Reducing and enlarging Formulas PDF

Reducing and enlarging formulas  Objectives Perform calculations to reduce or enlarge formulas for pharmaceutical preparations stated in metric quantities. Perform calculations to reduce or enlarge formulas for pharmaceutical preparations stated in proportional parts....

Reducing and enlarging formulas  Objectives Perform calculations to reduce or enlarge formulas for pharmaceutical preparations stated in metric quantities. Perform calculations to reduce or enlarge formulas for pharmaceutical preparations stated in proportional parts.  Introduction Most of the preparations made in a pharmacy are from proven formulas that have been tested and are listed in the United States Pharmacopeia/ National Formulary (USP/NF) as official formulas. These formulas list the amount of each ingredient needed to make a certain amount of the preparation. At time, it is necessary to reduce or enlarge a formula to satisfy the needs of pharmacy.  Ratio and proportion method 𝐴𝑚𝑜𝑢𝑛𝑡 𝑜𝑓 𝑒𝑎𝑐ℎ 𝑖𝑛𝑔𝑟𝑒𝑑𝑖𝑒𝑛𝑡 𝐴𝑚𝑜𝑢𝑛𝑡 𝑜𝑓 𝑒𝑎𝑐ℎ 𝑖𝑛 𝑡ℎ𝑒 𝑜𝑓𝑓𝑖𝑐𝑖𝑎𝑙 𝑓𝑜𝑟𝑚𝑢𝑙𝑎 𝑖𝑛𝑔𝑟𝑒𝑑𝑖𝑒𝑛𝑡 𝑛𝑒𝑒𝑑𝑒𝑑 𝑇𝑜𝑡𝑎𝑙 𝑞𝑢𝑎𝑛𝑡𝑖𝑡𝑦 𝑜𝑓 𝑡ℎ𝑒 = 𝑇𝑜𝑡𝑎𝑙 𝑞𝑢𝑎𝑛𝑡𝑖𝑡𝑦 𝑜𝑓𝑓𝑖𝑐𝑖𝑎𝑙 𝑓𝑜𝑟𝑚𝑢𝑙𝑎 𝑑𝑒𝑠𝑖𝑟𝑒𝑑 Example: Using the official formula below, calculate the amount of each ingredient needed to make 240 ml of Peppermint Spirit. (1) Solve first for the amount of peppermint oil needed: 100 𝑚𝑙 𝑃𝑒𝑝𝑝𝑒𝑟𝑚𝑖𝑛𝑡 𝑜𝑖𝑙 𝑋 𝑚𝑙 𝑝𝑒𝑝𝑝𝑒𝑟𝑚𝑖𝑛𝑡 𝑜𝑖𝑙 = 1000 𝑚𝑙 𝑠𝑝𝑖𝑟𝑖𝑡 240 𝑚𝑙 𝑠𝑝𝑖𝑟𝑖𝑡 (2) Cross multiply: (1000) X = 100 (240) 1000 X = 24000, X = 24 ml of peppermint oil (3) To solve for the amount of peppermint powder needed: 100 𝑚𝑙 𝑃𝑒𝑝𝑝𝑒𝑟𝑚𝑖𝑛𝑡 𝑜𝑖𝑙 𝑋 𝑚𝑙 𝑝𝑒𝑝𝑝𝑒𝑟𝑚𝑖𝑛𝑡 𝑜𝑖𝑙 = 1000 𝑚𝑙 𝑠𝑝𝑖𝑟𝑖𝑡 240 𝑚𝑙 𝑠𝑝𝑖𝑟𝑖𝑡 (4) Cross multiply: (1000)X = 10 (240) 1000 X = 2400, X = 2.4 g of Peppermint powder  Conversion factor method a. Find the conversion factor: 𝑇𝑜𝑡𝑎𝑙 𝑞𝑢𝑎𝑛𝑡𝑖𝑡𝑦 𝑑𝑒𝑠𝑖𝑟𝑒𝑑 𝑇𝑜𝑡𝑎𝑙 𝑞𝑢𝑎𝑛𝑡𝑖𝑡𝑦 𝑜𝑓 𝑜𝑓𝑓𝑖𝑐𝑖𝑎𝑙 𝑓𝑜𝑟𝑚𝑢𝑙𝑎 = Conversion Factor NOTE: The “Total Quantity Desired” and the “Total Quantity of Official Formula” must have the same units so the units will cancel and yield a conversion factor without units. b. Use conversion factor in formula:  Example: Use the official formula below to calculate how much of each ingredient would be needed to make 120 ml of Cocoa Syrup. (1) The first step is to find the conversion factor: 120 ml / 1,000 ml = conversion factor 0.12 = conversion factor (2) The second step is to multiply the conversion factor times the amount of each ingredient in the original formula: NOTE: The units for each answer are the same as the units in the original formula for that ingredient. Formulas that specify proportional parts The parts indicate the relative proportion of each of the ingredients in the formula by either weight or volume, but not both. A formula for solid or semisolid ingredients, therefore, may be considered in terms of grams, whereas a formula of liquids may be considered in terms of milliliters. Example: From the following formula, calculate the quantity of each ingredient required to make 1000 g of the ointment. Total number of parts (by weight) = 65 1000 g will contain 65 parts 5 (parts) / 65 (parts) = x (g) / 1000 (g) x = 76.92 g of Coal Tar, 10 (parts) / 65 (parts) = y (g) / 1000 (g) Y = 153.85 g of Zinc Oxide, 50 (parts) / 65 (parts) = z (g) / 1000 (g) z = 769.23 g of hydrophilic ointment, answers.