8.4.2　Ideal TDD technology

With the development of four generations，TDD technology has achieved many remarkable results and clinical applications，but the current technology still has its limitations.The ideal TDD technology should have the following characteristics.

（1）Be minimally invasive，painless，safe and convenient.

（2）Be suitable for administration of hydrophobic，hydrophilic drugs and macromolecular drugs（e.g.，peptides，proteins，RNAs，DNAs）；

（3）Ensure the stability of the drug properties and adequate dosage.(https://www.daowen.com)

（4）Ensure controllable and ideal release speed.

（5）Be accessible to self-administration without leaving sharp needles.