Comprehensive Notes on Pharmaceutical Aids and Necessities (Inorganic Acids, Buffers, Antioxidants, Water, and Glass)
Chapter II: Pharmaceutical Aids and Necessities
Focus on important to the preparation, preservation and storage of pharmaceutical products.
Major subject areas:
Acids and Bases: frequently employed in chemical forms convenient for converting drugs to their product formulation.
Buffers: maintain formulations within prescribed limits.
Antioxidants: maintain pH and prevent decomposition of oxidizable components.
Water: primary solvent or liquid phase in most liquid pharmaceutical preparations.
Glass: used for storage and as dispensing containers for most drug products.
Official Inorganic Acids
BORIC ACID NF 26 (H3BO3; Mol. wt. 61.83)
Synonyms: Boracid Acid, Hydrogen Borate, Orthoboric Acid, Agua Boricada.
Occurrence and sources:
Free boric acid found in sea waters, certain plants, nearly all fruits; native boric acid called sassolite.
Combined forms: Na2B4O7·4H2O (rasorite or kernite); CaB4O7·4H2O (borocalcite); Na2B4O7·10H2O (borax); Ca3B6O10·5H2O (colemanite); H3BO3·Na2B4O7·2CaB4O7·18H2O (tincal).
Forms and physical properties:
Three solid forms:
(2) six-scaled triclinic crystals;
(3) white odorless powder with a soapy touch. Powder tends to float on water; scales/crystals are better for making aqueous solutions.
(1) colorless, odorless pearly scales;
Stable in air; density ≈ 1.46.
Solubility: soluble in water and alcohol; freely soluble in glycerin, boiling water, and boiling alcohol.
Clear solutions: 1 g in 25 mL water yields clear solution; solubility decreases with addition of HCl.
Chemistry and salts:
Because boric acid is a weak acid, only salts formed by replacing one proton (primary salts) can form in aqueous solution.
Salts with alkali metals are water-soluble and give very alkaline solutions.
Salts with other metals hydrolyze to insoluble hydroxides.
Toxicity and absorption:
Not absorbed through intact skin; highly toxic if ingested; absorbed when applied to large areas of broken skin.
Official specification (NF XV):
Must contain n.l.t. ≤ content ≥ n.m.t. of boric acid calculated as an anhydrous form: n.l.t. ≈ 99.5%; n.m.t. ≈ 100.5%.
Uses:
Historically used in solutions, ointments, and dusting powders as antiseptic; acts as a weak bacteriostatic agent.
Eyewash solutions commonly 2.5%–4.5% for local antiseptic use; higher concentrations require dilution with water before use.
Used as a buffer component in ophthalmic solutions and in preparations like Aluminum Acetate Solution USP XVIII and Aluminum Subacetate Solution USP XVIII.
Reaction with glycerin at 140–150°C yields Boroglycerin (Glycerite NF XI); equimolar product known as Boroglycerin.
Internal use prohibited due to toxicity.
Note on safety and practical handling: boric acid has limited buffer capacity when used alone; it contributes to buffering in specific ophthalmic preparations.
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HYDROCHLORIC ACID NF 26 (HCl; Mol. wt. 36.46)
Synonyms: Muriatic acid, Spirit of Sea Salt, Marine Acid, Espiritu de Sal Marina.
Official definition: A solution of hydrogen chloride gas containing n.l.t. 35% and n.m.t. 38% by weight of HCl.
Properties:
Colorless fuming liquid with a pungent odor; specific gravity ≈ 1.18.
A non-fuming solution can be prepared by diluting highly ionized HCl with water.
Muriatic acid (technical grade) contains 35%–38% HCl with impurities (chlorine, arsenous and sulfurous acids, iron, etc.) giving a characteristic yellow color.
Uses:
Primary chemical use: acidifying agent in pharmaceutical preparations.
Reacts with weak organic bases to form water-soluble ammonium or organic hydrochloride salts, enabling extraction and separation of weak bases.
Salts of many organic amines with HCl are suitable for incorporation into solid dosage forms.
Disadvantages/considerations:
Some hydrochlorides are hygroscopic.
The chloride ion is of relatively low toxicity; care with handling due to acidity.
Diluted Hydrochloric Acid NF XV:
Contains n.l.t. ≈ 9.5 g and n.m.t. ≈ 10.5 g of HCl per 100 mL.
