Não há agências de financiamento suportado neste trabalho.

1. solução da amostra
<ol>
	<li>Calcule o limite de limpeza (CL) para uma droga com base na transição máxima permissível (MACO), de acordo com os critérios da dose terapêutica. Nota: Aqui, o limite de limpeza (CL) para drogas A foi calculado para ser 2.4 µ g por 50 cm2 baseia a transição máxima permissível (MACO), de acordo com os critérios da dose terapêutica. A verificação de limpeza é executada nos 50%, 100% e 150% limite de limpeza. Avaliou-se a verificação de limpeza para duas formulações (carga de 2,5% e 60% w/w de drogas).</li>
</ol>
2. procedimento de limpeza para cupons
<ol>
	<li>Abordagem inicial<ol>
		<li>Limpe os cupons lavando e limpando a superfície por 10-15 s duas vezes com água e duas vezes com metanol para eliminar qualquer depósito residual. Execute esse processo no bairro, como o metanol é tóxico e altamente volátil.</li>
	</ol>
	</li>
	<li>Abordagem avançada<ol>
		<li>Usando soluções de limpeza no local<ol>
			<li>Defina o sonicador à temperatura ambiente. O sonicador não tem nenhum ajuste de configuração de energia, portanto o tempo é definido para dar resultados de limpeza adequados.</li>
			<li>Mergulhe os cupons em água de grau de cromatografia líquida (HPLC) de alto desempenho e proceda à sonicação por 2 min.</li>
			<li>Mergulhe os cupons em 0,1% solução de detergente alcalino em água de grau HPLC e proceda à sonicação por 2 min.</li>
			<li>Mergulhe os cupons na água HPLC e proceda à sonicação por 2 min.</li>
			<li>Mergulhe os cupons em 0,1% solução de detergente ácido na água HPLC e proceda à sonicação por 2 min.</li>
			<li>Mergulhe os cupons na água HPLC e proceda à sonicação por 2 min.</li>
		</ol>
		</li>
		<li>Usando ácido-base-peróxido Nota: Este é um método alternativo incluído usando ácido, base e o peróxido em vez de detergentes alcalinos e ácidos.<ol>
			<li>Defina o sonicador à temperatura ambiente. O sonicador não tem nenhum ajuste de configuração de energia, portanto o tempo é definido para dar resultados de limpeza adequados.</li>
			<li>Mergulhe os cupons na água e proceda à sonicação por 2 min.</li>
			<li>Mergulhe os cupons em hidróxido de sódio 0,1 M e proceda à sonicação por 2 min.</li>
			<li>Mergulhe os cupons na água e proceda à sonicação por 2 min.</li>
			<li>Mergulhe os cupons em ácido clorídrico 0,1 M e proceda à sonicação por 2 min.</li>
			<li>Mergulhe os cupons na água e proceda à sonicação por 2 min.</li>
			<li>Mergulhe os cupons em 0,1 mg/mL de NaNo2 e proceda à sonicação por 2 min.</li>
			<li>Mergulhe os cupons na água e proceda à sonicação por 2 min.</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>
3. procedimento de limpeza
<ol>
	<li>Monte os cupons de aço inoxidável na parte inferior de um copo plástico 250 mL (ou 500 mL), usando uma fita dupla face.</li>
	<li>Segure o copo tornar spiking e limpeza processos fácil. Isso também minimiza alguns acidentes indesejáveis tais como superação da esquina quando esfregar.</li>
	<li>Infundi um volume definido em uma concentração específica e formulação (por exemplo, 200 µ l de 12 µ g/mL a carga de drogas p/p A 2,5%) em um padrão whirly na superfície do cupão usando uma pipeta volumétrica.</li>
	<li>Espere até que a superfície do cupão é seca (~ 3-10 min, dependendo da volatilidade da amostra).</li>
	<li>Um cotonete seco em um frasco com 2 mL de diluente (metanol: ácido fórmico 100:0.2 volumétrica).</li>
	<li>Remova o solvente em excesso espremendo-a contra o interior do frasco.</li>
	<li>Firmemente, limpe a superfície do cupom com traços de lado a lado mesmo, sobrepostos até a área de teste de2 total 50cm está apagada com um lado de um cotonete molhado.</li>
	<li>Repita o processo de limpeza (etapa 3.7) usando o mesmo lado do cotonete.</li>
	<li>Esfregue as quatro bordas de cupom duas vezes.</li>
	<li>O cotonete para o outro lado da aleta e girar o cupom 90°, no sentido horário ou no sentido anti-horário; assim, o sentido da limpeza de 90° de giro.</li>
	<li>Repita o movimento de limpeza conforme detalhado nas etapas 3.7-3.9. Após a amostragem da superfície, cortou a cabeça de cotonete com uma tesoura no frasco de solvente.</li>
	<li>Repita o processo de limpeza com um cotonete de segundo enquanto roda o cupom 90° para o mesmo sentido escolhido antes.</li>
