Topical ophthalmic antimicrobials: unfulfilled demands and possibility of new investments in Brazil and in the United States

In general, topical ophthalmic drug products, especially those used for treating infections, present low effectiveness because of various reasons, from unfavorable drug physicochemical properties to physiological protective mechanisms of the eye. The fact is such group of products holds room for improvement, which could mean the development of better drugs or dosage forms. To achieve this, the knowledge of market composition is essential. The present work studied and compared the antimicrobial ophthalmic markets of Brazil and of the United States (US). Official databank of Brazilian Health Regulatory Agency and of US Food and Drug Administration were assessed for registered antimicrobial topical ophthalmic drug products. Brazilian market has registered greater number of drug products (119) than the US (94), but the latter involves more variety of substances and dosage forms. In both countries, non-innovative products registered as solutions of antibacterials, especially fluoroquinolones and aminoglycosides lead the market. Despite the clinical demand, the US has only one group of antimycotics (polyenes) registered, while in Brazil, there is not any ophthalmic antimycotic product marketed. This study evidences there is not only space for development of newer drugs and formulations but also a demand for already existing technologies and products in both countries

Principais razões não técnicas para o indeferimento de registro de medicamentos em 2015

The registration of pharmaceutical drug products involves reviewing company’s administrative aspects as well as technical-scientific aspects related to efficacy, safety and quality. This study evaluated the main administrative reasons for registration refusals of new, generic and similar (branded generic) pharmaceutical drug products in Brazil. Actual submission procedure and process instruction is presented in detail. The aim is to contribute for the improvement of novel applications, reducing non-technical refusals. A retrospective search of registration refusals in 2015 published by the Brazilian Government Official Gazette using Anvisa database, called Datavisa, was performed. The main reasons for non-technical registration refusals of generic and similar pharmaceutical drug products were deadline non-compliance (61.7%), preliminary review (19.8%) and insufficient documentation to permit a substantial full review (18.5%). Disclosure of administrative reasons behind failed applications is a step forward on regulatory transparency, and on internal and external orientation about regulatory mechanisms.O registro de medicamentos contempla a avaliação do cumprimento do caráter administrativo da empresa requerente do registro e o caráter técnico-científico relacionado à eficácia, à segurança e à qualidade do medicamento. Esse trabalho buscou identificar os principais motivos administrativos de indeferimento de registro de medicamentos novos, genéricos e similares no Brasil, além de detalhar o procedimento atual de submissão e instrução de processos de registro. Espera-se que, a partir desta análise, futuros peticionamentos possam ser aprimorados e indeferimentos por tais razões, reduzidos. Para isso, foi realizado levantamento das normas vigentes para o detalhamento do processo de submissão de registro e uma análise retrospectiva dos indeferimentos publicados no Diário Oficial da União através do banco de dados da Agência Nacional de Vigilância Sanitária, Datavisa, do ano de 2015. As principais razões de indeferimento por motivos administrativos foram levantadas nos pareceres de indeferimento e constituem o não cumprimento de prazos (61,7%), a avaliação preliminar de processo (19,8%) e a documentação insuficiente para análise técnica (18,5%). A divulgação de tais razões contribui para a transparência do processo regulatório, orientação interna e externa quanto à aplicabilidade dos atos normativos

Liquid crystalline systems containing Vitamin E TPGS for the controlled transdermal nicotine delivery

