Transdermal Drug Delivery Research Articles

An Integrated Microcurrent Delivery System Facilitates Human Parathyroid Hormone Delivery for Enhancing Osteoanabolic Effect.

Human parathyroid hormone (1-34) (PTH) exhibits osteoanabolic and osteocatabolic effects, with shorter plasma exposure times favoring bone formation. Subcutaneous injection (SCI) is the conventional delivery route for PTH but faces low delivery efficiency due to limited passive diffusion and the obstruction of the vascular endothelial barrier, leading to prolonged drug exposure times and reduced osteoanabolic effects. In this work, a microcurrent delivery system (MDS) based on multimicrochannel microneedle arrays (MMAs) is proposed, achieving high efficiency and safety for PTH transdermal delivery. The internal microchannels of the MMAs are fabricated using high-precision 3D printing technology, providing a concentrated and safe electric field that not only accelerates the movement of PTH but also reversibly increases vascular endothelial permeability by regulating the actin cytoskeleton and interendothelial junctions through Ca2+-dependent cAMP signaling, ultimately promoting PTH absorption and shortening exposure times. The MDS enhances the osteoanabolic effect of PTH in an osteoporosis model by inhibiting osteoclast differentiation on the bone surface compared to SCI. Moreover, histopathological analysis of the skin and organs demonstrated the good safety of PTH delivered by MDS in vivo. In addition to PTH, the MDS shows broad prospects for the high-efficiency transdermal delivery of macromolecular drugs.

Microorganism microneedle micro-engine depth drug delivery

As a transdermal drug delivery method, microneedles offer minimal invasiveness, painlessness, and precise in-situ treatment. However, current microneedles rely on passive diffusion, leading to uncontrollable drug penetration. To overcome this, we developed a pneumatic microneedle patch that uses live Enterobacter aerogenes as microengines to actively control drug delivery. These microbes generate gas, driving drugs into deeper tissues, with adjustable glucose concentration allowing precise control over the process. Our results showed that this microorganism-powered system increases drug delivery depth by over 200%, reaching up to 1000 μm below the skin. In a psoriasis animal model, the technology effectively delivered calcitriol into subcutaneous tissues, offering rapid symptom relief. This innovation addresses the limitations of conventional microneedles, enhancing drug efficiency, transdermal permeability, and introducing a creative paradigm for on-demand controlled drug delivery.

Transdermal Drug Delivery Systems: Different Generations and Dermatokinetic Assessment of Drug Concentration in Skin.

Transdermal drug delivery systems (TDDS) are a highly appealing and innovative method of administering drugs through the skin, as it enables the drugs to achieve systemic effects. A TDDS offers patient convenience, avoids first-pass hepatic metabolism, enables local targeting, and reduces the toxic effect of drug. This review details several generations of TDDS and the advancements made in their development to address the constraints associated with skin delivery systems. Transdermal delivery methods of the first generation have been consistently growing in their clinical application for administering small, lipophilic, low-dose drugs. Second-generation TDDS, utilizing chemical enhancers and iontophoresis, have led to the development of clinical products. Third-generation delivery systems employ microneedles, thermal ablation, and electroporation to specifically target the stratum corneum, which is the skin's barrier layer. Dermatokinetics is the study of the movement of drugs and formulations applied to the skin over a period of time. It provides important information regarding the rate and extent to which drugs penetrate skin layers. Several dermatokinetic techniques, including tape stripping, microdialysis, and laser scanning microscopy, have been used to study the intricate barrier properties and clearance mechanisms of the skin. This understanding is essential for developing and improving effective TDDS.

A Self-Assembled Transdermal Nanomedicines Incorporating Pendant Disulfides for Non-Invasive, Synergistic Treatment of Melanoma.

