%0 Journal Article
%T Biodegradable In Situ Gel-Forming Controlled Drug Delivery System Based on Thermosensitive Poly(-caprolactone)-Poly(ethylene glycol)-Poly(-caprolactone) Hydrogel
%A Elham Khodaverdi
%A Ali Golmohammadian
%A Seyed Ahmad Mohajeri
%A Gholamhossein Zohuri
%A Farnaz Sadat Mirzazadeh Tekie
%A Farzin Hadizadeh
%J ISRN Pharmaceutics
%D 2012
%R 10.5402/2012/976879
%X Traditional drug delivery systems which are based on multiple dosing regimens usually pose many disadvantages such as poor compliance of patients and drug plasma level variation. To overcome the obstacles of traditional drug formulations, novel drug delivery system PCL-PEG-PCL hydrogels have been purposed in this study. Copolymers were synthesized by rapid microwave-assisted and conventional synthesis methods. Polymer characterizations were done using gel permeation chromatography and 1H-NMR. Phase transition behavior was evaluated by inverting tube method and in vitro drug release profile was determined using naltrexone hydrochloride and vitamin B12 as drug models. The results indicated that loaded drug structure and copolymer concentration play critical roles in release profile of drugs from these hydrogels. This study also confirmed that synthesis of copolymer using microwave is the most effective method for synthesis of this kind of copolymer. 1. Introduction Treatment of disease by multiple dosing strategies and using conventional drug formulation poses many drawbacks [1]. Among them are fluctuation of drug plasma concentration, the various side effects due to toxic plasma level of drug, or ineffectiveness treatment because of the lower concentration of drug than its therapeutic index [2, 3]. Another important limitation of multiple dosing regimens is poor patient compliance especially for diseases for which patient must take drugs for a long time such as epilepsy [4, 5] or for some specific drugs such as naltrexone hydrochloride which is used for maintenance abstinence in detoxified addicted persons after withdrawal phase of opioids and alcohol [6, 7]. Nowadays scientists are interested in novel drug delivery systems which are used to direct drugs to the specific site of action and to achieve a controlled release of drug with a desirable release kinetics [1, 8]. Among the most studied of these systems are hydrogels which are insoluble matrices of hydrophilic block copolymers which swell in presence of fluids [9, 10]. Smart hydrogels are the polymeric networks which release drugs in response to the environmental parameters such as temperature [11¨C13], pH [14, 15], light [16, 17], magnetisms [18, 19]. Thermoresponsive hydrogels are extensively investigated smart hydrogels because of their simple application, low adverse effect on tissues compared with some other stimuli, and the difference between room and body temperature [12, 20]. Amphiphilic triblock copolymers, PCL-PEG-PCL, composed of polyethylene glycol (PEG) and poly (¦Å-caprolactone) (PCL),
%U http://www.hindawi.com/journals/isrn.pharmaceutics/2012/976879/