{"title":"Low temperature properties of lyophilized solutions and their influence on lyophilization cycle design: pentamidine isethionate.","authors":"N A Williams, D L Schwinke","doi":"","DOIUrl":null,"url":null,"abstract":"<p><p>Pentamidine isethionate is a lyophilized antiprotozoal drug. Its solutions, when lyophilized, have been found to exhibit a range of properties that depend on its concentration and the manner in which it is allowed to freeze. These properties were examined by Differential Scanning Calorimetry (DSC), freeze-drying microscopy and X-ray powder diffraction. In DSC studies, the drug exhibited eutectic behavior with a eutectic temperature of -2.8 degrees C. Freeze-drying microscopic examination of a sample of solution after cooling at about 1 degrees C/min showed that the sample dried with retention up to -4 degrees C, where melting was observed. By using the appropriate drug concentration and manipulating the freezing stage, crystallization of the drug from solution could be induced during cooling to yield a crystalline end-product.</p>","PeriodicalId":79406,"journal":{"name":"Journal of pharmaceutical science and technology : the official journal of PDA","volume":"48 3","pages":"135-9"},"PeriodicalIF":0.0000,"publicationDate":"1994-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of pharmaceutical science and technology : the official journal of PDA","FirstCategoryId":"1085","ListUrlMain":"","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Pentamidine isethionate is a lyophilized antiprotozoal drug. Its solutions, when lyophilized, have been found to exhibit a range of properties that depend on its concentration and the manner in which it is allowed to freeze. These properties were examined by Differential Scanning Calorimetry (DSC), freeze-drying microscopy and X-ray powder diffraction. In DSC studies, the drug exhibited eutectic behavior with a eutectic temperature of -2.8 degrees C. Freeze-drying microscopic examination of a sample of solution after cooling at about 1 degrees C/min showed that the sample dried with retention up to -4 degrees C, where melting was observed. By using the appropriate drug concentration and manipulating the freezing stage, crystallization of the drug from solution could be induced during cooling to yield a crystalline end-product.