal patches can improve patient compliance because they are easy to use. Objective: This study aims to optimize the transdermal patch formula of corn silk extract and test the penetration of the optimum formula by in vitro. Method: Optimization of the formula using the Regular Two-Level Factorial Design method on Design Expert®. This study used 2 factors, namely HPMC with a concentration of 3%-4% and PVP with a concentration of 1%-2%. The optimum formula obtained was subjected to in vitro penetration test using Franz diffusion cell. Results: Based on the results of factorial design analysis, the optimum formula of transdermal patches is at HPMC and PVP concentrations of 3.49% and 1% with moisture content, moisture uptake, percentage of elongation, and folding endurance respectively of 7.79%, 4.19%, 13.26% and 470.58 fold. The optimum formula of corn silk extract transdermal patch preparation also had an optimum percent cumulative amount of penetrated flavonoids of 96.06% and flux of 6.17 µg/cm2.hour at 3 hours. Conclusion: Transdermal patch dosage of corn silk extract with HPMC and PVP concentrations of 3.49% and 1% proved to have good characteristics and penetration rate.

Formulation of Acne Patch from Garcinia mangostana L Peel Extract With a Combination of Chitosan Polymer and HPMC Against Propionibacterium acnes Bacteria

Garcinia mangostana or Mangosteen has main compounds derived from xanthones, one of them was alpha mangosteen known having antibacterial activity. The purpose of this study was to formulate an acne patch preparation from mangosteen peel extract with a combination of chitosan and HPMC polymer against Propionibacterium acnes bacteria. Acne patches were made by solvent evaporation by using oven at 70 ﹾC. Acne patch preparation was evaluated for physical characteristics, and tested for its antibacterial effectiveness activity. The acne patch formulation was made with the ratio of Chitosan :HPMC: mangosteen peel extract at F1 (800 mg: 400 mg: 120 mg), F2 (900 mg: 300 mg: 120 mg), F3 (800 mg: 400 mg: 240 mg), F4 (900 mg: 300 mg: 240 mg). All formulas have good organoleptic properties, thickness 0,7-0,9 mm, folding resistance>300 times, low vapor transmission rate 0,0030-0,0078 g.cm2/hour, moisture absorption capacity 13-23%, content moisture <10% and uniform active substance ingredient. The patch preparation has antibacterial effectiveness with strong inhibition in the range of 10-20 mm. F1 (800 mg: 400 mg: 120 mg) and F3 (800 mg: 400 mg: 240 mg) have the strongest inhibition with 11,2 and 11,0 mm respectively.

FORMULATION AND CHARACTERIZATION OF ANTI-INFLAMMATORY TRANSDERMAL PATCH PREPARATIONS FROM THE EXTRACT OF PATAH TULANG (Euphorbia tirucalli)

Transdermal patches are pharmaceutical preparations that aim to provide a drug delivery system across the surface of the skin and tissue, which is then delivered to the blood. is a plant that contains secondary metabolites with anti-inflammatory activity, such as alkaloids, flavonoids, polyphenols, tannins, steroids, and saponins. This study aimed to determine the characteristics of anti-inflammatory transdermal patch preparations prepared from Euphorbia tirucalli extract. The research method was laboratory experimental by preparing patches using varying concentrations of Euphorbia tirucalli extract, namely F1 (5%), F2 (10%), and F3 (15%). Next, an evaluation of patch preparation was carried out, including organoleptic tests, weight uniformity tests, thickness tests, fold durability tests, pH tests, and moisture tests. From the research results, it can be concluded that Euphorbia tirucalli extract at concentrations of 5%, 10%, and 15% can be made into patch preparations. The best characteristics of the patch preparation were F2 with an extract concentration of 10%, which had a smooth, flexible texture, folding durability >300 folds, pH 4.5, and moisture value of 7.30%. Keywords: Anti-inflammatory, Euphorbia tirucalli, Transdermal patch

OPTIMIZATION OF DICLOFENAC POTASSIUM TRANSDERMAL PATCH FORMULA USING A COMBINATION OF POLYVYNIL PYRROLIDONE K 30, ETHYL CELLULOSE AND MENTHOL WITH SIMPLEX LATTICE DESIGN METHOD

Diclofenac potassium is one of the NSAID drugs which can cause gastrointestinal irritation and damage to the small intestinal mucosa including erosion and ulceration. The purpose of this study was to determine the effect of the combination of PVP K 30, ethyl cellulose and menthol on organoleptic, thickness, weight uniformity, moisture and folding resistance of diclofenac potassium transdermal patch.This research is an experimental study that includes an experiment to optimize the formulation of a transdermal patch preparation with the active ingredient potassium diclofenac and a combination of PVP K 30, ethyl cellulose and menthol. The optimization method uses the simplex lattice design method. There are 13 formula designs consisting of a combination of PVP K 30, ethyl cellulose and menthol. Each formula was tested for organoleptic, thickness, weight uniformity, moisture and folding resistance. Then the optimum formula was determined and analyzed using the simplex lattice design method. The combination of PVP K 30, ethyl cellulose and menthol with a simplex lattice design has an effect on the transdermal patch of diclofenac potassium which increases the consistency of the patch surface, reduces the thickness directly proportional to the weight of the patch and increases folding resistance. The proportion of PVP K 30, ethyl cellulose and menthol that can produce the optimum formula for diclofenac potassium transdermal patches with the simplex lattice design on the critical parameters of thickness, moisture, folding resistance and penetration tests, namely PVP K 30 of 14.87%, ethyl cellulose of 10.00% and 5.13% menthol.