	<li>Proceda à sonicação do frasco contendo duas cabeças de cotonete por 5 min, em seguida, vórtice por 10 s.</li>
	<li>Transferir a solução para um frasco HPLC e rotulá-la como solução de trabalho.</li>
</ol>
4. cálculo de recuperação
<ol>
	<li>Recuperação de amostra<ol>
		<li>Prepare as soluções de controle misturando-se 200 µ l cada do cupom cravação soluções com 1.800 µ l de diluente.</li>
		<li>Execute o sistema de cromatografia de acordo com as condições listadas na tabela 1.</li>
		<li>Calcular a recuperação a cotonete da solução de trabalho com base na área relativa ao abrigo do pico das soluções de trabalho (AW) e a solução de controle (C).</li>
		<li>Repita o processo em três cupons e calcular a média de recuperação juntamente com desvio-padrão relativo (Srel). Nota: Todos os métodos analíticos utilizados aqui foram validados de acordo com as diretrizes ICH Q2(R1). As condições cromatográficas estão listadas na seção de material.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Validation of cleaning processes (7/93). Guide to inspections validation of cleaning processes. , (2004).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Warning Letter: 320-12-08, Gulf Pharmaceuticals. , (2012).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Warning Letter: 320-12-058, Novartis Internationsl AG. , (2012).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Warning Letter: 05-10, Teva Parenterals Medicines, Inc. , (2009).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Warning Letter: 320-14-09, Tianjin Zhongan Pharmaceutical Co., Ltd. , (2014).</li><li>Mantel, M., Wightman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+the+surface+chemistry+on+the+wettability+of+stainless+steel.">Influence of the surface chemistry on the wettability of stainless steel.</a> Surf Interface Anal. 21, 595-605 (1994).</li><li>Odaka, K., Ueda, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dependence+of+outgassing+rate+on+surface+oxide+layer+thickness+in+type+304+stainless+steel+before+and+after+surface+oxidation+in+air.">Dependence of outgassing rate on surface oxide layer thickness in type 304 stainless steel before and after surface oxidation in air.</a> Vacuum. 47, 689-692 (1996).</li><li>Kerber, S. J., Tverberg, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stainless+Steel+Surface+Analysis.">Stainless Steel Surface Analysis.</a> Adv. Mater. Processes. , 33-36 (2000).</li><li>Kusumaningrum, H. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Survival+of+foodborne+pathogens+on+stainless+steel+surfaces+and+cross-contamination+to+foods.">Survival of foodborne pathogens on stainless steel surfaces and cross-contamination to foods.</a> Int J Food Microbiol. 85, 227-236 (2003).</li><li>Liu, L., Pack, B. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cleaning+verification+assays+for+highly+potent+compounds+by+high+performance+liquid+chromatography+mass+spectrometry:+Strategy,+validation,+and+long-term+performance.">Cleaning verification assays for highly potent compounds by high performance liquid chromatography mass spectrometry: Strategy, validation, and long-term performance.</a> J Pharmaceut. Biomed. 43, 1206-1212 (2007).</li><li>Lambropoulos, J., Spanos, G. A., Lazaridis, N. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+validation+of+an+HPLC+assay+for+fentanyl,+alfentanil,+and+sufentanil+in+swab+samples.">Development and validation of an HPLC assay for fentanyl, alfentanil, and sufentanil in swab samples.</a> J Pharmaceut. Biomed. 23, 421-428 (2000).</li><li>Chisti, Y., Moo-Young, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clean-in-place+systems+for+industrial+bioreactors:+Design,+validation+and+operation.">Clean-in-place systems for industrial bioreactors: Design, validation and operation.</a> J. Ind. Microbiol. 13, 201-207 (1994).</li><li>Haidar Ahmad, I. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cleaning+verification:+Exploring+the+effect+of+the+cleanliness+of+stainless+steel+surface+on+sample+recovery.">Cleaning verification: Exploring the effect of the cleanliness of stainless steel surface on sample recovery.</a> J Pharmaceut. Biomed. 134, 108-115 (2017).</li></ol>

