Statistical Considerations in Assessing In Vivo Adhesion with Transdermal and Topical Delivery Systems for New Drug Applications.

Proper adhesion plays a critical role in maintaining a consistent, efficacious, and safe drug delivery profile for transdermal and topical delivery systems (TDS). As such, in vivo skin adhesion studies are recommended by regulatory agencies to support the approval of TDS in new drug applications (NDAs). A draft guidance for industry by the US Food and Drug Administration outlines a non-inferiority comparison between a test product and its reference product for generic TDS in abbreviated new drug applications (ANDAs). However, the statistical method is not applicable for evaluating adhesion of TDS for NDAs, because no reference product exists. In this article, we explore an alternative primary endpoint and a one-sided binomial test to evaluate in vivo adhesion of TDS in NDAs. Statistical considerations related to the proposed approach are discussed. To understand its potential use, the proposed approach is applied to data sets of in vivo adhesion studies from selected NDAs and ANDAs.

Comparison of a transdermal contraceptive patch with a newly sourced adhesive component versus EVRA patch: A double-blind, randomized, bioequivalence and adhesion study in healthy women.

OBJECTIVE: To evaluate the bioequivalence of norelgestromin and ethinyl estradiol (NGMN-EE) and adhesion of a transdermal contraceptive patch containing a newly sourced adhesive component (test) compared with the marketed (reference) patch. STUDY DESIGN: In this randomized, double-blind, 2-way crossover study, healthy women received single 7-day application of both test and reference patches. Treatment phase included two treatment periods of 11 days each separated by a 21-day washout period starting from day of patch removal (day 8) of treatment period 1. Assessments included NGMN and EE pharmacokinetics (PK), adhesion using European Medicines Agency (EMA) 5-point scale, irritation potential and application-site reactions, and safety. Patches were bioequivalent if 90% CIs of ratios of means of test/reference for AUC168h, AUCinf, and Css fell within 80-125%. Patch adhesion was comparable if ratios of mean cumulative adhesion percentage values of test/reference were ≥90.0%. RESULTS: Seventy women were randomized; 57 completed both treatments with ≥80% adhesion (score 0-1). Bioequivalence of test and reference patches was demonstrated as 90% CI of ratio of geometric means for AUC168h, AUCinf, and Css for NGMN and EE fell within 80-125%. Both patches had similar adhesion properties (geometric mean ratio was 100.3% [90% CI, 93.2-107.9]). Similar rates of mild-to-moderate itching (11% vs 10%) and erythema events (79% vs 74%) were reported for test and reference patches, respectively, on day 8. CONCLUSIONS: The test patch with the newly sourced adhesive component is bioequivalent to the currently marketed NGMN-EE transdermal patch and has similar adhesion and irritation potential. IMPLICATIONS STATEMENT: The norelgestromin and ethinyl estradiol transdermal patch containing a newly sourced adhesive component is bioequivalent to the currently marketed patch for both active moieties. Both patches had similar adhesion, irritation potential, and safety profiles.

Enhanced anti-tumor immunotherapy by dissolving microneedle patch loaded ovalbumin.

The skin is a very suitable organ for the induction of immune responses to vaccine antigens. Antigen delivery systems to the skin by needle and syringe directly deposit the antigen into the epidermal-dermal compartment, one of the most immunocompetent sites due to the presence of professional antigen-presenting cells aimed at the induction of antigen-specific T cells. In this study, we analyzed the amount of ovalbumin as an antigen delivered to the skin by a microneedle. When ovalbumin protein as an antigen was delivered to the skin of mice using a dissolving microneedle, it induced an immune response through the enhanced proliferation and cytokines production by the splenocytes and lymph nodes. Also, it effectively increased the ovalbumin-specific CD8+ T cell and CD4+ T cell population and induced an ovalbumin-specific CTL response against the graft of ovalbumin-expressing EG7 tumor cells in the immunized mice. Also, we identified the inhibition of tumor growth and prevention of tumor formation in the context of the therapeutic and prophylactic vaccine, respectively through EG-7 tumor mouse model. Finally, these data show the potential of patches as attractive antigen delivery vehicles.

Generic patches containing fentanyl: In vitro equivalence and abuse deterrent evaluation according to EMA and FDA guidelines.