Gastric and therapeutic relevance:
In gastric juice, diluted HCl (~0.2%) aids in converting pepsinogen to pepsin and proteids to peptones.
Used as an antiseptic in certain contexts.
Administration considerations:
Doses typically 1–10 mL, highly diluted with water; administered through a glass tube or straw to protect tooth enamel.
Related preparations:
Acid Hydrochloride and Betaine Hydrochloride: crystalline forms that liberate HCl in the stomach; used in some capsules.
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NITRIC ACID NF 26 (HNO3; Mol. wt. 63.01)
Synonyms: Spirit of Nitre, Aqua Fortis, Agua Fuerte.
Official definition: Aqueous solution of HNO3 containing n.l.t. 68% and n.m.t. 71% by weight.
Properties:
Highly corrosive, fuming liquid with a characteristic irritating odor; boiling point ≈ 120°C; density ≈ 1.41.
Oxidizing and nitrating monoprotic acid.
Produces a yellow stain on animal tissue due to nitration of aromatic amino acids (phenylalanine, tyrosine, tryptophan) in skin (Xanthoproteic Test).
Enhanced oxidizing power with small amounts of nitrous acid (HNO2).
Uses:
Similar acidifying function to HCl, but with strong oxidizing and nitrating properties.
Used in manufacturing sulfuric acid, coal tar dyes, and explosives.
Nitrating agent in Pyroxylin USP XVIII; source of nitrate ion in the preparation of Milk of Bi; used externally to destroy chancres and warts.
Example reaction (nitration):
Nitration of toluene to produce trinitrotoluene (TNT):
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PHOSPHORIC ACID NF 26 (H3PO4; Mol. wt. 98)
Synonyms: Orthophosphoric Acid, Acido Orthofosforico.
Properties:
Aqueous solution containing n.l.t. 85% and n.m.t. 88% by weight of H3PO4.
Colorless, odorless, syrupy liquid; specific gravity ≈ 1.71; non-volatile and non-oxidizing.
Uses:
Acidifying agent; can be treated with sodium hydroxide to form HPO4^{2-} and H2PO4^{-} species (buffer system).
Useful in buffers where phosphate species act as the basic and acidic components of the buffer system.
Listed as a solvent in Anileridine Injection NF XVIII (per NF 21 category).
Diluted Phosphoric Acid NF 26:
Contains n.l.t. ≈ 9.5 g and n.m.t. ≈ 10.5 g of H3PO4 in 100 mL.
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SULFURIC ACID NF 26 (H2SO4; Mol. wt. 98)
Synonyms: Oil of Vitriol, Vitriolic Acid, Aceite de Vitriol.
Properties:
Colorless, odorless liquid of oily consistency; contains n.l.t. 94% and n.m.t. 98% H2SO4; density ≈ 1.84.
When strongly heated, it vaporizes and releases dense white fumes of SO3; if sulfur trioxide is not volatilized at lower heat, it behaves as a strong diprotic acid and oxidizing/sulfonating/sulfating agent.
Commercial “oleum” or Nordhausen Acid contains about 10% dissolved SO3 (H2S2O7).
Preparation (industrial processes):
Lead Chamber Process and Contact Process both oxidize SO2 to SO3 and then absorb water to form H2SO4.
The Contact Process yields most sulfuric acid commercially at any desired strength; catalysts include vanadium or platinized materials.
Uses:
Strong diprotic acid; forms salts with basic organic drug molecules;
Dehydrating agent; sulfonating or sulfating agent; preparation of Pyroxylin USP 26.
Oleum (disulfuric acid) H2S2O7 used in certain reactions.
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DILUTED HYDROCHLORIC ACID NF XV
Contains n.l.t. 9.5 g and n.m.t. 10.5 g of HCl per 100 mL.
Used as a diluted form of HCl for various pharmaceutical purposes including gastric acidity adjustments and acidifying agents in formulations.
STRONG AMMONIA SOLUTION NF 26 (10% Household ammonia; 28- Strong Ammonia)
Synonyms: Ammonium Hydroxide, Stronger Ammonia Water.
Properties:
Contains n.l.t. 27% and n.m.t. 30% NH3 by weight.
Upon exposure to air, loses ammonia; solution is clear, colorless, with a pungent odor; specific gravity ≈ 0.90.
Caution: caustic in handling; avoid inhalation of vapors; keep container closed.