Transdermal drug delivery system (TDDS) offers lower systemic toxicity and good patient compliance, making it a promising treatment option for skin-related cancers. However, physiological barriers in the skin frequently impede the therapeutic efficiency of TDDS. To address this, a unique self-assembled TDDS that incorporates disulfide pendant groups (termed Sup-TDDS) is presented. It is formulated with dithiolane-containing lipoic acid (LA), photosensitizers Ce6, and chemotherapeutic agents trametinib. Pendant disulfide moieties on Sup-TDDS facilitate thiol-disulfide exchange reactions with exofacial thiols on cell surfaces, thus enhancing stratum corneum penetration. In contrast to intravenous injection, topical administration of Sup-TDDS can penetrate deeper into the skin (> 500 µm) and promote drug accumulation in subcutaneous tumors. In a B16F10-bearing mouse model, Sup-TDDS treatment demonstrates significant anti-tumor effects in primary and recurrent melanoma, benefiting from the synergistic effects of Ce6 and trametinib. These results underscore that Sup-TDDS's transdermal properties allow non-invasive melanoma therapy, implying the potential of nanodrugs containing pendant disulfides for transdermal treatment of skin illnesses.

Bilateral Globus Pallidus Lesions and Delayed Hypoxic Encephalopathy Induced by Overuse of Transdermal Fentanyl Patches

Bilateral Globus Pallidus Lesions and Delayed Hypoxic Encephalopathy Induced by Overuse of Transdermal Fentanyl Patches

Invasomes: An Artificial Vesicle Nanocarrier to Enhance Transdermal Drug Delivery

Abstract: The greatest and most noticeable organ in the body is the skin. The stratum corneum, or top layer of skin, acts as a vital barrier to prevent skin penetration for many drugs. To over-come this barrier, numerous nanocarrier frameworks have been developed, which are important for the functioning of active agents. Vascular systems known as invasomes contain low levels of ethanol as well as terpenes or terpene combinations, which have a higher skin penetration rate and function as potential carriers. Improved drug delivery via the skin using a carrier that can pene-trate these barriers presents a wide range of difficulties and possibilities for further study and the creation of new and better treatment options. The main objective of an invasome-based delivery system is to significantly improve patient compliance and therapeutic value, in addition to bol-stering the safety and efficacy of the drug. This article gives a summary of the synthesis process, invasome characterizations, penetration mechanisms, and applications. This review paper also in-cludes phospholipids and their classification. Phospholipids are present in the cell membrane and provide ceramide, a bioactive molecule that moisturizes skin and protects against environmental damage in transdermal drug delivery systems. Pharmaceutical studies demonstrate that many drug molecules have less solubility, stability, bioavailability, and penetrating power. Invasomes repre-sent a novel dosage form with promising properties for enhancing transdermal drug delivery.

Exploring Innovations in Transdermal Drug Delivery: Microneedle Technologies and the Latest in Patent Developments

Introduction/Objective: Microneedle technology has emerged as a promising approach for drug delivery, offering advantages such as improved patient compliance and enhanced therapeutic efficacy. This review aims to provide a comprehensive overview of recent advancements in microneedle- based drug delivery systems, emphasizing their potential to overcome limitations associated with traditional transdermal drug delivery methods. The objective is to synthesize existing knowledge, identify key trends, and highlight potential applications of microneedle technology in various medical fields. Methods: A systematic approach was employed to select and analyse relevant studies on microneedle technology. Databases were searched for peer-reviewed articles published and patents or patent applications worldwide within the last decade, focusing on innovations in microneedle materials, design, fabrication techniques, and applications. Studies were evaluated based on their methodology, outcomes, and relevance to current trends in drug delivery. Key data were extracted and synthesized to provide an integrated perspective on the state of microneedle technology. Results: The review highlights significant progress in microneedle technology; innovations in materials, fabrication techniques, and applications. Advancements include biodegradable microneedles, vaccine drug delivery systems, and integration with biosensors. Innovations led to improved drug bioavailability and reduced side effects. Challenges such as scalability, standardization, and regulatory considerations were also identified. Conclusion: In conclusion, microneedle technology has evolved significantly, offering a versatile platform for controlled drug delivery and various medical applications. The diversity in design and fabrication methods allows customization for specific therapeutic or diagnostic needs, with numerous patents filed for microneedle innovations, reflecting the intense research and development in this field.

Optimization, Formulation, and Ex vivo Evaluation of Solid Lipid Nanoparticles for Transdermal Delivery of Diltiazem Hydrochloride.

