Adherence to Angiotensin‐Converting Enzyme Inhibitor Therapy for Heart Failure

This study examined adherence to angiotensin-converting enzyme inhibitor therapy among 171 heart failure clinic patients. Adherence was monitored over a 3-month period with an electronic event monitor housed in a medication bottle cap, which recorded the date and time the cap was opened and closed. The average percentage of days that the prescribed number of doses (regimen adherence) was taken over the observation period was 84%. Seventy-one percent of patients showed 85%-100% adherence with their daily regimen; 19% exhibited less than 70% adherence. The overall high rates of adherence to angiotensin-converting enzyme inhibitor therapy observed among heart failure clinic patients is consistent with research that shows improved outcomes for patients managed in heart failure clinics. Electronic medication monitoring can be useful in identifying a substantial fraction of patients who are poorly adherent so that interventions to improve adherence can be targeted toward them. Additional research is needed to develop and test adherence-enhancing interventions. Copyright 2002 CHF, Inc

Floating microspheres: a review

Gastric emptying is a complex process, one that is highly variable and that makes in vivo performance of drug delivery systems uncertain. A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI) transit time and to the non-uniformity of drug absorption throughout the alimentary canal. Floating or hydrodynamically controlled drug delivery systems are useful in such applications. Various gastroretentive dosage forms are available, including tablets, capsules, pills, laminated films, floating microspheres, granules and powders. Floating microspheres have been gaining attention due to the uniform distribution of these multiple-unit dosage forms in the stomach, which results in more reproducible drug absorption and reduced risk of local irritation. Such systems have more advantages over the single-unit dosage forms. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres.<br>O esvaziamento gástrico é um processo complexo, com elevada variabilidade e responsável pela incerteza do desempenho dos medicamentos in vivo. Dessa forma, os sistemas de liberação modificada de fármacos, com tempo de residência prolongado no estômago, em especial, considerando aqueles fármacos com janela de absorção na porção superior do intestino delgado, apresentam fundamental importância. As principais limitações relativas à absorção do fármaco são, no geral, atribuídas à variabilidade inter e intra-paciente do tempo de trânsito gastro-intestinal (GI) e da não-uniformidade da absorção do fármaco na extensão do canal alimentar. Assim, justifica-se a utilização dos sistemas flutuantes ou hidrodinâmicos de liberação de fármacos. Vários medicamentos gastrorretentivos estão disponibilizados no mercado e incluem comprimidos, cápsulas, pílulas, filmes laminados, microesferas flutuantes, grânulos e pós. As microesferas flutuantes apresentam maior destaque em função da distribuição granulométrica uniforme dessas formulações de dose múltipla. Como resultado, a absorção do fármaco apresenta maior reprodutibilidade e os riscos associados à irritação local são reduzidos. Tais sistemas apresentam maior vantagem quando comparado às formulações de dose única. A presente revisão tem como objetivo apresentar as publicações recentes referentes aos métodos de preparação, os vários parâmetros que afetam o desempenho e a caracterização das microesferas flutuantes. Além disso, o presente trabalho aborda a fisiologia do processo de esvaziamento gástrico no que se refere aos sistemas flutuantes de liberação de fármacos