tailieunhanh - Báo cáo hóa học: " Intestine-Specific, Oral Delivery of Captopril/ Montmorillonite: Formulation and Release Kinetics"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Intestine-Specific, Oral Delivery of Captopril/ Montmorillonite: Formulation and Release Kinetics | Madurai et al. Nanoscale Res Lett 2011 6 15 http content 6 1 15 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Intestine-Specific Oral Delivery of Captopril Montmorillonite Formulation and Release Kinetics 1 112 1 Suguna Lakshmi Madurai Stella Winnarasi Joseph Asit Baran Mandal John Tsibouklis Boreddy SR Reddy Abstract The intercalation of captopril CP into the interlayers of montmorillonite MMT affords an intestine-selective drug delivery system that has a captopril-loading capacity of up to ca. 14 w w and which exhibits near-zero-order release kinetics. Introduction Captopril CP 1- 2s -3-mercapto-2-methyl propionyl -L- proline an orally active inhibitor of angiotensinconverting enzyme ACE 1 2 is in many countries the medication of choice for the management of hypertension and is often used to treat some types of congestive heart failure 3-6 . CP contains a reactive thiol group which is postulated to bind to the Zn2 of the angiotensin-converting enzyme 7 and which forms the disulfide linkages with thiol-containing residues of plasma proteins that are responsible for the extensive tissue binding of the drug 8 . Owing to its pKa at 25 C CP is highly soluble in water at acidic pH 125-160 mg ml at pH . At pH pKa the amidic linkage of the molecule becomes increasingly susceptible to hydrolysis under basic conditions the drug exhibits a pseudo-first-order degradation reaction 9 10 . In man CP reduces plasma angiotensin II and aldosterone levels increases plasma renin activity and produces a significant decrease in blood pressure in hypertensive patients 11 . It blocks the enzyme system that causes the relaxation of artery walls reducing blood pressure decreasing symptoms of cystinuria and reducing rheumatoid arthritis symptoms. The duration of the antihypertensive action of a single oral dosing of CP is 6-8 h with the implication that clinical administration requires the daily dose of mg to be .