Percorrer por autor "Brown, Marc"
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- Drilling down the bioequivalence assessment of topical antifungal products : microstructure and releasePublication . Miranda, Margarida; Cardoso, Catarina; Pais, Alberto A.C.C.; Brown, Marc; Vitorino, CarlaIn recent years, the regulatory mechanisms for topical generic product bioequivalence (BE) assessment have been subjected to noteworthy changes, with the FDA issuing product specific guidances, and the EMA adopting a more universal approach with the quality and equivalence of topical products draft guideline. The agencies advise on a modular strategy for BE documentation. Nevertheless, their scope, data analysis and criteria are rather distinct. This study aims to tackle bioequivalence assessment issues of complex topical formulations starting by statistical implications of the EMA/FDA approaches concerning the documentation of qualitative (Q1), quantitative (Q2), microstructure (Q3) and performance requirements (Q4). As a model drug product, a bifonazole 10 mg/g cream formulation was selected. For this specific formulation, the commercially available Reference Product (RP) was compared with two comparator products, also commercially available, referred to as comparator product A (CPA) and comparator product B (CPB). The former displays Q1 sameness and Q2 differences, whilst CPB is categorically considered as Q1/Q2 different. Furthermore, intending to establish a regulatory rationale for the submission of a generic product according to the updated regulatory requirements, the RP was likewise compared with a Test Product (TP). This formulation was designed to display equal Q1/Q2 profile to that of the RP. Validated rheology and in vitro release test (IVRT) methods were used to infer on Q3/Q4 characteristics. During rheology studies, statistically significant RP batch to batch differences were observed. Therefore, in an attempt to surpass this heterogeneity, the initial pool of RP batches was expanded to include RP product batches at different lifecycle stages. Despite this effort, it was not possible to classify the RP/TP, RP/CPA or RP/CPB as rheologically equivalent products. Nevertheless, product performance results, retrieved from IVRT, were able to sustain equivalence between the RP and the formulations exhibiting Q1 sameness (TP and CPA). It should however be mentioned, that for some RP batch combinations, the IVRT results failed to demonstrate equivalence according to the EMA requirements. Enlarging the RP batch pool was then a critical step in further understanding an optimum statistical approach for establishing equivalence in product performance. This study highlights the need to that a ‘one-fits-all approach’ may not be an optimum path way for establishing the regulatory strategy and requirements to support generic product bioequivalence.
- In vitro studies into establishing therapeutic bioequivalence of complex topical products : weight of evidencePublication . Miranda, Margarida; Volmer, Zoe; Cornick, Alicia; Goody, Aidan; Cardoso, Catarina; Pais, Alberto A.C.C.; Brown, Marc; Vitorino, CarlaOver the past decade, topically applied drug products have experienced extraordinary price increases, due to the shortage of multisource generic drug products. This occurrence is mainly related to the underlying challenges evolved in topical bioequivalence documentation. Although there has been continuing regulatory efforts to present surrogate in vitro methods to clinical endpoint studies, there is still a continued need for cost- and time-efficient alternatives that account for product specificities. Hence, this work intended to expose bioequivalence assessment issues for complex topical formulations, and more specifically those related with product efficacy guidance. As a model drug and product, a bifonazole 10 mg/g cream formulation was selected and two different batches of the commercially available Reference Product (RP) were used: RP1 that displayed lower viscosity and RP4 which presented high, but not the highest, viscosity. In vitro human skin permeation testing (IVPT) was carried out and the results were evaluated by means of the traditional bioequivalence assessment approach proposed by the EMA, as well as by the Scaled Average Bioequivalence assessment approach proposed by the FDA. Based on previous experience, there was an expectation of a high level of variability in the results, thus alternative methods to evaluate local drug skin availability were developed. More specifically, an infected skin disease model, where ex vivo human skin was infected and ATP levels were used as a biological marker for monitoring antifungal activity after product application. The results showed that permeation equivalence could not be supported between the different RP batches. In contrast, this statistical difference between the formulation batches was not indicated in the disease model. Nevertheless, in pivotal IVPT studies, the lowest permeant formulation (RP4) evidenced a higher antifungal in vitro activity as reported by the lower levels of ATP. A critical appraisal of the results is likewise presented, focusing on an outlook of the real applicability of the regulatory guidances on this subject.
- Nebulised heparin as a treatment for lung diseases : formulation challenges and pulmonary drug delivery strategiesPublication . Miranda, Margarida; Brown, Marc; Haren, Frank M. P. van; Brown, Beth; Page, Clive P.The COVID-19 pandemic further emphasized the global demand for heparin and its expanding clinical relevance, indicating that even one of the oldest drugs in medicine continues to reveal new therapeutic horizons. Traditionally recognized for its anticoagulant and antithrombotic activities, heparin is increasingly being explored for its versatile therapeutic potential in the treatment of a range of pulmonary diseases, including respiratory infections (e.g. COVID-19), Acute Respiratory Distress Syndrome (ARDS), asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis. In all of these diseases, inhaled unfractionated heparin (UFH) therapy has been investigated in a number of clinical trials that have demonstrated promise for this drug when administered directly to the lungs. However, using heparin by this “off label” route of administration, poses a number of technical challenges: the physicochemical properties of heparin at therapeutic doses often results in highly viscous formulations, causing device blockage and drug sorption during nebulization. These limitations underscore the need for innovative formulation strategies to improve aerosol flow, reduce dosing inefficiencies, and enable reliable pulmonary administration. Advancing heparin formulations for delivery to the lung could therefore unlock significant benefits for a wide spectrum of respiratory disorders, marking a new chapter in the long medical history of this drug as discussed below.