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Os principais contribuintes para recuperações baixas e variáveis de resíduos de API de cupons de aço inoxidável foi traçado para a falta de um procedimento bem definido para limpeza de superfícies o cupom. Limpar a superfície dos cupons resultou na recuperação cravada consistente, precisa e resultados reprodutíveis. Com a demonstração de altas recuperações de cupons de aço inoxidável, os resultados da verificação limpeza real obtidos a partir do equipamento de fabricação usando o método validado (s...

A limpeza do equipamento não dedicado deve ser verificada antes de seu lançamento subsequente para utilização no fabrico dos produtos intermédios e ingrediente farmacêutico ativo (APIs), em produto mudar para evitar a contaminação cruzada. Os procedimentos de limpeza devem conter detalhes suficientes para permitir que os operadores de limpar cada tipo de equipamento de forma reprodutível e eficaz, e estes procedimentos devem ser validados de acordo com os requisitos de E.U. Food and Drug Administration (FDA)1. Inúmeras cartas de aviso devido à inadequada limpeza2,3,4, falha ao validar o método de verificação de limpeza e cumprimento de procedimentos de limpeza5 foram emitidos pelo FDA. 21 CFR §211.67 descreve os requisitos necessários para a verificação de limpeza bem-sucedida.
É o padrão na indústria que a validação dos métodos analíticos para verificação da limpeza é executada em aço inoxidável cupons com o mesmo revestimento de superfície/como o equipamento de fabricação. Cupons de aço inoxidável (por exemplo, 50 cm2) são usados para representar as superfícies do equipamento para limpeza de experimentos de verificação em laboratório. Durante o desenvolvimento e a validação dos métodos analíticos, a amostra de interesse (ou seja, os resíduos que devem ser recuperados a partir da superfície do equipamento) é cravada no resíduo de destino para o aço inoxidável cupom determinado pelo limite máximo permitido ao reporte (MACO). Este nível é determinado com base no limite de exposição aceitável, que é definido como o limite em que um paciente pode ficar exposto sem efeitos adversos para a saúde (não observada-adversos-efeito-nível, NOAEL).
O analista ou operador de fabricação, realizando a limpeza deve seguir um procedimento estruturado para assegurar que as recuperações são reprodutíveis, independentemente de quem executa a limpeza. O procedimento explicitamente deverá especificar o tipo de amostra, número de cotonetes usados, o diluente, a quantidade de solvente utilizado, o padrão de varredura exato, o número de traços aplicada à superfície da amostra, a quantidade de tempo gasto limpeza/extração de amostras, o método de deteção (ultra-violeta, fluorescência, espectrometria de massa, carbono orgânico total, etc.), a técnica de extração do material da cabeça do cotonete , etc.
Além disso, todos os fatores acima mencionados que afetam a recuperação da amostra, a superfície do cupom e assim, a superfície do equipamento também desempenham um papel. A superfície do cupão pode ser modificada devido a deposição de uma fina camada de material na superfície ou a mudança no estado de oxidação de um ou mais dos elementos em aço inoxidável (por exemplo, Fe, Cr e Ni)6,7,8. A regeneração da superfície do aço inoxidável cupons volta ao seu estado original é vital para o sucesso do processo de trocando quantitativo. Estudos, em que os cupons de aço inoxidável não foram devidamente limpos, apresentou variabilidade em recuperação, incluindo analista para drogas de outro, diferentes, ou vários pico níveis9,10,11. O desvio-padrão na recuperação de dez repetições com um cupão pode ser de até 14% e 26% em cinco cupons9. É importante notar que os valores de desvio padrão relativo (Srel) aumentaram com o aumento do número de repetições ou com aumento do número de cupons utilizados (ou seja, cinco cupons em vez de cravação cinco vezes no mesmo cupom)11. Em tais casos, a variabilidade não pode ser interpretada como flutuação aleatória. No entanto, seus resultados podem ser explicados por nossa constatação que a limpeza da superfície do cupão irá afetar a recuperação. Os resultados descritos neste artigo ilustram um aumento significativo nos resultados de recuperação e diminuição de variabilidade depois de limpar corretamente a superfície de aço inoxidável cupons.
Limpeza no local (CIP) é uma forma automatizada de limpar a superfície do equipamento que envolve um mínimo ou sem desmontagem do equipamento. Durante o processo de limpeza do CIP, um procedimento definido de lavagem consecutivo com uma base, seguida de um ácido é executado para remover os resíduos orgânicos e inorgânicos. Surfactantes, compostos quelantes ou agentes complexantes são usualmente adicionados às soluções para melhorar a eficiência de qualquer produto da superfície do equipamento de limpeza CIP. A eficiência da limpeza depende de vários parâmetros, incluindo a escolha e a concentração das soluções CIP (i.e., tipo e composição do surfactante, ácido e base), o tempo de limpeza, temperatura (tipicamente 60-80 ° C), tipo de contaminação e a presença de dificuldade para limpar peças12. Com base no tipo de produto de drogas, soluções CIP 100 e 200 foram escolhidas para usar para limpar os cupons de aço inoxidável, usados para a limpeza de verificação, uma vez que simula o processo CIP, usado para a fabricação de equipamentos de limpeza.
Este estudo relata a influência de diferentes fatores que afetam a recuperação de resíduos farmacêuticos da superfície do aço inoxidável cupons e recomenda as melhores práticas para desenvolvimento de método analítico limpeza para pequenas moléculas, proteínas terapêuticas e anticorpos. A falta de um procedimento bem definido que consistentemente limpos superfície cupom foi identificada como o maior contribuinte para recuperações de baixas e variáveis. Recuperação de alta e reprodutível obteve-se quando a superfície do cupom foi limpada corretamente13.

