Boulton D W, Fawcett J P, Woods D J
School of Pharmacy, University of Otago, Dunedin, New Zealand.
Am J Health Syst Pharm. 1996 May 15;53(10):1157-61. doi: 10.1093/ajhp/53.10.1157.
The stability of levothyroxine sodium in oral liquid dosage forms compounded from commercially available tablets was studied. Levothyroxine sodium oral liquids (25 micrograms/mL) were prepared from tablets and from powder with and without methylparaben preservative and transferred to amber, high-density polyethylene bottles. Five bottles of each tablet-based formulation were stored at 2-8 degrees C, 23-27 degrees C, and 38-42 degrees C, and five bottles of each powder-based formulation were stored at 38-42 degrees C. On days 3, 8, 14, 22, 31, 61, and 90, samples were taken from each bottle and analyzed for drug concentration by stability-indicating high-performance liquid chromatography. There was significant degradation of levothyroxine sodium in all the formulations. However, the tablet-based formulation without preservative stored at 4 degrees C retained at least 90% of its initial concentration for eight days after compounding. Degradation occurred faster in the tablet-based formulation with preservative. None of the formulations retained > or = 90% initial potency by day 14. An extemporaneous oral liquid formulation of levothyroxine sodium 25 micrograms/mL compounded from crushed tablets was stable for eight days when stored in amber bottles at 4 degrees C.
研究了由市售片剂配制的左甲状腺素钠口服液体制剂的稳定性。用片剂和粉末分别制备含和不含对羟基苯甲酸甲酯防腐剂的左甲状腺素钠口服液（25微克/毫升），并转移至琥珀色高密度聚乙烯瓶中。每种基于片剂的制剂取五瓶分别储存在2 - 8℃、23 - 27℃和38 - 42℃，每种基于粉末的制剂取五瓶储存在38 - 42℃。在第3、8、14、22、31、61和90天，从每个瓶子中取样，通过稳定性指示高效液相色谱法分析药物浓度。所有制剂中的左甲状腺素钠均有显著降解。然而，不含防腐剂且储存在4℃的基于片剂的制剂在配制后八天内至少保留了其初始浓度的90%。含防腐剂的基于片剂的制剂降解更快。到第14天，没有一种制剂保留≥90%的初始效价。由碾碎的片剂配制的25微克/毫升左甲状腺素钠临时口服液体制剂，储存在4℃的琥珀色瓶中时，八天内稳定。