Transdermal nicotine patches have been used in smoking cessation therapy, suggested for the treatment of skin disorders with eosinophilic infiltration and have been found to improve attention performance in patients with Alzheimer's disease and age-associated memory impairment. However, skin irritation with extended patch use is still a problem. The aim of this work was to develop a simple to prepare liquid crystalline system containing vitamin E TPGS that would be able to control nicotine delivery and reduce irritation and sensitization problems. The liquid crystalline phases were macroscopically characterized by visual analysis and examined microscopically under a polarized light microscope. Topical and transdermal delivery of nicotine were investigated in vitro using porcine ear skin mounted on a Franz diffusion cell. Nicotine skin permeation from the developed cubic phase followed zero-order kinetics (r = 0.993) and was significantly enhanced after 12 h when compared to the control formulation (nicotine solution) (p < 0.05) (138.86 ± 20.44 and 64.91 ± 4.06 μg/cm2, respectively). Cubic phase was also able to target viable skin layers in comparison to control solution (8.18 ± 1.89 and 2.63 ± 2.51 μg/cm2, respectively). Further studies to evaluate skin sensitization and irritation are now necessary.Adesivos transdérmicos de nicotina são utilizados para cessação de fumar, tratamento de problemas de pele com infiltração de eosinófilos e para melhorar a atenção em pacientes com doença de Alzheimer e enfraquecimento da memória associada à idade. No entanto, a irritação da pele com o uso prolongado dos adesivos ainda é um problema. O objetivo deste trabalho foi desenvolver sistema líquido cristalino (SLC) de preparo simples contendo vitamina E TPGS capaz de controlar a liberação de nicotina e reduzir os problemas de irritação cutânea. Os SLCs foram caracterizados por análise visual e microscopia de luz polarizada. As administrações tópica e transdérmica de nicotina foram investigadas in vitro utilizando pele de orelha de porco em célula de difusão de Franz. A permeação da nicotina veiculada pela fase cúbica desenvolvida seguiu cinética de ordem zero (r = 0,993) e foi significativamente maior do que o controle (solução de nicotina) após 12 h (p < 0,05) (138,86 ± 20,44 e 64,91 ± 4,06 µg/cm2, respectivamente). A fase cúbica também promoveu aumento da penetração de nicotina nas camadas viáveis da pele quando comparado ao controle (8,18 ± 1,89 e 2,63 ± 2,51 µg/cm2, respectivamente). Estudos futuros para avaliar a sensibilização e irritação da pele são necessários

As boas práticas de fabricação de medicamentos e suas determinantes

Good Manufacturing Practices (GMP) ensure that drugs are consistently produced and controlled according to previously established quality standards. They are designed to manage and minimize the inherent risks involved in the manufacture of drugs in order to ensure the quality, efficacy and safety of the finished product. Since their inception as we know them today, several versions have taken place in Brazil and worldwide. This work proposes to analyze GMP, through the analysis of the content of Brazilian regulatory frameworks, identifying the determinants that can explain their evolution over the last decades. GMP were broken down into topics and subtopics and their versions present in the five regulatory frameworks studied were evaluated. It was possible to verify, in the evolution of drug manufacturing requirements, the interference of technological innovation and the influence of new practices related to quality, identifying the GMP transformation dynamics.As Boas Práticas de Fabricação (BPF) garantem que os medicamentos sejam consistentemente produzidos e controlados de acordo com padrões de qualidade previamente estabelecidos. Têm por objetivo gerenciar e minimizar os riscos inerentes à fabricação de medicamentos com vista a garantir a qualidade, eficácia e segurança do produto acabado. Desde o seu surgimento da forma como conhecemos hoje, várias versões se sucederam no Brasil e no mundo. Esse trabalho se propõe a analisar as BPF, por meio da análise de conteúdo dos marcos regulatórios brasileiros, identificando as determinantes que podem explicar a sua evolução através das últimas décadas. As BPF foram decompostas em temas e subtemas e suas versões, presentes nos cinco marcos regulatórios estudados, foram avaliadas. Foi possível comprovar, na evolução dos requisitos de fabricação de medicamentos, a interferência da inovação tecnológica e a influência de novas práticas relacionadas à qualidade, identificando, dessa forma, a dinâmica de transformação das BPF

Effect of physical stimuli on hair follicle deposition of clobetasol-loaded Lipid Nanocarriers