<table style="border-collapse:collapse;width:964pt" width="1285">
	<colgroup>
		<col style="width:265pt" width="353" />
		<col style="width:401pt" width="535" />
		<col style="width:250pt" width="333" />
		<col style="width:48pt" width="64" />
	</colgroup>
	<tbody>
		<tr height="21" style="height:15.75pt">
			<td height="21" style="width:265pt;height:15.75pt" width="353">stainless steel coupons</td>
			<td class="xl67" style="width:401pt" width="535">&#160;GlobePharma (New Brunswick, NJ ).&#160;</td>
			<td class="xl16" style="width:250pt" width="333">SS316-20RA-50cm2</td>
			<td style="width:48pt" width="64"></td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl16" height="21" style="height:15.75pt">Clean in place solutions (CIP100 and CIP200)&#160;</td>
			<td class="xl68" style="width:401pt" width="535">were obtained from Steris Corporation (Mentor, OH)</td>
			<td>1D10BG</td>
			<td>Alkaline detergent and acid detergent, respectively</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl16" height="21" style="height:15.75pt">Positive displacement pipettes</td>
			<td class="xl68" style="width:401pt" width="535">Gilson (Middleton, WI).&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="34" style="height:25.5pt">
			<td height="34" style="height:25.5pt">HPLC grade water</td>
			<td class="xl68" style="width:401pt" width="535">Millipore Milli-Q Advantage Water Purification System (Darmstadt, Germany)&#160; or from Honeywell Burdick &#38; Jackson (Muskegon, Michigan)</td>
			<td>7732-18-5</td>
			<td></td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl16" height="21" style="height:15.75pt">HPLC grade Methanol</td>
			<td class="xl68" style="width:401pt" width="535">EMD</td>
			<td>MX0475-1</td>
			<td></td>
		</tr>
		<tr height="17" style="height:12.75pt">
			<td height="17" style="height:12.75pt">glacial acetic acid&#160;</td>
			<td class="xl68" style="width:401pt" width="535">EMD</td>
			<td>MAX0073P5</td>
			<td></td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl16" height="21" style="height:15.75pt">HPLC grade Acetonitrile&#160;</td>
			<td class="xl68" style="width:401pt" width="535">J.T. Baker (Avantor Performance Materials, Center Valley, PA)</td>
			<td>75-05-8</td>
			<td></td>
		</tr>
		<tr height="17" style="height:12.75pt">
			<td height="17" style="height:12.75pt">Trifluoroacetic acid</td>
			<td class="xl68" style="width:401pt" width="535">J.T. Baker (Avantor Performance Materials, Center Valley, PA)</td>
			<td>75-05-8</td>
			<td></td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl17" height="21" style="height:15.75pt">Chromatography column Zorbax Eclipse</td>
			<td class="xl68" style="width:401pt" width="535">&#160;XDB-C18, 4.6 x 100 mm, 3.5 &#181;m HPLC column</td>
			<td>UNSPSC &#8211; 41115709</td>
			<td></td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl16" height="21" style="height:15.75pt">Vanquish UHPLC system&#160;</td>
			<td class="xl68" style="width:401pt" width="535">Thermo Fisher Scientific, Germering, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl16" height="21" style="height:15.75pt">Branson B8510 Ultrasonic cleaner&#160;</td>
			<td class="xl68" style="width:401pt" width="535">Branson Ultrasonics (Danbury, CT, USA)</td>
			<td>model (8510-D7H)</td>
			<td></td>
		</tr>
	</tbody>
</table>

failure of cleaning verification in pharmaceutical industry due to uncleanliness of stainless steel surface

O objetivo deste trabalho é identificar os parâmetros que afetam a recuperação de resíduos farmacêuticos da superfície do aço inoxidável cupons. Uma série de fatores foram avaliados, incluindo níveis de pico do produto de droga, procedimento de cravação, rácios de droga-excipiente, Analista-Analista de variabilidade, variabilidade intradiário e procedimento de limpeza dos cupons. A falta de um procedimento bem definido que consistentemente limpa a superfície de cupom foi identificada como o maior contribuinte para recuperações de baixas e variáveis. Avaliação da limpeza da superfície dos cupons com soluções de limpeza no local (CIP) deu alta recuperação (&#62; 90%) e resultados reprodutíveis (Srel≤ 4%) independentemente das condições em que foram avaliados previamente. A abordagem foi aplicada com êxito para a limpeza de verificação de pequenas moléculas (MW &#60; Da 1.000) bem como grandes biomoléculas (MW até 50.000 Da).

Resultados representativos das tentativas iniciais para a limpeza de verificação para droga A são resumidos na tabela 2. Antes que os cupons foram limpos de acordo com o procedimento detalhado na seção experimental, obtiveram-se resultados inconsistentes em níveis diferentes de pico, para várias relações de API/excipiente, analistas diferentes e mesmo para o analista mesmo em dias diferentes. A variabilidade observada nas recuperações precisava ser abordadas, c...

