title: Inclusion complex of piroxicam with beta-cyclodextrin and incorporation in hexadecyltrimethylammonium bromide based microemulsion.
abstract: The interaction of piroxicam with beta-cyclodextrin (beta-CD), hexadecyltrimethylammonium bromide-based microemulsion (ME), and ME in the presence of beta-CD aimed at the optimization of topical drug delivery was studied. UV-VIS absorption spectra at pH 5.5 were obtained with and without beta-CD and ME. The stability constant (K) values for the piroxicam/beta-CD complex in the pH range 4.5-6.0 varied from 87 to 29 M-1. The cationic microemulsion was characterized by pseudo-ternary phase diagram. The association constant (Ks) of piroxicam/ME was determined using the framework of the pseudophase model. The value of Ks obtained for piroxicam at pH 5.5 was 132 M-1. At the same pH, the value of Ks for the incorporation of piroxicam/beta-CD complex in the ME was 150 M-1.
authors.affiliation: Departamento de Farmácia Industrial, Centro de Ciências da Saúde, UFSM, Campus Universitário Camobí, 97119-900, Santa Maria, RS, Brazil.
authors.forename: M E
authors.initials: ME
authors.lastname: Dalmora
authors.forename: A G
authors.initials: AG
authors.lastname: Oliveira
mesh_terms: D000287:Administration, Topical; D000465:Algorithms; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000737:chemistry*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D003505:Cyclodextrins / Q000008:administration & dosage / Q000737:chemistry*; D016503:Drug Delivery Systems; D004355:Drug Stability; D004655:Emulsions; D005079:Excipients; D006863:Hydrogen-Ion Concentration; D010894:Piroxicam / Q000008:administration & dosage / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D047392:beta-Cyclodextrins
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002593:Cetrimonium Compounds; D003505:Cyclodextrins; D004655:Emulsions; D005079:Excipients; D047392:beta-Cyclodextrins; D010894:Piroxicam; C031215:betadex; D000077286:Cetrimonium