Formulasi Sediaan Patch dari Ekstrak Daun Salam (Syzygium polyanthum [Wight.] Walp.)dan Uji Aktivitas Antibakteri Propionibacterium acne Secara In Vitro

The use of S. polyanthum as an alternative to treat acne has been widely studied because it contains active substances that have antibacterial properties against Propionibacterium acne. The formulation of S. polyanthum extract into a patch preparation has many advantages. This study aimed to formulate and evaluate the physical properties of S. polyanthum extract patches, and determine their antibacterial activity against Propionibacterium acne. Patch preparations were made using the solvent casting method in 6 formulas with various polymer concentrations. Evaluation of the preparations included organoleptic tests, weight uniformity, thickness, pH, folding resistance, swelling, and turbidity. Antibacterial activity test against Propionibacterium acne was carried out on the resulting extract and patch preparations. The resulting patch provides a distinctive color and aroma of the extract, with a weight between 0.036–0.050 mm, thickness between 0.21–0.30 mm, pH between 4.43–5.06, folding power >500 folds, swelling percentage in medium phosphate buffer, pH 5.8, between 19.2%-30.8%, and distilled water between 18.8%-29.2%, and turbidity in medium phosphate buffer, pH 5.8, between 5.50–8.16 NTU, and distilled water between 4.02–5.57 NTU. S.polyanthum extract had the largest inhibition zone at 5% concentration, namely 13.56±1.40 mm. Meanwhile, patch preparations had the greatest inhibition in F1, namely 11.31±0.175 mm. S. polyanthum extract can be formulated into patches with a concentration of 5% at various concentrations of HPMC and chitosan. Patch preparations on F1 with a comparison of HPMC : chitosan (7:3) gave the largest inhibition zone against Propionibacterium acne, namely 11.31±0.175 mm.

EFFECTIVENESS TEST OF WOUND PATCH PREPARATIONS OF GOTU KOLA LEAF EXTRACT (Centella asiatica (L.) Urb.) ON INCISION WOUND IN RABBITS

A wound patch is a dosage form that delivers drugs through the skin to produce systemic effects, with the advantage of controlled drug release. Centella asiatica (L.) Urb.) is widely used to heal incision wounds on the skin. The most important component was asiaticoside, which plays a major role in accelerating wound healing. This study was conducted to test the effectiveness of transdermal patches from Centella asiatica (L.) Urb.) against incision wounds was performed on 5 rabbits divided into different treatment groups, namely group I without treatment, group II wound patch base (negative control), group III plaster (positive control), and groups IV and V, comprising a wound patch of gotu kola leaf extract at concentrations of 16% and 32%, respectively. The data obtained were statistically tested for normality using the Shapiro-Wilk test. The results showed that the wound patch preparation of 16% gotu kola leaf extract showed a significant difference (p < 0.05) in wound length reduction compared to the negative and normal controls. The wound healing time observed at concentrations of 16% and 32% provided wound healing effects. The best effect was observed at a concentration of 16%, with an average wound closure time of 12 days. It can be concluded that gotu kola leaf extract in the form of a wound patch preparation was effective in wound healing. Keywords: Gotu kola leaf extract; incision wound; Wound patch; Effectiveness test

ANTI-ACNE PATCH FORMULATION SILKWORM COCOON WASTE WITH HPMC AND PVP VARIATIONS

Some topical preparations for acne have been developed in the form of gels and creams. However,it is still rarely developed in the form of a patch dosage form. Waste from silkworm cocoons has theactivity of inhibiting the growth of acne-causing bacteria, can be formulated into patch preparations.This study aims to formulate anti-acne patches from silkworm cocoon waste with variations of HPMCand PVP. The formulation of the anti-acne patch from silkworm cocoon waste was made by mixingthe lyophilisate of silkworm cocoon waste with a patch base with variations of HPMC and PVP. Theformulations were divided into 3 with different concentrations of HPMC and PVP additives, namelyformulas 1 (4:1), 2 (2,3:1), and 3 (1:1), respectively, The evaluations carried out included organolepticexamination, patch thickness, weight uniformity, fold resistance, moisture absorption, drying shrinkage.The results obtained showed that the concentration of the combination of HPMC and PVP polymersin the patch preparation gave different results from all evaluations that had been carried out, includingorganoleptic evaluation, weight uniformity, fold resistance, and drying shrinkage were in accordancewith the requirements of a good patch. The optimum concentration of the combination of HPMC andPVP as a polymer in the anti-acne patch preparation from silkworm cocoons is formula 2 with a ratioof (2,3:1) as novelty in this study.

