Aseptic Manufacturing & IPQC for Emulsions and Dry Powders

ASEPTIC PROCESS TECHNOLOGY

Manufacturing Flowcharts & In-Process Quality Control (IPQC) Tests — Emulsions & Dry Powders for Injection

Standards: I.P. • B.P. • U.S.P.

Department of Pharmaceutics | School of Pharmaceutical Sciences | Lovely Professional University

TABLE OF CONTENTS

Department of Pharmaceutics | School of Pharmaceutical Sciences | Lovely Professional University

Definition of Pharmaceutical Emulsion

Why IPQC is Needed for Emulsions

Materials Used in Emulsion Formulation

Batch Formula — Emulsion

Aseptic Manufacturing Flowchart — Emulsion

IPQC Tests for Emulsions (Part 1: Tests 1–4)

IPQC Tests for Emulsions (Part 2: Tests 5–8)

IPQC Tests for Emulsions (Part 3: Tests 9–14)

Definition of Dry Powder for Injection

Why IPQC is Needed for Dry Powders

Materials Used in Dry Powder Formulation

Batch Formula — Dry Powder

Aseptic Manufacturing Flowchart — Lyophilization

IPQC Tests: Dry Powder (Part 1: Tests 1–4)

IPQC Tests: Dry Powder (Part 2: Tests 5–8)

IPQC Tests: Dry Powder (Part 3: Tests 9–14)

Lyophilization Process Monitoring

Comparative Summary: Emulsion vs. Dry Powder

Conclusion & Key Takeaways

PART A | EMULSIONS

PART A:<br>Pharmaceutical Emulsion<br>— Definition

An <span style="color: #00C9B1; font-weight: 600;">emulsion</span> is a <span style="color: #FFFFFF; font-weight: 500;">thermodynamically unstable, heterogeneous system</span> consisting of at least <span style="color: #FFFFFF; font-weight: 500;">two immiscible liquids</span> (oil and water), where one liquid is <span style="color: #00C9B1; font-weight: 600;">dispersed</span> in the other as droplets, stabilized by <span style="color: #00C9B1; font-weight: 600;">emulsifying agents</span> (surfactants).

Per IP/BP/USP: <span style="color: #00C9B1;">Must be physically stable, chemically stable, microbiologically sound, and therapeutically effective.</span>

Why IPQC is Essential for Emulsions

Physical Instability

Prone to creaming, sedimentation, coalescence, Ostwald ripening, and phase inversion.

Droplet Size Safety

Large droplets (>5μm) in IV emulsions can cause life-threatening pulmonary embolism.

pH & Osmolality

Must be continuously monitored to guarantee patient safety and physiological stability.

Sterility

Non-negotiable for injectable emulsions; any microbial contamination is fatal.

Zeta Potential

Must be >±30 mV to critically prevent aggregation and ensure long-term stability.

Batch Reproducibility

Continuous monitoring directly catches deviations early during manufacturing stages.

Regulatory Compliance

IP/BP/USP proactively mandates rigorous IPQC standards at every manufacturing step.

Department of Pharmaceutics | School of Pharmaceutical Sciences | Lovely Professional University

Materials Used in Emulsion Formulation

OIL PHASE

Soybean Oil (LCT)

20% w/v IV

MCT Oil

Rapid energy source

Castor Oil

Topical/oral

Mineral Oil

Topical emollients

EMULSIFYING AGENTS

Egg Lecithin

1.2% IV (Intralipid)

Soy Lecithin

Vegan alternative

Polysorbate 80

Tween 80, oral/topical

Pluronics

Block copolymers

AQUEOUS PHASE

WFI

Endotoxin <0.25 EU/mL

Purified Water

Non-injectable

Glycerol 2.25%

Tonicity agent

Propylene Glycol 5–20%

Topical

Sorbitol 5%

Oral emulsions

STABILIZERS & PRESERVATIVES

Oleic Acid

Negative charge stabilizer

EDTA

Chelating agent

Benzyl alcohol

Preserved vials

Citric acid / NaOH

pH adjustment

Vitamin E (α-tocopherol)

