B Pharmacy Sem 2: Pharmaceutical Inorganic Chemistry

Subject 4. Pharmaceutical Inorganic Chemistry

1. Water: Grades, Purification & Hardness
2. Inorganic Excipients & Their Applications
3. Acids, Bases & Buffer Systems
4. Heavy Metals: Limits, Detection & Removal
5. Antacids, Dental Products & Medical Gases
6. Radiopharmaceuticals & Isotonic Solutions
7. Quality Control Tests & Safety/Disposal of Inorganics

Unit 1: Water – Grades, Purification & Hardness

This unit covers the types of water used in pharmaceutical processes, methods to purify water to various grades, the concept and measurement of water hardness, and its control to meet quality specifications.

1.1 Grades of Water in Pharmacy

1.2 Water Purification Methods

1.2.1 Distillation

• Principle: vaporization of water, leaving non‑volatile impurities, then condensation.

• Features: effective removal of inorganic salts, most organics, and microbes; energy‑intensive.

1.2.2 Ion Exchange / Deionization

• Principle: cation and anion exchange resins remove ionic impurities.

• Features: produces water low in ions; requires periodic resin regeneration (acid/base).

1.2.3 Reverse Osmosis (RO)

• Principle: high‑pressure forcing of water through a semi‑permeable membrane, rejecting salts and larger molecules.

• Features: continuous operation; removes > 95 % of dissolved solids; pre‑treatment and periodic sanitation needed.

1.2.4 Membrane Filtration / Ultrafiltration

• Principle: size‑exclusion via membranes to remove particulates, bacteria, endotoxins (for WFI).

• Features: used downstream of RO or distillation for sterilization and pyrogen removal.

1.2.5 Combination Systems

• Polishing Trains: RO → deionization → UV oxidation → ultrafiltration to meet WFI or highly purified water standards.

• Monitoring: conductivity, TOC (total organic carbon), microbial counts, endotoxin tests.

1.3 Water Hardness

1.3.1 Definition

• Hardness: concentration of calcium (Ca²⁺) and magnesium (Mg²⁺) ions in water, expressed as mg CaCO₃/L.

1.3.2 Types of Hardness

1.3.3 Classification (USP)

• Soft: < 17.1 mg CaCO₃/L

• Slightly hard: 17.1–60 mg/L

• Moderately hard: 61–120 mg/L

• Hard: 121–180 mg/L

• Very hard: > 180 mg/L

1.4 Determination of Hardness

1.4.1 EDTA Titrimetric Method

1. Buffer sample to pH 10 (ammonia buffer).

2. Add Eriochrome Black T indicator → wine‑red complex with Ca²⁺/Mg²⁺.

3. Titrate with standard EDTA until color changes to blue (indicator liberated).

4. Calculate hardness as mg CaCO₃/L from EDTA volume:

$$\text{Hardness (mg CaCO₃/L)} = \frac{V_{\rm EDTA}\times M_{\rm EDTA}\times 100\,000}{\text{Volume of sample (mL)}}$$

1.5 Control of Hardness

1.6 Significance in Pharmaceutical Manufacturing

• Equipment Scaling & Fouling: hardness leads to deposit formation in boilers, heat exchangers.

• Effect on Formulations: interaction with drugs/excipients (e.g., soap formation, altered dissolution).

• Analytical Accuracy: hard water can interfere in titrimetric and spectrophotometric assays.

1.7 Key Points for Exams

• List and define water grades and their pharmaceutical uses.

• Compare major purification methods (distillation, RO, deionization).

• Define temporary vs. permanent hardness and classify hardness levels.

• Outline the EDTA titration procedure for hardness determination.

• Describe softening techniques and their industrial applications.

Unit 2: Inorganic Excipients & Their Applications

This unit covers key inorganic excipients used in pharmaceutical formulations, their chemical nature, functional roles, and selection criteria.

2.1 Definition & Importance of Excipients

• Excipients: inactive ingredients added to formulations to aid manufacturing, stability, delivery, or patient acceptability.

• Roles: diluents, binders, disintegrants, glidants, coatings, absorbents, buffering agents, and more.