Uses:
Ammonia acts as a Bronsted base (proton acceptor) and forms ammonium salts with acids.
Used in the manufacture of ammonium bicarbonate and in Aromatic Ammonia Spirit NF XV to stabilize ammonium carbonate against hydrolysis.
Used in Ammoniacal Silver Nitrate Solution NF 21.
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CALCIUM HYDROXIDE USP 31 (Ca(OH)2; Mol. wt. 74.09)
Synonyms: Slaked Lime, Calcium Hydrate.
Properties:
Official solution: Calcium Hydroxide Solution USP 26 (Lime Water) – contains n.l.t. 140 mg Ca(OH)2 per 100 mL; prepared by slaking lime with water (3 g CaO to 1000 mL water), mixing for ~1 hour, and using the clear supernatant.
Solubility: very soluble in water; insoluble in alcohol; soluble in glycerin.
Taste: alkaline and bitter.
Absorbs CO2 from air forming calcium carbonate, giving a cloudy appearance.
Preparation:
Prepared by slaking CaO with water; heat evolution and disintegration into a fine powder.
Uses:
Medically as a fluid electrolyte and topical astringent.
Reacts with free fatty acids to form calcium soaps with emulsifying properties.
CO2 absorption usefulness in gas traps; used with NaOH in Soda Lime for CO2 absorption in metabolic tests.
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POTASSIUM HYDROXIDE NF 26 (KOH; Mol. wt. 56.11)
Synonyms: Caustic Potash, Potassa.
Properties:
Official as white or nearly white fused masses, small pellets, flakes or sticks; very deliquescent; rapidly absorbs moisture and CO2 from air; very strong base; caustic and tissue-destructive.
Uses:
Used as a caustic in veterinary practice.
Used as a saponifying agent to hydrolyze esters in fats to alcohols and potassium salts.
Used for aqueous and alcoholic titrations of acids; widely used as a base or alkaline reagent.
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SODIUM HYDROXIDE NF 26 (NaOH; Mol. wt. 40)
Synonyms: Caustic Soda, Soda Lye.
Properties:
Occurs in various forms: dry hard sticks, fused masses, small pellets, flakes; highly deliquescent; rapidly absorbs moisture and CO2 from air.
1 g NaOH dissolves in about 0.9 mL water at 25°C with heat evolution; very soluble in alcohol, ether, glycerin.
Attacks soft glass; use hard glass with stoppers or apply petroleum around stopper to seal.
Reacts with salts of many metals to precipitate insoluble metal hydroxides; catalyzes ester hydrolysis (saponifying agent).
Highly caustic and tissue-damaging; NF XV cautions to handle with care.
Uses:
Primary use as a strong base; similar to KOH but less deliquescent, often milder and cheaper; extensively used in industry.
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SODIUM CARBONATE NF 26 (Na2CO3·H2O; Mol. wt. 124)
Synonyms: Monohydrated Sodium Carbonate.
Properties:
Monohydrate is a colorless crystal or white crystalline powder; odorless and alkaline.
Some moisture absorption from air; effloresces to anhydrous at ≥100°C.
1 g dissolves in 3 mL water; 1 g in 1.8 mL boiling water; 7 mL glycerin.
Existence of well-characterized hydrates in addition to the anhydrous form: monohydrate, heptahydrate (Na2CO3·7H2O), decahydrate (Na2CO3·10H2O, washing soda).
Preparation (industrial):
Major production via Solvay Process: ammonia-saturated and CO2-treated brines yield NaHCO3 which upon calcination gives anhydrous Na2CO3; secondary hydration forms Na2CO3·H2O.
Uses:
Not to be given as such due to marked alkalinity and irritating properties.
Used for basicity in pharmaceutical preparations to form sodium salts of acidic drugs (example:Nitromerosal Solution NF XVIII with NaOH to form water-soluble sodium salt of nitromerosal).
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SODA LIME NF 26
Composition: A mixture of calcium hydroxide and sodium and/or potassium hydroxide.
Uses:
For metabolism tests, anesthesia, and oxygen therapy.
Contains an indicator to signal exhaustion of CO2 absorption capacity.
Function: In a closed system, absorbs CO2 from expired air; NaOH and Ca(OH)2 react with CO2 to form Na2CO3 and CaCO3, regenerating hydroxides; color indicator signals exhaustion.