Improved removal efficiency of partial bridge deck repair patches using the saw and patch method

ABSTRACT Partial-depth repair is a concrete bridge deck rehabilitation method used when the deterioration is limited to the top half of the slab. The process includes removing the deteriorated concrete in small patch areas and replacing it with new repair material. While many advances have been made in repair material products to decrease the traffic closure times during curing, the patch preparation time still requires a significant amount of time which delays the repair time and adversely affects the transportation network. The most commonly used technique is the saw and patch due to its advantages which include cost-effectiveness, the capability to remove concrete from confined areas, and familiar to construction workers. In contrast, this method has two disadvantages; it is time consuming and labor intensive. Therefore, this study aims to decrease the patch preparation time by experimentally evaluating different sub-techniques in the saw and patch method to develop a specific methodology that reduces patch preparation time. The sub-techniques studied are patch discretization, sawing and jackhammering times, investigating four different discretized sawing and jackhammering methods in terms of removal time, equipment usage, damage to the surrounding concrete, and the labor efforts. The results of this study identify a time optimal sawing and jackhammering technique.

Validation of a laser projection platform for the preparation of surgical patches used in paediatric cardiac surgery.

Reconstruction of cardiovascular anatomy with patch material is integral to the repair of congenital heart disease. We present validation of a laser projection platform for the preparation of surgical patches as a proof-of-concept for intraoperative use in patient-specific planning of paediatric cardiac surgery reconstructions. The MicroLASERGUIDE, a compact laser projection system that displays computer-aided designs onto 2D/3D surfaces, serves as an alternative to physical templates. A non-inferiority comparison of dimensional measurements was conducted between laser projection ('laser') and OZAKI AVNeo Template ('template') methods in creation of 51 (each group) size 13 valve leaflets from unfixed bovine pericardium. A digital version of the OZAKI AVNeo Template dimensions served as control. Feasibility testing was performed with other common patch materials (fixed bovine pericardium, PTFE and porcine main pulmonary artery as a substitute for pulmonary homograft) and sizes (13, 23) (n = 3 each group). Compared to control (height 21.5, length 21.0 mm), template height and length were smaller (height and length differences of -0.3 [-0.5 to 0.0] and -0.4 [-0.8 to -0.1] mm, P < 0.01 each); whereas, both laser height and length were relatively similar (height and length differences of height 0.0 [-0.2 to 0.2], P = 0.804, and 0.2 [-0.1 to 0.4] mm, P = 0.029). Template percent error for height and length was -1.5 (-2.3 to 0.0)% and -1.9 (-3.7 to -0.6)% vs 0.2 (-1.0 to 1.1)% and 1.0 (-0.5 to 1.8)% for the laser. Similar results were found with other materials and sizes. Overall, laser sample dimensions differed by a maximum of 5% (∼1 mm) from the control. The laser projection platform has demonstrated promise as an alternative methodology for the preparation of surgical patches for use in cardiac surgery. This technology has potential to revolutionize preoperative surgical planning for numerous congenital anomalies that require patient-specific patch-augmented repair.

Poly(2-Hydroxyethyl Methacrylate) Hydrogel-Based Microneedles for Metformin Release.

The release of metformin, a drug used in the treatment of cancer and diabetes, from poly(2-hydroxyethyl methacrylate), pHEMA, hydrogel-based microneedle patches is demonstrated in vitro. Tuning the composition of the pHEMA hydrogels enables preparation of robust microneedle patches with mechanical properties such that they would penetrate skin (insertion force of a single microneedle to be ≈40 N). Swelling experiments conducted at 20, 35, and 60°C show temperature-dependent degrees of swelling and diffusion kinetics. Drug release from the pHEMA hydrogel-based microneedles is fitted to various models (e.g., zero order, first order, second order). Such pHEMA microneedles have potential application for transdermal delivery of metformin for the treatment of aging, cancer, diabetes, etc.

Transdermal Drug Delivery System: An Emphasis on Transdermal Patches

Transdermal drug delivery system was presented to overcome the difficulties of drug delivery especially oral route. A transdermal patch is a medicated adhesive patch that is placed on the skin to deliver a specific dose of medication through the skin and into the bloodstream. It promotes healing to an injured area of the body. An advantage of a transdermal drug delivery route over other types of delivery system such as oral, topical, i.v., i.m., etc. is that the patch provides a controlled release of the medication into the patient, usually through either a porous membrane covering a reservoir of medication or through body heat melting thin layers of medication embedded in the adhesive. The main disadvantage to transdermal delivery systems stems from the fact that the skin is a very effective barrier, as a result, only medications whose molecules are small can easily penetrate the skin, so it can be delivered by this method. This review article describes the overall introduction of transdermal patches including type of transdermal patches, method of preparation of transdermal patches and factor affecting etc.