Pharmaceutical Technology I Past Lecture Notes (University of Al-Kafeel, 2024)

# University of Al-Kafeel College of Pharmacy ## Pharmaceutical Technology I - الأستاذ الدكتور حيدر كاظم الاسماعيلي - 10/9/2024 ## Elixirs - Elixirs are clear, sweetened hydroalcoholic solutions intended for oral use and are usually flavored to enhance their palatability. - Non medicated elixirs ar...

# University of Al-Kafeel College of Pharmacy ## Pharmaceutical Technology I - الأستاذ الدكتور حيدر كاظم الاسماعيلي - 10/9/2024 ## Elixirs - Elixirs are clear, sweetened hydroalcoholic solutions intended for oral use and are usually flavored to enhance their palatability. - Non medicated elixirs are employed as vehicles. - Medicated elixirs are used for the therapeutic effect of the medicinal substances they contain. ## What are the differences between elixir and syrup? - Compared with syrups, elixirs are usually less sweet and less viscous because they: - Contain a lower proportion of sugar. - Are less effective than syrups in masking the taste of medicinal substances. - Because of their hydroalcoholic character, elixirs are better able than aqueous syrups to maintain both water-soluble and alcohol-soluble components in solution. - Elixirs are preferred to syrups from a manufacturing standpoint because: - They have stable characteristics. - They are easily prepared by simple solution. - The proportion of alcohol in elixirs varies widely because the individual components of the elixirs have different water and alcohol solubility characteristics. ## Each Elixir Requires a Specific Blend of Alcohol and Water - This is required to maintain all of the components in solution. - For elixirs containing agents with poor water solubility, the proportion of alcohol required is greater than for elixirs prepared from components having good water solubility. ## In Addition to Alcohol and Water, Other Solvents are Frequently Employed in Elixirs - These include glycerin and propylene glycol, which are used as adjunctive solvents. ## Elixirs Sweeteners - Although many elixirs are sweetened with sucrose or with a sucrose syrup, some use sorbitol, glycerin, or artificial sweeteners. - Elixirs having a high alcoholic content usually use an artificial sweetener, such as saccharin, which is: - Required only in small amounts, rather than sucrose. - Slightly soluble in alcohol. - Requires greater quantities for equivalent sweetness. ## Elixir Appearance - All elixirs contain flavorings to increase their palatability. - Most elixirs have coloring agents to enhance their appearance. ## Elixir Alcohol Content - Elixirs containing more than 10% to 12% of alcohol are usually self-preserving and do not require the addition of an antimicrobial agent. - A disadvantage of elixirs for children and for adults who choose to avoid alcohol is their alcoholic content. - Because of their usual content of volatile oils and alcohol, elixirs should be stored in tight, light-resistant containers and protected from excessive heat. ## Advantages of Elixirs 1. Insoluble drug compounds can be incorporated into the hydroalcoholic vehicle. 2. Drug concentrates can be prepared in high-alcohol-containing elixirs. 3. Hydroalcoholic vehicles can be self-preserving. 4. Elixirs are less viscous and contain a lower proportion of sugar. ## Disadvantages of Elixirs 1. They cannot be administered to pediatric patients and patients on antidepressant medication. 2. The concentration of active and inactive ingredients may vary if not preserved in cool places. 3. Water-insoluble drug compounds may precipitate due to alcohol evaporation. ## Preparation of Elixirs - Elixirs are usually prepared by simple solution with agitation and/or by admixture of two or more liquid ingredients. - Alcohol soluble and water-soluble components are generally dissolved: - Separately in alcohol. - In purified water, respectively. - The aqueous solution is added to the alcoholic solution, rather than the reverse, to: - Maintain the highest possible alcoholic strength at all times so that minimal separation of the alcohol-soluble components occurs. ## Elixir Preparation: Mixing Solutions - When the two solutions are completely mixed, the mixture is made to the volume with the specified solvent or vehicle. - Frequently, the final mixture will be cloudy because of separation of some of the flavoring oils due to the reduced alcoholic concentration. The elixir is usually