Pharmaceutical Preparations Quiz

Solvents for Pharmaceutical Use

• Water: Purified water, widely used, dissolves polar and semi-polar substances, miscible with water, used internally, and has antimicrobial activity.
• Ethanol (C₂H₅OH): Dissolves polar and semi-polar substances, miscible with water, used internally, has antimicrobial activity.
• Isopropyl alcohol (70%): External use, vehicle for topical preparations.
• Glycerin (CH₂OHCHOHCH₂OH): Clear, viscous liquid with sweet taste, miscible with water and alcohol, viscous liquid, miscible, substitute glycerin in pharmaceutical preparations.
• Propylene Glycol (CH₃CH(OH)CH₂OH): Viscous liquid, miscible, substitute glycerin in pharmaceutical preparations.
• Corn oil, Cottonseed oil, Peanut oil, Sesame oil: Organic solvents for oleaginous injection.

Additives: Buffers

• pH required: 7.4 for injectable solutions, eye, nose; 5.5 for dermal application (vaginal 4-5).
• Buffering capacity.
• Compatibility with other excipients.
• Low toxicity.
• Carbonates, citrates, gluconates, lactates, phosphates, and tartrates are widely used.
• Borates are used for external application, but not on abraded skin or internally.

Taste Masking

• Salty: Apricot, butterscotch, liquorice, peach, vanilla.
• Bitter: Anise, chocolate, mint, passion fruit, wild cherry.
• Sweet: Vanilla, fruits, berries.
• Sour: Citrus fruits, liquorice, raspberry.

Additives: Colors

• The color of the product is associated with the flavor.
• Mint: Green
• Chocolate: Brown
• Cherry/Strawberry: Pink/Red
• Product identification
• Safe and acceptable

Solvents: Water USP

• Drinking water must be clear, colorless, odorless, and neutral or only slightly acid or alkaline.
• Not accepted for manufacture of aqueous pharmaceutical preparations due to chemical compatibility issues with dissolved solids in the medicinal agents (ppt, discoloration, effervescence).
• Used for washing, in extraction of crude vegetable drugs.

Purified Water USP

• Prepared from tap water complying with the Environmental Protection Agency for drinking water.
• Purified water has fewer solids impurities than ordinary drinking water. When evaporated to dryness, it must not yield more than 1 mg solids per 100 mL water.
• Intended for use in preparation of aqueous dosage forms, except those intended for parenteral administration.
• Used in preparation of all medications containing water, except injectable preparations and other specialized products.
• Purification methods: Distillation, De-ionization (ion exchange), Reverse osmosis.

Distillation Method

• Distilled water: Water with impurities removed through distillation.
• Distillation process involves boiling water, then condensing the steam into a clean container.

Ion Exchange Method

• Ion exchange method eliminates the need for heat and costly maintenance of complex distillation apparatus.
• Simpler equipment and method for water purification lead to easier operation, minimal maintenance, and greater mobility.
• Purified water in this method is referred to as demineralized or deionized water and is used in pharmaceutical preparations and prescriptions that require distilled water.

Ion Exchange Resin or Polymer Beads

• Water-insoluble synthetic polymeric resin with high molecular weights, containing phenolic, carboxylic, amino, or sulfonated groups.
• Beads are typically porous, providing high surface area.

Ion Exchange Polymer Types

• 1-Acid or cationic exchanger: Permits exchange of cations in solution with hydrogen ions from the resin.
• 2-Base or anionic exchanger: Allows removal of anions.

Water Softener

• Ion exchange is a method widely used in water filters to produce soft water.
• The process involves trapping calcium (Ca²⁺) and magnesium (Mg²⁺) cations against sodium (Na⁺) or hydrogen (H⁺) cations.
• Commercial resins are made of polystyrene sulfonate, having higher affinity for divalent cations than monovalent cations.