Cardiac arrhythmia, is a medical condition that reduces the heart's efficiency in pumping blood, and can be fatal, requires long-term management with conventional drugs, despite their limited efficacy. Diltiazem hydrochloride, chosen as a model drug, has a short biological half-life and extensive metabolism. Administering drug through skin is challenging, particularly due to the penetration via stratum corneum. However, solid lipid nanoparticles as a particulate carrier system can enhance its permeation and bioavailability. The study aimed to develop a matrix type transdermal patch with diltiazem hydrochloride encapsulated in solid lipid nanoparticles Methods: The study used the solvent diffusion technique to prepare SLNs by mixing the drug and solid lipid in an organic phase at 80°C, then slowly adding it to an aqueous phase with continuous stirring for 45 minutes. The resulting nanodispersion was freeze-dried and analyzed for morphological studies, encapsulation efficiency & drug content. A patch was formulated using solvent evaporation technique, incorporating HPMC E50 (2% w/v), propylene glycol, and ethanolic oleic acid (1.5% v/v). SLNs loaded with diltiazem hydrochloride taken equivalent to diltiazem hydrochloride dose in the transdermal patch. The patch was then evaluated for In vitro and skin permeation studies. The result showed a positive correlation between lipid concentration and particle size. Probe sonication and homogenization increased particle size, while stirring speed reduced it. SEM and TEM images confirmed spherical particles with a size of 488.1±4.01nm and an entrapment efficiency of 55.03±1.99%. Drug release studies demonstrated 70.7% drug release from lipid matrix over 24 hrs. The formulated patch with uniform SLN distribution, had a drug content 89.37 ± 0.04% with a surface pH of 6.1 ± 0.53, close to skin pH. The uniformity of content in 3x3 patch estimated to be 14.587 ± 1.404 mg, close to the theoretical content 16.318 ± 1.08 mg, confirmed homogenous distribution of diltiazem hydrochloride SLNs throughout the patch diameter. Cumulative amount released from patch formulation at pH 5.6 and pH 7.4 was 518.1414μg/cm2 and 404.4466 μg/cm2. Synergistic flux enhancement was observed with oleic acid propylene glycol blend. Ex vivo study of the patch showed steady-state flux of 6.9 μg/cm2/hr, permeability coefficient 0.00362 cm/hr, diffusion coefficient 0.000103 cm/hr, cumulative drug permeation (Dmax) 814.885 μg after 24 hrs, and followed a Higuchi-matrix release model. The developed patch possessed improved bioavailability with reduced dosing and enhanced patient compliance.

The Design Features, Quality by Design Approach, Characterization, Therapeutic Applications, and Clinical Considerations of Transdermal Drug Delivery Systems—A Comprehensive Review

Transdermal drug delivery systems (TDDSs) are designed to administer a consistent and effective dose of an active pharmaceutical ingredient (API) through the patient’s skin. These pharmaceutical preparations are self-contained, discrete dosage forms designed to be placed topically on intact skin to release the active component at a controlled rate by penetrating the skin barriers. The API provides the continuous and prolonged administration of a substance at a consistent rate. TDDSs, or transdermal drug delivery systems, have gained significant attention as a non-invasive method of administering APIs to vulnerable patient populations, such as pediatric and geriatric patients. This approach is considered easy to administer and helps overcome the bioavailability issues associated with conventional drug delivery, which can be hindered by poor absorption and metabolism. A TDDS has various advantages compared to conventional methods of drug administration. It is less intrusive, more patient-friendly, and can circumvent first pass metabolism, as well as the corrosive acidic environment of the stomach, that happens when drugs are taken orally. Various approaches have been developed to enhance the transdermal permeability of different medicinal compounds. Recent improvements in TDDSs have enabled the accurate administration of APIs to their target sites by enhancing their penetration through the stratum corneum (SC), hence boosting the bioavailability of drugs throughout the body. Popular physical penetration augmentation methods covered in this review article include thermophoresis, iontophoresis, magnetophoresis, sonophoresis, needle-free injections, and microneedles. This review seeks to provide a concise overview of several methods employed in the production of TDDSs, as well as their evaluation, therapeutic uses, clinical considerations, and the current advancements intended to enhance the transdermal administration of drugs. These advancements have resulted in the development of intelligent, biodegradable, and highly efficient TDDSs.

