胃幽門螺旋桿菌是一種影響著全世界過半的人口數的細菌，而這種細菌與慢性胃炎、胃十二指腸潰瘍與最常見並會導致死亡的胃癌有所關聯。最常見治療胃幽門桿菌感染的方法是服用一或二個抗生素添加鉍檸檬鹽長達兩星期。然而， 商用的藥品在胃的滯留時間是短暫的兩到四小時，而這種情況是很難在具有胃幽門螺旋桿菌的區域達到最小抑制濃度。但若此藥物在胃中迅速釋放，會導致有些患者會產生嚴重的副作用。
在本研究中的tetracycline搭載著海藻酸浮珠主要是用來提升現有的抗菌特性藥物。為了達成此實驗目的，準備了聚合物─海藻酸、HPMC以及殼聚醣所製成七種形式載有tetracycline的浮珠，而在這研究中選擇tetracycline是因為它的抗菌特性最廣。浮珠的物性測試包含了浮珠的外部型態、大小、膨脹率測量以及表面型態研究，體外試驗評估包含了藥物搭載量與包埋研究，體外的藥物釋放和漂浮特性，而抗菌測試包含了液態培養實驗與進行瓊脂盤擴散法。研究結果指出，搭載著tetracycline的乾燥橢圓型浮珠寬度分別介於1.02 ± 0.04 到 1.38 ± 0.10之間，而長度分別介於1.34 ± 0.03 到1.76 ± 0.05之間，可觀察出與無搭載藥物的珠相比，搭載著tetracycline的浮珠是相對較大的。由SEM結果可顯示出，整顆珠內含有小孔可以使它們浮在胃酸上面。
從橫切結構面的影像中可以得知，搭載Tetracycline的浮珠具有高密度的核心結構，而這是無搭載藥物的浮珠所缺乏的。若將核心含有HPMC的浮珠與核心僅含有海藻酸的浮珠作相互比較，可發現前者具有穩定且持續釋放的功能。藥物搭載量與包埋率的研究指出，含有殼聚醣塗層與相同製成但沒有殼聚醣塗層的浮珠相比下，前者比後者高出16%-18%的藥物包埋率。此外，發現殼聚醣塗層具有浮力支撐效果。在藥物濃度0.3 μg/ml的環境下，若要探討抑菌效果: 經過的優化製成 (Optimized formulation-F7) 搭載Tetracycline的浮珠與free drug 相比之下， 在24小時的細菌培育下有多了8%的抑菌效果，並且在48小時細菌培育下具有多了53%的抑菌效果。
此實驗研究結果顯示出，經過製成的浮珠有延長持續在胃滯留時間的能力以及從海藻酸基質中持續釋放tetracycline，此項結果有助於提升現有的療程與提高患者的治療接受度。

Helicobacter pylori is a bacterium which colonizes more than half of the world population that is linked to chronic gastritis, gastroduodenal ulcer diseases, and eventually gastric cancer, the fifth most common cancer and third most common cause of cancer death. Most common treatment of H. pylori infection is to take one or two effective antibiotics with bismuth citrate for 2 weeks. However, due to commercial tablets’ short gastric retention time which is 2 to 4 hours, it is difficult to reach minimum inhibition concentration to the area where H. pylori locates. Also due to rapid release of drug in stomach, some patients tend to experience serious side effects. In this study, tetracycline loaded alginate floating beads were prepared in help to improve current antibacterial medications. For this prospect, seven formulations of tetracycline loaded floating beads have been prepared using polymers - alginate, HPMC and chitosan, and tetracycline was chosen in this study due to its broad spectrum of antibacterial property. Beads characterization containing appearance of the beads, beads size and swelling measurement and surface morphology study, in-vitro evaluation containing drug loading and encapsulation study, in-vitro drug release and in-vitro floating properties and antibacterial tests containing liquid culture experiment and agar disk-diffusion method have been conducted.
Results have shown that width and length of the ellipse shaped tetracycline loaded dried beads ranged from 1.02 ± 0.04 to 1.38 ± 0.10 and from 1.34 ± 0.03 to 1.76 ± 0.05 respectively which is relatively bigger than blank beads due to drug loading. SEM photographs suggests that prepared beads contain small pores throughout its body that would provide them to float on medium. Cross-sectional images suggest that Tetracycline loaded beads have dense core structure which is absent in blank beads. Beads which contains HPMC in core matrix has more sustained release compared to beads that only consisted of alginate in core polymer. Drug loading and encapsulation efficiency results have shown beads coated with chitosan have 16-18% higher drug entrapment compared to same formulation that non-coated with chitosan beads. Furthermore, chitosan coating has been found to be supporting buoyancy. Optimized formulation (F7) of Tetracycline loaded beads at concentration of 0.3 μg/ml have shown 8% more inhibition in 24 hours of incubation and 53% more inhibition in 48 hours of incubation compared to free drug inhibition. The results have displayed that formulated beads have ability to remain in stomach for prolonged gastric retention time and sustained and prolonged release of tetracycline from alginate matrix that would improve current treatment method and patient compliance.

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