Tallury Padmavathy, Airrabeelli Ramadevi, Li Jun, Paquette David, Kalachandra Sid
Department of Periodontology, School of Dentistry, University of North Carolina, Chapel Hill, NC 27599-7455, USA.
Dent Mater. 2008 Feb;24(2):274-80. doi: 10.1016/j.dental.2007.05.008. Epub 2007 Jul 12.
To study the release of antiviral drug acyclovir (ACY) and antibacterial drug chlorhexidine diacetate (CDA) from synthesized copolymers of ethyl methacrylate and hexyl methacrylate of different molecular weights. The effect of the copolymer molecular weight and the effect of drug loading into the copolymer on the release of the drugs have been studied.
Copolymers (I-IV) of ethyl methacrylate (EMA) and hexyl methacrylate (HMA) were synthesized by free radical solution polymerization with a yield of 76-82%. The copolymer composition was determined by proton NMR spectroscopy. The molecular weight of the copolymers was determined by gel permeation chromatography (GPC). Copolymers I and II were of higher molecular weight while copolymers III and IV were of lower molecular weight. The copolymers were impregnated with 2.5 wt.% of ACY and CDA individually and the release rate of these drugs in water at 37 degrees C was examined. Drug loading was studied with 2.5, 5.0 and 7.5 wt.% of ACY and CDA incorporated into a separate polymer.
Measurements of the in vitro rate of drug release showed a sustained release of drug over extended period of time. ACY release rate increases with decrease in copolymer molecular weight from copolymers I to IV (p<0.001) while CDA showed a different release profile. CDA release rate was higher from higher molecular weight copolymers I and II than from lower molecular weight copolymers III and IV (p<0.001). ACY release rate increases steadily with increase in drug load (p=0.011) while CDA release rate had a leveling effect with increase in drug load.
Varying the copolymer molecular weight as well as the drug concentration alters the drug release rates and thus it is possible to control the drug release rates to a desired value.
研究不同分子量的甲基丙烯酸乙酯与甲基丙烯酸己酯合成共聚物中抗病毒药物阿昔洛韦（ACY）和抗菌药物醋酸氯己定（CDA）的释放情况。研究了共聚物分子量以及药物载入共聚物对药物释放的影响。
通过自由基溶液聚合法合成甲基丙烯酸乙酯（EMA）和甲基丙烯酸己酯（HMA）的共聚物（I-IV），产率为76-82%。通过质子核磁共振光谱法测定共聚物组成。通过凝胶渗透色谱法（GPC）测定共聚物的分子量。共聚物I和II分子量较高，而共聚物III和IV分子量较低。分别用2.5 wt.%的ACY和CDA浸渍共聚物，并检测这些药物在37℃水中的释放速率。研究了将2.5、5.0和7.5 wt.%的ACY和CDA载入单独聚合物中的载药量情况。
体外药物释放速率测量显示药物在较长时间内持续释放。从共聚物I到IV，随着共聚物分子量降低，ACY释放速率增加（p<0.001），而CDA呈现不同的释放曲线。较高分子量的共聚物I和II中CDA的释放速率高于较低分子量的共聚物III和IV（p<0.001）。ACY释放速率随载药量增加而稳步增加（p=0.011），而CDA释放速率随载药量增加有趋于平稳的效应。
改变共聚物分子量以及药物浓度会改变药物释放速率，因此有可能将药物释放速率控制到理想值。
