Linked Life Data

10053214

Source:http://linkedlifedata.com/resource/pubmed/id/10053214

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1999-4-29
pubmed:abstractText
This review focuses on the thermal analysis of hydroxypropylmethylcellulose (HPMC) and methylcellulose. Differential scanning calorimetry (DSC) of their powders is used to determine temperatures of moisture loss (in conjunction with thermogravimetric analysis) and glass transition temperatures. However, sample preparation and encapsulation affect the values obtained. The interaction of these cellulose ethers with water is evaluated by DSC. Water is added to the powder directly in DSC pans or preformed gels can be evaluated. Data quality depends on previous thermal history but estimates of the quantity of water bound to the polymers may be made. Water uptake by cellulose ethers may be evaluated by the use of polymeric wafers and by following loss of free water, over a series of timed curves, into wafers in contact with water. Cloud points, which assess the reduction of polymer solubility with increase of temperature, may be assessed spectrophotometrically. DSC and rheometric studies are used to follow thermogelation, a process involving hydrophobic interaction between partly hydrated polymeric chains. The advantages and disadvantages of the various methodologies are highlighted.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0378-5173
pubmed:author
pubmed:copyrightInfo
Copyright.
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
179
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
209-28
pubmed:dateRevised
2010-6-25
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Thermal analysis of hydroxypropylmethylcellulose and methylcellulose: powders, gels and matrix tablets.
pubmed:affiliation
School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK. j.l.ford@livjm.ac.uk
pubmed:publicationType
Journal Article, Review