The aim of this work was to characterize in vitro and ex vivo the performances of Durogesic and of two bioequivalent generic products, by evaluating: (a) fentanyl release; (b) fentanyl permeation across porcine skin and (c) fentanyl ease of extraction. Additional characteristics studied are the effect of temperature and skin integrity, applied individually or combined, to check a possible synergism. The two generic patches resulted equivalent to the originator according to the new Guideline. Nevertheless, the same data reported in a different way, i.e. considering the total amount of drug permeated from the whole patch over the application time, highlight differences among the patches. The additional tests performed showed that skin integrity does not represent a barrier for fentanyl permeation across the skin, regardless of the type and complexity of the patch. The effect of temperature resulted critical for two out of three patches, probably due to the different composition and to the different structure. The combination of skin damage and elevated temperature did not produce a synergistic effect. Fentanyl extraction was different for the different products and variable according to the conditions used. The results reported in the present work underline the influence of patch composition and complexity on fentanyl extraction, release and skin permeation, in particular in conditions that can be critical, such as elevated temperature. In particular, the effect of critical variables, such as skin integrity and temperature, should be addressed to in the development of a new or new generic patch and new discriminant tests should be developed.

Fabrication, Physicochemical Characterization, and Performance Evaluation of Biodegradable Polymeric Microneedle Patch System for Enhanced Transcutaneous Flux of High Molecular Weight Therapeutics.

A revolutionary paradigm shift is being observed currently, towards the use of therapeutic biologics for disease management. The present research was focused on designing an efficient dosage form for transdermal delivery of α-choriogonadotropin (high molecular weight biologic), through biodegradable polymeric microneedles. Polyvinylpyrrolidone-based biodegradable microneedle arrays loaded with high molecular weight polypeptide, α-choriogonadotropin, were fabricated for its systemic delivery via transdermal route. Varied process and formulation parameters were optimized for fabricating microneedle array, which in turn was expected to temporally rupture the stratum corneum layer of the skin, acting as a major barrier to drug delivery through transdermal route. The developed polymeric microneedles were optimized on the basis of quality attributes like mechanical strength, axial strength, insertion ratio, and insertion force analysis. The optimized polymeric microneedle arrays were characterized for in vitro drug release studies, ex vivo drug permeation studies, skin resealing studies, and in vivo pharmacokinetic studies. Results depicted that fabricated polymeric microneedle arrays with mechanical strength of above 5 N and good insertion ratio exhibited similar systemic bioavailability of α-choriogonadotropin in comparison to marketed subcutaneous injection formulation of α-choriogonadotropin. Thus, it was ultimately concluded that the designed drug delivery system can serve as an efficient tool for systemic delivery of therapeutic biologics, with an added benefit of overcoming the limitations of parenteral delivery, achieving better patient acceptability and compliance.

Evaluation of rotigotine transdermal patch for the treatment of depressive symptoms in patients with Parkinson's disease.

OBJECTIVE: To evaluate the dopamine receptor agonist, rotigotine, for improving depressive symptoms in patients with Parkinson's disease (PD). METHODS: Patients were randomized 1:1 to rotigotine or placebo, titrated for ≤7 weeks, and maintained at optimal/maximum dose for 8-weeks. Primary efficacy variable: 17- item Hamilton Depression Rating Scale (HAM-D 17) total score change from baseline to end-of-maintenance. Secondary variables: changes in Beck Depression Inventory-II, Unified Parkinson's Disease Rating Scale (UPDRS) II (activities of daily living [ADL]) and III (motor) subscores, UPDRS II+III total, patient-rated Apathy Scale (AS), and Snaith-Hamilton Pleasure Scale. RESULTS: Of 380 patients randomized, 149/184 (81.0%) rotigotine-treated and 164/196 (83.7%) placebo-treated patients completed the study. PATIENTS: mean (±SD) age 65.2 (±8.5) years; time since PD-diagnosis 2.74 (±3.08) years; 42.6% male. The treatment difference (LS mean [95% CI]) in change from baseline HAM-D 17 was -1.12 (-2.56, 0.33; p = 0.1286). UPDRS II, III, II+III and AS scores improved numerically with rotigotine versus placebo. Common adverse events with higher incidence with rotigotine: nausea, application/instillation site reactions, vomiting, and pruritus. Forty-one (10.8%) patients discontinued owing to adverse events (25 rotigotine/16 placebo). CONCLUSIONS: No statistically significant improvement in depressive symptoms were observed with rotigotine versus placebo. ADL, motor function, and patient-rated apathy improved numerically. ClinicalTrials.gov: NCT01523301.

