Urokinase is a serine protease used as a thrombolytic agent; its chemistry involves a single‑chain prourokinase (scuPA) activated to a two‑chain enzyme (uPA) that converts plasminogen to plasmin. Sources include human urine and recombinant expression systems (e.g., CHO cells). Preparation covers fermentation, purification (ion‑exchange, affinity, gel filtration), and formulation as sterile lyophilized product. Evaluation uses activity assays, SDS‑PAGE, HPLC, ELISA, endotoxin and sterility tests. Preservation and storage focus on lyophilization, cold chain, avoiding freeze‑thaw, and validated shelf life. Therapeutic uses are systemic and catheter thrombolysis; commercial utility spans clinical drugs, device coatings, and research reagents. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What class of enzyme is urokinase?
- Tyrosine kinase
- Serine protease
- Metalloprotease
- Threonine protease
Correct Answer: Serine protease
Q2. Urokinase primarily converts which zymogen to its active form?
- Prothrombin to thrombin
- Plasminogen to plasmin
- Fibrinogen to fibrin
- Proconvertase to convertase
Correct Answer: Plasminogen to plasmin
Q3. The native biosynthetic source of urokinase historically was:
- Human serum albumin
- Human urine
- Bacterial fermentation broths
- Plant extraction
Correct Answer: Human urine
Q4. Which molecular forms are associated with urokinase activity?
- Single‑chain prourokinase and two‑chain urokinase
- Double‑helix and quadruplex forms
- Monomeric and polymeric fibrils
- Alpha and beta glycoforms only
Correct Answer: Single‑chain prourokinase and two‑chain urokinase
Q5. A common recombinant host for large‑scale urokinase production is:
- Escherichia coli without processing
- CHO (Chinese Hamster Ovary) cells
- Baker’s yeast only
- Plant suspension cultures only
Correct Answer: CHO (Chinese Hamster Ovary) cells
Q6. Which purification technique is especially useful for isolating active urokinase?
- Size‑exclusion chromatography alone
- Affinity chromatography targeting protease active site
- Simple precipitation without chromatography
- Dialysis only
Correct Answer: Affinity chromatography targeting protease active site
Q7. A standard activity assay for urokinase measures:
- DNA cleavage rate
- Amidolytic or fibrinolytic activity against chromogenic substrates or fibrin
- ATP hydrolysis
- Glucose oxidation
Correct Answer: Amidolytic or fibrinolytic activity against chromogenic substrates or fibrin
Q8. Which analytical method assesses purity and molecular weight of urokinase preparations?
- GC‑MS
- SDS‑PAGE
- pH titration
- Polarimetry
Correct Answer: SDS‑PAGE
Q9. Endotoxin testing is critical for urokinase because endotoxin can cause:
- Enhanced thrombolysis
- Pyrogenic reactions and sepsis‑like symptoms in patients
- Improved storage stability
- Increased glycosylation
Correct Answer: Pyrogenic reactions and sepsis‑like symptoms in patients
Q10. Lyophilization of urokinase is performed primarily to:
- Increase enzymatic turnover number
- Improve long‑term stability and shelf life
- Make it more immunogenic
- Reduce molecular weight
Correct Answer: Improve long‑term stability and shelf life
Q11. Optimal storage conditions for lyophilized urokinase typically require:
- High humidity and room temperature
- Cold chain storage (refrigeration or freezing as per label) and protection from moisture
- Constant exposure to light
- Repeated freeze–thaw cycles for activation
Correct Answer: Cold chain storage (refrigeration or freezing as per label) and protection from moisture
Q12. After reconstitution, urokinase vials are generally:
- Stable at room temperature for months
- Intended for immediate use or short controlled storage per product label
- Safe to use after multiple refreezes
- Stored at pH 1–2 for activity
Correct Answer: Intended for immediate use or short controlled storage per product label
Q13. Urokinase’s mechanism of action in thrombolysis is best described as:
- Direct lysis of platelet membranes
- Activation of plasminogen to plasmin which degrades fibrin
- Inhibition of clotting factor VIII
- Crosslinking fibrin to strengthen clots
Correct Answer: Activation of plasminogen to plasmin which degrades fibrin
Q14. A major adverse effect associated with urokinase therapy is:
- Hypoglycemia
- Hemorrhage, including intracranial bleeding
- Hypercalcemia
- Renal stone formation
Correct Answer: Hemorrhage, including intracranial bleeding
Q15. Compared to tissue plasminogen activator (tPA), urokinase is generally:
- Non‑proteolytic
- Less fibrin‑selective and often more systemic in plasmin generation
- More fibrin‑specific with longer half‑life
- Identical in all pharmacologic properties
Correct Answer: Less fibrin‑selective and often more systemic in plasmin generation
Q16. Immunogenicity concerns for urokinase preparations mainly arise from:
- Patient exposure to viral DNA
- Non‑human glycosylation patterns or impurities in recombinant products
- Excessive salt content
- Low molecular weight contaminants only
Correct Answer: Non‑human glycosylation patterns or impurities in recombinant products
Q17. Which regulatory quality test ensures no microbial contamination in sterile urokinase vials?
