Simultaneous Estimation of Two Drugs in a Formulation

1. Aim

To complete the Year 3 syllabus practical simultaneous estimation of two drugs in a formulation using an instructor-approved method or dataset. Actual analyte, measurements, and result must be entered in the student record.

2. Requirements

Instructor-approved sample and reference standard, validated method, instrument and calibration records, blank and controls, observation sheet, calculator or graphing aid, protective equipment, and chemical waste route. Confirm sample identity from its label and use the college method sheet for reagent quantities, concentrations, wavelengths, pH, and temperature. Acceptance criteria are to be recorded from the assigned current monograph or approved college method in the student record.

3. Theory

When two analytes both contribute to a signal, one wavelength may not separate them. A validated two-wavelength UV method can form two simultaneous equations from absorptivities, path length, and measured mixture absorbances. The equations must be well conditioned and matrix effects controlled. Another validated separation method may be chosen instead.

4. Procedure

Confirm sample identity, method version, hazards, instrument calibration, and required controls.
Record raw standards, blanks, sample readings, units, and any preparation or dilution factors.
Follow the verified laboratory method under instructor supervision, or analyze its supplied dataset.
Record both analytes, formulation matrix, blank, selected wavelengths, absorptivities, and mixture readings. Solve the approved equations and verify recovery against controls.
Check the fit, control recovery, and measurement range before applying a formula.
Report the calculation with units, method limitations, and unresolved details recorded in the student record.

5. Observation and calculation

Student record field	Entry
Case or product	Record here
Method	Record here
Observation	Record here
Inference	Record here
Supervisor check	Record here
Outcome	Record here

Assumed values for calculation practice only: Assumed equations are A1 = 2C1 + C2 and A2 = C1 + 2C2, with assumed A1 = 5 and assumed A2 = 4 in arbitrary units. The assumed solution is C1 = 2, C2 = 1 arbitrary units. These are invented algebra, not drug concentrations. Each invented input and output is assumed, not a reagent instruction or actual laboratory result.

6. Output or final result

Submit a labelled two-wavelength signal map, calculations where justified, and a conditional conclusion. Record the supervised outcome here.

Teaching-lab safety: Use instructor-supervised chemical handling and the approved disposal method. No assumed value here authorizes a preparation or analytical release decision.

This page is a supervised-activity guide; it does not report a completed case.

7. Sources

← Colourimetric Estimation of Sulpha Drugs Using BMR ReagentAssay of Salicylic Acid by Colourimetry →

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