Formulation and evaluation of anti-rheumatic dexibuprofen transdermal patches: a quality-by-design approach.

Dexibuprofen (DXIBN) transdermal patches were formulated using various concentrations of selected polymeric excipients (matrix material; ethyl cellulose and polyvinylpyrrolidone, plasticizer (di-N-butyl phthalate), and a conventional permeation enhancer (almond oil)). Initial patch formulations were evaluated for their physiochemical properties (thickness, moisture uptake, final moisture content, and DXIBN content). Also, impact of patch components on resulting tensile strength and in vitro permeation were used to predict an optimal patch formulation using a quality-by-design (QbD) approach, which was subsequently evaluated and further compared with a commercial oral tablet dosage form for in vitro and in vivo release (rabbit model). Initially formulated patches demonstrated uniform thickness (0.44 ± 0.02 cm), relatively low moisture uptake (7.87 ± 1.11 w/w %), and highly acceptable drug loading values (100.0 ± 0.026%). The tensile strength of patches increased significantly with matrix polymer concentration and to a lesser degree with increase in plasticizer and permeation enhancer content, although these affected the permeation of DXIBN. Predicted properties (tensile strength and DXIBN steady-state flux) for the QbD-optimized formulation were in close agreement to experimental results. The QbD optimal patch formulation behavior differed significantly from the commercial tablet formulation in vivo. Such model-based predictions (QbD approach) will reduce cost and time in formulation development sciences.

Microneedle patches for vaccination in developing countries.

Millions of people die of infectious diseases each year, mostly in developing countries, which could largely be prevented by the use of vaccines. While immunization rates have risen since the introduction of the Expanded Program on Immunization (EPI), there remain major challenges to more effective vaccination in developing countries. As a possible solution, microneedle patches containing an array of micron-sized needles on an adhesive backing have been developed to be used for vaccine delivery to the skin. These microneedle patches can be easily and painlessly applied by pressing against the skin and, in some designs, do not leave behind sharps waste. The patches are single-dose, do not require reconstitution, are easy to administer, have reduced size to simplify storage, transportation and waste disposal, and offer the possibility of improved vaccine immunogenicity, dose sparing and thermostability. This review summarizes vaccination challenges in developing countries and discusses advantages that microneedle patches offer for vaccination to address these challenges. We conclude that microneedle patches offer a powerful new technology that can enable more effective vaccination in developing countries.

On the characterization of medicated plasters containing NSAIDs according to novel indications of USP and EMA: adhesive property and in vitro skin permeation studies.

Abstract This work aims to establish if the assays recently introduced by EMA (Guideline on quality of transdermal patches-draft) and USP (Specific tests for transdermal delivery systems) to characterize transdermal patches (TP) are suitable for medicated plasters (MP). Six approved MP differing for type and characteristics of adhesive and backing layer were selected and characterized in terms of adhesive performances by tack, shear adhesion, peel adhesion and release liner removal tests and in vitro skin permeation. As far as the adhesive properties are concerned, the major drawback is related to the measurement of shear adhesion of MP made of an adhesive hydrogel and/or a stretchable backing layer which could be solved by reducing the applied load. Moreover, a concern on the mass balance prescribed by EMA draft for the acceptance of the results of in vitro penetration studies remains. Indeed, the acceptance range is narrow than that reported by Ph. Eur. requirement for uniformity of content. Finally, a novel calculation for evaluating the in vitro efficiency of MP in releasing the loaded drug through the skin was proposed.

Novel cosmetic patches for wrinkle improvement: retinyl retinoate- and ascorbic acid-loaded dissolving microneedles.

