Water sorption properties of HM-pectin and liposomes intended to alleviate dry mouth.
Pharmaceutical formulations intended for treatment of xerostomia (dry mouth) should be able to keep the oral mucosa hydrated for a prolonged period of time. The products already existing on the market contain water-soluble polymers, however their ability to moisturize the oral mucosa for a longer period of time seems limited. In this paper the sorption properties of water vapor of high-methoxylated pectin (HM-pectin, a hydrophilic biopolymer) and phosphatidylcholine-based (Soya-PC) liposomes have been studied and compared using a gravimetric method. The kinetics of water desorption and sorption have been recorded over the relative humidity range RH=95-0-95%, at 35°C. The obtained isotherms were found to be well described by the n-layer Brunauer-Emmet-Teller (BET) adsorption model. The water isotherms on HM-pectin were Type II (IUPAC), while water isotherms on liposomes were Type III. The maximum water sorption capacity of liposomes (1.2mg water per mg of adsorbent at 95% RH) was found to be twice as high as for pectin. Due to the slower water release from the liposomes, as well as their high water sorption capacity, they seem to have great potential in relieving the symptoms of dry mouth syndrome.
Department of Pharmacy, School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, 0316 Oslo, Norway. Electronic address: m.i.adamczak@farmasi.uio.no.
Małgorzata I
MI
Adamczak
Department of Physics, University of Oslo, P.O. Box 1048 Blindern, 0316 Oslo, Norway; Department of Clinical and Biomedical Engineering, Oslo University Hospital, 0372 Oslo, Norway.
Ørjan G
ØG
Martinsen
Department of Pharmacy, School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, 0316 Oslo, Norway.
Gro
G
Smistad
Department of Pharmacy, School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, 0316 Oslo, Norway.
Marianne
M
Hiorth
D000327:Adsorption; D002626:Chemistry, Pharmaceutical / Q000379:methods; D006813:Humidity; D007700:Kinetics; D008081:Liposomes; D010368:Pectins / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012995:Solubility; D013997:Time Factors; D014867:Water / Q000737:chemistry*; D014987:Xerostomia / Q000188:drug therapy
D008081:Liposomes; D010713:Phosphatidylcholines; D011108:Polymers; D014867:Water; D010368:Pectins
DVS; Dry mouth; HM-pectin; Hydration capacity; Liposomes; Oral mucosa; Water sorption