Pharmaceutical Solution Dosage Form Slides

This presentation will explain more on pharmaceutical solutions

1. Pharmaceutical Solution Mr Mateyo Fackswell Bachelor of Pharmacy(Honours)(University of Zimbabwe)

2. Solution Definition- pharmaceutical dosage form in which the solute and solvent form a homogenous mixture. Some of the type of solutions include oral solutions, ocular solutions, parenteral solutions, topical solutions, otic solutions, nasal solutions. Oral solutions can be classified based on their chemical composition as will be discussed next

3. Classification Of Oral Solution Syrups These are aqueous solution which contain high concentration of sugar. Sucrose(66.7% w/w) is mainly used, with its sweetness used to mask unpleasant taste of some medicines . Its hypertonic in nature hence it doesn’t promote growth of microorganisms. Other ingredients such as dextrose, sorbitol or glycerin can be used partly or completely as a substitute for sucrose

4. Tinctures Alcoholic or hydroalcoholic solution which contains chemical or vegetable extract. Due to its high alcoholic content (15-70%), it does not promote bacterial growth and easily evaporates at high temperatures  Elixirs These are sweetened alcoholic or hydroalcoholic solutions. They contain less sugar than syrup and less alcohol content than tinctures

5. Linctus These are thick viscous liquids which contain sugar and alcohol. Due to their viscosity, they are mainly used in cough mixture preparations

6. Components of a Solution These are what constitute a pharmaceutical solution These include: a) Drug- It is the active ingredient which produces a pharmacological effect b) Co-solvents- They help less soluble drugs to be more soluble in solution Examples include propylene glycol, ethanol or glycerol

7. c) Preservatives - Are used to preserve medicines from microorganism growth These include parabens (methyl, propyl, butyl), benzakolnium chloride, benzy alcohol and chlorobutanol d) Tonicity adjuster- These include sodium chloride, glucose, potassium chloride e) pH Changing Agents and Buffers- these include citric acid and its salts or sodium hydroxide and its salts

8. f) Flavoring and Sweeting agents- Used to mask unpleasant taste and ease of administration in certain population groups, for example children. Some flavorings include vanilla, orange, chocolate Sweeteners such as sucrose, mannitol, sorbitol are commonly used g) Antioxidants- Prevent oxidation reactions from occurring during determined shelf life of medicine. These include ascorbic acid, sodium sulphate h)Thickening Agents- Aim at adding viscosity to solution. This prolong duration of action of drug on targeted site, for example on skin or in the eyes. Examples include carbomer 940, hydroxyethylcellulose , dextran

9. Solubility Solubility of solute(API) in the solvent(solution) can be increased by Adjusting pH Ionized form of drugs are more soluble than unionized form. This implies that weak acids are ionized at basic pH and weak bases are ionized at acidic pH. Adjusting pH of solution can increase solubility of drug . A buffer will be required to prevent pH shift which might result in crystallization

10. Surfactants/ Cosolvents Surfactant contain both hydrophobic and hydrophilic groups. The hydrophobic group will form a concentration dependent interaction with the less soluble drug and hydrophilic group will interact with the solvent thereby increasing solubility Cosolvents alter dielectric constant and hydrogen bonding of solutions with their polar groups on their chemical structure, as well as interacting with the hydrophobic drug with their hydrophobic groups, thus in turn increase solubility

11. Solution Stability All pharmaceutical solution should be able to have physical stability, microbial stability and chemical stability Physical stability- Solution should not precipitate or form crystals under given storage conditions during its shelf life Chemical Stability- Solutions are likely to undergo hydrolysis or oxidation, thus it is important to have antioxidants to maintain its chemical integrity Microbial Stability- Most solutions generally have the conditions for microbial growth. It is important to have microbial preservatives to inhibit microorganism growth

12. THANK YOU !!