What factors will have an impact on the drug preparation

What factors will have an impact on the drug preparation

Temperature

 (1) according to the usual rough theory, for most reactions, for every 10 ℃ increase, the reaction rate increases 2 ≤ 3 times. Although this may be quite accurate for some drugs, it is not generally applicable because some reactions change so rapidly in the range of 10 ℃ that they cannot be determined by general analytical methods. Most of the reaction rates increase with the increase of temperature, which is very important. For example, the effect of temperature on drug stability must be fully taken into account in the process of heating sterilization or preparing or storing preparations in tropical areas, or promoting the dissolution of solid drugs by heating. Some biological preparations (such as insulin, vasopressin, oxytocin, serum, vaccine, etc.) and antibiotics, which are sensitive to heat, should be avoided and should be stored in refrigerators. There are also individual drugs, the temperature decreases, the decomposition rate increases. For example, the polymerization rate of formaldehyde below 15 ℃ is higher than that at room temperature.

Water

(2) Water is often a necessary medium for chemical reaction. In most reactions, without water, the reaction will not take place. Some solid drugs with poor chemical stability, such as aspirin, penicillin G potassium (sodium) salt, acetylcholine chloride, ferrous sulfate and so on, after adsorption of water on the surface of particles, although they are still open powder, form an imperceptible liquid membrane on the solid surface, and the decomposition reaction is carried out in this liquid membrane.

Catalyst

(3) the decomposition of many drugs catalyzed by special acid-base catalysis and general acid-base catalyst can be called special acid-base catalysis by H or OH catalyzed reaction. In addition to H work OH, the decomposition of some drugs can also be generalized acid-base, that is, it belongs to all acids or bases of Bronsted-Lowry acid-base theory, which is called general acid-base catalysis. Commonly used buffer salt, such as acetate. Both citrate and borate belong to the acid or base of Bronsted-Lowry theory, which can catalyze the decomposition of some drugs. For example, phosphate catalyzed decomposition of penicillin G salt, acetic acid, citrate and HPO for chloromycetes. To confirm whether a drug is catalyzed by the buffer used, first of all, the ion strength should be kept unchanged and the concentration of buffer salt should be changed (but the proportion of buffer salt should remain the same. If different concentrations of buffer salt have decomposition of drugs, the decomposition reaction can be catalyzed by general acid-base. In order to reduce the effect of this catalysis, buffer salt should be kept as low as possible.

(4) Light

As with light and heat, the activation energy necessary to produce a chemical reaction can be provided. In ord to activate that molecule, it is necessary to have an appropriate frequency and sufficient energy for the primary radiation to be absorbed. The energy of the radiation is called a photon, and the energy of the photon is equivalent to a quantum. The energy of the photons is inversely proportional to the wavelength of the absorbed radiant energy, so the shorter the wavelength of the light, the more the energy absorbed by each molecule of the molecule. The photochemical decomposition of the pharmaceutical formulation is usually caused by the absorption of purple and ultraviolet light in the sunlight. The oxidation, reduction, ring rearrangement or cyclic change, combination, hydrolysis, and the like of certain drugs may occur or accelerate under the action of a special wavelength of the Shen line, such as the hydrolysis of the amyl nitrite. Morphine, codeine, quinine, and volatile oil. The photochemical reaction is independent of humidity, but when a molecule absorbs a quantum of radiant energy, the humidity in the system rises as it collides with other molecules. This was originally a photochemical reaction followed by a thermal reaction table 44-2. The drug is sensitive to the light, mainly related to the chemical structure of the drug, and the phenolic drugs (such as phenol, epinephrine, diphenylephrine, etc.) and the drug (such as vitamin A, D, vitamin B12, medium acid, reserpine, etc.) with double bonds in the molecule are very sensitive to light. The halogen-containing drugs such as iodination, iodoform, chloroform, trichloroethylene and the like are also easy to be classified under the influence of light. The photoreaction is much more complex than the decomposition, for the intensity, the wavelength of the light, the type of the container, the shape, size and thickness of the container, the distance between the sample and the light, and the speed of the photochemical reaction. The photochemical reaction is often accompanied by a reaction. Once the thermal reaction is carried out, the reaction can continue even if the light is stopped. The photochemical reaction may be zero order, primary or secondary. Due to the complexity of the photochemical reaction, the drugundefineds characterization in this respect is generally only qualitative. In the solution of P3.5-6.5, the vitamin B can generate the hydroxyl B12 and the cyanide in the lower part of the light, which is reversible and anti-Qing. the activity of the hydroxyl group 12 is lower than b12 and is readily further decomposed into a physiologically active substance: The neutral solution of B12, under the irradiation of scattered sunlight (intensity of about 100 lumens per square meter or 3000 lumens/ square meters), is not very significant. The 12-hour loss of B12 is about 10% per half an hour with direct exposure to 8000 lumens/ square meter of sunlight. When the wavelength of the light is 600-700 nm, the vitamin B12 does not produce the decomposition reaction. In order to reduce the effect of light on the stability of the drug, the brown glass bottle shall be used for packaging, and the bottle wall shall have a certain thickness. The thin brown bottle has a poor effect. The light-sensitive notes should be protected from light in the process of production and storage.