A fully nanofiber-based ultrathin electronic patch for self-powered and multifunctional on-skin applications

On-skin electronics that simultaneously ensure biocompatibility and stable electrical operation on soft tissue is still challenging. This study introduces a dual-layered and natural material based nanofiber platform designed for multifunctional on-skin operation (from energy harvesting to transdermal drug delivery). The ultrathin electronic patch consists of polyaniline (PANI)-coated cellulose nanofibers and silk fibroin nanofibers. The top PANI/cellulose nanofiber layer, exhibiting the resistivity of 0.315 Ω·m and over 90 % light absorbance in full visible range, functions as a flexible electrode. The silk nanofiber layer offers the skin-compatibility and strong adhesion to biological tissues, along with the capability of drug-loading. The nanofiber mesh structure withstands mechanical deformation, including compression, stretching, and bending, while its porous nature enhances breathability and hygiene. The fully nanofiber-based electronic patch platform is flexible, adheres well to the skin, and conforms to curved surfaces. By integrating the conductive properties of PANI with the biocompatibility of silk fibroin, this dual-layered membrane enhances the efficacy of transdermal drug delivery while offering multifunctional capabilities such as energy harvesting in a triboelectric nanogenerator (TENG), programmable drug delivery, and thermal therapy. This innovative approach paves the way for advanced biomedical applications by combining multiple functionalities in a single platform.

Revolutionizing Transdermal Patches: Navigating Clinical Challenges and Technological Progress

ransdermal patches, conceived to extend drug release, enhance bioavailability, and foster patient adherence, witnessed their inaugural approval by the USFDA in the 1980s. These patches, varying in size, constitute medicinal formulations with one or more active components that permeate the bloodstream through the skin. This review undertakes a comprehensive examination of recent strides in transdermal patch technology, encompassing critical facets such as their merits and demerits, advancements in microneedle technology, the evolution of transdermal patch generation, the integration of Artificial Intelligence, and the role of 3D printing technology. Additionally, the focus is placed on USFDA-approved patches. Various literature databases viz. Science Direct, PubMed, and Web of Sciences were explored for this research. The review furnished insights into the application of 3D printing technology in the fabrication of transdermal patches and disseminated information on USFDA-approved patches. The exploration delved into diverse strategies aimed at augmenting the efficiency of drug delivery and promoting patient compliance. Major transdermal products being marketed with details of their active substance have been discussed. Various applications of artificial intelligence in drug delivery have been summarized. It may be summarized that transdermal patch technology is not a thing of the past but a technology to stay and meet the demands of drug delivery in the present and future.

Recent Advancement of Novel Drug Delivery Systems for Topical Anaesthesia Formulations

Abstract: In recent years, there have been exciting developments in improving how we deliver anaesthesia through the skin. Nanotechnology is a key player, using tiny particles to encapsulate and transport anaesthetic agents, ensuring a controlled and steady release. This helps overcome challenges like inconsistent absorption and short-lasting effects seen with traditional methods. Transdermal patches are gaining attention too; they release drugs slowly and steadily, eliminating the need for frequent reapplication while maintaining a constant drug level at the application site. Smart polymers are bringing innovation by responding to specific triggers, enabling on-demand drug release. This allows for personalized anaesthesia based on individual patient needs. In recent years, there have been exciting developments in improving how we deliver anaesthesia through the skin. Nanotechnology is a key player, using tiny particles to encapsulate and transport anaesthesia agents, ensuring a controlled and steady release. This helps overcome challenges like inconsistent absorption and other short-lasting effects seen with traditional methods. Microemulsion systems, made of water, oil, surfactants, and co-surfactants, are another promising approach. They enhance drug solubility and availability, providing a stable environment for including anaesthesia agents. Transdermal patches are gaining attention too; they release drugs slowly and steadily, eliminating the need for frequent reapplication and maintaining a constant drug level at the application site. Smart polymers are bringing innovation by responding to specific triggers, enabling on-demand drug release. This allows for personalized anaesthesia based on individual patient needs. Together, these advancements mark a significant shift towards more effective, patient-friendly, and personalized topical anaesthesia delivery systems.