Antioxidant

FORMULATION DEPT | ADVANCED PHARMACEUTICS MODULE

Aseptic Manufacturing Flowchart

— Emulsion

RAW MATERIAL TESTING & RELEASE

WFI, oil, emulsifier, excipients tested

OIL PHASE PREPARATION

Heat oil + emulsifier to 60–70°C

AQUEOUS PHASE PREPARATION

Dissolve glycerol, adjust pH

Oil phase clarity & temp; aqueous phase pH & conductivity

HOMOGENIZATION

High-pressure homogenizer (500–1500 bar, 3–5 cycles)

Droplet size (DLS); zeta potential; visual appearance

pH ADJUSTMENT & TONICITY

Adjust to target pH and osmolality

pH; osmolality; viscosity

STERILE FILTRATION

0.22 μm filter; Grade A environment

FILLING & SEALING

Aseptic fill into vials/bags

Fill volume/weight; visual inspection; container-closure integrity

TERMINAL STERILIZATION / AUTOCLAVE

(If applicable)

FINAL QC RELEASE

Review and certification of batch records

LEGEND

Process Step

In-Process Quality Control (IPQC)

Standard Operating Procedure • Aseptic Process Emulsions

IPQC Tests for Emulsions — Part 1 (Tests 1–4)

TEST 1 — APPEARANCE & VISUAL INSPECTION

Black & white background; 2000–3750 lux; invert 2–3 times; automated cameras at 4–6 angles

Uniform milky-white, no visible oil droplets, no phase separation, no foreign particles

TEST 2 — DROPLET SIZE DISTRIBUTION (Critical Quality Attribute)

Instrument: DLS (Malvern Zetasizer) / Laser Diffraction (Mastersizer 3000)

Dilute 1:100–1:1000; 3 independent runs; report Z-average and PDI

Topical: 1–10 μm; IV fat: &lt;500 nm (D90); PDI &lt;0.25; PFAT5 &le;0.05% (USP &lt;729&gt;)

TEST 3 — ZETA POTENTIAL

Instrument: Zetasizer Nano ZS — Electrophoretic Light Scattering

Dilute 1:1000 in 1mM NaCl; folded capillary cell; Smoluchowski equation

&gt;+30 mV or &lt;−30 mV = stable; IV fat emulsions: −35 to −60 mV

TEST 4 — pH MEASUREMENT

Instrument: Calibrated pH meter (Mettler Toledo SevenMulti)

Calibrate at pH 4.01 & 7.00; 20 mL sample at 25°C; stable reading 60–90 sec

IV: pH 6.0–9.0; Topical: 4.5–7.5; Oral: 3.0–7.0

Department of Pharmaceutics | School of Pharmaceutical Sciences | Lovely Professional University

IPQC Tests for Emulsions

Part 2: In-Process Quality Control (Tests 5–8)

ASEPTIC PROCESS TECHNOLOGY | IN-PROCESS QUALITY CONTROLS

5

TEST 5 — VISCOSITY MEASUREMENT

Instrument

Brookfield DV-II+ Viscometer / Anton Paar Rheometer

Method

200mL sample at 25°C; SC4-21/SC4-25 spindle; 0.5–100 rpm stepwise; flow curve plotted

IV: 2–10 mPa·s; Topical creams: 2,000–100,000 cP; Oral: 50–500 cP

6

TEST 6 — OSMOLALITY / TONICITY TEST

Instrument

Freezing Point Depression Osmometer (Advanced OSMO-1 / Fiske 210)

Method

Centrifuge 5000 rpm 10 min; collect aqueous phase; 50 μL; supercool to −8°C; ΔTf measurement

Isotonic: 280–320 mOsm/kg; Intralipid 10% ≈300; Intralipid 20% ≈350 mOsm/kg

7

TEST 7 — PARTICULATE MATTER TEST

Methods

Light Obscuration (HIAC Royco) + Microscopic method

Procedure

Invert 20×; pool ≥10 containers; 4 portions ≥5 mL; count ≥10μm and ≥25μm particles

