Pharmaceutical Formulation Additives PDF

# Other Formulation Additives ## 1. Buffers - Enable the solution to resist change in pH should an acid or an alkali be added - Choice: pH and buffering capacity/compatibility/toxicity. - Carbonates, citrates, gluconates, lactates, phosphates or tartrates - Injections, eye drops and nasal drops (pH...

# Other Formulation Additives ## 1. Buffers - Enable the solution to resist change in pH should an acid or an alkali be added - Choice: pH and buffering capacity/compatibility/toxicity. - Carbonates, citrates, gluconates, lactates, phosphates or tartrates - Injections, eye drops and nasal drops (pH 7.4/no irritation) - Optimum stability, solubility, and bioavailability vs. physiological pH. ## 2. Isotonicity Modifiers - Injection/application to mucous membranes/large-volume solutions for ophthalmic (pain/irritation/damage). - After the addition of all other ingredients - Dextrose and sodium chloride ## 3. Viscosity Enhancement - Remain in place on the skin or in the eyes. - Low concentrations of gelling agents: povidone, Hydroxyethylcellulose (HEC) and carbomer ## 4. Preservatives - Choice - Adsorption onto the container - Efficiency vs. pH - Parahydroxybenzoicacid esters vs. micelles ## 5. Reducing Agents and Antioxidants - Decomposition of pharmaceutical products by oxidation - Sodium metabisulphite/BHA and BHT ## 6. Sweetening Agents - Low molecular weight carbohydrates - Sucrose - Colourless/soluble/stable over a pH range 4-8 - Increase viscosity = pleasant texture in the mouth - Mask the tastes salty and bitter - Soothing effect on membranes of the throat (antitussive preparations) - Disadv: Cariogenic - Polyhydric alcohols - Sorbitol/mannitol/glycerol - For diabetic use - Artificial sweeteners - On their own/in conjunction with sugars and alcohols - Intense sweeteners because hundreds and even thousands of times sweeter than sucrose (Conc. < 0.2%) - Sodium or calcium salts of saccharin (E954): high water solubility/chemically and physically stable over a wide pH range - Aspartame (E951) - Disadv: a bitter or metallic aftertaste, so, formulated with sugars. ## 7. Flavours and Perfumes - Uses - A drug with an unpleasant taste (sweetener is insufficient) - Paediatric products - Easy identification of liquid products - Sources - Natural: fruit juices, aromatic oils such as peppermint and lemon, herbs and spices, and distilled fractions - Synthetic: cheaper/more readily available/more stable. Solutions (aq/alc)/powders | Taste of Product | Suitable Masking Flavour | |:---|:---| | Salty | Apricot, butterscotch, liquorice, peach, vanilla | | Bitter | Anise, chocolate, mint, passion fruit, wild cherry | | Sweet | Vanilla, fruits, berries | | Sour | Citrus fruits, liquorice, raspberry | ## 8. Colours - Uses: - Improve the attractiveness of the product (compatible with flavor) - Easy product identification # Types Of Preparation ## 1. Liquids For Cutaneous Application - a) Lotions: - Designed to be applied to the skin without friction. - Humectants/alcohol. - b) Liniments: - Massage into the skin. - Counterirritants (methyl salicylate or camphor). - c) Paints: - Liquids for application to the skin or mucous membranes in small amounts (small brush) - Solvent evaporates quickly (alcohol, acetone or ether) leaving a film on the skin that contains the active agent. - Viscosity modifier (glycerol): ensure prolonged contact with the skin. ## 2. Ear Preparations - Syn. otic or aural products - Simple solutions of drugs in a vehicle for local use - Vehicle: water, glycerol, propylene glycol, or alcohol/water mixtures - Applied to the external auditory canal as drops, sprays, or washes - Uses: antibiotics, antiseptics, cleansing solutions, and wax softeners ## 3. Eye Preparations - Small-volume sterile liquids - To be instilled on to the eyeball or within the conjunctival sac - For a local effect ## 4. Irrigation Solutions - Sterile, large-volume aqueous-based solutions for the cleansing of body cavities and wounds. - Isotonic ## 5. Nasal Products - [Unable to ascertain text on this image. The text appears to be faded or truncated. The image does not provide enough information to properly convert the text into a structured format.] ## 6. Oral Liquids - a) Elixir - Clear, sweetened, hydroalcoholic solutions intended for oral use, and are usually flavoured to enhance their palatability. - Types - Non-medicated and are employed as vehicles. - Medicated which contain medicinal substances and have a therapeutic effect - b) Mixtures and Draughts - Mixtures: aqueous preparations that can be in the form of either a solution or a suspension (small scale/few weeks shelf-life) - Draughts: mixtures of which only one or two large doses of about 50 mL are given ## 7. Rectal Preparations - Enema: - Aqueous or oily solutions, as well as emulsions and suspensions, are available for the rectal administration of medicaments for cleansing, diagnostic or therapeutic reasons ## 8. Intermediate Products - Aromatic waters and spirits - Aqueous solutions of volatile materials and are used mainly for their flavouring properties. - Designed for use during the manufacture of other preparations and which are rarely administered themselves. - Peppermint water and anise water (carminative) - Conc (1:40) ## 9. Extracts, Infusions, and Tinctures - Concentrated solutions of active principles from animal or vegetable sources. - Infusions: 25% alcohol, no heat (1:10). - Extracts: concentrated by evaporation. - Tinctures: weak alcoholic extracts. ## 10. Syrups - Cosolvent for drugs/no crystallization/solubility - Problems: - Surface dilution/preservatives. - Sugar crystallization inside cap/polyhydric alcohols or invert syrup. - Concentrated solutions of sucrose or other sugars to which medicaments or flavourings are often added. - Codeine Phosphate Syrup (cough suppressant), Orange Syrup (dried bitter orange peel = flavoring agent). - Resist bacterial growth (85% sugar, osmosis). - Lower concentrations of sugars - polyhydric alcohol (sorbitol, glycerol, propylene glycol = osmotic pressure). ## Manufacture Of Solutions - Small- and large-scale/mixing vessels/agitation and a nitration system. - Solute is simply added to the solvent/stirring/complete dissolution. - Heat/Size reduction - speed up. - Volatile or thermolabile materials - end/cooling/no adsorption to filter. - Solutes in low concentrations (dyes) - predissolved in a small volume of the solvent. ## Stability of Solutions - Chemical and Physical. - Clarity, color, odor, taste, and viscosity. - Clarity (visual examination/optical density after agitation) - Color (visually, and spectrophotometrically). - Flavours and perfumes (chromatographic methods).