Simvastatin and Captopril Combined Transdermal Delivery System for Controlling Blood Pressure and Fat: Design, Characterization, and In Vivo Pharmacokinetic Evaluation

We developed a sustained-release transdermal drug delivery system (TDDS) containing simvastatin (SIM) and captopril (CAP) to treat hypertension and hyperlipidemia and overcome treatment drawbacks, including significant liver first-pass effects, low bioavailability, and the short half-life of SIM and CAP oral tablets. We used a transdermal diffusion meter to preselect the formula of the SIM-CAP TDDS. Based on in vitro permeation experiments, we optimized the formula of the SIM-CAP TDDS to include 24% SIM, 24% CAP, 34% polyvinyl alcohol (PVA), 16% oleic acid (OA)–azone, and 2% polyacrylic acid resin II. We evaluated the optimized SIM-CAP TDDS formula by its appearance, stability, stickiness, drug content, in vivo pharmacokinetics, and skin irritation tests. The results indicated that the patch had good stability and stickiness. The SIM and CAP contents were 5.02 ± 0.41 mg/cm2 in the 1 cm2 SIM-CAP TDDS. The pharmacokinetic results indicated that the system continuously released SIM and CAP for 24 h and significantly enhanced their bioavailability, with a higher area under the curve. The SIM-CAP TDDS exhibits a sustained-release effect with good characteristics and pharmacokinetics. And it is safe and has no irritating effects on the skin; therefore, it is an ideal formulation.

Assessment of basic pharmacokinetic parameters of dapagliflozin in TTS formulations in male minipigs

Given the extended time over which diabetes treatment is administered, the transdermal delivery system is anticipated to be a more suitable option for older individuals who may experience difficulty swallowing. The continuous delivery of dapagliflozin and more stable plasma levels are anticipated to reduce the incidence of side effects and the frequency of dosing. The objectives of the study were to determine the safety and plasma pharmacokinetics of dapagliflozin in male minipigs following application of the ointment and skin patch. In the initial phase of the study, the potential for transdermal permeation of dapagliflozin from ointment and transdermal patch to blood plasma of 15 male Göttingen minipigs was investigated. In the subsequent phase, the efficacy of utilising patches of varying strengths and sizes was assessed. The LC/MS method was employed to quantify the concentration of the active substance. The transportation of the studied API to the general circulation and accumulation in tissues were confirmed. The maximum drug concentration (122.99 ng/mL) in plasma was observed on the fourth day of application. The highest calculated Cmax was 131.91 ng/mL with a mean AUC0-last of 6620.7 ng h/mL. Following transdermal administration, dapagliflozin is excreted in the urine. The trend between urinary dapagliflozin 3-O-glucuronide levels and urinary glucose excretion was also observed. The transdermal patch has been demonstrated to be an effective drug delivery system for dapagliflozin.

Multilayer patch functionalized microfibrillated cellulosic paper sensor for sweat glucose monitoring.

Electrochemical analysis of glucose monitoring without painful blood collection provides a new noninvasive route for monitoring glucose levels. Thus, in this study, biobased cellulosic papers (methylated and phosphorylated one) based glucose monitoring sensor is developed. To achieve high hydrophilicity, microfibrillated cellulose (MFC) were functionalized using hexokinase mediated phosphorylation (-OH to -[Formula: see text]). The instinctive increased surface charge density from 36.2 ± 3.4 to 118.4 ± 1.2 µmol/g and decrease contact angle (45°-22°) confirms the increased hydrophilicity of paper. Furthermore, functionalized phos-MFC paper increase the capillary flow of sweat, required low quantity (1µl) of sweat for accurate analysis of glucose level. Additionally, chemically induced methyl groups (-CH3) make the sensor more barrier to other chemicals. In addition, a multilayer patch design combined with sensor miniaturization was used to lead to an increase in the efficiency of the sweat collection and sensing processes. Besides, this paper sensor integrated with artificial transdermal drug delivery unit (agarose gel as skin) for monitoring glucose levels in sweat. The patch monitoring system increase the accuracy of sensing with fluctuation in sweat vol. (1-4µl), temperature (20-70 °C), and pH (4.0-7.0). In addition, temperature dependency artificial transdermal delivery (within agarose gel) of drug metformin agrees the measurement accuracy of sensor, called "switch system" without any error. As a result, the reported MFC paper based multi-patch disposable sensing system provides a novel closed-loop solution for the noninvasive sweat-based management of diabetes mellitus.

