Protein drug VS aggregation(聚合)

 

蛋白質很特別, 他由胺基酸組成很大一條, 上面可能有正電與負電, 可能產生不正常的鍵結(可能自我錯誤摺疊, 或是與其他條蛋白連結), 此狀態稱為aggregation(聚合).

 

部分內在疾病與protein aggregation有關, (例如Alzheimer disease就是beta-amyloid, 可稱為澱粉樣變性病).

 

產品的外觀(appearance)是最基本的重要放行項目(release specification), 在ICH中也提及這是基本的檢測項目, 但要怎麼做呢? 要做什麼呢?

ICH Q6B (Specifications: Test Procedures and Acceptance Criteria for Biotechnological/Biological Products)也只有提到:

A qualitative(量化) statement describing the physical state (e.g. solid, liquid) and color of DS/DP should be provided.

 

只有訂出general, 但可以更細膩的SOP大概是

-      取樣sampling procedure

n   取多少量(有不須取樣, 直接看syringe的嗎?)

n   怎麼取樣[eg從syringe的needle打出來, 還是bottom用pipet取出] (若有沉澱, 是否從needle打出來就不一定可以收集到?)

n   取到哪裡(先用WFI 清洗過且烘乾過的test tube?)

-      怎麼檢測testing method

n   肉眼/黑白板inspect sample with eyes against black and white board

n   光源intensity of illumination should not be less than 1000Lux.

-      標準criteria (液體, 透明/白色, 澄清/沉澱)

-      紀錄: 拍照黏貼

 

另外, 參考US FDA: Guidance for Industry – Immunogenicity Assessment for Therapeutic Protein Products

 

若是在product上產生, that can potential to elicit or enhance immune responses include the following:

-      extensive cross-linking of B-cell receptors, causing efficient B-cell activation;

-      enhancing antigen uptake, processing and presentation;

-      triggering immuno-stimulatory danger signal

 

建議Therefore, Recommend as following:

-      Selecting manufacturing condition

-      Employing a robust purification scheme (remove aggregates to the greatest extent possible)

-      Choosing formulation

-      Choosing container closure system

-      Expiration date take account any increase in protein aggregation associated with protein denaturation or degradation during storage.

 

【Guidance for Industry – Immunogenicity Assessment for Therapeutic Protein Products】

https://www.fda.gov/media/85017/download