Clobetasol propionate (CLO) is a potent glucocorticoid used to treat inflammation-based skin, scalp, and hair disorders. In such conditions, hair follicles (HF) are not only the target site but can also act as drug reservoirs when certain formulations are topically applied. Recently, we have demonstrated nanostructured lipid carriers (NLC) containing CLO presenting epidermal-targeting potential. Here, the focus was evaluating the HF uptake provided by such nanoparticles in comparison to a commercial cream and investigating the influence of different physical stimuli [i.e., infrared (IR) irradiation (with and without metallic nanoparticles-MNP), ultrasound (US) (with and without vibration) and mechanical massage] on their follicular targeting potential. Nanosystems presented sizes around 180 nm (PdI < 0.2) and negative zeta potential. The formulation did not alter skin water loss measurements and was stable for at least 30 days at 5 °C. Nanoparticles released the drug in a sustained fashion for more than 3 days and increased passively about 40 times CLO follicular uptake compared to the commercial cream. Confocal images confirmed the enhanced follicular delivery. On the one hand, NLC application followed by IR for heat generation showed no benefit in terms of HF targeting even at higher temperatures generated by metallic nanoparticle heating. On the other hand, upon US treatment, CLO retention was significantly increased in deeper skin layers. The addition of mechanical vibration to the US treatment led to higher follicular accumulation compared to passive exposure to NLC without stimuli. However, from all evaluated stimuli, manual massage presented the highest follicular targeting potential, driving more than double the amount of CLO into the HF than NLC passive application. In conclusion, NLC showed great potential for delivering CLO to HF, and a simple massage was capable of doubling follicular retention

Pouteria macrophylla fruit extract microemulsion for cutaneous depigmentation : evaluation using a 3D pigmented skin model

Here, we verify the depigmenting action of Pouteria macrophylla fruit extract (EXT), incorporate it into a safe topical microemulsion and assess its effectiveness in a 3D pigmented skin model. Melanocytes-B16F10- were used to assess the EXT effects on cell viability, melanin synthesis, and melanin synthesis-related gene transcription factor expression, which demonstrated a 32% and 50% reduction of intra and extracellular melanin content, respectively. The developed microemulsion was composed of Cremophor EL®/Span 80 4:1 (w/w), ethyl oleate, and pH 4.5 HEPES buffer and had an average droplet size of 40 nm (PdI 0.40 ± 0.07). Skin irritation test with reconstituted epidermis (Skin Ethic RHETM) showed that the formulation is non-irritating. Tyrosinase inhibition was maintained after skin permeation in vitro, in which microemulsion showed twice the inhibition of the conventional emulsion (20.7 ± 2.2% and 10.7 ± 2.4%, respectively). The depigmenting effect of the microemulsion was finally confirmed in a 3D culture model of pigmented skin, in which histological analysis showed a more pronounced effect than a commercial depigmenting formulation. In conclusion, the developed microemulsion is a promising safe formulation for the administration of cutite fruit extract, which showed remarkable depigmenting potential compared to a commercial formulation

Mathematical models to describe iontophoretic transport in vitro and in vivo and the effect of current application on the skin barrier

The architecture and composition of the stratum corneum make it a particularly effective barrier against the topical and transdermal delivery of hydrophilic molecules and ions. As a result, different strategies have been explored in order to expand the range of therapeutic agents that can be administered by this route. Iontophoresis involves the application of a small electric potential to increase transport into and across the skin. Since current flow is preferentially via transport pathways with at least some aqueous character, it is ideal for hydrosoluble molecules containing ionisable groups. Hence, the physicochemical properties that limit partitioning and passive diffusion through the intercellular lipid matrix are beneficial for electrically-assisted delivery. The presence of fixed ionisable groups in the skin (pI 4-4.5) means that application of the electric field results in a convective solvent flow (i.e., electroosmosis) in the direction of ion motion so as to neutralise membrane charge. Hence, under physiological conditions, cation electrotransport is due to both electromigration and electroosmosis-their relative contribution depends on the formulation conditions and the physicochemical properties of the permeant. Different mathematical models have been developed to provide a theoretical framework in order to explain iontophoretic transport kinetics. They usually involve solutions of the Nernst-Planck equation - using either the constant field (Goldman) or electroneutrality (Nernst) approximations - with or without terms for the convective solvent flow component. Investigations have also attempted to elucidate the nature of ion transport pathways and to explain the effect of current application on the electrical properties of the skin-more specifically, the stratum corneum. These studies have led to the development of different equivalent circuit models. These range from simple parallel arrangements of a resistor and a capacitor to the inclusion of the more esoteric "constant phase element"; the latter provides a better mathematical description of the "non-ideal" behaviour of skin impedance. However, in addition to simply providing a "mathematical" fit of the observed data, it is essential to relate these circuit elements to biological structures present in the skin. More recently, attention has also turned to what happens when the permeant crosses the epidermis and reaches the systemic circulation and pharmacokinetic models have been proposed to interpret data from iontophoretic delivery studies in vivo. Here, we provide an overview of mathematical models that have been proposed to describe (i) the effect of current application on the skin and the implications for potential iontophoretic transport pathways, (ii) electrotransport kinetics and (iii) the fate of iontophoretically delivered drugs once they enter the systemic circulation