permitted to stand for a prescribed number of hours to ensure saturation of the hydroalcoholic solvent and to permit the oil globules to coalesce so that they may be more easily removed by filtration. - Talc, a common filter aid in the preparation of elixirs, absorbs the excessive amounts of oils and therefore assists in their removal from the solution. ## Viscosity of Elixirs - The presence of glycerin, syrup, sorbitol, and propylene glycol in elixirs contributes to: - The solvent effect of the hydroalcoholic vehicle. - Assists in the dissolution of the solute. - Enhances the stability of the preparation. - The presence of these materials adds to the viscosity of the elixir and slows the rate of filtration. ## Nonmedicated Elixirs - Nonmedicated elixirs may be useful in the extemporaneous filling of prescriptions involving the addition of a therapeutic agent to a pleasant-tasting vehicle and dilution of an existing medicated elixir. ## In Selecting a Liquid Vehicle for a Drug Substance - You should consider the solubility and stability of the drug substance in water and alcohol. - If a hydroalcoholic vehicle is selected, the proportion of alcohol should be only slightly above the amount needed to effect and maintain the drug’s solution. ## Diluting Medicated Elixirs - When the non medicated elixir used as the diluent in preparation of medicated elixir, it should have approximately the same alcoholic concentration as the elixir being diluted. - The flavor and color characteristics of the diluent should not be in conflict with those of the medicated elixir, and all components should be chemically and physically be compatible. ## Medicated Elixirs’ Therapeutic Benefit - Medicated Elixirs are employed for the therapeutic benefit of the medicinal agent. - Most official and commercial elixirs contain a single therapeutic agent. - The main advantage of having only a single therapeutic agent is that the dosage of that single drug may be increased or decreased by simply taking more or less of the elixir. - When two or more therapeutic agents are present in the same preparation, it is impossible to increase or decrease the dose of one without an automatic and corresponding adjustment in the dose of the other, which may not be desired. ## Spirits - Spirits are alcoholic or hydroalcoholic solutions of volatile substances. - The alcoholic concentration of spirits is relatively high, usually over 60%. - Because of the greater solubility of aromatic or volatile substances in alcohol than in water, spirits can contain a greater concentration of these materials than the corresponding aromatic waters. - When mixed with water; Spirits generally separate from the solution and form a milky preparation. ## Spirits’ Uses: Flavoring & Medicinal Value - Spirits may be used pharmaceutically as flavoring agents and medicinally for the therapeutic value of the aromatic solute. - As flavoring agents, they are used to impart the flavor of their solute to other pharmaceutical preparations. - For medicinal purposes, spirits may be taken orally, applied externally, or used by inhalation, depending upon the particular preparation. When taken orally, they are generally mixed with a portion of water to reduce the pungency of the spirit. - Depending on the materials, spirits may be prepared by simple solution, solution by maceration, or distillation. The spirits most recently official in the USP-NF are aromatic ammonia spirit, camphor spirit, compound orange spirit, and peppermint spirit. ## Tinctures - Tinctures are alcoholic or hydroalcoholic solutions prepared from vegetable materials or from chemical substances. - They vary in method of preparation, strength of the active ingredient, alcoholic content, and intended use in medicine or pharmacy. - When tinctures are prepared from chemical substances (e.g., iodine, thimerosal), they are prepared by simple solution of the chemical agent in the solvent. ## Tincture Alcohol Content - Depending on the preparation, tinctures contain alcohol in amounts ranging from approximately 15% to 80%. - Traditionally, tinctures of potent vegetable drugs essentially represent the activity of 10 g of the drug in each 100 mL of tincture, the potency being adjusted following assay. The alcohol content protects against microbial growth and keeps the alcohol-soluble extractives in solution. - In addition to alcohol, other solvents, such as glycerin, may be