Mixtures PDF

# Mixtures ## Mixtures - Mixtures are fluid preparations intended for internal administration. - **Simple Mixture:** if the solute is soluble in the vehicle (large fluid component of the mixture). - **Compound Mixture:** if the solute is insoluble or dispersed in the vehicle. - Mixtures are...

# Mixtures ## Mixtures - Mixtures are fluid preparations intended for internal administration. - **Simple Mixture:** if the solute is soluble in the vehicle (large fluid component of the mixture). - **Compound Mixture:** if the solute is insoluble or dispersed in the vehicle. - Mixtures are used in acute cases such as cough, indigestion, diarrhea, constipation for which a short period of treatment is adequate. ## Classification of Mixtures - **A.** Simple mixtures. - **B.** Mixtures containing insoluble diffusible solids. - **C.** Mixtures containing insoluble in-diffusible solids. - **D.** Mixtures containing slightly miscible liquids. - **E.** Mixture containing precipitate forming liquids. - **F.** Miscellaneous mixtures. ## Simple Mixtures - Those preparations containing soluble ingredients e.g Iron Ammonium Citrate Mixture (used in case of iron deficiency) - Formula: | Ingredient | Quantity | |---------------------------------|----------| | Iron ammonium citrate..... | 0.3 gm | | Tr. Nux Vomica.......... | 0.1 ml | | Spirit Chloroform........ | 0.1 ml | | Aqua ad................... | 30 ml | | **Fait Mixture, Mitte ii** | | | **Sig.** Fl.oz **T.D.S.** | | | **N.B.** Tincture Nux Vomica is tonic | | - **Procedure:** - Calculate the required weight and volume. - Dissolve iron ammonium citrate in 3/4 of the vehicle volume noting that iron ammonium citrate is added to vehicle and not the reverse. - Measure the liquid ingredients and add to iron ammonium citrate solution. - Complete the volume to 60 ml with water. - Transfer to clean dry glass bottle and affix the label. ## **B.** Mixtures Containing Insoluble Diffusible Solids - Mixtures containing insoluble ingredients that diffuse readily in the vehicle by shaking the bottle and remain dispersed long enough so that a dose can be poured out. - **A** (Shake the Bottle) label must be used. - Examples: magnesium carbonate, light kaolin, magnesium trisilicate, bismuth sulphate and bismuth carbonate ### **White Mixture:** - Formula: | Ingredient | Quantity | |-----------------------------|----------| | Magnesium sulphate | 4 gm | | Magnesium carbonate (light) | 2 gm | | Peppermint water ad | 30 ml | | **Fait Mixture, Mitte ii (60 ml)** | | | **Sig.** Two table spoonful to be taken half an hour before breakfast. | | | **Used as laxative.** | | - **Procedure:** - Dissolve magnesium sulphate in about 30 ml of peppermint water. - In dry clean mortar triturate magnesium carbonate (light) to smooth past with a little of vehicle, transfer to a measuring cylinder with successive portions of the vehicle. - Add to the magnesium carbonate suspension, the prepared magnesium sulphate solution with stirring and complete to volume with vehicle. - Transfer to white glass bottles and affix the label together with shake the bottle label。 ## **C.** Mixtures Containing Insoluble In-Diffusible Solids - These mixtures containing insoluble solids that settle down very rapidly and not remain evenly distributed in the vehicle long enough to ensure uniformity of the measured dose. - They require a suspending agent. - As a general rule, the suspending agent ordered by the prescriber should be used, when no suspending agent is ordered, the dispenser must select the most suitable one for a particular solid. ### Suspending Agents: These are substances included to keep insoluble medicament(s) in a state of suspension at least sufficiently long for a dose to be poured out of the container. - **1.** Gum Acacia Powder: - mixed with substance to be suspended before adding the vehicle. - used in concentration of 6-10% w/v of the mixture - **2.** Gum Tragacanth Powder: - it usually make lumps when vehicle is added to it, so it is better to use it a mucilage. - used in concentration of 0.25-2.3% w/v. - used only when ordered by the prescriber. - **3.** Compound Tragacanth Powder: - It consists of tragacanth powder, acacia powder, starch and sucrose. - Starch grains prevent formation of lump. - Mixed with substance to be suspended in the mortar and vehicle is added gradually with trituration. - Used in concentration of 2% w/v of the mixture. - Usually used when no particular suspending agent is ordered. - Disadvantage: starch impart opacity to the final mixture. - **4.** Mucilage of Acacia or Tragacanth, used in concentration of 25% of final volume, Disadv: form solid mass with some insoluble solid e.g. bismuth salts - Formula: | Ingredient | Quantity | |-----------------------------------|----------| | Prepared chalk.............. | 0.6 gm | | Tincture of catechu........ | 0.3 ml | | Glycerin.................. | 1.0 ml | | Chloroform water to.......... | 15 ml | | Prepare mixture, send 10 dose | | - **N.B.** prepared chalk (calcium carbonate) is insoluble in-diffusible solid. - This formula is used as antacid. - **Calculation of the amount of suspending agent:** If no suspending agent is ordered we usually use the compound tragacanth powder in 2% concentration. $$ \frac{15 \times 2}{100} = 0.3 \text{ gm for each dose} $$ - So, for 10 doses = 0.3 gm X 10 = 3 gm ## **D.** Mixtures Containing Slightly Miscible Liquids - **Example:** | Ingredient | Quantity | |------------------------------------|----------| | Creasote..................... | 0.3 ml | | Sodium benzoate................. | 0.3 gm | | Syrup tolu.................... | 2.0 ml | | liquid extract of liquorices.... | 2.0 ml | | Camphor water ad.............. | 30.0 ml | | **Fait Mistura, Mitte ii** | | - **Procedure:** - Calculate the weight and volumes enough to make 60 ml. - Dissolve sodium benzoate in about 10 ml of camphor water, add other liquid ingredients (syrup tolu and liquorices) - In a clean dry mortar triturate 1.2 gm of compound tragacanth powder (2% w/v) with about 10 ml of camphor water. - Creasote is added dropwise to the gum mucilage with continuous trituration. - Transfer to cylinder containing the solution of step 2, and complete volume to 60 ml with camphor water. ## **E.** Mixtures Containing Precipitate Forming Liquids - Spirit (for example) is an alcoholic solution of volatile liquid. - On dilution of spirits with water, they yield a fine precipitate (ppt). - In the finally divided state the ppt is more easily dissolved by the vehicle than in case if it was added directly to it. - As a rule it is necessary to shake until the precipitated substance is dissolved.