配制注射液或眼用溶液时要注意将溶液调成与血掖或泪液渗透压相等的等渗溶液。等渗溶液的调制需要预先计算好,其方法有几种,通常是采用渗透压法或冰点下降法来求得欲配制药液的渗透压,然后再将其调成等渗。在进行运算时,我们要参看计算公式和查表,以求得一些计算公式中需用的数值。当然,利用一些公式和查表会使计算更方便一些,但是从根本理论上了解计算法则的来源则更为重要。这样可以记得牢,手头上缺乏现成的书或表也能计算,同时对一些表上不包括的新药的渗透压或冰点下降值,也可以根据原理推导演算出来。从理论上推导演算出来的数值与实际测定出来的数值有时会有一些误差,但由于临床使用的等渗溶液均是较为稀薄的溶液,不会产生大的误差,也很少影 When preparing injection or ophthalmic solution, be careful to adjust the solution to an isotonic solution of the same volume as the tampon or tear osmotic pressure. The preparation of isotonic solution needs to be pre-calculated, there are several ways, usually by using osmotic pressure or freezing point descent method to obtain the osmotic pressure of the liquid to be prepared, and then adjusted to be isotonic. In the calculation, we have to refer to the calculation formula and look-up table, in order to obtain some calculation formula required values. Of course, using some formulas and look-up tables makes calculations more convenient, but it is even more important to understand the sources of computational rules from a fundamental point of view. This can be remembered, the lack of ready-made books or tables on hand can be calculated, while the osmotic pressure or freezing point of some new drugs not included in the table can also be deduced based on the principle. There is sometimes some error in deriving the calculated and actual measured values ​​theoretically, but due to the clinical use of isotonic solutions that are relatively dilute solutions, they do not produce large errors and few images