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Buffers (Buffer Systems and Selection)
Importance: Control of pH in solutions is essential for chemical stability, drug solubility, and patient comfort.
Principle: Buffers resist large pH changes upon addition of small amounts of acid or base via a conjugate pair (weak acid + conjugate base or weak base + conjugate acid).
Selection criteria for buffer systems:
Should not participate in oxidation–reduction reactions.
Should not alter solubility of other components.
Should not form complexes with active ingredients.
Should exhibit chemical stability; avoid volatile species (e.g., ammonia, CO2) which can alter pH and buffer capacity.
Inorganic buffers of importance in pharmaceutical preparations:
Phosphate buffer system: includes dihydrogen phosphate and monohydrogen phosphate ions, a physiological buffer pair; disadvantages include insolubility of certain metal phosphates (Ag, Zn, Al) and microbial growth support; Sorensen phosphate buffer is a classic example.
Borate buffer system: used when metals would precipitate in phosphate buffers; borates are toxic, so borate buffers are suitable for external preparations (ophthalmic and nasal solutions) but contraindicated in parenteral solutions.
Primary borate buffers (3 common systems):
1) Feldman’s Buffer System (pH 7–8.2): acid solution contains boric acid, NaCl to make isotonic, and alkaline solution containing sodium borate.
2) Atkins and Pantin Buffer System (pH 7.6–11): alkaline solution of sodium carbonate and acid buffer solution of boric acid and sodium chloride.
3) Gifford Buffer System (pH 6–7.8): similar to Feldman but uses potassium chloride instead of NaCl to make hypotonic.Sodium borate NF 26 (Na2B4O7·10H2O; Mol. wt. 381.37)
Synonyms: Borax, Sodium Tinkal, Pyroborate, Sodium Tetraborate.
Properties: colorless crystals or white crystalline powder; odorless; effloresces in warm, dry air; soluble in water and glycerin; aqueous solutions are alkaline to phenolphthalein.
Role in buffers: used as the alkaline member of the borate buffer system (in situ formation of borate in solution).
Incompatibilities: metals borates (except alkali metals) are insoluble; potential incompatibility with zinc salts due to precipitation of basic zinc borate or zinc hydroxide; can be avoided by using boric acid to keep zinc borate water soluble.
Toxicology: same toxicity as boric acid; hydrolyzed to boric acid in aqueous solution.
Uses: eyewashes used when acids get into mucosa; mouthwashes and powders for ulcers; antibacterial properties; emulsion formation via borax soap in preparations like Cold Cream USP and Rose Water Ointment NF.
Antioxidants
Definition: compounds acting as reducing agents to protect easily oxidizable substances (e.g., iodide or ferrous) by maintaining reduced states.
Mechanisms (two practical viewpoints, both valid):
Antioxidant is oxidized in place of the active constituent.
Active constituent oxidizes and the antioxidant reduces it back to its normal state.
Selection considerations:
1) Antioxidant should be physiologically inert.
2) Assess possible toxicity of reducing agent and its oxidation product.
3) Consider solubility between antioxidant and drug.
4) Very strong reducing agents may form explosive mixtures with strong oxidizing agents when dry or concentrated.
Hypophosphorous Acid NF 26 (HPH2O2; Mol. wt. 66)
Properties: colorless or slightly yellow liquid; n.l.t. ≈ 30% and n.m.t. ≈ 32% HPH2O2; density ≈ 1.13 at 25°C; exists as syrupy solid at 17°C and melts at 26°C.
Reducing agent: phosphorus center in +1 oxidation state; capable of reducing many compounds to form H3PO3 and eventually H3PO4, transferring four electrons in total; illustratively reduces molecular iodine to iodide and decolorizes permanganate solutions.
Uses: primarily as an antioxidant; prevents formation of free iodine in diluted hydriodic acid and syrups; present in Ferrous Iodide Syrup NF XI to prevent ferric ions and iodine formation.
Salts (hypophosphites) used as preservatives (e.g., sodium hypophosphate in foods; ammonium hypophosphate in various preparations).
Handling: hypophosphites should never be triturated with oxidizing agents (nitrates, chlorates, permanganates); typical antioxidant concentrations not exceeding about 1%.
SULFUR DIOXIDE NF 26 (SO2; Mol. wt. 64.06)
Synonym: Sulfurous Anhydride.
