title: Investigation of interaction of promethazine with cyclodextrins.
abstract: The effect of beta-CD and its substituted derivatives (DM-beta-CD and HP-beta-CD) on the solubility and photostability of promethazine was investigated in solution and in the solid state. The soluble complexes of protonated (pH = 6.8) and basic (pH = 10.8) forms of promethazine with CDs were studied using the spectral method. The influence of pH and CD complexation on photostability of PM in solution was followed. It was found that the photochemical decomposition of promethazine (PM) alone and in the presence of CD proceeds according to the first order reaction. It was also established that as well the presence of CD as the acidic medium of reaction increased the photostability of PM in solution. Formation of solid inclusion complexes of PM with CDs was evaluated using FT IR, 13C NMR and DSC methods. The results obtained indicate that independently of the complexation method in the solid state (kneading or heating), the presence of CD decreases the solubility of PM; the reason may be that the phenothiazine ring of PM did not enter into the cavity of beta-CD and its derivatives.
authors.affiliation: Department of Inorganic and Analytical Chemistry, K. Marcinkowski Medical University, Poznań, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Lutka
mesh_terms: D003505:Cyclodextrins / Q000032:analysis* / Q000737:chemistry / Q000493:pharmacokinetics; D004347:Drug Interactions; D006634:Histamine H1 Antagonists / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics; D011398:Promethazine / Q000032:analysis* / Q000737:chemistry / Q000493:pharmacokinetics; D012995:Solubility
chemical_list: D003505:Cyclodextrins; D006634:Histamine H1 Antagonists; D011398:Promethazine