OBJECTIVE: To evaluate wrinkle improvement and safety of a novel cosmetic dissolving microneedle patches loaded with two active compounds with different hydrophilicities, namely ascorbic acid and retinyl retinoate. METHODS: Clinical studies were performed on 24 Korean women for 12 weeks. Patients in group A were treated with retinyl retinoate-loaded dissolving microneedle patches on the left eye crow's feet area, and patients in group B were treated with ascorbic acidloaded patches on the right eye crow's feet area twice daily. Wrinkle improvement was evaluated by skin Visiometer SV 600. RESULTS: Both the retinyl retinoate- and ascorbic acid-loaded dissolving microneedle patches demonstrated statistically significant differences in all Visiometer R-values (P < 0.05). In particular, highly significant differences were shown at R1 (skin roughness) and R5 (arithmetic average roughness) (P < 0.001). Also, there were no side effects such as allergies or irritant contact dermatitis. CONCLUSION: Retinyl retinoate and ascorbic acid were successfully loaded into dissolving microneedles and used to produce novel cosmetic patches. These novel patches can be used efficiently in cosmetics given their patient usability, safety and effectiveness in wrinkle improvement.

Critical attributes of transdermal drug delivery system (TDDS)--a generic product development review.

Bioequivalence testing of transdermal drug delivery systems (TDDS) has always been a subject of high concern for generic companies due to the formulation complexity and the fact that they are subtle to even minor manufacturing differences and hence should be clearly qualified in terms of quality, safety and efficacy. In recent times bioequivalence testing of transdermal patches has gained a global attention and many regulatory authorities worldwide have issued recommendations to set specific framework for demonstrating equivalence between two products. These current regulatory procedures demand a complete characterization of the generic formulation in terms of its physicochemical sameness, pharmacokinetics disposition, residual content and/or skin irritation/sensitization testing with respect to the reference formulation. This paper intends to highlight critical in vitro tests in assessing the therapeutic equivalence of products and also outlines their valuable applications in generic product success. Understanding these critical in vitro parameters can probably help to decode the complex bioequivalence outcomes, directing the generic companies to optimize the formulation design in reduced time intervals. It is difficult to summarize a common platform which covers all possible transdermal products; hence few case studies based on this approach has been presented in this review.

Capsaicina al 8 por ciento para controlar el dolor neuropático periférico: una estrategia basada en casos clínicos / No disponible

La reunión multidisciplinar organizada por Astellas tuvo lugar en Milán el 28 de agosto de 2012. Alrededor de 150 médicos invitados, especializados en el dolor, procedentes de toda Europa y con conocimientos o experiencia en el uso de los parches de capsaicina al 8 % para tratar el dolor neuropático (DN) periférico, asistieron a la reunión para escuchar la presentación de distintos casos clínicos tratados con el parche de capsaicina al 8%, por parte de un grupo de ponentes europeos expertos en la clínica del dolor. El objetivo de la reunión era compartir experiencia clínica real sobre el uso del parche de capsaicina al 8% para controlar el DN siguiendo un formato interactivo y dando a los asistentes la oportunidad de intercambiar experiencia práctica directa con el uso de este medicamento. La reunión estuvo presidida por el Dr. Arun Bhaskar del Reino Unido. Este inauguró la reunión dando la bienvenida a los delegados, presentando a los ponentes, resumiendo los objetivos de la reunión y realizando una demostración del ThoughtSort, el software que por grupos a través de un iPad, hizo posible que todos los participantes de la sesión pudiesen interactuar. Los detalles de los casos clínicos que se presentaron en la reunión y que se resumen en este artículo responden a las opiniones personales de los ponentes (AU)

The Astellas peer-to-peer meeting took place in Milan on the evening of Tuesday 28 August, 18:00-20:00. Approximately 150 invited pain physicians from across Europe, all with some knowledge or experience of using the high-dose capsaicin patch to treat peripheral neuropathic pain (NP), attended the meeting to hear an expert European faculty of practising physicians present different case studies involving treatment with high-dose capsaicin. The objective of the meeting was to share real-world experience in the use of high-dose capsaicin for the management of NP in an interactive format to provide delegates with the opportunity to liaise with physicians who have direct, handson experience of high-dose capsaicin. Interactivity was a key component of the meeting and iPad technology was utilised to encourage discussions between the faculty and the delegates. The ThoughtSort application enabled both the faculty to ask delegates questions related to their case studies and the delegates to ask the faculty questions throughout their presentations. The meeting was chaired by Dr Arun Bhaskar from the UK. He opened the meeting by welcoming the delegates, introducing the faculty, outlining the objectives of the meeting and performing a demonstration of ThoughtSort. The delegates had to work in groups to answer questions via ThoughtSort, using one iPad between four and five delegates. Details of the case studies that were presented at the meeting and summarised within this report are the personal opinions of the faculty members (AU)