LVP: ≤25/mL (≥10μm); ≤3/mL (≥25μm). SVP: ≤6000/container (≥10μm); ≤600 (≥25μm)

8

TEST 8 — STERILITY TEST (Injectable only)

Method

Membrane filtration in ISO 5/Grade A; emulsion diluted in isopropyl myristate or polysorbate 80

Procedure

0.45μm membrane; wash ≥3×; split into FTM (30–35°C) and SCDM (20–25°C); 14 days

No microbial growth in either medium after 14 days

IPQC Tests for Emulsions — Part 3 (Tests 9–14)

BACTERIAL ENDOTOXIN (LAL Test)

Gel-Clot method; EL = K/M (K=5 EU/kg/hr); demulsify first; 37°C 60 min; firm gel = positive.

Test = Negative; EL below calculated limit.

CONTENT UNIFORMITY / ASSAY

10 containers; HPLC after demulsification; 20μL injection; compare vs standard.

85–115% label claim; RSD ≤6.0% (USP Stage 1).

CREAMING INDEX / STABILITY

100 mL cylinder; 25°C and 40°C; measure cream layer at 0,1,4,8,24,48,72,168 hrs. CI(%) = (cream/total height)×100.

<5% after 24h; <10% after 1 week.

LEAKAGE TEST

0.5% Methylene Blue dye bath; 200–300 mmHg vacuum 5 min; restore pressure 5 min; inspect for dye.

ZERO dye in any container.

MICROBIAL LIMIT TEST (Non-sterile)

1g in 9mL Fluid A + polysorbate 80; serial dilutions; SCDA (TAMC) + SDA (TYMC).

Topical: TAMC ≤10² cfu/g; TYMC ≤10¹ cfu/g. Absent: S. aureus, P. aeruginosa.

EXTRACTABLE VOLUME

SVP ≤25mL: combine 5 containers; LVP: single container; must meet or exceed labeled volume.

Average ≥nominal volume; max 115%; individual ≥95%.

Department of Pharmaceutics | School of Pharmaceutical Sciences | Lovely Professional University

PART B

DRY POWDER FOR INJECTION

Lyophilized / Spray-Dried Preparations

As per I.P. · B.P. · U.S.P.

Department of Pharmaceutics | School of Pharmaceutical Sciences | LPU

Dry Powder for Injection — Definition & Types

PART B | DRY POWDERS

<b>Definition:</b> Sterile, dry solid preparations that, when dissolved/suspended in sterile vehicles (WFI, saline), yield solutions or suspensions suitable for parenteral administration. <br><b>Key Implication:</b> Manufactured specifically when the API is unstable in aqueous solution.

LYOPHILIZATION (Freeze-Drying)

Most common. Aqueous solution frozen, water removed by sublimation under vacuum. Produces dry cake.

Ceftriaxone, Vancomycin, Amphotericin B, mAbs, vaccines.

SPRAY DRYING

Atomization of solution into droplets dried by hot air. Produces free-flowing powder.

Peptide drugs, inhalation powders.

STERILE CRYSTALLIZATION

API crystallized from sterile solution aseptically. Produces pure crystal variants.

Penicillin G sodium, some antibiotics.

ASEPTIC POWDER FILLING

Sterile dry powder filled into vials aseptically. Uses highly controlled environments.

Ampicillin, Piperacillin/Tazobactam.

After reconstitution, must meet all parenteral requirements: sterility, endotoxin, particulate matter, pH, clarity.

WHY IPQC IS CRITICAL FOR DRY POWDERS FOR INJECTION

QUALITY ASSURANCE & IN-PROCESS CONTROLS | DRY POWDERS FOR INJECTION

API Stability

Dry powders formulated because API is unstable in solution; moisture ingress causes degradation.

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Residual Moisture

Must be precisely controlled; excess = degradation & microbial growth; insufficient = cake collapse.

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Reconstitution

Must dissolve completely within 1 min and yield clear/correct solution.

⏱️

Sterility

All post-sterilization operations must be aseptic; contamination is life-threatening.