Properties: colorless, non-flammable gas with a characteristic suffocating odor; contains n.l.t. ≈ 97% by volume SO2.
Under pressure condenses to a colorless liquid (bp ≈ −10°C); density ≈ 1.5.
Solubility: soluble in water (≈ 36:1 water to gas ratio).
Pharmacological profile: sulfur dioxide is a strong reducing agent with sulfur in the +4 oxidation state; functions as an antioxidant by reducing oxidized species back to their reduced form.
Uses: protects susceptible compounds from oxidation by acting as a scavenger for oxygen; used in injectable preparations enclosed in single-dose ampoules or multidose vials owing to gaseous nature; also used industrially for bleaching, fumigation, and fermentation control; employed for fumigating houses via sulfur candles.
SODIUM BISULFITE NF 26 (NaHSO3; Mol. wt. 104.06)
SODIUM METABISULFITE NF 26 (Na2S2O5; Mol. wt. 190.10)
Notes:
Bisulfite and metabisulfite often supplied as mixtures; must yield SO2 on warm acid dissolution (n.l.t. ≈ 58.5%–67.4% SO2 for NaHSO3 and ≈ 66%–67% SO2 for Na2S2O5).
Practical observation: most commercial sodium bisulfite is actually metabisulfite; metabisulfite converts to bisulfite in water.
Incompatibilities: sulfites/bisulfites have solubility constraints; soluble salts exist mainly with alkali metals; sulfites of alkaline earth metals are less soluble.
Uses:
Predominant antioxidant in many pharmaceutical formulations; protects phenol- or catechol-containing drugs from oxidation to quinones.
Ascorbic acid injections may include bisulfite as a reducing agent.
May be used to prepare water-soluble derivatives of poorly soluble drugs (e.g., Menadione Sodium Bisulfite) for parenteral administration.
Hydrolysis and chemical stability considerations dictate careful handling with oxidants.
Nitrogen NF 26 (N2; Mol. wt. 28.01)
Properties: colorless, odorless inert gas; non-flammable; does not support combustion.
Solubility: one volume dissolves in about 65 volumes water and in about 9 volumes of alcohol at 20°C and 760 mm Hg.
Uses:
Inert atmosphere to retard oxidation in sensitive products (cod liver oil, olive oil, multivitamin preparations).
Replaces air in containers for parenterals and topical solutions; product label must declare use.
Used to retard oxidation in qualitative tests for carbon monoxide.
Water and Water-Related Topics
Water properties:
Pure water: tasteless, odorless, clear; colorless in small quantities; greenish-blue in depth.
Water forms extensive hydrogen bonding; high dielectric constant; small molecular size allows penetration of crystal lattices and stabilization of ions and macromolecules.
Water is the solvent of choice in most liquid dosage forms; body prevalence lowers concerns about toxicity, metabolism, and excretion when used as a solvent.
Hardness of water:
Due to calcium, iron, magnesium salts; causes soap scum and formation of insoluble calcium/metal soaps.
Temporary hardness (bicarbonate hardness): removed by boiling or adding hydroxide.
Permanent hardness: due to sulfates, chlorides, or hydroxides of Ca/Mg; not removed by boiling or hydroxide addition.
Water purification approaches in pharmaceutical practice:
1) Addition of soluble carbonates (e.g., washing soda) to precipitate Ca/Mg as insoluble carbonates.
2) Zeolite (Permutit) process: ion-exchange to replace Ca/Mg with Na; regeneration with saline solution to restore activity.
3) Deionizers or demineralizers: synthetic resins remove both cations and anions; yields high-purity water at lower cost than distillation.
4) Polyphosphate chelation (detergency): phosphates chelate divalent calcium, reducing hardening effects.Official Waters (USP/NF):
Purified Water USP 31: produced by distillation or ion-exchange; odorless; defined pH, chloride, sulfide, total solids, ammonia, calcium, carbon dioxide, heavy metals, oxidizable substances; bacteriological purity; primary water for extemporaneous compounding.
Water for Injection USP 31: distillation/purified; pyrogen test (rabbits) and bacterial endotoxin testing (LAL); used for parenteral solution preparation; finished products sterilized.
Sterile Water for Injection USP 31: glass Type I or II packaging; single-dose containers ≤1000 mL; no antimicrobial agents added; label indicates additive substances.
