Barza M, Baum J, Szoka F
Invest Ophthalmol Vis Sci. 1984 Apr;25(4):486-90.
Subconjunctival injections of antibiotics produce very high corneal levels of drug that fall rapidly as the drug is dissipated. The authors studied the effects of liposome-encapsulation as a means of slowing release from the subconjunctival depot. Liposomes (0.1-1.0 micron) were made of phosphatidic acid, phosphatidylcholine, and alpha-tocopherol. The final suspension contained gentamicin 10 mg/ml with 60-70% encapsulated. Rabbits were given a single subconjunctival injection of liposome-encapsulated gentamicin, gentamicin with "empty" liposomes, or gentamicin alone. In each instance the dose of antibiotic was 5 mg. Gentamicin levels in the sclera and cornea, measured 3,9, and 24 hr after injection, were generally markedly higher with the liposome-encapsulated drug than with the other two preparations. The differences were 5- to 20-fold in the cornea at 24 hr and were statistically significant for temporal cornea. Liposome-encapsulation may be a useful means of extending the effects of a subconjunctival injection of antibiotic.
结膜下注射抗生素可使角膜药物浓度达到很高水平，但随着药物消散，浓度会迅速下降。作者研究了脂质体包裹作为一种减缓结膜下药物库释放药物的方法的效果。脂质体（0.1 - 1.0微米）由磷脂酸、磷脂酰胆碱和α-生育酚制成。最终悬浮液含有10毫克/毫升庆大霉素，其中60 - 70%被包裹。给兔子单次结膜下注射脂质体包裹的庆大霉素、含“空”脂质体的庆大霉素或单纯庆大霉素。在每种情况下，抗生素剂量均为5毫克。注射后3、9和24小时测量的巩膜和角膜中的庆大霉素水平，脂质体包裹的药物通常明显高于其他两种制剂。24小时时角膜中的差异为5至20倍，对颞侧角膜具有统计学意义。脂质体包裹可能是延长结膜下注射抗生素效果的一种有用方法。