Watch this Scientific Journal Video about Failure of Cleaning Verification in Pharmaceutical Industry Due to Uncleanliness of Stainless Steel Surface at JoVE.com

Failure of Cleaning Verification in Pharmaceutical Industry Due to Uncleanliness of Stainless Steel Surface

A falta de um processo bem definido que consistentemente limpas as superfícies de cupom foi identificada como o maior contribuinte para baixos e variáveis recuperações em verificação de limpeza. Este manuscrito descreve o protocolo correto de limpeza cupons de aço inoxidável.

Falha de verificação na indústria farmacêutica devido à sujeira da superfície de aço inoxidável de limpeza

The aim of this work is to identify the parameters that affect the recovery of pharmaceutical residues from the surface of stainless steel coupons. A ...

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8.1K visualizações.  Novartis Pharmaceuticals Corporation. A falta de um processo bem definido que consistentemente limpas as superfícies de cupom foi identificada como o maior contribuinte para baixos e variáveis recuperações em verificação de limpeza. Este manuscrito descreve o protocolo correto de limpeza cupons de aço inoxidável.

Vídeo: Failure of Cleaning Verification in Pharmaceutical Industry Due to Uncleanliness of Stainless Steel Surface

A Method to Manipulate Surface Tension of a Liquid Metal via Surface Oxidation and Reduction

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where interfacial tension is a dominant force. A variety of methods exist for controlling the interfacial tension of aqueous and organic liquids on this scale; however, these techniques have limited utility for liquid metals due to their large interfacial tension.
Liquid metals can form soft, stretchable, and shape-reconfigurable components in electronic and electromagnetic devices. Although it is possible to manipulate these fluids via mechanical methods (e.g., pumping), electrical methods are easier to miniaturize, control, and implement. However, most electrical techniques have their own constraints: electrowetting-on-dielectric requires large (kV) potentials for modest actuation, electrocapillarity can affect relatively small changes in the interfacial tension, and continuous electrowetting is limited to plugs of the liquid metal in capillaries.
Here, we present a method for actuating gallium and gallium-based liquid metal alloys via an electrochemical surface reaction. Controlling the electrochemical potential on the surface of the liquid metal in electrolyte rapidly and reversibly changes the interfacial tension by over two orders of magnitude ( &#820;500 mN/m to near zero). Furthermore, this method requires only a very modest potential (&#60; 1 V) applied relative to a counter electrode. The resulting change in tension is due primarily to the electrochemical deposition of a surface oxide layer, which acts as a surfactant; removal of the oxide increases the interfacial tension, and vice versa. This technique can be applied in a wide variety of electrolytes and is independent of the substrate on which it rests.

We present a method to control the interfacial energy of a liquid metal in an electrolyte via electrochemical deposition (or removal) of a surface oxide layer. This simple method can control the capillary behavior of gallium-based liquid metals by tuning the interfacial energy rapidly, significantly, and reversibly using modest voltages.

Um Método para Manipular a Tensão Superficial de um Metal Líquido via Oxidação e Redução Superficial

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where ...

Química

Application and Methodology of the Non-destructive 19F Time-domain NMR Technique to Measure the Content in Fluorine-containing Drug Products

Here, we describe a protocol developed by our group that uses low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) to measure the average content of fluorinated drugs in their formulated drug product forms: tablets or capsules. This method is specific to fluorinated drugs because it detects only the content of fluorine, avoiding interference from the excipients that lack fluorine. The advantages of measuring the active content of fluorinated drugs using low-field 19F TD-NMR versus high-field 19F solid-state (SS) NMR are the simplicity of the method; the low cost; and the non-destructive nature of the technique, with all samples recoverable in intact forms (e.g., powders, tablets, and capsules), making this technique affordable for any laboratory.
We have tested the method with three fluorinated drug products available on the market - cinacalcet, lansoprazole, and ciprofloxacin - with doses ranging from 15 to 500 mg. The results of the analyses, measured by low-field 19F TD-NMR, supported the reported label claims for the average drug content.
Based on the simplicity and reproducibility of the analysis, we envision this methodology being implemented in any laboratory, including manufacturing plants, as a process analytical technology (PAT) tool in the pharmaceutical industry.

Application and Methodology of the Non-destructive 19F Time-domain NMR Technique to Measure the Content in Fluorine-containing Drug Products

A simple and non-destructive technique that measures the average content of drug substances in formulated drug products containing fluorine using low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) is presented here. The technique can be applied to the development and manufacturing of drugs in the pharmaceutical industry.

Aplicação e metodologia da técnica não-destrutiva 19F no domínio do tempo NMR para medir o teor em flúor-contendo produtos de droga

Here, we describe a protocol developed by our group that uses low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) to measure the ...

