Pharmaceutical process development internships: a worked yield example

Write down the basis of every percentage

A percentage needs an input quantity, output quantity and definition of what counts as output. In a multistep process, the input to the second step is usually smaller than the original input. Averaging the stage percentages loses that distinction.

Use a fictional material-handling example with no added material and the same mass basis throughout. This is an accounting exercise, not a manufacturing procedure or a claim about any drug's yield.

90%, 80% and 95% do not produce an 88.3% overall yield

Start with 100 kg of an abstract material. Track each stage's retained output and separately recorded side stream.

• Step 1 retains 90%: 100 kg becomes 90 kg, with 10 kg in the side stream.
• Step 2 retains 80% of its 90 kg input: 72 kg remains, with 18 kg in the side stream.
• Step 3 retains 95% of its 72 kg input: 68.4 kg remains, with 3.6 kg in the side stream.
• Overall retained yield is 0.90 × 0.80 × 0.95 = 68.4%. Retained output plus the three side streams is 68.4 + 10 + 18 + 3.6 = 100 kg.

Investigate the apparent improvement before celebrating it

Now suppose the second-step record reports 78 kg retained plus the same 18 kg side stream from 90 kg input. It accounts for 96 kg, six more than entered. With no additions permitted in this exercise, those values cannot all be correct. The immediate task is to check the records, measurement basis and units, not claim a yield improvement.

A useful work sample contains the stage calculations, the original inconsistent entry and the question sent to its owner. It should distinguish material deliberately sent elsewhere from material not accounted for. A low retained yield and an unexplained balance error are different problems.

An application paragraph could say: 'Reconciled a three-stage synthetic balance and found that a reported yield improvement depended on an impossible input/output record. I traced the discrepancy before comparing the process versions.' Use a real project of your own in the application, and distinguish computational practice from supervised laboratory experience.

Before you apply

Eligibility

Separate undergraduate process-engineering roles from advanced research projects. The particular assignment determines whether it requires engineering, analytical or specialized laboratory preparation.

Timing

Merck distinguishes 10–12-week summer internships from 4–6-month co-ops. A laboratory assignment labeled student opportunity may therefore require more than a summer break.

Location

Identify the development laboratory, technical center or manufacturing site. Ask whether your project is experimental, computational or a combination.

Pay

Amgen describes paid internships separately from its other graduate programs. Compare the chosen role's rate and duration, not an unrelated operations-leadership salary.

Sources: Merck student opportunities · Amgen students and graduates

Job titles to search

Process development intern

Investigate a process question and compare explanations for the observed result.

Technical development intern

Connect a research method with a process that can be repeated and reviewed.

Manufacturing process engineering intern

Support an established operation; the main task may be monitoring or resolving an exception.

Where to look

Search routes, not confirmed vacancies.

Compare the work and try an example

Use a role comparison or worked exercise to choose your preparation before tailoring an application.

• Medical-device engineering versus commercial internships
• Clinical operations versus research internships: read the assignment carefully
• Healthcare finance and analytics internships without a clinical role