{"title":"冻干无定形材料表面熔化和膨化的预测模型。","authors":"Sukritta Anantawittayanon, Kiyoshi Kawai","doi":"10.1016/j.cryobiol.2024.104938","DOIUrl":null,"url":null,"abstract":"<div><p>It is thought that surface melting and puffing of freeze-dried amorphous materials are related to the difference between the surface temperature (<em>T</em><sub>sur</sub>) and freeze-concentrated glass transition temperature (<em>T</em><sub>g</sub>’) of the materials. Although <em>T</em><sub>g</sub>’ is a material-specific parameter, <em>T</em><sub>sur</sub> is affected by the type and amount of solute and freeze-drying conditions. Therefore, it will be practically useful for preventing surface melting and puffing if <em>T</em><sub>sur</sub> can be calculated using only the minimum necessary parameters. This study aimed to establish a predictive model for the surface melting and puffing of freeze-dried amorphous materials according to the calculated <em>T</em><sub>sur</sub>. First, a <em>T</em><sub>sur</sub>-predictive model was proposed under the thermodynamic equilibrium assumptions. Second, solutions with various solute mass fractions of sucrose, maltodextrin, and sucrose-maltodextrin mixture were prepared, and three material-specific parameters (<em>T</em><sub>g</sub>’, unfrozen water content, and true density) were experimentally determined. According to the proposed model with the parameters, the <em>T</em><sub>sur</sub> of the samples was calculated at chamber pressures of 13, 38, and 103 Pa. The samples were freeze-dried at the chamber pressures, and their appearance was observed. As expected, surface melting and puffing occurred at calculated <em>T</em><sub>sur</sub> > <em>T</em><sub>g</sub>’ with some exceptions. The water activity (<em>a</em><sub>w</sub>) of the freeze-dried samples increased as the <em>T</em><sub>sur</sub> − <em>T</em><sub>g</sub>’ increased. This will have resulted from surface melting and puffing, which created a covering film, thereby preventing subsequent dehydration. The observations suggest that the proposed model is also useful for predetermining the drying efficiency and storage stability of freeze-dried amorphous materials.</p></div>","PeriodicalId":2,"journal":{"name":"ACS Applied Bio Materials","volume":null,"pages":null},"PeriodicalIF":4.6000,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Predictive model for the surface melting and puffing of freeze-dried amorphous materials\",\"authors\":\"Sukritta Anantawittayanon, Kiyoshi Kawai\",\"doi\":\"10.1016/j.cryobiol.2024.104938\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>It is thought that surface melting and puffing of freeze-dried amorphous materials are related to the difference between the surface temperature (<em>T</em><sub>sur</sub>) and freeze-concentrated glass transition temperature (<em>T</em><sub>g</sub>’) of the materials. Although <em>T</em><sub>g</sub>’ is a material-specific parameter, <em>T</em><sub>sur</sub> is affected by the type and amount of solute and freeze-drying conditions. Therefore, it will be practically useful for preventing surface melting and puffing if <em>T</em><sub>sur</sub> can be calculated using only the minimum necessary parameters. This study aimed to establish a predictive model for the surface melting and puffing of freeze-dried amorphous materials according to the calculated <em>T</em><sub>sur</sub>. First, a <em>T</em><sub>sur</sub>-predictive model was proposed under the thermodynamic equilibrium assumptions. Second, solutions with various solute mass fractions of sucrose, maltodextrin, and sucrose-maltodextrin mixture were prepared, and three material-specific parameters (<em>T</em><sub>g</sub>’, unfrozen water content, and true density) were experimentally determined. According to the proposed model with the parameters, the <em>T</em><sub>sur</sub> of the samples was calculated at chamber pressures of 13, 38, and 103 Pa. The samples were freeze-dried at the chamber pressures, and their appearance was observed. As expected, surface melting and puffing occurred at calculated <em>T</em><sub>sur</sub> > <em>T</em><sub>g</sub>’ with some exceptions. The water activity (<em>a</em><sub>w</sub>) of the freeze-dried samples increased as the <em>T</em><sub>sur</sub> − <em>T</em><sub>g</sub>’ increased. This will have resulted from surface melting and puffing, which created a covering film, thereby preventing subsequent dehydration. The observations suggest that the proposed model is also useful for predetermining the drying efficiency and storage stability of freeze-dried amorphous materials.</p></div>\",\"PeriodicalId\":2,\"journal\":{\"name\":\"ACS Applied Bio Materials\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":4.6000,\"publicationDate\":\"2024-07-11\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"ACS Applied Bio Materials\",\"FirstCategoryId\":\"99\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0011224024000932\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATERIALS SCIENCE, BIOMATERIALS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Applied Bio Materials","FirstCategoryId":"99","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0011224024000932","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, BIOMATERIALS","Score":null,"Total":0}
Predictive model for the surface melting and puffing of freeze-dried amorphous materials
It is thought that surface melting and puffing of freeze-dried amorphous materials are related to the difference between the surface temperature (Tsur) and freeze-concentrated glass transition temperature (Tg’) of the materials. Although Tg’ is a material-specific parameter, Tsur is affected by the type and amount of solute and freeze-drying conditions. Therefore, it will be practically useful for preventing surface melting and puffing if Tsur can be calculated using only the minimum necessary parameters. This study aimed to establish a predictive model for the surface melting and puffing of freeze-dried amorphous materials according to the calculated Tsur. First, a Tsur-predictive model was proposed under the thermodynamic equilibrium assumptions. Second, solutions with various solute mass fractions of sucrose, maltodextrin, and sucrose-maltodextrin mixture were prepared, and three material-specific parameters (Tg’, unfrozen water content, and true density) were experimentally determined. According to the proposed model with the parameters, the Tsur of the samples was calculated at chamber pressures of 13, 38, and 103 Pa. The samples were freeze-dried at the chamber pressures, and their appearance was observed. As expected, surface melting and puffing occurred at calculated Tsur > Tg’ with some exceptions. The water activity (aw) of the freeze-dried samples increased as the Tsur − Tg’ increased. This will have resulted from surface melting and puffing, which created a covering film, thereby preventing subsequent dehydration. The observations suggest that the proposed model is also useful for predetermining the drying efficiency and storage stability of freeze-dried amorphous materials.