2.2 Common Inorganic Excipients

2.3 Functional Categories & Mechanisms

1. Diluents/Fillers

   • Provide bulk to low‑dose drugs

   • Should be inert, compressible, and flowable

2. Binders

   • Promote adhesion of powder particles in wet granulation

   • Examples: DCP, MCC

3. Lubricants & Glidants

   • Reduce friction between powder and equipment

   • Magnesium stearate coats particles; colloidal silica reduces interparticle cohesion

4. Disintegrants

   • Facilitate breakup of tablets into particles for dissolution

   • Inorganic options: sodium starch glycolate (though organic), croscarmellose

5. Adsorbents & Suspending Agents

   • Kaolin, bentonite: adsorb moisture and stabilize suspensions by increasing viscosity

6. Antacids & Buffers

   • Neutralize gastric acid (e.g., CaCO₃, Mg(OH)₂, sodium bicarbonate)

   • Buffers maintain pH in formulations and physiological compatibility

7. Protective & Topical Agents

   • Zinc oxide: protectant, astringent in dermal products

   • Talc: reduces stickiness in ointment bases

2.4 Selection Criteria for Inorganic Excipients

• Purity & Grade: pharmaceutical grade with defined impurity limits

• Physicochemical Properties: particle size, surface area, pH, solubility

• Compatibility: chemical inertness with API and other excipients

• Functionality: meets intended role without adverse effects

• Regulatory Status: recognized in pharmacopeias (USP, EP, JP)

2.5 Applications & Formulation Examples

• Tablet Formulation:

  • API + DCP (60 %) + MCC (15 %) + magnesium stearate (1 %) + colloidal silica (0.5 %)

• Oral Suspension:

  • API dispersed in water with bentonite (4 %) + sodium bicarbonate buffer + preservative

• Topical Cream:

  • Zinc oxide (15 %) + talc (5 %) in emulsion base for barrier ointment

• Effervescent Granules:

  • Citric acid + sodium bicarbonate + CaCO₃ filler + flavor

2.6 Key Points for Exams

• List major inorganic excipients and their chemical compositions.

• Match each excipient to its primary function in formulations.

• Explain how particle size and surface characteristics influence excipient performance.

• Describe selection criteria for excipients in pharmaceutical manufacturing.

• Provide formulation examples illustrating the use of inorganic excipients.

Unit 3: Acids, Bases & Buffer Systems

This unit provides an in‑depth study of acid‑base chemistry as applied in pharmaceutical formulations and biological systems. You’ll learn definitions and strength scales, pH and pKa concepts, buffer theory, buffer design and calculations, pharmaceutical applications of buffers, and quality control considerations.

3.1 Fundamental Definitions

• Acid (Arrhenius): proton donor in aqueous solution (e.g., HCl → H⁺ + Cl⁻).

• Base (Arrhenius): hydroxide donor (e.g., NaOH → Na⁺ + OH⁻).

• Brønsted–Lowry Acid/Base: acid donates H⁺; base accepts H⁺ (broader, includes non‑aqueous).

• Lewis Acid/Base: acid accepts electron pair; base donates electron pair (most general).

3.2 Strength of Acids & Bases

• Acid Dissociation Constant (Ka):

  $$\text{HA} \rightleftharpoons \text{H}^+ + \text{A}^-,\quad K_a = \frac{[\text{H}^+][\text{A}^-]}{[\text{HA}]}$$

• Base Dissociation Constant (Kb):

  $$\text{B} + \text{H}_2\text{O} \rightleftharpoons \text{BH}^+ + \text{OH}^-,\quad K_b = \frac{[\text{BH}^+][\text{OH}^-]}{[\text{B}]}$$

• Relationship: $K_a \times K_b = K_w = 1.0 \times 10^{-14}$ at 25 °C.

3.3 pH, pKa & pKb

• pH: negative logarithm of hydrogen ion activity:

  $$\text{pH} = -\log [\text{H}^+]$$

• pKa: negative log of Ka, indicates acid strength (lower pKa = stronger acid).

• pKb: negative log of Kb.

• pKa + pKb = pK_w = 14 at 25 °C.

Henderson–Hasselbalch Equation (for buffers):

$$\text{pH} = \text{pKa} + \log\!\frac{[\text{A}^-]}{[\text{HA}]}$$

• For basic buffer:

  $$\text{pOH} = \text{pKb} + \log\!\frac{[\text{BH}^+]}{[\text{B}]} \quad\Longrightarrow\quad \text{pH} = 14 – \text{pOH}$$

3.4 Buffer Solutions

3.4.1 Definition & Function

• Buffer: a solution of a weak acid and its conjugate base (or vice versa) that resists pH change upon addition of small amounts of acid or base.

• Buffering Capacity: ability to resist pH change; maximal when pH ≈ pKa and [A⁻] ≈ [HA].

