title: Assessment of polymer-polymer interactions in blends of HPMC and film forming polymers by modulated temperature differential scanning calorimetry.
abstract: OBJECTIVE
  To assess the miscibility and phase behavior of binary blends of hydroxypropylmethyl cellulose (HPMC) with hydroxypropyl cellulose (HPC), methylcellulose (MC), and polyvinylpyrrolidone (PVP).
  
  
  METHODS
  Polymer-polymer miscibility was assessed by measurement of the glass transition temperature (Tg) and the width of the glass transition temperature (W-Tg), using modulated temperature differential scanning calorimetry (MTDSC).
  
  
  RESULTS
  HPMC K4M/PVP and HPMC E5/MC blends were miscible as evidenced by a single, composition dependent, Tg throughout the entire composition range. HPMC/HPC blends were immiscible at all compositions. For the miscible blends, the variation in Tg with blend composition was compared to the values predicted by the Fox and Couchman-Karasz equations. At intermediate blend compositions, HPMC K4M/PVP blends exhibited negative deviations from ideal behavior. The Tg of the HPMC E5/MC blends was found to follow the Fox equation. The W-Tg measurements of the miscible blends gave evidence of phase separation at certain compositions.
  
  
  CONCLUSIONS
  MTDSC was shown to be a useful technique in characterizing the interactions between some commonly used pharmaceutical polymers.
authors.affiliation: Pharmaceutical Sciences, University of Maryland, School of Pharmacy, Baltimore 21201, USA.
authors.forename: N
authors.initials: N
authors.lastname: Nyamweya
authors.forename: S W
authors.initials: SW
authors.lastname: Hoag
mesh_terms: D002152:Calorimetry, Differential Scanning; D002482:Cellulose / Q000031:analogs & derivatives / Q000737:chemistry; D003460:Crystallization; D007700:Kinetics; D007785:Lactose / Q000031:analogs & derivatives* / Q000737:chemistry; D008567:Membranes, Artificial; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D008970:Molecular Weight; D010078:Oxazines; D011108:Polymers / Q000737:chemistry*; D011205:Povidone / Q000737:chemistry
chemical_list: D008567:Membranes, Artificial; D010078:Oxazines; D011108:Polymers; D002482:Cellulose; D008747:Methylcellulose; C071191:MK 458; C008079:hydroxypropylcellulose; D011205:Povidone; D007785:Lactose