藥物傳輸系統已經研究了許多年，而許多擁有相當高活性的分子，往往因為其相對高的毒性，而無法當作藥物使用，因此，使用藥物傳輸系統，可以有效的降低其活性，並增加其可當作藥物使用之機率。再者，適當調整藥物傳輸系統，可以有效控制釋放藥物在病兆處。
於本篇論文中，本人提出一個新的概念，將諾里什反應(Norrish reaction) 引導至藥物載體聚乳酸-甘醇酸中，我們用乙醯乙酸乙酯作為起始物並將其位置導入三甲基矽基，為了在末端生成羥基，我們先用兩個鹼移除掉ethyl -[(trimethylsilyl)methyl]acetoacetate上之兩個氫，再與chloromethyl benzyl ether進行加成反應，此後在氫氣條件下，使用鈀金屬催化移除苄基得到末端羥基產物，且再用鹼性條件使其成為設計之單體，最後將其與lactide及glycolide進行聚合反應，得到產率為78%之高分子，其平均分子量約為24,000。
我們將合成出之聚合物藉由中壓汞燈的照射，得到斷裂後的碎片，其分子量約為8,000，經過計算，平均鍵結斷裂數為1.8，而斷裂效率為92.4%。

Drug delivery system has been investigated for several years. Several excellent drug candidates failed to be applied on clinical usage, as their high toxicity to both tumor and normal cells. Therefore, by using drug delivery system, the toxicity of these candidates could be neutralized, and potential new therapeutics could be developed. Furthermore, effective drug controlled release could be well manipulated by drug delivery system.
In this thesis, we have developed a new concept to apply Norrish Type reaction on poly(lactic-co-glycolic acid) to produce a novel polymer for drug delivery and release. First, we used ethyl acetoacetate as starting materials and introduced silyl group on position of acetate. Second, to modify the monomer with the hydroxyl group, we treated ethyl -[(trimethylsilyl)methyl]acetoacetate with two kinds of bases and chloromethyl benzyl ether, then we used palladium to deprotect benzyl group under hydrogen and the following basic treatment to get the desired monomer. Furthermore, we carried out polymerization with lactide, glycolide and the designed monomer in 78% yield; the average molecular weight of polymeric product is about 24,000 Da, estimated by GPC.
Finally, the photo treatment of designed polymer was performed with medium-pressure mercury UV lamp. After photo-irradiated induction, the synthesized polymer was cleaved into the fragments of molecular weight about 8,000 Da; the average numbers of bond broken is 1.8, and the efficiency of bond broken is 92.5%. This photo sensitivity of polymer can be modified to control the polymer cleavage, as well as to control and release the drug bound to the polymer. With the delivery of polymeric carrier, the cellular local density of drug concentration would be higher than delivery without any assistance. Also, the polymeric shielding could decrease the rate of metabolism of drug in the body and keep the drug concentration in the blood at the proper range.

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