Observation and Analysis of Blinking Surface-enhanced Raman Scattering

From a single molecule at a silver nanoaggregate junction, blinking surface-enhanced Raman scattering (SERS) is observed. Here, a protocol is presented on how to prepare the SERS-active silver nanoaggregate, record a video of certain blinking spots in the microscopic image, and analyze the blinking statistics. In this analysis, a power law reproduces the probability distributions for bright events relative to their duration. The probability distributions for dark events are fitted by a power law with an exponential function. The parameters of the power law represent molecular behavior in both bright and dark states. The random walk model and the speed of the molecule across the entire silver surface can be estimated. It is difficult to estimate even when using averages, autocorrelation functions, and super-resolution SERS imaging. In the future, power law analyses should be combined with spectral imaging, because the origins of blinking cannot be confirmed by this analysis method alone.

This protocol describes the analysis of blinking surface-enhanced Raman scattering due to the random walk of a single molecule on a silver surface using power laws.

Observação e Análise da Espalhamento Raman Aprimorado por Superfície do Piscar de Olhos.

From a single molecule at a silver nanoaggregate junction, blinking surface-enhanced Raman scattering (SERS) is observed. Here, a protocol is presented on ...

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and porous metal-dithiolene network in the highly ordered single crystalline state. Unlike the highly reactive free-standing thiols, which tend to decompose and complicate the crystallization of metal-thiolate open frameworks, the thioester reacts in situ to provide the thiol species, serving to mitigate the reaction between the mercaptan units and the metal centers, and to improve crystallization consequently. Specifically, the thioester was synthesized in a one-pot procedure: an aromatic bromide (hexabromotriphenylene) reacted with excess sodium thiomethoxide under vigorous conditions to first form the thioether intermediate product. The thioether was then demethylated by the excess thiomethoxide to provide the thiolate anion that was acylated to form the thioester product. The thioester was conveniently purified by standard column chromatography, and then used directly in the framework synthesis, wherein NaOH and ethylenediamine serve to revert in situ the thioester to the thiol linker for assembling the single-crystalline Pb(II)-dithiolene network. Compared with other methods for thiol synthesis (e.g., by cleaving alkyl thioether using sodium metal and liquid ammonia), the thioester synthesis here uses simple conditions and economical reagents. Moreover, the thioester product is stable and can be conveniently handled and stored. More importantly, in contrast to the generic difficulty in accessing crystalline metal-thiolate open frameworks, we demonstrate that using the thioester for in situ formation of the thiol linker greatly improves the crystallinity of the solid-state product. We intend to encourage broader research efforts on the technologically important metal-sulfur frameworks by disclosing the synthetic protocol for the thioester as well as the crystalline framework solid.

Here, we present a one-pot, transition-metal-free synthesis of thiols and thioesters from aromatic halides and sodium thiomethoxide, followed by the preparation of single crystals of a metal-dithiolene network using thiol species generated in situ from the more stable and tractable thioester.

Síntese de um Bloco de Construção Tiol para a Cristalização de uma Estrutura Semicondutora de Metal-Enxofre com Geometria Giroidal

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and ...

Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes

We present the chemoselective synthesis of 1-(iodoethynyl)-4-methylbenzene, 1-(1,2-diiodovinyl)-4-methylbenzene, and 1-methyl-4-(1,2,2-triiodovinyl)benzene as representative examples for the practical chemoselective preparation of 1-iodoalkynes, 1,2-diiodoalkenes, and 1,1,2-triiodoalkenes from the chemoselective iodination of terminal alkynes mediated by hypervalent-iodine reagents. The chemoselectivity was confirmed by using p-tolylethyne as a model substrate to screen a variety of iodine sources and/or the hypervalent-iodine reagents. A combination of tetrabutylammonium iodide (TBAI) and (diacetoxyiodo)benzene (PIDA) selectively generates 1-iodoalkynes, while a combination of KI and PIDA generates 1,2-diiodoalkenes. A one-pot synthesis based on both TBAI-PIDA and KI-PIDA yields the corresponding 1,1,2-triiodoalkenes. These protocols were subsequently applied to the synthesis of synthetically important aromatic and aliphatic 1-iodoalkynes, 1,2-diiodoalkenes, and 1,1,2-triiodoalkenes, which were obtained in good yield with excellent chemoselectivity.

Herein, detailed protocols for the oxidative iodination of terminal alkynes using hypervalent-iodine reagents are presented, which chemoselectively afford 1-iodoalkynes, 1,2-diiodoalkenes, and 1,1,2-triiodoalkenes.

Preparação Quimiosseletiva de 1-iodoalquinos, 1,2-diiodoalqueenos e 1,1,2-triiodoalqueenos Baseada na Iodação Oxidativa de Alquinos Terminais

We present the chemoselective synthesis of 1-(iodoethynyl)-4-methylbenzene, 1-(1,2-diiodovinyl)-4-methylbenzene, and ...

