What is a liquid medicine? What are the characteristics?

liquid medicine refers to the medicine in liquid form prepared by dispersing the medicine in a suitable dispersion medium. Can be taken orally or externally. The drugs in the liquid medicine can be dispersed in the medium in molecular state or particle state, thus forming a homogeneous liquid medicine or a heterogeneous liquid medicine. The dispersion degree of drug particles in liquid medicine is closely related to the efficacy, stability and toxic and side effects of the medicine. Different preparation methods should be used for liquid drugs with different dispersion States.

1. Advantages of liquid medicine: ① The medicine has a large dispersion in the medium and a large contact area with the human body, so it is absorbed quickly, takes effect quickly and has a high bioavailability. ② It can avoid local drug concentration being too high, thus reducing the irritation of some drugs to human body. ③ There are many routes of administration, which can be used for both oral administration and external application to skin, mucosa and human body cavity. (4) it is convenient to divide the dose. ⑤ Convenient medication, especially suitable for infants and elderly patients.

2. Disadvantages of liquid medicine: ① The dispersion of medicine is large, and the chemical stability is poor due to the influence of dispersion medium, which is easy to cause the decomposition and failure of medicine. (2) Water-based liquid medicine is easy to mildew, and preservatives need to be added. ④ Heterogeneous liquid medicine tends to be unstable. ② It is bulky and inconvenient to carry, transport and store.