What factors will affect the pharmaceutical preparations


What factors will affect the pharmaceutical preparation?Our editor briefly sorted out six factors for reference.


(A) the temperature according to the usual rough statement, for most of the reaction, the temperature increased by 10 ℃, the reaction rate increased 2-3 times. Although this may be quite accurate for certain drugs, it can not be used universally because some reactions are very rapid in the 10 ° C range and can not be determined by general analytical methods. The basic concept is important for increasing the reaction rate as the temperature increases. For example, it is important that the injection is in the process of heat sterilization or preparation or storage in the tropics, or by heating the solid solution Taking full account of the effect of temperature on drug stability. Heat-sensitive drugs Certain biological agents (eg, insulin, vasopressin, oxytocin and other injections and serum, vaccines, etc.) and antibiotics should not be heated and should normally be stored in a refrigerator. There are individual drugs, the temperature decreases, the decomposition rate increases. For example, the polymerization rate of formaldehyde below 15 ° C increases at room temperature.


(B) water is often the necessary chemical reaction medium, in most reactions, no water, the reaction will not be carried out. Some chemical stability of solid drugs such as aspirin, penicillin G potassium (sodium) salt, acetylcholine chloride, ferrous sulfate, the surface of the particles after the adsorption of water, although still the evacuation of the powder, but the formation of the solid surface of the naked eye is not easy Aware of the liquid film, the decomposition reaction in the liquid film carried out.


(C) the special acid - base catalysis with the general acid - base catalyzes the decomposition of many drugs can be H or OH catalyzed by the reaction called special acid - base catalysis. In addition to H OH, the decomposition of certain drugs can also be broadened acid-base, that is, Bronsted-Lowry acid-base theory of all the acid or alkali catalysis, which is called the general acid-base catalysis. Common buffers such as acetate. Citric acid, borate are Bronsted-Lowry theory of acid or alkali, can catalyze the decomposition of certain drugs, such as phosphate, phosphate, penicillin G salt, acetic acid, citrate, HPO on the catalytic decomposition of chloramphenicol, to be sure whether a drug is used by the buffer catalytic, first of all to maintain the same ionic strength and change the concentration of buffer salt (but the proportion of buffer salt should be constant, so as not to cause changes in PH value) Of the buffered salts such as the decomposition of the drug, then the decomposition reaction can be the general acid-base catalysis, in order to reduce the impact of this catalytic effect, the buffer salt should be kept at the lowest possible concentration.


(D) light and heat, as can be generated to produce chemical reactions necessary for activation energy. To make the molecules activated, there must be an appropriate frequency and sufficient energy for the raw radiation to be absorbed. Radiation energy units called photons, the energy of photons is equivalent to a quantum. The energy of the photon is inversely proportional to the frequency of the absorbed radiant energy, so the shorter the wavelength of the light, the greater the energy absorbed per gram of the molecular drug. The photochemical decomposition of pharmaceutical preparations is usually due to the absorption of sunlight in the purple and ultraviolet light caused. The oxidation of some drugs, ring rearrangement or ring change, joint, hydrolysis and other reactions, in the special wavelength of the sinking line may occur or accelerate, such as amyl nitrite hydrolysis. Morphine, codeine, quinine oxidation, volatile oil polymerization. The photochemical reaction is independent of humidity, but when a molecule absorbs a quantum of radiant energy, it collides with other molecules, and the humidity in the system rises. This was originally a photochemical reaction followed by the thermal reaction of Table 44-2.

Whether the drug is sensitive to light, mainly related to the chemical structure of the drug, phenolic drugs (such as phenol, adrenaline, hee, etc.) and molecules with double bonds in the drug (such as vitamin A, D, vitamin B12, Blood equal) are very sensitive to light. Halogen-containing drugs such as iodization, iodoform, chloroform, trichlorethylene, etc., under the influence of light, but also easily divided into quality. Light reaction ratio decomposition should be much more complex, the country for the light intensity, wavelength, the type of container and its shape, size and thickness, like Lu and light distance and other conditions, can significantly affect the speed of photochemical anti-Qing. Photochemical reactions are often accompanied by reactions. Once the thermal reaction is carried out, the reaction can continue even if the light is stopped. The photochemical reaction may be zero, first or second. Due to the complexity of the photochemical reaction, the characterization of the drug in this respect is generally only qualitative. Vitamin B in P3.5-6.5 solution, in the light can produce hydroxyl B12 and cyanide, which is reversible anti-celebration. The activity of hydroxy B12 is lower than that of B12 and is further decomposed into physiologically active substances:

B12 neutral solution, in the scattered sunlight (intensity of about 100 lumens / square meter or 3000 lumens / square meter) decomposition is not significant. Direct exposure to 8000 lumens / square meters of sunlight, B12 half an hour loss of about 10% of the value of light wavelength of 600-700nm, vitamin B12 does not produce decomposition reaction. In order to reduce the impact of light on drug stability, should be used brown glass bottle packaging, bottle wall should have a certain thickness. The thin brown bottle is less effective. Sensitive to light, in the time of production and storage should be dark.

ionic strength 

(E) ionic strength of the drug decomposition.


(F) Radiation ionizing radiation is a method of sterilization of pharmaceutical preparations, particularly heat-sensitive pharmaceutical preparations, but radiation can be used to disintegrate antibiotics such as polymyxin sulfate, thymosin alkaloid drugs such as atropine sulfate , Steroid drugs such as corpus luteum, sulfonamides, biochemical agents such as progesterone, iodine drugs, biochemical agents such as insulin, heparin, 60Co for γ-ray radiation source, 2.5 radas (Mrad) ) And 25 megarads, the results and the amount of drug decomposition are different.