Synthesis and Structure Determination of &#181;-Conotoxin PIIIA Isomers with Different Disulfide Connectivities

Peptides with a high number of cysteines are usually influenced regarding the three-dimensional structure by their disulfide connectivity. It is thus highly important to avoid undesired disulfide bond formation during peptide synthesis, because it may result in a completely different peptide structure, and consequently altered bioactivity. However, the correct formation of multiple disulfide bonds in a peptide is difficult to obtain by using standard self-folding methods such as conventional buffer oxidation protocols, because several disulfide connectivities can be formed. This protocol represents an advanced strategy required for the targeted synthesis of multiple disulfide-bridged peptides which cannot be synthesized via buffer oxidation in high quality and quantity. The study demonstrates the application of a distinct protecting group strategy for the synthesis of all possible 3-disulfide-bonded peptide isomers of &#181;-conotoxin PIIIA in a targeted way. The peptides are prepared by Fmoc-based solid phase peptide synthesis using a protecting group strategy for defined disulfide bond formation. The respective pairs of cysteines are protected with trityl (Trt), acetamidomethyl (Acm), and tert-butyl (tBu) protecting groups to make sure that during every oxidation step only the required cysteines are deprotected and linked. In addition to the targeted synthesis, a combination of several analytical methods is used to clarify the correct folding and generation of the desired peptide structures. The comparison of the different 3-disulfide-bonded isomers indicates the importance of accurate determination and knowledge of the disulfide connectivity for the calculation of the three-dimensional structure and for interpretation of the biological activity of the peptide isomers. The analytical characterization includes the exact disulfide bond elucidation via tandem mass spectrometry (MS/MS) analysis which is performed with partially reduced and alkylated derivatives of the intact peptide isomer produced by an adapted protocol. Furthermore, the peptide structures are determined using 2D nuclear magnetic resonance (NMR) experiments and the knowledge obtained from MS/MS analysis.

Cysteine-rich peptides fold into distinct three-dimensional structures depending on their disulfide connectivity. Targeted synthesis of individual disulfide isomers is required when buffer oxidation does not lead to the desired disulfide connectivity. The protocol deals with the selective synthesis of 3-disulfide-bonded peptides and their structural analysis using NMR and MS/MS studies.

Síntese e determinação da estrutura de µ-conotoxina PIIIA isômeros com bissulfeto diferentes conetividades

Peptides with a high number of cysteines are usually influenced regarding the three-dimensional structure by their disulfide connectivity. It is thus ...

Surface Properties of Synthesized Nanoporous Carbon and Silica Matrices

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) with a 4.6 nm pore size, and ordered silica porous matrix, SBA-15, with a 5.3 nm pore size. This work describes the surface properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the differently ordered porous materials with similar pore sizes. For this purpose, OMC and SBA-15 with highly ordered nanoporous structures are synthesized via impregnation of the silica matrix by applying a carbon precursor and by the sol-gel method, respectively. The porous structure of investigated systems is characterized by an N2 adsorption-desorption analysis at 77 K. To determine the electrochemical character of the surface of synthesized materials, potentiometric titration measurements are conducted; the obtained results for OMC shows a significant pHpzc shift toward the higher values of pH, relative to SBA-15. This suggests that investigated OMC has surface properties related to oxygen-based functional groups. To describe the surface properties of the materials, the contact angles of liquids penetrating the studied porous beds are also determined. The capillary rise method has confirmed the increased wettability of the silica walls relative to the carbon walls and an influence of the pore roughness on the fluid/wall interactions, which is much more pronounced for silica than for carbon mesopores. We have also studied the melting behavior of D2O confined in OMC and SBA-15 by applying the dielectric method. The results show that the depression of the melting temperature of D2O in the pores of OMC is about 15 K higher relative to the depression of the melting temperature in SBA-15 pores with a comparable 5 nm size. This is caused by the influence of adsorbate/adsorbent interactions of the studied matrices.

Here we report the synthesis and characterization of ordered nanoporous carbon (with a 4.6 nm pore size) and SBA-15 (with a 5.3 nm pore size). The work describes the surface and textural properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the materials.

Propriedades de superfície de carbono de Nanoporous sintetizado e matrizes de sílica

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) ...