- Endotoxin test
- Sterility test
- SDS‑PAGE
- UV‑Vis absorbance at 280 nm
Correct Answer: Sterility test
Q18. In manufacturing, ion‑exchange chromatography helps to:
- Remove endotoxin only
- Separate proteins based on charge to improve purity
- Change primary amino acid sequence
- Reduce enzymatic activity intentionally
Correct Answer: Separate proteins based on charge to improve purity
Q19. Common stability‑indicating parameters studied for urokinase formulations include:
- pH, potency, aggregation, and degradation profile
- Color under infrared only
- Magnetic susceptibility and refractive index
- Evaporation rate at 100°C
Correct Answer: pH, potency, aggregation, and degradation profile
Q20. Which assay would specifically quantify urokinase protein amount independent of activity?
- Amidolytic activity assay
- ELISA targeting urokinase
- Fibrin plate lysis test only
- Chromogenic substrate turnover only
Correct Answer: ELISA targeting urokinase
Q21. For catheter clearance, urokinase is typically applied:
- As an oral tablet
- Locally instilled into the catheter lumen to dissolve fibrin clots
- Via topical cream
- As an inhaled aerosol
Correct Answer: Locally instilled into the catheter lumen to dissolve fibrin clots
Q22. A key commercial advantage of recombinant urokinase over urine‑derived product is:
- Higher endotoxin levels
- Consistent supply and reduced donor‑derived impurities
- Lower regulatory scrutiny
- Unlimited room‑temperature stability
Correct Answer: Consistent supply and reduced donor‑derived impurities
Q23. Which parameter directly measures fibrinolytic potency in international terms?
- IU defined by a fibrin plate or reference standard
- mg of protein only
- Optical rotation units
- pH units
Correct Answer: IU defined by a fibrin plate or reference standard
Q24. During downstream processing, removal of host cell proteins is important to:
- Increase viscosity only
- Reduce immunogenicity and improve product purity
- Guarantee lyophilization failure
- Increase endotoxin content
Correct Answer: Reduce immunogenicity and improve product purity
Q25. Which preservative approach is commonly avoided in parenteral urokinase formulations to minimize toxicity?
- Use of benzyl alcohol in multidose vials at high concentrations
- Lyophilization without preservatives for single‑use vials
- Aseptic single‑use presentation
- Cold chain storage
Correct Answer: Use of benzyl alcohol in multidose vials at high concentrations
Q26. A validated potency assay for urokinase should be:
- Non‑specific and variable
- Specific, reproducible, and traceable to a reference standard
- Based solely on color change with no controls
- Performed only once during development
Correct Answer: Specific, reproducible, and traceable to a reference standard
Q27. Major therapeutic indications for urokinase include:
- Treatment of bacterial infections
- Thrombolysis in acute pulmonary embolism and catheter occlusions
- Chronic asthma control
- Treatment of hyperlipidemia
Correct Answer: Thrombolysis in acute pulmonary embolism and catheter occlusions
Q28. Which test is most useful to detect aggregates that may affect urokinase immunogenicity?
- Dynamic light scattering or size‑exclusion HPLC
- pH meter reading
- Simple visual inspection only
- Karl Fischer titration
Correct Answer: Dynamic light scattering or size‑exclusion HPLC
Q29. Commercial utility of urokinase outside direct thrombolytic therapy includes:
- Use as a fuel additive
- Research reagent for plasminogen activation studies and device coatings
- Substitute for housekeeping detergents
- Imaging contrast agent
Correct Answer: Research reagent for plasminogen activation studies and device coatings
Q30. A critical precaution before initiating urokinase therapy is to evaluate:
- History of active bleeding, recent surgery, or intracranial pathology
- Blood glucose only
- Urine color exclusively
- Skin pigmentation level
Correct Answer: History of active bleeding, recent surgery, or intracranial pathology
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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