Skin adhesion of a newly developed, bioequivalent rotigotine patch formulation in comparison to the originator product: Results of a multi-center, randomized, crossover trial in patients with Parkinson's disease.

To demonstrate adequate skin adhesion of a new once-daily rotigotine transdermal patch (ROT-TDS) compared to the originator product (reference) in patients with Parkinson's disease (PD). Pharmacokinetic bioequivalence (PK BE) was assessed with the 4 mg/24h patches in healthy adults in a single-/multiple-dose, crossover trial. The trial investigating skin adhesion in PD patients (stable dose ≥ 8 mg/day rotigotine) was performed with the 8 mg/24h patches as a multiple-dose, crossover trial (4 alternating once-daily patch applications). Skin status (seborrhea, sweating) was characterized at screening. Adhesion was assessed 5 minutes after application and 5 minutes before removal of each patch. Systemic safety and skin irritation/sensitization were monitored. ROT-TDS was bioequivalent to the reference product in the PK BE trial in 48 randomized healthy subjects. In the skin adhesion trial in 43 randomized PD patients, the cumulative mean percentage of adhesion (90% CI) at the end-of-dosing interval was 92.948% (90.156 - 95.740%) for ROT-TDS and 90.471% (87.574 - 93.367%) for the reference. For ROT-TDS, 80.23% of patches were ≥ 90% adhered at the end-of-dosing interval, while this was the case for 67.44% of the reference patches. Safety and skin tolerability of both products were comparable; the most frequent treatment-related adverse event was application-site pruritus for both treatments at comparable extent. ROT-TDS - with shown BE to the originator reference product - displayed similar safety and local tolerability as the reference product in patients with PD. The results show a trend to improved skin adhesion of the new patch compared to the reference in the target population.

Reusable and non-invasive TiO2-based photodynamic transdermal patch (RPT) for treating MDR-negative bacteria strain and promote wound healing through a synergistic approach of ROS-induced RNS

Wound healing is delayed due to the infection and biofilm formation of antibiotic-resistant species of gram-negative bacteria especially Pseudomonas aeruginosa and Escherichia coli. Antibacterial photodynamic therapy provides an efficient therapeutic strategy for overcoming drug resistance by producing reactive oxygen species (ROS) and reactive nitrogen species (RNS). Here, we have designed a low-cost light emitting diode (LED) based reusable and non-invasive titanium dioxide nanoparticles patch which is sandwiched between the thin polymer layers. The light-induced pore formation in the polymeric film due to the free radical, in turn, passes through the system and kills the bacteria rather than nanoparticles entering the system resulting in the reusability nature of the patch. The patch's in vitro antibacterial and antibiofilm activity and their mechanism (synergic ROS-induced RNS) were studied. In addition, the reusable antibacterial properties, biocompatibility and wound-healing properties of the patch were also successfully elucidated.