Sterile Water for Inhalation USP 31: prepared from Water for Injection; no antimicrobial agents unless used in humidifiers; intended for inhalation therapy only; not for parenteral administration; packaged in Type I or II glass or plastic.
Sterile Water for Irrigation USP 31: prepared from Water for Injection; sterile; single-dose glass/plastic containers; volumes >1 L; designed for rapid emptying; free of antimicrobial agents.
Bacteriostatic Water for Injection USP 31: sterile water for injection containing one or more antimicrobial agents (e.g., benzyl alcohol). Stored in single-dose or multiple-dose containers ≤30 mL. Intended for small-volume extemporaneous parenterals for intramuscular injection. Not for intravenous use. Label must state: “Not for use in Newborns” in bold, capital letters.
Glass (general notes):
Glass is a generic term for vitreous material; most commercial glasses are vitreous silicates with additives conferring special properties (e.g., boron reduces thermal expansion).
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Practical and Miscellaneous Notes
Glycerol and boric acid interaction:
Boric acid can react with glycerin at high temperatures (140–150°C) to form Boroglycerin (Glycerite NF XI), a suppository base.
Buffers and compatibility considerations:
Buffer components should not participate in redox chemistry, alter solubility, or form complexes with active ingredients.
Borate buffers, while effective in external preparations, are avoided in parenteral solutions due to borate toxicity.
Miscellaneous cautions and handling notes:
Many strong bases (NaOH, KOH) are highly caustic; handle with extreme care to avoid tissue damage.
Solutions containing strong acids or bases should be prepared and stored in compatible glass, avoiding corrosive interactions with containers.
When preparing parenteral solutions with volatile or reactive buffers, consider losses due to volatilization (CO2, NH3) and buffer capacity stability.
Connections to foundational principles and real-world relevance:
The acids, bases, buffers, and antioxidants discussed are foundational for formulating stable, safe pharmaceutical products.
Water quality and appropriate water types (Purified, Water for Injection, Sterile variants) are essential for avoiding pyrogens, endotoxins, and microbial contamination.
Glass packaging selection and stability considerations affect product safety, shelf-life, and compatibility.
Ethical/PHR implications and practical considerations:
Accurate labeling (e.g., not for newborns on bacteriostatic water) is critical for patient safety.
Adherence to NF/USP specifications ensures product quality, efficacy, and regulatory compliance.
Understanding buffer systems and incompatibilities prevents adverse interactions and maintains drug stability.
Key numerical values and formulas (selected):
Boric acid: NF specification n.l.t. ≈ 99.5%, n.m.t. ≈ 100.5% (as anhydrous form).
HCl: NF 26 specified as 35%–38% by weight; diluted HCl: ≈ 9.5–10.5 g HCl per 100 mL.
HNO3: NF 26 specified as 68%–71% by weight; boiling point ~ ; density ~ .
H2SO4: NF 26 specified as 94%–98% by weight; density ~ ; oleum contains ~10% SO3.
NH3 in Strong Ammonia Solution: ~ by weight; density ~ 0.90; pH high basicity.
Ca(OH)2: molecular weight ; slaked lime; prepared by slaking CaO with water (3 g CaO to 1000 mL water).
NaOH: molecular weight ; density and solubility properties described; 1 g dissolves in ~0.9 mL water at 25°C.
Na2CO3·H2O (Sodium Carbonate Monohydrate): molecular weight ; hydrates: Na2CO3·7H2O, Na2CO3·10H2O; Solubility: 3 mL water per gram; 1.8 mL boiling water; 7 mL glycerin.
NaHSO3: hydrogen sulfite; Na2S2O5: metabisulfite – both provide SO2 upon hydrolysis or dissolution.
N2 (Nitrogen): inert gas; used for inert atmospheres in containers and antioxidant protection.
Important cross-references to exam-ready points:
Definition and roles of buffers (weak acid/base + conjugate salt) and examples (phosphate, borate).
Distinctions between Purified Water, Water for Injection, Sterile Water variants, and Bacteriostatic Water for Injection.
Industrial versus pharmaceutical relevance of sulfuric and nitric acids, including nitration vs. acidifying roles.
Safety keywords and cautions for caustic/basic and corrosive acids/bases and their handling in pharmacy practice.
The role of soda lime in CO2 absorption and how indicators signal exhaustion.
For the exclusive use of Pharmacy students in the UST Faculty of Pharmacy