Improvement of drug loading onto ion exchange resin by cyclodextrin inclusion complex.
BACKGROUND
Ion exchange resins have ability to exchange their counter ions for ionized drug in the surrounding medium, yielding "drug resin complex." Cyclodextrin can be applied for enhancement of drug solubility and stability.


OBJECTIVE
Cyclodextrin inclusion complex of poorly water-soluble NSAIDs, i.e. meloxicam and piroxicam, was characterized and its novel application for improving drug loading onto an anionic exchange resin, i.e. Dowex® 1×2, was investigated.


METHODS
β-Cyclodextrin (β-CD) and hydroxypropyl β-cyclodextrin (HP-β-CD) were used for the preparation of inclusion complex with drugs in solution state at various pH. The inclusion complex was characterized by phase solubility, continuous variation, spectroscopic and electrochemistry methods. Then, the drug with and without cyclodextrin were equilibrated with resin at 1:1 and 1:2 weight ratio of drug and resin.


CONCLUSIONS
Solubility of the drugs was found to increase with increasing cyclodextrin concentration and pH. The increased solubility was explained predominantly due to the formation of inclusion complex at low pH and the increased ionization of drug at high pH. According to characterization studies, the inclusion complex was successfully formed with a 1:1 stoichiometry. The presence of cyclodextrin in the loading solution resulted in the improvement of drug loading onto resin.


CONCLUSIONS
Enhancing drug loading onto ion-exchange resin via the formation of cyclodextrin inclusion complex is usable in the development of ion-exchange based drug delivery systems, which will beneficially reduce the use of harmful acidic or basic and organic chemicals.
Pharmaceutical Development of Green Innovations Group (PDGIG), Faculty of Pharmacy, Silpakorn University , Nakhon Pathom , Thailand.
Wipada
W
Samprasit
Theerasak
T
Rojanarata
Prasert
P
Akkaramongkolporn
Tanasait
T
Ngawhirunpat
Warisada
W
Sila-on
Praneet
P
Opanasopit
D000073738:2-Hydroxypropyl-beta-cyclodextrin; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis / Q000737:chemistry*; D003505:Cyclodextrins / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D004355:Drug Stability; D004553:Electric Conductivity; D005079:Excipients / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007475:Ion Exchange Resins / Q000737:chemistry*; D007700:Kinetics; D000077239:Meloxicam; D008958:Models, Molecular; D010894:Piroxicam / Q000032:analysis / Q000737:chemistry*; D012117:Resins, Synthetic / Q000737:chemistry; D064449:Sequestering Agents / Q000737:chemistry; D012995:Solubility; D013843:Thiazines / Q000032:analysis / Q000737:chemistry*; D013844:Thiazoles / Q000032:analysis / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry
D000894:Anti-Inflammatory Agents, Non-Steroidal; D003505:Cyclodextrins; D004337:Drug Carriers; D005079:Excipients; D007475:Ion Exchange Resins; D012117:Resins, Synthetic; D064449:Sequestering Agents; D013843:Thiazines; D013844:Thiazoles; D047392:beta-Cyclodextrins; D010894:Piroxicam; D000073738:2-Hydroxypropyl-beta-cyclodextrin; C036240:Dowex 1X2; C031215:betadex; D000077239:Meloxicam