Reverse Osmosis

• Reverse osmosis is a process for membrane filtration, where the flow is from a more concentrated solution to a less concentrated one.
• The flow through the semipermeable membrane is from a less concentrated solution to a more concentrated solution.
• Reverse osmosis removes virtually all viruses, bacteria, pyrogens, and organic molecules, and 90-99% of ions.
• Depending on pore size:
  • Microfiltration (0.1-2 μm): Bacteria
  • Ultrafiltration (0.01-0.1 μm): Viruses
  • Nanofiltration (0.001-0.01 μm): Organic compounds
  • Reverse osmosis (particles <0.001 μm)

Solutions Water for Injection

• Pyrogen-free water (polysaccharide byproduct of bacterial origin).
• Purified by distillation and used within 24 hours after collection.
• Intended to be used as a solvent for parental products to be sterilized after preparation.
• Sterilization achieved by autoclave (steam under pressure).

Sterile Solutions- Sterile Water for Injection USP

• Sterilized and packed in suitable single-dose containers, preferably Type I glass, not exceeding 1000mL size.
• Used as solvent, vehicle, or diluent for already sterilized and packaged injectable medications.
• Used to reconstitute antibiotics.

Sterile Solutions- Bacteriostatic Water for Injection USP

• Sterile water for injection containing a bacteriostatic agent (benzyl alcohol).
• Packed in single-dose containers (not larger than 5 mL) or multiple-dose containers (not larger than 30 mL).
• Not used for neonates.

Other Sterile Diluents

• Sodium chloride injection USP
• Bacteriostatic sodium chloride injection USP
• Ringer injection USP
• Lactated Ringer injection USP
• Dextrose 5% solution

Ophthalmic Solutions

• Sterile, by autoclave or filtration
• Isotonic
• Preserved (e.g., phenyl ethyl alcohol, chlorobutanol, benzalkonium chloride, phenyl mercuric nitrate)
• Optimum pH, low buffer capacity

Oral Solutions

• Final solution components:
  • Sweetening agent
  • Flavoring agent
  • Preservative
  • Colors
  • Buffers
  • Density modifiers
  • Viscosity enhancers
  • Reducing agents
• Types of oral solutions: Dry for reconstitution (unstable in aqueous media, uniform dose)

Oral Rehydration Solution (ORS)

• Used for diarrhea to replenish electrolytes.
• Contains: 45 mEq sodium, 35 mEq chlorine, 20 mEq potassium, 30 mEq citrate, and 25 g dextrose per liter of fluid.
• Available as liquid or powder/packets for reconstitution.

Oral Colonic Lavage Solution

• Used before bowel procedures (colonscopy).
• Balanced solutions of electrolytes with PEG-3350,
• Lactulose is a colonic acidifier that increases stool water content and softens the stool; a man-made sugar solution laxative to treat constipation.

Mouthwashes and Gargles

• Designed for treatment of oral cavity infections and inflammation.
• Water is the vehicle, but co-solvents (e.g., alcohol) may be employed to solubilize active ingredients.
• Alcohol may enhance antimicrobial properties.
• Other components (preservatives, colors, flavoring agents, non-cariogenic sweetening agents) enhance palatability.

Vaginal Solutions (Douches)

• Used for irrigation, cleansing, hygienic effect.
• Astringents, antimicrobials.
• pH adjusting agents.
• Powders, liquid solutions, or concentrates.
• Used externally or internally.

Rectal Solutions (Enemas)

• Retention enemas: Local effect (hydrocortisone), systemic absorption (aminophylline).
• Evacuation enemas: Used to cleanse the bowel.
• Administered rectally. May include viscosity-enhancing agents (e.g., glycerol) to aid retention and reduce seepage.

Evacuation Enemas

• Pharmaceutical solutions administered rectally to clear the bowel.
• Oil-based solutions aid bowel evacuation, e.g., arachis oil.
• Aqueous formulations (e.g., phosphates) alter osmolality, increase rectal water content.
• Increases water in large bowel (osmotic laxatives).

Topical Solutions (Infection)

• Concentration and vehicle for various topical solutions used to treat infections.

Topical Solutions

• Drug, Concentration, Vehicle, Use
• Fluorouracil, 2.5%, PG, antineoplastic
• Minoxidil, 2.5%, Alcohol, water, PG, Baldness
• Hydroquinone, Water Alcohol,, PG
• Podophyllum, Benzoin tincture, Warts
• Fluocinolone acetonide, PG, Adrenocortical steroid
• Betamethasone,
• Mometasone