employed. The solvent mix of each tincture is important in maintaining the integrity of the product. ## Mixing Tinctures - Tinctures cannot be mixed successfully with liquids too varied in solvent character because the solute may precipitate. For example, compound benzoin tincture, contains alcohol-soluble principles that are immediately precipitated from solution upon addition of water. - Because of the alcoholic content, tinctures must be tightly stoppered and not exposed to excessive temperatures. - Because many of the constituents found in tinctures undergo a photochemical change upon exposure to light, many tinctures must be stored in light-resistant containers and protected from sunlight. ## Tincture Solvents - Herbal tinctures are not always made using ethanol as the solvent. Other solvents include vinegar, glycerol, ether, and propylene glycol. - Not all of these solvents can be used for internal consumption. - Ethanol has the advantage of being an excellent solvent for both acidic and basic (alkaline) constituents. - Glycerin can also be used, but when used in tincturing fashion, is generally a poorer solvent. - Vinegar, being acidic, is a better solvent for obtaining alkaloids but a poorer solvent for acidic components. - For individuals who choose not to ingest alcohol, non-alcoholic extracts offer an alternative for preparations meant to be taken internally non-alcoholic. ## General Method of Tincture Preparation 1. Herbs are put in a container, and an alcohol of 40% or more is added. 2. The jar is left to stand for 2–3 weeks and shaken occasionally in order to maximize extraction. ## More Accurate Tincture Measurement - More accurate measuring can be done by combining 1 part herbs with a water-ethanol mixture of 2–10 parts, depending on the herb itself. - For most tinctures, 1 part water to 5 parts ethanol is typical. ## Topical Tinctures ### Iodine Tincture - Iodine tincture is prepared by dissolving iodine crystals and sodium iodide in an amount of alcohol equal to half the volume of tincture to be prepared and diluting the solution to volume with sufficient purified water. - The sodium iodide reacts with the iodine to form sodium triiodide: $I_2 + NaI = NaI_3$. ## Iodine Tincture: Ethyl Iodide Prevention & Water Solubility - This reaction prevents formation of ethyl iodide from the interaction between iodine and alcohol. This would result in the loss of the antibacterial activity of the tincture. - An added benefit of the triiodide form of iodine is its water solubility. This is important for the tincture, which contains between 44% and 50% alcohol, and needs to be diluted with water during use. - The tincture is a popular local anti-infective agent applied to the skin in general household first aid. - The tincture should be stored in a tight container to prevent loss of alcohol. ## Compound Benzoin Tincture - Compound benzoin tincture is prepared by maceration of benzoin, aloe, storax, and Tolu balsam in alcohol. - The drug mixture is best macerated in a wide-mouthed container because it is difficult to introduce storax, a sticky semiliquid material, into a narrow-mouthed container. - It is advisable to weigh the storax in the container in which it will be macerated to avoid possible loss through a transfer of the material from one container to another. - The tincture is categorized as a protectant. - It is used to protect and toughen skin in the treatment of bedsores, ulcers, cracked nipples, and fissures of the lips and anus. - Compound benzoin tincture is best stored in tight, light-resistant containers. Exposure to direct sunlight or to excessive heat should be avoided. ## Fluidextracts - Fluidextracts are liquid preparations of vegetable drugs prepared by percolation. - They contain alcohol as a solvent and preservative. - They are made so that each milliliter contains the therapeutic constituents of 1 g of the standard drug that it represents. - Because of their concentrated nature, many fluidextracts are considered too potent to be safely self-administered, and their use is almost nonexistent in medical practice. ## Fluidextracts: Palatability & Bitter Taste - Many fluidextracts are simply too bitter-tasting or otherwise unpalatable to be accepted by the patient. - Most fluidextracts today are either modified by the addition of flavoring or sweetening agents before use or used as the drug source of other liquid dosage forms, such as syrups.