🦠

Fill Weight Uniformity

Directly determines dose accuracy; critical for antibiotics, oncologics, hormones.

⚖️

Particle Size

Affects reconstitution rate, solubility, and injectability for sterile suspensions.

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Closure Integrity

Must maintain hermetic seal to prevent moisture ingress throughout shelf life.

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Cake Appearance

Cake collapse indicates temperature excursion or incomplete drying.

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Materials & Batch Formula

Dry Powder for Injection

API

Beta-lactam antibiotics (Ampicillin, Ceftriaxone, Meropenem); Glycopeptides (Vancomycin); Antifungals (Amphotericin B); Biologics (Adalimumab, Infliximab)

BULKING AGENTS (Lyoprotectants)

Mannitol (1–5%); Sucrose (1–10%); Trehalose (biologics); Lactose; Glycine

BUFFERS & pH ADJUSTERS

Sodium phosphate buffer; Citrate buffer; Histidine buffer (mAbs); HCl / NaOH for adjustment

TONICITY & STABILIZERS

NaCl (0.9%); Dextrose (5%); Polysorbate 80 (0.01%); HSA (human serum albumin); EDTA

Lyophilized Ceftriaxone Sodium 1g — Lab Batch (1000 vials)

Department of Pharmaceutics | School of Pharmaceutical Sciences | Lovely Professional University

Aseptic Manufacturing Flowchart

— Lyophilization (Freeze-Drying)

Department of Pharmaceutics | School of Pharmaceutical Sciences | Lovely Professional University

IPQC TESTS — DRY POWDER FOR INJECTION

Part 1: Tests 1–4 (Appearance, Moisture, Reconstitution, Fill Weight)

Standards: I.P. • B.P. • U.S.P.

DEPARTMENT OF PHARMACEUTICS | SCHOOL OF PHARMACEUTICAL SCIENCES | LOVELY PROFESSIONAL UNIVERSITY

TEST 1 — APPEARANCE OF LYOPHILIZED CAKE

Inspect each vial at 2000 lux; black and white backgrounds

Evaluate: cake integrity, colour, volume (>80% of vial), surface texture

Defects: full collapse (reject), melt-back (reject), cracks (investigate), partial collapse (investigate)

White to off-white, intact, porous cake; >80% vial volume; no collapse, foaming, or foreign particles

TEST 2 — RESIDUAL MOISTURE CONTENT

<span style="color: #FFFFFF; font-weight: 600;">Method 1: Karl Fischer Titration (KFT)</span> — Reference standard; 100–500 mg powder; iodine/SO₂ endpoint

<span style="color: #FFFFFF; font-weight: 600;">Method 2: Near-Infrared Spectroscopy (NIR)</span> — At-line/inline; real-time monitoring during secondary drying

≤1.0–3.0% w/w (product-specific); Biologics ≤1.0%; Antibiotics ≤2.0–3.0%

TEST 3 — RECONSTITUTION TIME & CLARITY

Add specified diluent (WFI / 0.9% NaCl / SWI); gentle swirl; stopwatch from diluent addition to complete dissolution

Inspect reconstituted solution for clarity vs. black/white backgrounds; measure pH, osmolality, particulates

≤1 minute; clear or slightly opalescent; no visible particles; colour and pH within specification

TEST 4 — UNIFORMITY OF FILL WEIGHT

Inline 100% checkweighing + manual check of 10 vials every 15–30 min

Tare 10 empty vials; weigh filled; net fill weight = gross − tare; calculate mean and RSD

Mean ±3% of nominal; RSD ≤2.0%; No individual vial outside ±5% of nominal

IPQC Tests — Dry Powder for Injection

Part 2 (Tests 5–8)

Department of Pharmaceutics | School of Pharmaceutical Sciences | Lovely Professional University

STERILITY TEST

Direct inoculation (for dry powders): reconstitute with sterile Fluid A or WFI in Grade A LAF

Transfer to FTM (30–35°C) and SCDM (20–25°C); incubate both for 14 days; observe daily for turbidity