3.4.2 Buffer Components & Selection

3.4.3 Preparing a Buffer

1. Calculate ratio of conjugate base to acid using Henderson–Hasselbalch.

2. Select appropriate total concentration (0.05–0.2 M typical).

3. Weigh and dissolve calculated amounts of acid and salt (or titrate acid with base).

4. Adjust pH with acid or base to target, verify with calibrated pH meter.

5. Dilute to final volume with purified water.

Example: Prepare 1 L acetate buffer at pH 5.0, 0.1 M total acetate.

• pKa = 4.76 → pH – pKa = 0.24 → [A⁻]/[HA] = 10^0.24 ≈ 1.74

• Let [HA] = x, [A⁻] = 1.74x; x + 1.74x = 0.1 → x = 0.0363 M (HA), A⁻ = 0.0637 M

• Mass CH₃COOH (60.05 g/mol) = 0.0363 mol × 60.05 = 2.18 g

• Mass sodium acetate trihydrate (136 g/mol) = 0.0637 mol × 136 = 8.66 g

3.5 Pharmaceutical Applications of Buffers

1. Injectable Formulations

   • Blood‑compatible pH (7.0–7.4) phosphate or histidine buffers to maintain physiological compatibility and drug stability.

2. Ophthalmic Drops

   • Borate or phosphate buffers to ensure comfort and minimize irritation; isotonic with tears.

3. Oral Liquids & Syrups

   • Citrate or acetate buffers to control drug ionization, taste, and chemical stability.

4. Tablet Coating Solutions

   • Buffered systems to prevent API degradation during film coating processes.

5. Biological Assays

   • Tris, phosphate, HEPES buffers for enzyme assays and nucleic acid work.

3.6 Quality Control & Stability

• pH Measurement:

  • Calibrated pH meter with appropriate buffer standards (pH 4, 7, 10).

  • Temperature compensation (measure and adjust at 25 ± 0.5 °C).

• Buffer Sterility:

  • Aseptic preparation or membrane filtration for parenteral use.

• Buffer Capacity Testing:

  • Titrate buffer with known acid/base and record ΔpH; calculate capacity (moles added per pH unit change).

• Compatibility Studies:

  • Ensure buffer salts do not precipitate with API or excipients (e.g., calcium phosphate precipitation in phosphate buffers).

3.7 Clinical Correlations

• Metabolic Acidosis/Alkalosis: disturbance in blood buffer systems (bicarbonate system) leading to pH imbalance.

• Antacid Therapy: neutralization of gastric acid using base salts (Mg(OH)₂, Al(OH)₃, CaCO₃); buffers control rate of pH change.

• Intravenous Fluid Buffers: lactate in Hartmann’s solution metabolizes to bicarbonate, correcting acidosis.

3.8 Key Points for Exams

• Define Ka, Kb, pKa, pKb, and pH.

• Apply Henderson–Hasselbalch equation for buffer design.

• List common buffer systems, their pKa, and useful pH ranges.

• Calculate component quantities for buffer preparation.

• Describe pharmaceutical applications and QC measures for buffer solutions.

Unit 4: Heavy Metals – Limits, Detection & Removal

This unit covers the significance of heavy metal impurities in pharmaceuticals, regulatory limits, analytical methods for their detection, and strategies to remove or control them in raw materials and finished products.

4.1 Significance of Heavy Metal Impurities

• Toxicity: heavy metals such as lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As) can accumulate in tissues, causing nephrotoxicity, neurotoxicity, and carcinogenicity.

• Sources: raw materials (minerals, botanical extracts), manufacturing equipment (leaching from stainless steel), water, and excipients.

• Regulatory Concern: International pharmacopeias (USP <232>/<233>, ICH Q3D) set permissible daily exposure (PDE) limits to ensure patient safety.

4.2 Regulatory Limits & Permissible Daily Exposure (PDE)

4.3 Sample Preparation for Heavy Metal Analysis

1. Acid Digestion:

   • Procedure: heat sample with concentrated HNO₃ (and HCl for aqua regia) to oxidize organic matrix and solubilize metals.

   • Microwave Digestion: closed-vessel system for rapid, reproducible digestion with minimal loss.

2. Wet Ashing: slow digestion on hotplate with H₂SO₄/HNO₃ mixture for botanicals.

3. Dilution & Filtration: dilute digested solution to volume with deionized water, filter through 0.45 µm membrane to remove particulates.

4.4 Analytical Techniques

4.5 Limit Tests for Heavy Metals (USP Method)

• Principle: General heavy metals precipitated as sulfides form turbidity; compared against standard lead reference.

• Procedure Outline:

  1. Dissolve test sample in water/acetic acid.

  2. Add ammonium chloride–ammonium hydroxide buffer (pH ~9).

  3. Introduce sodium sulfide → heavy metal sulfides precipitate.

  4. Compare turbidity visually or spectrophotometrically with reference solution containing specified Pb²⁺ concentration.

4.6 Removal & Control Strategies

4.7 Quality Control & Documentation

• System Suitability: calibration with multi-element standards; verify linearity, precision, and detection limits.

• Validation Parameters: specificity, accuracy (recovery studies), precision (repeatability), linearity, LOD/LOQ, robustness.

• Batch Records: document sample ID, digestion conditions, instrument parameters, calibration data, and results.

• Rejection Criteria: any value exceeding regulatory limits triggers investigation, root‑cause analysis, and possible batch rejection or rework.

4.8 Key Points for Exams

• List major toxic heavy metals, their PDE limits, and health effects.

• Describe sample digestion methods for heavy metal analysis.

• Compare AAS, ICP–MS, and ICP–OES in terms of sensitivity and throughput.

• Outline the USP limit test for total heavy metals.

• Discuss removal strategies (ion exchange, adsorption, precipitation) used in pharmaceutical manufacturing.

Unit 5: Antacids, Dental Products & Medical Gases

This unit covers inorganic compounds used to neutralize gastric acid, materials for dental care, and the collection, storage, and pharmaceutical uses of medical gases.

5.1 Antacids

5.1.1 Definition & Mechanism

• Antacids: weak bases that react with excess gastric hydrochloric acid to form water and salt, thereby raising gastric pH and relieving symptoms of hyperacidity.

• General Reaction:

  $$\text{MOH} + \text{HCl} \;\longrightarrow\; \text{MCl} + \text{H}_2\text{O}$$

  where M = Mg²⁺, Al³⁺, Ca²⁺, or Na⁺.

5.1.2 Common Antacid Agents

5.1.3 Formulation Considerations

• Buffering Capacity: ability to neutralize a given amount of acid, influenced by dose and solubility.

• Onset vs. Duration: combine fast‑ and slow‑acting agents (e.g., Mg + Al hydroxides) for balanced effect.

• Dosage Forms: tablets, suspensions, chewable granules; palatability and ease of dosing.

5.2 Dental Products

5.2.1 Toothpastes & Powders

• Abrasives: calcium carbonate, hydrated silica—to remove plaque without excessive enamel wear.

• Fluoride Sources: sodium fluoride, sodium monofluorophosphate—for caries prevention by promoting enamel remineralization.

• Detergents: sodium lauryl sulfate—to aid foaming and dispersion of debris.

• Humectants & Binders: glycerin, sorbitol, carboxymethylcellulose—to retain moisture, stabilize paste.

5.2.2 Mouthwashes & Rinses

• Antimicrobials: chlorhexidine gluconate—to reduce plaque and gingivitis.

• Astringents: zinc chloride, alum—to tighten mucosal proteins and reduce minor bleeding.

• Buffers: phosphate salts—to maintain pH and protect enamel.

5.2.3 Dental Impression Materials

• Gypsum Products: calcium sulfate dihydrate (plaster, stone) for model casting.

• Alginate: sodium or potassium alginate for primary impressions; mixed with calcium salts to gel.

5.3 Medical Gases

5.3.1 Oxygen (O₂)

• Purity Requirements: ≥ 99 % v/v, water and oil content strictly controlled.

• Production: fractional distillation of liquefied air or PSA (pressure swing adsorption).

• Storage & Delivery: compressed cylinders (200–300 bar) with regulator, nasal cannula or mask; liquid oxygen systems for large users.

• Pharmaceutical Uses: treatment of hypoxemia, anesthesia adjunct.

5.3.2 Nitrous Oxide (N₂O)

• Properties: colorless, sweet‑smelling gas; analgesic and weak anesthetic.

• Storage: cylinder under pressure; vaporizes to gas on release.

• Uses: dental analgesia (“laughing gas”), procedural sedation.

5.3.3 Medical Air

• Definition: compressed air filtered and dried for respiratory therapy.

• Standards: oil‑free compressors; particulate and microbial filters.

• Uses: driving nebulizers, ventilators, CPAP devices.

5.3.4 Carbon Dioxide (CO₂)

• Purity: medical grade, ≥ 99.5 %.

• Uses: insufflation during laparoscopic surgery, vascular contrast in angiography.

5.3.5 Other Specialty Gases

• Helium (He): mixed with O₂ (heliox) to reduce airway resistance in obstructive lung disease.

• Entonox: premixed 50 % N₂O and 50 % O₂ for obstetric analgesia.

5.4 Quality Control & Safety

• Antacids & Dental Products: assay of active ingredients; pH, buffering capacity, abrasive particle size; microbial limits (for oral suspensions).

• Gases: certificate of analysis for purity, moisture, hydrocarbons; cylinder integrity tests; periodic recertification.

• Storage Conditions: antacids and dental pastes at controlled humidity; gases in secure, ventilated areas away from heat.

5.5 Key Points for Exams

• List major antacid agents, their formulas, and adverse effects.

• Identify inorganic components of toothpastes and their functions.

• Describe production, storage, and uses of oxygen and nitrous oxide.

• Understand quality tests for pharmaceutical gases and dental formulations.

Unit 6: Radiopharmaceuticals & Isotonic Solutions

This unit covers the use of radioactive compounds in diagnostics and therapy, and the principles behind preparing solutions isotonic with body fluids to ensure safety and comfort.

6.1 Radiopharmaceuticals

6.1.1 Definition & Uses

• Radiopharmaceutical: a sterile preparation containing radionuclides used for diagnostic imaging or radiotherapy.

• Diagnostic: emit γ‑rays (e.g., technetium‑99m) for SPECT or positrons (e.g., fluorine‑18) for PET.

• Therapeutic: deliver β‑ or α‑particle radiation to destroy diseased tissue (e.g., iodine‑131 for thyroid ablation, lutetium‑177 for neuroendocrine tumors).

6.1.2 Radionuclide Generators & Labeling

• Molybdenum‑99/Technetium‑99m Generator: parent (^99Mo) decays to ^99mTc, which is eluted (“milked”) as pertechnetate (^99mTcO₄⁻).

• Labeling Techniques:

  • Chelation: ^99mTc bound to chelators (DTPA, HMPAO) for blood‑brain barrier imaging.

  • Iodination: radioiodine attached to tyrosine residues in proteins (e.g., I‑131 labeled antibodies).

6.1.3 Preparation & Quality Control

6.1.4 Safety & Handling

• Radiation Protection: time, distance, shielding principles; use of lead shielding and dose calibrators.

• Waste Management: decay-in‑storage protocols; segregation of solid, liquid, and sharps waste.

• Personnel Monitoring: dosimeters, thyroid probes, regular bioassays for internal contamination.

6.2 Isotonic Solutions

6.2.1 Definition & Importance

• Isotonic Solution: has the same osmotic pressure as blood plasma (~0.9 % NaCl or 285–295 mOsm/kg).

• Purpose: prevent cell lysis or crenation on administration (intravenous, ophthalmic, nasal).

6.2.2 Methods to Adjust Tonicity

$$\text{Required solute (g)} = \frac{E_{\rm NaCl} \times \text{Desired NaCl (g)}}{\text{Potency of drug}}$$

where E_NaCl of a solute expresses its tonicity effect relative to NaCl.

6.2.3 Common Isotonic Preparations

6.2.4 Preparation & Quality Checks

1. Calculate solute quantities for desired osmolarity using E_NaCl or cryoscopic data.

2. Weigh & Dissolve in purified water; adjust pH if necessary.

3. Sterilize by filtration (0.22 µm) for ophthalmic or terminal autoclaving for IV (if compatible).

4. Test: measure osmolarity (osmometer), pH, clarity, sterility (membrane filtration), endotoxin (LAL).

6.3 Key Points for Exams

• Describe the role and preparation of ^99Mo/^99mTc generators and common radiolabeling methods.

• List quality control tests for radiopharmaceuticals (radiochemical purity, sterility, pH, isotonicity).

• Explain fundamentals of radiation safety and waste disposal.

• Define isotonic solution, its osmotic parameters, and calculation methods (freezing‑point depression, E_NaCl).

• Provide examples of common isotonic fluids and their applications.

Unit 7: Quality Control Tests & Safety/Disposal of Inorganics

This unit covers the analytical methods to ensure purity and compliance of inorganic pharmaceutical ingredients, and the safe handling, storage, and disposal practices for inorganic chemicals in pharmaceutical settings.

7.1 Quality Control Tests for Inorganic Compounds

7.1.1 Identification Tests

• Color and Appearance: verify crystalline form, color, and absence of visible impurities.

• Solubility Tests: confirm expected solubility profile in water or specified solvents.

• pH of Solution: prepare standard concentration (e.g., 1 % w/v) and confirm pH falls within pharmacopeial limits.

7.1.2 Assay Procedures

7.1.3 Impurity and Limit Tests

• Heavy Metals: USP <233> elemental impurities by ICP–MS or ICP–OES; general limit test via sulfide precipitation.

• Sulphates & Chlorides: gravimetric or titrimetric limit tests to confirm levels below specified thresholds.

• Arsenic & Lead: specific limit tests (e.g., Gutzeit’s or mercuric bromide methods for arsenic; dithizone extraction for lead).

• Residual Solvents: headspace GC for solvents used in synthesis or purification.

7.1.4 Physical Tests

• Moisture Content: Karl Fischer titration for hygroscopic inorganics (e.g., magnesium trisilicate); loss on drying for non‑volatile water.

• Particle Size Distribution: sieve analysis or laser diffraction for excipients like talc, kaolin, and bentonite—ensuring consistent flow and suspension properties.

• Bulk and Tapped Density: used for tablet excipients (e.g., DCP, MCC) to predict flow (Carr’s Index, Hausner Ratio).

7.2 Stability and Storage

7.2.1 Stability Testing

• Accelerated Conditions: 40 °C ± 2 °C / 75% RH ± 5% for 6 months (ICH Q1A) to predict shelf life.

• Photostability: exposure to defined light sources to assess degradation of photosensitive inorganics (e.g., peroxide formation in silver compounds).

• Container–Closure Compatibility: evaluate potential interaction with glass, plastic, rubber stoppers (e.g., leaching of phthalates from PVC).

7.2.2 Storage Requirements

• Temperature: ambient (15–25 °C) unless otherwise specified; some inorganic reagents require refrigeration (2–8 °C).

• Humidity Control: desiccators or controlled humidity chambers for hygroscopic materials.

• Light Protection: amber glass or opaque containers for light‑sensitive compounds (e.g., iodine solutions).

• Labeling: include grade, batch number, expiry date, hazard pictograms, and storage conditions.

7.3 Safety Handling of Inorganic Chemicals

7.3.1 Hazard Classification

• Corrosives: strong acids/bases (HCl, NaOH) require gloves, face shields.

• Toxic Metals: lead, cadmium compounds—work in fume hood, avoid inhalation.

• Oxidizers: permanganate, chromates—keep away from organics, store separately.

• Compressed Gases: cylinders secured, valve protection, regular leak checks.

7.3.2 Personal Protective Equipment (PPE)

• Laboratory coat, nitrile gloves (some chemicals require neoprene), safety goggles or face shields.

• Respiratory protection (e.g., N95, half‑mask cartridges) for dust or fume exposure.

7.3.3 Engineering Controls

• Fume Hoods: for volatile, toxic, or dusty inorganics.

• Ventilated Storage Cabinets: for corrosives and oxidizers.

• Spill Kits: neutralizing agents (sodium bicarbonate for acids, acid for alkali), absorbents.

7.4 Waste Disposal of Inorganic Materials

7.4.1 Segregation

• Aqueous Waste: collect in compatible containers; neutralize pH before disposal per local regulations.

• Solid Waste: label “hazardous”—heavy metal salts collected separately; do not discard with regular trash.

• Sharps & Broken Glass: in puncture‑resistant containers.

7.4.2 Treatment Methods

• Chemical Neutralization: acids with base addition; alkalis with acid.

• Precipitation: remove heavy metals by pH adjustment to precipitate hydroxides, then filter and send solids to hazardous waste.

• Adsorption: activated carbon for trace organics or silver; cementation (e.g., Zn to remove Ag).

• Autoclaving: for sterile inorganic solutions, before disposal of biologically contaminated liquids.

7.4.3 Regulatory Compliance

• Local & National Regulations: e.g., EPA (USA), EU Waste Framework Directive, local environmental agencies.

• Documentation: waste manifests, SDS‑based disposal instructions, training records.

7.5 Key Points for Exams

• List QC tests for identification, assay, and impurity limits of inorganics.

• Describe stability testing and storage conditions for moisture‑ and light‑sensitive inorganics.

• Name PPE and engineering controls required for handling corrosives, toxic metals, and oxidizers.

• Outline waste segregation, treatment, and disposal procedures for inorganic chemical waste.