Non-invasive iontophoretic delivery of peptides and proteins across the skin

INTRODUCTION: Peptides and proteins are playing an increasingly important role in modern therapy. Their potency and specificity make them excellent therapeutic agents; however, their physicochemical properties and stability requirements almost invariably necessitate their administration by subcutaneous, intramuscular or intravenous injection. Controlled non-invasive administration using more patient-friendly advanced delivery technologies may combine the precision afforded by parenteral administration with improved compliance and the potential for individualized therapy. AREAS COVERED: Transdermal iontophoresis enables hydrophilic charged molecules to be administered through the skin in an effective, non-invasive, patient-friendly manner. This review presents the basic concepts and an analysis of the effect of iontophoretic parameters and molecular properties on electrotransport rates across the skin along with a summary of experimental studies with peptides and proteins. The last section covers other techniques used in conjunction with iontophoresis. EXPERT OPINION: It has long been known that iontophoresis can administer therapeutic amounts of biologically active peptides into the body. More recent studies have shown that it is also capable of delivering structurally intact, functional proteins non-invasively into and across intact human skin. The next step is to develop cost-effective and easy-to-use iontophoretic patch systems that ensure biomolecule stability, optimize delivery efficiency and address unmet therapeutic needs

Development and validation of a HPAE-PAD method for the quantification of CGP69669A, a sialyl Lewis^x mimetic, in skin permeation studies

A simple, rapid, precise and specific isocratic HPAE-PAD method for quantification of CGP69669A was developed and validated. CGP69669A is a glycomimetic of sialyl Lewis(x) and an antagonist of E-selectin with potential application in the treatment of inflammatory skin disease. Quantification was performed using a Dionex CarboPac(TM) PA-200 anion-exchange column (3 × 250 mm) with 100 mm NaOH solution as mobile phase, a flow rate of 0.50 mL/min and an injection volume of 10 μL. A quadruple potential waveform was used to detect the carbohydrate (+0.1 V from 0.00 to 0.40 s, -2.0 V from 0.41 to 0.42 s, +0.6 V at 0.43 s and -0.1 V from 0.44 to 0.50 s with current integrated between 0.20 and 0.40 s for detection) and rafinose was employed as an internal standard. The optimized conditions enabled rapid elution of CGP69669A (at 3.0 min) without interference from solvent peaks or substances present in the skin. The method showed good intra- and inter-day precision and accuracy and the response was linear from 1.0 to 25 µg/mL. This is the first validated direct method for the quantification of CGP69669A. It will now be employed in studies investigating the topical and transdermal delivery of CGP69669A in vitro and in vivo and it should also be of use for other applications of this molecule

Tissue Levels of Flurbiprofen in the Rat Plantar Heel after Short-Duration Topical Iontophoresis are Sufficient to Induce Pharmacodynamic Responses to Local Pain Stimuli

The objective of this study was to investigate the topical iontophoresis of flurbiprofen (FBF) as a means to enhance its local bioavailability and thereby provide an improved and targeted treatment of plantar heel pain. Initial in vitro experiments using porcine ear skin investigated iontophoretic transport of FBF under different conditions. Local FBF biodistribution in the rat paw in vivo was compared after topical or oral administration. Efficacy of pain management was investigated using a plantar incisional model by evaluating pharmacodynamic responses to local pain stimuli. The results demonstrated that iontophoresis of FBF significantly increased cutaneous deposition and transdermal permeation of FBF as compared to passive delivery-it also enabled drug input to be controlled by modulation of current density and drug concentration (r2 > 0.99). Topical iontophoresis of FBF in vivo enabled higher drug levels in skin and muscle in rat plantar aspect and superior pharmacodynamic responses to local pain stimuli, in comparison to oral and passive delivery. In conclusion, short-duration topical iontophoresis of FBF may better help to relieve plantar heel pain than oral or passive administration, which should be of clinical interest