Containers tested: <100 = 4 or 10%; 100–500 = 10; >500 = 20 or 2%

No turbidity in either medium after 14 days = PASS

BACTERIAL ENDOTOXIN TEST (BET)

Reconstitute with endotoxin-free WFI; dilute to below MVD

Gel-Clot / Kinetic Turbidimetric / Kinetic Chromogenic LAL test; 37°C ± 1°C for 60 ± 2 min

Include: A (test), B (PPC at 2λ), C (CSE standards), D (negative control)

Test = Negative; PPC = Positive; EL = K/M (K=5 EU/kg/hr); for antibiotics: EL = 0.2–0.5 EU/mg

ASSAY / POTENCY TESTING

10 vials reconstituted with WFI or HPLC solvent; diluted to 100 mL with mobile phase

HPLC (C18 column, UV detection); 20 μL injection; compare vs. reference standard

% Label Claim = (Area_sample / Area_standard) × (Conc_std / Nominal_conc) × 100

90–110% label claim (APIs); 80–125% (biologics); RSD ≤2.0%

pH OF RECONSTITUTED SOLUTION

Reconstitute per label; calibrate pH meter (pH 4.01 & 7.00); measure at 25 ± 0.2°C

Examples: Ceftriaxone 1g: pH 6.0–8.0; Vancomycin: pH 2.5–4.5; Amphotericin B: pH 5.0–7.0; mAbs: pH 5.0–7.0

Product-specific per pharmacopoeial monograph

IPQC Tests — Dry Powder for Injection: Part 3

Tests 9–14: Particulates, CCIT, Lyophilization, Bioburden, and Container Integrity

Department of Pharmaceutics | School of Pharmaceutical Sciences | Lovely Professional University

Lyophilization Cycle Monitoring — In-Process Parameters

Primary drying endpoint confirmed when: Product temperature rises to shelf temperature AND Pirani ≈ Capacitance pressure

Lyophilization Cycle Profile

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SHELF TEMPERATURE

Thermocouples / RTDs; ≥2 sensors/shelf; ±2°C uniformity; logged every 1–2 min

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CHAMBER PRESSURE

Pirani gauge (gas-dependent) + Capacitance manometer (gas-independent). Endpoint = Pirani ≈ Capacitance

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CONDENSER TEMPERATURE

−50 to −70°C; must be ≥20°C colder than product temp to drive sublimation

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PRODUCT TEMPERATURE

Wireless thermocouples in representative vials (front, middle, back shelves); must NOT exceed collapse temperature (Tc)

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WATER VAPOR FLUX (TDLAS)

Tunable Diode Laser Absorption Spectroscopy; real-time water vapor measurement; most accurate endpoint determination

Comparative Summary: Emulsion vs. Dry Powder for Injection — All IPQC Tests

KEY TAKEAWAYS

IPQC IS THE CORNERSTONE

IPQC is essential for both emulsions and dry powders; early detection of deviations reduces batch failures and ensures patient safety

EMULSION-SPECIFIC TESTS

Focus on physical stability: droplet size (DLS), zeta potential (>±30mV), creaming index, viscosity, and osmolality alongside sterility and assay

DRY POWDER-SPECIFIC TESTS

Unique tests include residual moisture (Karl Fischer/NIR ≤1–3%), lyophilization cycle monitoring, cake appearance, reconstitution time (≤1 min), and CCIT

SHARED MANDATORY TESTS

Both dosage forms require: sterility (14-day incubation), bacterial endotoxin (LAL test), particulate matter, and content uniformity per IP/BP/USP

REGULATORY & ENVIRONMENT

ISO 5–8 cleanrooms, validated instruments (DLS, KFT, lyophilizers), cGMP-trained personnel, and approved SOPs are mandatory

HARMONIZED PHARMACOPOEIAS

Differences between IP, BP, and USP are largely harmonized for critical tests; global regulatory compliance ensured

R. Bansal & Sunita, IJPRA, Volume 11, Issue 1, Jan–Feb 2026, pp:352–367 | DOI: 10.35629/4494-1101352367

Department of Pharmaceutics | LPU