Characteristics chemical physics material drug and medicinal additives The physico-chemical properties of drug ingredients and drug additives that must be known before drug formulation are: a.Taste, smell and color of substances. The taste, smell and color of substances must be known in order to determine additional medicinal ingredients such as: corrigens saporis, corrigens odoris, and corrigenscoloris required. b.Solubility. - It is important to know the solubility of medicinal substances, especially the solubility in water. -Medicinal ingredients that are easily soluble in water will be more easily absorbed so they will provide a therapeutic effect more quickly. So for active substances that are easily soluble and stable in water, it is better if they are made in liquid form. -Medicinal ingredients are relatively insoluble in water, their absorption is less than perfect. Therefore, efforts are made to increase drug solubility by: *omicronization (reducing the particle size of a substance to make it easier todissolve). *form complex compounds that are soluble in water (for example in the formation of NaI complex compounds3, K.I3).ousing the salt form (eg: Phenobarbital is difficultsoluble in water, replaced by the salt form, namely Phenobarbital Na which is easily soluble in water). *using a mixed solvent (eg: water and ethanol as in Elixir preparations). *If the medicinal substance is difficult to dissolve in water but a liquid form is desired, then a suspension form is made by adding a suspending agent. c.Particle size. Particle size affects: -The dissolution rate of the drug substance (the speed at which the drug dissolves). The smaller the particle size of the drug, the more easily it dissolves, making it easier to absorb. -Uniformity The more homogeneous the particle size, the more uniform the dose is guaranteed. -Rate deposition The larger the particle size of the suspension preparation can beThe addition of a suspending agent will slow down the rate fill. d.Stability of medicinal substances Chemical reactions that affect the stability of medicinal substances: -Hydrolysis. *The hydrolysis reaction is the reaction of the decomposition of a substance by water. Examples of medicinal substances that easily undergo hydrolysis areAspirin and antibiotics in the class of drugs (for example: Ampicillin, Amoxicillin, Tetracycline, etc.). The hydrolysis of Aspirin is characterized by the appearance of an acetic acid/vinegar odor. *Medicinal substances that are easily hydrolyzed must be made in solid form (tablets, capsules, powder), because in a humid or watery atmosphere the medicinal substance will decompose so that it is no longer effective as a medicine and may even form compounds that are toxic. *For medicinal substances that are easily hydrolyzed, if they are still to be made into liquid form, a non-water solvent should be chosen, for example: Ethanol, Propylene glycol, Glycerin or made into a preparation.dry syrup / dry syrup. (Note: Dry syrup is a syrup containing medicinal powder, which must be added to a certain amount of distilled water or boiled water when it is to be used. After dissolving this dry syrup, it must not be used again after 7 days, because the medicinal substance has undergone hydrolysis). -Oxidation. *In some medicinal materials an oxidation reaction will occur ifexposed to light for too long, exposed to heat or when it reacts with oxygen gas. Example: Iodine, Potassium Permanganate (PK). *The occurrence of an oxidation reaction is indicated by a change in color,the smell of medicinal substances, or the formation of sediment. *To avoid oxidation reactions, antioxidants need to be added. *Antioxidants for pharmaceutical preparations whose carrier is water are sodium bisulfite and ascorbic acid (vitamin C). Meanwhile, in pharmaceutical preparations in the form of oil, the antioxidant Alphatocopherol (Vitamin E) is used. These physico-chemical properties can be seen in several sources which contain monographs/descriptions of the requirements for purity of substances, physico-chemical properties of substances, methods of identification and other provisions relating to drugs, including books: