Chapter 4 - Physical Pharmaceutical Procedures PDF

# Chapter 4 - Physical Pharmaceutical Procedures ## Physical Process: It consists of a group of primary operations in order that the pharmacist needs to prepare the pharmaceutical dosage form in its final shape, so that the patient can use it easily to get its desired therapeutic effect and the ph...

# Chapter 4 - Physical Pharmaceutical Procedures ## Physical Process: It consists of a group of primary operations in order that the pharmacist needs to prepare the pharmaceutical dosage form in its final shape, so that the patient can use it easily to get its desired therapeutic effect and the pharmaceutical process are classified to: **1. Mechanical Pharmaceutical Process:** * **Partitioning:** it consists (includes) * **Separation (isolation)**: a process of cutting the substance by size, * **2. Physical Pharmaceutical Process:** * **Plain Physical Process:** * **Physical Process Which Needs Cooling or Heating:** * **Physical Process Which Needs Solvents:** ## Detailed Demonstration for the Above Classification of Pharmaceutical Process ### **1. Mechanical Pharmaceutical Process:** #### **First: Partitioning:** It is an essential primary pharmaceutical process in order to prepare pharmaceutical dosage form, and it is aimed to decrease the size of the used medicament in order to be useful (been fitting from it) pharmaceutically. * **Portioning the Solid, Hard Particles:** It is done by the following method: * **Cutting:** This operation needs a force to cut the medicaments to smaller pieces, and this is done by using sharp instruments, these instruments differ, according to the hardness of the medicaments such as liquor ice root or leaves of thyme and for such operations the following instruments are used: * laboratory scissors, * hand cutter, * scissors with parallel blades (this has a special type for pharmacy), * **Impact:** This method is used in partitioning the hard and dried objects and we get finer product form the one before, Ex. Used in partitioning, gum Arabic, dried leaves of peppermints, we need to conduct this operation in closed vessel (container) because after using process of impact on the drug dust will be produced as irrelative odors, as plant charcoal, for this operation the following instruments are used: * wooden hammer or stone hammer or iron hammer, * pestle and mortar, and it will be made of iron or porcelain or wood and we should take care about the oxidizing metallic salts and not impacting in an iron mortar, and also metallic salts and not impacted in a glass mortar, * the mortar with a hanging pestle is used for continuous operational impact, * **Hammer mill:** it is used in pharmaceutical industry for its strength and capability in production. * **Attrition:** This operation following the impact operation or cutting operation and is aimed to get a very fine powdered medicament and the following methods are used: * **Levigation:** It is called direct attrition and carried by using a hard tangable mortar and hard tangable. Pestle, and it is aimed for cutting the substance by size and it is done by applying friction. In order not to slip the materials to the sides of the mortar and after this operation is following is usually sifting procedure to get the required degree of fine powder. Here the mortar should be covered during the process of levigation for materials having smoke (dust), such as lead oxide and digitalis leaves and generate explosion such as potassium chlorate. * **Rrasping:** It is done by placing the substance on the surface of the sieve and is gently applied friction and this will let the powdered substance pass through the holes of the sieves, and the finesse of the powder is controlled by the diameter of the holes in the sieves, which is used for sifting, Ex. Lead carbonate and magnesium carbonate. * **Crushing:** This operation is used for substances containing oil, such as aniseed and coffee, using either mechanical or hand operated mills. * **Trituration:** This operation is used for fatty (greasy) substances, using a mortar and pestle. * **Combined attrition and impact:** This operation is done by using **two types of mills**: * **Ball Mill:** Here the partials of the substance meet the balls where the powder is attrited (change the powder) and impacted when coming in contact with each other (the balls). * **Fluid Energy Mill:** When attrition and impact operation are combined together, the process carried through the fast moving particle by each other, the particles which are needed to be changed to finer powder particles. ### **2. Partitioning of Liquids and Viscous (Sticky) Materials:** Here homogenizers are used where the liquid is distributed like very small droplets forms, Ex. Partitioning the water in the oil by using emulsifying agent. And for the viscous (sticky) materials we use mechanical or manually operated kneading machines. ### **Second: Separation** Is divided into: * **Seperation of Solid Substances From Each Other:** This is done by one of the two methods: * Choice and purification is aimed to get rid of the foreign substances and impurities and unimportant part from the drug. * It is done by: * **Manually (by hand):** Ex. Separation of plants leaves from its flowers or removal of pebble and sand from the seeds of lentils. * **By Water:** As light objects float on water surface or dissolution of dissolution of some substances with water, and it is precipitated or removed (get rid of) some of the shells, such as almond with water. * **By Air:** Here the light objects are removed (get rid of) when they are exposed to air. * **Sieving (sifting):** They depend on this separating operation by using different sized of sieves to separate objects, according to the dimensions of their parts. * **Separating solid objects from liquids and liquids from other liquids:** This happens by using one of the following methods: * By decantation: This operation is used to separate solid objects from liquids, depending on their heaviness of weight, then the liquid is separated from the surface of the precipitate found in the bottom of the vessel * By expression: This operation is used to separate the liquids from the solid objects. Here we need pressure to expel the liquid found in between the particles (molecular) of the solid object as in the case of fruit expression * By centrifugation: This operation depends on the characteristic of central expulsion force, to separate solid objects from liquids, and liquids from other liquids, a clear example of this is by separating the components of the blood (R.B.C) and(W.B.C) from plasma by centrifugation. * By filtration: This operation is aimed to separate solid objects from liquids. And for filtration we use: * Funnels and different types of filtration papers or cotton. * Cloth filters such as the ones used in preparation of cheese or for preparation of syrups and liquid extracts. * Glass and porcelain funnels, ex. Buchner funnels, which depends on evacuation of air and filtration of large quantities in shorter times depending on that (the vacuum), and sinter glass filters, and Pyrex filters and filters consisting of cellulosic fiber filters, and Millipore filter which is made of cellulose acetate of different dimensions, where we can separate bacteria from liquids and it is used in drug industry, because it can withstand heat and we can use it for several times. * Clarification: This operation is a method of isolating solid objects form liquids and is done by adding chemical substances to liquids where it works by attracting impurity particles to facilitate filtration, Ex. For such substances are kaolin, and talc, sili ca gel(used as clarifying substances), also water of Eau de colon is clarified by using magnesium.