Pharmaceutical Technology I (Dispersed Systems and Solutions) - Lec 1 PDF

Pharmaceutical Technology I (Dispersed Systems and Solutions) LEC.1 College of pharmacy \ 3rd stage 1 Lecturer: Hanan Hasan 2024 Reference: Ansel’s Pharmaceutical Dosage Forms and Drug Delivery Systems / Tenth Edition...

Pharmaceutical Technology I (Dispersed Systems and Solutions) LEC.1 College of pharmacy \ 3rd stage 1 Lecturer: Hanan Hasan 2024 Reference: Ansel’s Pharmaceutical Dosage Forms and Drug Delivery Systems / Tenth Edition 2 3  Pharmaceutics ▪ Converts a DRUG into a MEDICINE ▪ Pharmaceutics is the science and technology of the design and manufacture of dosage form. ▪ This covers : ▪ Physical pharmaceutics (the drug itself) ▪ Biopharmaceutics (therapeutic consideration) ▪ Dosage form design ▪ Manufacture of these medicines either on small scale (compounding) or on large scale (industrial) 4  Pharmaceutical Preparation (Medicine) pharmaceutical preparations must be: ▪ Elegant ▪ Safe ▪ Stable ▪ Palatable ▪ Therapeutically effective 5  Dispersed System ▪ Dispersed system is a biphasic system, consist of two phases, one is known as dispersed phase (internal phase), which is dispersed throughout in a continuous phase called as dispersion medium (external phase or vehicle). ▪ The volume of dispersion medium or continuous phase is greater than the dispersed phase. ▪ Example of dispersed phase includes; dust in the air, starch in water, Starch represents the dispersed phase in a starch solution, while water is the dispersing medium. The internal and external phase may be: Solids, liquids or gases. e.g. Suspensions, emulsions or aerosols. 6 7  Classification of dispersed systems 1- According to the particle size of the dispersed phase, dispersion can be divided into: a) Molecular Dispersion (fine dispersion):particle size less than1 nm, e.g., solutions b) Colloidal Dispersion: particle size from 1 nm to 0.5 µm. e.g., e.g., gels c) Coarse Dispersion: include: particle size greater than 0.5 µm. e.g., suspensions 8 μm= 1000 nm 9  Classification of dispersed systems 2. According to the interaction between the two phases, dispersion system can be classified as: ▪ Lyophilic dispersion (solvent-like) e.g. sugar in water, starch in water, (very stable) ▪ Lyophobic dispersion (solvent-hating) e.g. benzene with water, oil with water. (less stable 10 11  Examples Of Dispersed System ▪ A solution describes a homogeneous mixture of one material dispersed into another. The dispersed particles will not settle if the solution is left undisturbed for a prolonged period of time. A suspension is a heterogeneous dispersion of larger particles in a medium. Unlike solutions and colloids, if left undisturbed for a prolonged period of time, the suspended particles will settle out of the mixture. 12 ▪ Although suspensions are relatively simple to distinguish from solutions and colloids ‫اﻟﻐﺮوﯾﺎت‬, it may be difficult to distinguish solutions from colloids since the particles dispersed in the medium may be too small to distinguish by the human eye. ▪ Aerosols are liquids dispersed in a gas ▪ Emulsions are liquids dispersed in liquids (more specifically a dispersion of two immiscible liquids) 13  Molecular Dispersion 1. It is a true solutions of a solute phase in a solvent. 2. The dispersed phase (solute) is homogeneously distributed throughout the dispersion medium(solvent). 3. The molecule size is less than 1 nm. ✔ The examples of molecular dispersions: air (a molecular mixture of Oxygen, Nitrogen and some other gases), electrolytes (aqueous solutions of salts), 14  Colloidal Dispersions ▪ Colloids are micro-heterogeneous dispersed systems, in which the size of the dispersed phase particles is within the range 1nm – 0.5μm. ▪ The colloids phases can not be separated under gravity, centrifugal or other forces. Dispersed phase of colloids may be separated from the dispersion medium by micro-filtration. ▪ Examples: microemulsion 15  Coarse Dispersions ▪ Coarse dispersions are heterogeneous dispersed systems, in which the dispersed phase particles are larger than 0.5μm. ▪ Coarse dispersions are characterized by relatively fast sedimentation of the dispersed phase caused by gravity or other forces. ▪ Dispersed phase of coarse dispersions may be easily separated from the continuous phase by filtration. ▪ Examples: ▪ Emulsion, suspensions 16 17 18  Solutions and Types of Solutions In pharmaceutical term, solutions are "liquid preparations that contain one or more chemical substances dissolved in a suitable solvent or mixture of mutually miscible solvents". ▪ Types of Solutions According to Route of Administration: 1. Oral solution 2. Otic solution (‫)ﻣﺤﻠﻮل اﻷذن‬ 3. Ophthalmic solution 4. Nasal solution (e.g. normal saline nasal drop) 5. Topical solutions 19 Otic solution Ophthalmic solution Nasal solution Topical solution 20  The Advantages of Solutions as Pharmaceutical Products immediately available forOF 1) The drug isADVANTAGES SOLUTIONS AS absorption. PHARMACEUTICAL PRODUCTS 2) Flexible dosing is possible. The active ingredient within the solution will be present in a certain concentration per unit volume. 3) They may be designed for any route of absorption. Although when discussing solutions the oral route of administration is often considered, solutions can be administered via a number of other routes. Parenteral preparations (injections), enemas for rectal use, topical (for use on the skin) preparations and ophthalmic preparations can all be solutions. 4) They facilitate swallowing in difficult cases. Some patients may find it hard to swallow traditional solid dosage forms (e.g. infants or the elderly). 21  The Disadvantages of Solutions 1. Drug stability is often reduced in solution by solvolysis, hydrolysis or oxidation. 2. It is difficult to mask unpleasant tastes. 3. They are bulky, difficult to transport and prone to breakages. 4. Technical accuracy is needed to measure the dose on administration. 5. Some drugs are poorly soluble. The solubility of a drug needs to be taken into consideration when preparing a solution to ensure that the final volume produced is not excessive. 22  Types of solutions according to composition or use: ▪ Other solutions, because of their composition or use, may be classified as other pharmaceutical dosage forms. ▪ For example, aqueous solution containing sugar are classified as syrups. ▪ Whereas, sweetened hydroalcoholic solutions are termed elixirs. ▪ On the other hand solutions of aromatic materials are termed spirits if the solvent is alcohol and aromatic water if the solvent is aqueous 23 ▪ Solutions prepared by extracting active constituents from crude drugs are termed tincture or fluid extracts, depending on their method of preparation and concentration. ▪ Tinctures may also be solutions of chemical substances dissolved in alcohol or in a hydroalcoholic solvent. ▪ Certain solutions prepared to be sterile and pyrogen free and intended for parenteral administration are classified as injections. 24  Types of solutions according to physical state: 1. Solution of solid in liquid : Most of true solutions are example of solid in liquid solution. 2. Solution of liquid in liquid 3. Solution of gas in liquid such as ammonia solution 25 26