Pharmacy & Pharmaceutical Sciences / Shake-Flask Partition Coefficient
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LABORATORY 03 · PHARMACY & PHARMACEUTICAL SCIENCES

Lipophilicity Determination: Octanol-Water Shake-Flask Partitioning of Ibuprofen

Quantify the 1-octanol/water partition coefficient (log P) of unionized ibuprofen using the standardized OECD shake-flask method and UV spectrophotometry. Explore interactive pharmaceutical simulation, formulation physics, and analytical assays.

PHARMACY & PHARMACEUTICAL SCIENCES · PHARMACEUTICS · ANALYSIS · PHARMACOKINETICS · PHARMACOLOGY

Your virtual pharmacy & pharmaceutical sciences laboratory.

ORGANIC OCTANOL PHASE EQUILIBRIUM MASS—
CALIBRATED PHARMACEUTICAL TELEMETRY

Ready to sample with Initial Conc = 2.0 mg/mL.

2.0 mg/mL
Standardized USP / Ph. Eur. pharmaceutical testing protocol.

Adjust Initial Conc, then execute analytical assay.

Active pharmaceutical ingredient (API) concentration and physicochemical telemetry are recorded using high-precision digital instrumentation and 64-bit IEEE 754 floating-point logging under temperature-controlled laboratory conditions. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support comprehensive pharmaceutics, analytical, and pharmacokinetic evaluation.

Pharmaceutical constitutive model and compendial boundary limits

All pharmaceutical assays, dissolution profiles, and pharmacokinetic parameters are evaluated under standardized USP and ICH laboratory protocols. Linear constitutive models reflect small-perturbation concentrations, stoichiometric reactions, and standard calibration limits.

Laboratory apparatus & testing equipment.

Precision Orbital Thermostatted Shaker (25.0 ± 0.2 °C)

Primary standardized university-grade instrument delivering calibrated, traceable measurements for Shake-Flask Partition Coefficient protocols.

Separatory Funnels with PTFE Stopcocks (100 mL)

Essential secondary analytical hardware maintaining environmental, photometric, or mechanical equilibrium during Shake-Flask Partition Coefficient procedures.

UV-Vis Spectrophotometer with Quartz Microcuvettes

Specialized sample holding vessel, reaction column, or sensor cell eliminating matrix artifacts.

Refrigerated Benchtop Centrifuge (4000 rpm)

High-precision digital telemetry recording interface capturing 64-bit real-time analytical readings in accordance with pharmacopoeial standards.

Analytical Balance (0.1 mg)

Analytical reagent grade reference standard or carrier fluid ensuring calibration traceability.

Digital pH Meter with Gel Combination Electrode

Precision measurement tool verifying transducer zero-drift and alignment prior to analytical testing.

FOLLOW THE METHOD

A reason behind every step.

Quantify the 1-octanol/water partition coefficient (log P) of unionized ibuprofen using the standardized OECD shake-flask method and UV spectrophotometry. Standardized parameter settings: 0.5, 1.4, 2.3, 3.2, 4.1, 5.0 mg/mL.

  1. Step 1

    Instrument Initialization & Baseline Tare

    Power on the analytical instrumentation for Shake-Flask Partition Coefficient, allow a 30-minute electronic warm-up period, and verify transducer zero-tare using certified standards.

  2. Step 2

    Standard Solution & Matrix Specimen Preparation

    Accurately compound, dilute, or compress active pharmaceutical ingredient (API) specimens under strictly regulated environmental conditions (25.0 ± 0.5 °C).

  3. Step 3

    Systematic Independent Variable Setting

    Adjust the independent testing parameter (Initial Conc) across the designated analytical range (0.5 to 5.0 mg/mL) in uniform calibrated steps.

  4. Step 4

    Analytical Signal Acquisition & Telemetry Logging

    Execute the measurement cycle and record steady-state telemetry for Organic Octanol Phase Equilibrium Mass with high-precision digital integration.

  5. Step 5

    Replicate Verification & Equilibrium Inspection

    Perform triplicate test acquisitions at each testing setpoint to verify signal stability, absence of thermal drift, and sample reproducibility.

  6. Step 6

    Regression Modeling & Pharmacopoeial Parameter Derivation

    Plot Initial Conc (mg/mL) against Octanol Phase Conc (mg/mL), execute ordinary least-squares (OLS) linear regression, and calculate Octanol Partition Mass Transfer Fraction (m) against compendial benchmarks.

YOUR NOTEBOOK · 0 OBSERVATIONS

Turn measurements into pharmaceutical insight.

See a complete example report ↗

Points are your recorded observations. The solid regression line validates Shake-Flask Partition Coefficient mathematical scaling.

LINEAR REGRESSION FIT · y = mx + b
C_octanol (mg/mL) = 0.8250 · C_total (mg/mL) + 0.0200
#Initial System Drug Concentration (mg/mL)Organic Octanol Phase Equilibrium Mass (mg/mL)Initial Conc (mg/mL)Octanol Phase Conc (mg/mL)

No readings yet. Execute an analytical assay and record it.

CHECK YOUR UNDERSTANDING

Explain what the pharmaceutical metrics mean.

Question 1: The primary physicochemical principle investigated in Shake-Flask Partition Coefficient is:

Question 2: In the evaluation of Shake-Flask Partition Coefficient, increasing Initial Conc results in:

Question 3: Which regulatory compendium defines official testing specifications for Shake-Flask Partition Coefficient?

Question 4: Ordinary least-squares (OLS) regression in Shake-Flask Partition Coefficient is utilized to:

THEORY AND CLINICAL CONTEXT

Pharmacy & Pharmaceutical Sciences background & chemical principles.

Quantify the 1-octanol/water partition coefficient (log P) of unionized ibuprofen using the standardized OECD shake-flask method and UV spectrophotometry.

C_octanol (mg/mL) = 0.8250 · C_total (mg/mL) + 0.0200

Pharmaceutical science principles integrate medicinal chemistry, physical pharmaceutics, dosage form technology, and clinical pharmacokinetics into rigorous quantitative frameworks.