根据《Manual on developmentand use of FAO and WHOspecifications forpesticides》Clauses for free active ingredient content and releaserate of the active ingredient are required only for the encapsulated activeingredient(s) and only if appropriate to the intended properties of thecapsules. A clause to control release rate is usually required for capsulesintended to possess slow- or controlled-release properties. A clause to controlfree active ingredient is usually required where encapsulation is intended tocontrol the release or stability of the active ingredient, or to decrease therisk to users from accidental exposure to the active ingredient. If more thanone active ingredient is encapsulated, limits must be provided for each.Methods for determination of free active ingredient and release rate may beproduct-specific.
由此可以看出：对胶囊中的有效成分抱有某种特殊目的才需要规定游离有效成分含量和有效成分释放速率。
释放速率：对胶囊具有缓释或者控制释放性能的需求规定此项目指标。
游离有效成分含量：为了控制有效成分释放或稳定性或者降低使用者偶然接触有效成分的危险，规定此项目指标
通常微囊悬浮剂、微囊悬浮-水乳剂、微囊悬浮-悬浮剂、微囊悬浮-悬乳剂等均要求设定释放速率和游离有效成分含量项目和指标
例：高效氯氟氰菊酯属于神经毒剂，皮肤接触后会感到刺痛。将高效氯氟氰菊酯包囊后能有效减轻中毒症状。