Bio-inspired Polydopamine Surface Modification of Nanodiamonds and Its Reduction of Silver Nanoparticles

Surface functionalization of nanodiamonds (NDs) is still challenging due to the diversity of functional groups on the ND surfaces. Here, we demonstrate a simple protocol for the multifunctional surface modification of NDs by using mussel-inspired polydopamine (PDA) coating. In addition, the functional layer of PDA on NDs could serve as a reducing agent to synthesize and stabilize metal nanoparticles. Dopamine (DA) can self-polymerize and spontaneously form PDA layers on ND surfaces if the NDs and dopamine are simply mixed together. The thickness of a PDA layer is controlled by varying the concentration of DA. A typical result shows that a thickness of ~5 to ~15 nm of the PDA layer can be reached by adding 50 to 100 &#181;g/mL of DA to 100 nm ND suspensions. Furthermore, the PDA-NDs are used as a substrate to reduce metal ions, such as Ag[(NH3)2]+, to silver nanoparticles (AgNPs). The sizes of the AgNPs rely on the initial concentrations of Ag[(NH3)2]+. Along with an increase in the concentration of Ag[(NH3)2]+, the number of NPs increases, as well as the diameters of the NPs. In summary, this study not only presents a facile method for modifying the surfaces of NDs with PDA, but also demonstrates the enhanced functionality of NDs by anchoring various species of interest (such as AgNPs) for advanced applications.

A facile protocol is presented to functionalize the surfaces of nanodiamonds with polydopamine.

Modificação de superfície de Polydopamine bio-inspirada de nanodiamantes e sua redução de nanopartículas de prata

Surface functionalization of nanodiamonds (NDs) is still challenging due to the diversity of functional groups on the ND surfaces. Here, we demonstrate a ...

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of &#945;-Imino &#947;-Lactones and Alkylidene Pyrazolones

Bispirocyclic scaffolds are one of the important structural subunits in many natural products that exhibit diverse and attractive biological activities. Recently, we have developed an efficient organocatalytic strategy, which provides facile access to a variety of enantiomerically enriched bispiro[&#947;-butyrolactone-pyrrolidin-4,4&#39;-pyrazolone] skeletons. In this paper, we demonstrate a detailed protocol for the asymmetric synthesis of drug-like bispirocyclic compounds with two spirocyclic carbon centers via an organocatyltic 1,3-dipolar cycloaddition reaction. Spirocyclization synthons &#945;-imino &#947;-lactones and alkylidene pyrazolones are prepared first, which are then subjected to a cycloaddition reaction in the presence of a bifunctional squaramide organocatalyst to afford the desired bispirocycles in high yields and excellent stereoselectivities. Chiral high-performance liquid chromatography (HPLC) is carried out to determine the enantiomeric purity of the products, and the d.r. value is examined by proton nuclear magnetic resonance (1H NMR). The absolute configuration of the product is assigned according to an X-ray crystallographic analysis. This synthetic strategy allows scientists to prepare a diversity of bispirocyclic scaffolds in high yields and excellent diastereo- and enantioselectivities.

Enantiomerically enriched bispiro[&#947;-butyrolactone-pyrrolidin-4,4&#39;-pyrazolone] skeletons are asymmetrically synthesized through a simple organocatalytic 1,3-dipolar cycloaddition reaction.

Construção eficiente de andaimes de drogas, como Bispirocyclic Via Organocatalytic cicloadições de γ-lactonas α-Imino e pirazolonas Alkylidene

Bispirocyclic scaffolds are one of the important structural subunits in many natural products that exhibit diverse and attractive biological activities. ...

Chemical Inactivation of the E3 Ubiquitin Ligase Cereblon by Pomalidomide-based Homo-PROTACs

The immunomodulatory drugs (IMiDs) thalidomide and its analogs, lenalidomide and pomalidomide, all FDA approved drugs for the treatment of multiple myeloma, induce ubiquitination and degradation of the lymphoid transcription factors Ikaros (IKZF1) and Aiolos (IKZF3) via the cereblon (CRBN) E3 ubiquitin ligase for proteasomal degradation. IMiDs have recently been utilized for the generation of bifunctional proteolysis targeting chimeras (PROTACs) to target other proteins for ubiquitination and proteasomal degradation by the CRBN E3 ligase. We designed and synthesized pomalidomide-based homobifunctional PROTACs and analyzed their ability to induce self-directed ubiquitination and degradation of CRBN. Here, CRBN serves as both, the E3 ubiquitin ligase and the target at the same time. The homo-PROTAC compound 8 degrades CRBN with a high potency with only minimal remaining effects on IKZF1 and IKZF3. CRBN inactivation by compound 8 had no effect on cell viability and proliferation of different multiple myeloma cell lines. This homo-PROTAC abrogates the effects of IMiDs in multiple myeloma cells. Therefore, our homodimeric pomalidomide-based compounds may help to identify CRBN&#8216;s endogenous substrates and physiological functions and investigate the molecular mechanism of IMiDs.

This work describes the synthesis and characterization of a pomalidomide-based, bifunctional homo-PROTAC as a novel approach to induce ubiquitination and degradation of the E3 ubiquitin ligase cereblon (CRBN), the target of thalidomide analogs.

Inativação química da E3 ubiquitina ligase Cereblon por Homo-PROTACs à base de Pomalidomida

The immunomodulatory drugs (IMiDs) thalidomide and its analogs, lenalidomide and pomalidomide, all FDA approved drugs for the treatment of multiple ...