7472 Estrogen Monotherapy for Testosterone Suppression in Gender Diverse Patients

Abstract Disclosure: C. Zhou: None. Q. Jones: None. S. Kokosa: None. C. Kelley: None. Background: For gender diverse individuals assigned male at birth (AMAB), gender-affirming hormone therapy consists of estrogen in combination with anti-androgen medications. Exogenous estrogen use results in the development of feminine secondary sex characteristics while indirectly decreasing testosterone. Anti-androgens such as spironolactone, leuprolide, finasteride, or dutasteride work to further suppress testosterone with successful suppression levels <50ng/dL. However, use of these agents increases the risk of adverse side effects like hyperkalemia, polyuria, and orthostatic hypotension, thus is not suitable for everyone. Anecdotally, estrogen monotherapy has been sufficient in reducing testosterone levels to goal in some patients, however at this time there are no known studies which evaluate estrogen monotherapy and suppression of testosterone. The purpose of this study is to retrospectively review estrogen formulations and dosages in patients who have adequate testosterone suppression in the absence of anti-androgen medications. Methods: The study was a retrospective chart review of adult patients ages 18- 84.99 AMAB receiving gender-affirming estrogen between 9/2020 and 12/2023 seen within an endocrine clinic at a single academic institution. Patients younger than 18, those receiving anti-androgen medications, and those with history of orchiectomy were excluded from the study. Charts were reviewed for estrogen formulations and dosages and total serum testosterone levels. Retrospective chart review will continue with additional data expected in 2024. Results: Ten patients between the ages of 19-81 met the inclusion criteria. Of these, 7 patients identified as transfeminine and 3 identified as nonbinary. The 3 patients who identified as non-binary were not included in analysis as their treatment goals may not align with full feminization or testosterone suppression (total serum testosterone <50ng/dL). Testosterone suppression from estrogen monotherapy was achieved in 100% (n=7) of the transfeminine patients when serum estradiol was >100pg/mL. In those who achieved testosterone suppression, 5 used injectable formulations (estradiol valerate 4-6mg weekly) and 2 used transdermal patches (range of estradiol from 0.2mg twice weekly to 0.3mg three times weekly). Conclusions: Estrogen monotherapy may be effective in suppressing testosterone without the need for anti-androgen medications. So far, this was noted most commonly with use of injectable estrogen formulations. A limitation of the study is the small sample size, however ongoing data collection is anticipated. Additional research evaluating estrogen monotherapy and testosterone suppression is needed and has potentially significant implications for simplified treatment protocols for transfeminine patients. Presentation: 6/2/2024

7472 Estrogen Monotherapy for Testosterone Suppression in Gender Diverse Patients

Abstract Disclosure: C. Zhou: None. Q. Jones: None. S. Kokosa: None. C. Kelley: None. Background: For gender diverse individuals assigned male at birth (AMAB), gender-affirming hormone therapy consists of estrogen in combination with anti-androgen medications. Exogenous estrogen use results in the development of feminine secondary sex characteristics while indirectly decreasing testosterone. Anti-androgens such as spironolactone, leuprolide, finasteride, or dutasteride work to further suppress testosterone with successful suppression levels <50ng/dL. However, use of these agents increases the risk of adverse side effects like hyperkalemia, polyuria, and orthostatic hypotension, thus is not suitable for everyone. Anecdotally, estrogen monotherapy has been sufficient in reducing testosterone levels to goal in some patients, however at this time there are no known studies which evaluate estrogen monotherapy and suppression of testosterone. The purpose of this study is to retrospectively review estrogen formulations and dosages in patients who have adequate testosterone suppression in the absence of anti-androgen medications. Methods: The study was a retrospective chart review of adult patients ages 18- 84.99 AMAB receiving gender-affirming estrogen between 9/2020 and 12/2023 seen within an endocrine clinic at a single academic institution. Patients younger than 18, those receiving anti-androgen medications, and those with history of orchiectomy were excluded from the study. Charts were reviewed for estrogen formulations and dosages and total serum testosterone levels. Retrospective chart review will continue with additional data expected in 2024. Results: Ten patients between the ages of 19-81 met the inclusion criteria. Of these, 7 patients identified as transfeminine and 3 identified as nonbinary. The 3 patients who identified as non-binary were not included in analysis as their treatment goals may not align with full feminization or testosterone suppression (total serum testosterone <50ng/dL). Testosterone suppression from estrogen monotherapy was achieved in 100% (n=7) of the transfeminine patients when serum estradiol was >100pg/mL. In those who achieved testosterone suppression, 5 used injectable formulations (estradiol valerate 4-6mg weekly) and 2 used transdermal patches (range of estradiol from 0.2mg twice weekly to 0.3mg three times weekly). Conclusions: Estrogen monotherapy may be effective in suppressing testosterone without the need for anti-androgen medications. So far, this was noted most commonly with use of injectable estrogen formulations. A limitation of the study is the small sample size, however ongoing data collection is anticipated. Additional research evaluating estrogen monotherapy and testosterone suppression is needed and has potentially significant implications for simplified treatment protocols for transfeminine patients. Presentation: 6/2/2024

Formulation, Development and Evaluation of Herbal Transdermal Patches from Leaf Extract of Thespesia Populnea Linn. for Anti- Inflammatory Activity

Formulation, Development and Evaluation of Herbal Transdermal Patches from Leaf Extract of Thespesia Populnea Linn. for Anti- Inflammatory Activity