The solubility of certain pharmaceuticals is very small, if procaine penicillin is oily ketone of agent, corpus luteum is oily the agent, inject is in constant because absorb slow and form scleroma.

• 某些药物的溶解度很小，如普鲁卡因青霉素油剂、黄体酮油剂等，注射处常因吸收缓慢而形成硬结。