Liquid formulation of therapeutic proteins is a maturing technology. Demand for products that are easy to use in the clinic or that are amenable to self-administration make a ready to use liquid formulation desirable. Most modern liquid formulations have a simple composition; comprising a buffer, a tonicity modifier, a surfactant, sometimes a stabiliser, the therapeutic protein and water. Recent formulations of monoclonal antibodies often use histidine or acetate as the buffer, sucrose or trehalose as the tonicity modifier and polysorbate 20 or 80 as the surfactant with a pH of 5.7 +/− 0.4. The mechanisms for the behaviour of excipients is still debated by academics so formulation design is still a black art. Fortunately, a statistical approach like design of experiment is suitable for formulation development and has been successful when combined with accelerated stability experimentation. The development of prefilled syringes and pens has added low viscosity and shear resistance to the quality attributes for a successful formulation. To achieve patient compliance for self-administration, formulations that cause minimal pain and tissue damage is also desirable.

治疗性蛋白质的液体制剂是一种成熟的技术。对易于在诊所使用的产品或易于自我管理的产品的需求使得现成的液体制剂成为人们所希望的。大多数现代液体制剂具有简单的组成；包含缓冲剂，张力调节剂，表面活性剂，有时是稳定剂，治疗性蛋白质和水。单克隆抗体的最新制剂经常使用组氨酸或乙酸盐作为缓冲剂，蔗糖或海藻糖作为张力调节剂，而聚山梨酯20或80作为pH值为5.7 +/- 0.4的表面活性剂。赋形剂的行为机理仍被学者争论，因此制剂设计仍是一门妖术。幸运的是，像实验设计这样的统计方法适用于制剂开发，并且在与加速稳定性实验结合使用时已经成功。预充式注射器和笔的发展为成功配制的质量属性增加了低粘度和抗剪切性。为了达到患者自我给药的依从性，还需要引起最小程度的疼痛和组织损伤的制剂。