Streptokinase is a bacterial plasminogen activator widely studied for its thrombolytic properties. This concise primer for B.Pharm students covers streptokinase chemistry, microbial sources, fermentation and recombinant preparation, purification and potency evaluation, formulation, preservation and storage strategies (including lyophilization and stabilizers), therapeutic uses (acute myocardial infarction, pulmonary embolism, DVT), safety, antigenicity and comparative commercial utility versus other thrombolytics. Emphasis is placed on quality-control assays, stability testing, cold-chain requirements and practical pharmacy considerations for manufacturing and clinical use. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which best describes streptokinase’s primary mechanism of action?
- Direct enzymatic cleavage of fibrin
- Formation of a complex with plasminogen to generate plasmin
- Inhibition of plasmin to stabilize clots
- Activation of antithrombin III
Correct Answer: Formation of a complex with plasminogen to generate plasmin
Q2. Streptokinase is produced naturally by which organisms?
- Beta-hemolytic streptococci (groups A, C and G)
- Escherichia coli strains only
- Bacillus subtilis strains
- Fungal species such as Aspergillus
Correct Answer: Beta-hemolytic streptococci (groups A, C and G)
Q3. Approximate molecular weight of streptokinase is:
- 10 kDa
- 25 kDa
- 47 kDa
- 100 kDa
Correct Answer: 47 kDa
Q4. Which feature distinguishes streptokinase from tissue plasminogen activator (tPA)?
- Streptokinase is fibrin-specific while tPA is non-specific
- Streptokinase is a non-enzymatic activator of plasminogen and not fibrin-specific
- Both are identical in mechanism and specificity
- Streptokinase directly degrades fibrin without plasminogen
Correct Answer: Streptokinase is a non-enzymatic activator of plasminogen and not fibrin-specific
Q5. Common industrial production of native streptokinase involves which culture process?
- Solid-state fermentation on agar plates
- Submerged fermentation in peptone-rich broth
- Plant tissue culture expression
- Direct chemical synthesis
Correct Answer: Submerged fermentation in peptone-rich broth
Q6. Which purification technique is routinely used in streptokinase downstream processing?
- Affinity chromatography against human antibodies only
- Ion-exchange chromatography followed by gel filtration
- Simple dialysis without chromatography
- Precipitation with organic solvents exclusively
Correct Answer: Ion-exchange chromatography followed by gel filtration
Q7. Which assay is standard for measuring streptokinase potency in pharmacopeias?
- UV absorbance at 280 nm only
- Fibrin clot lysis (fibrin plate) assay expressed in IU
- Gram staining
- pH titration
Correct Answer: Fibrin clot lysis (fibrin plate) assay expressed in IU
Q8. Preferred storage condition for lyophilized streptokinase vials is:
- Room temperature (20–25°C)
- Freezer at −20°C
- Refrigerated at 2–8°C
- Exposed to light at ambient humidity
Correct Answer: Refrigerated at 2–8°C
Q9. Which excipient is commonly used as a stabilizer in streptokinase formulations?
- Human serum albumin
- Benzalkonium chloride
- Sodium lauryl sulfate
- Polymethyl methacrylate
Correct Answer: Human serum albumin
Q10. Typical plasma half-life of streptokinase after IV administration is closest to:
- 1 minute
- 5 hours
- 23 minutes
- 48 hours
Correct Answer: 23 minutes
Q11. Primary clinical indication for streptokinase therapy is:
- Chronic hypertension management
- Acute myocardial infarction within recommended window
- Long-term anticoagulation for atrial fibrillation
- Hyperlipidemia treatment
Correct Answer: Acute myocardial infarction within recommended window
Q12. Which is an absolute contraindication to streptokinase use?
- Uncontrolled hypertension
- Active internal bleeding
- Stable angina
- Recent uncomplicated dental extraction
Correct Answer: Active internal bleeding
Q13. Most common adverse reactions associated with streptokinase include:
- Hypersensitivity and hypotension
- Severe hyperglycemia only
- Ototoxicity and vision loss
- Renal stones
Correct Answer: Hypersensitivity and hypotension
Q14. Why is repeated administration of streptokinase often less effective?
- Rapid renal clearance prevents activity
- Formation of neutralizing anti-streptokinase antibodies
- Streptokinase is converted to inactive peptides by stomach acid
- Lack of oxygen reduces its action
Correct Answer: Formation of neutralizing anti-streptokinase antibodies
Q15. Compared to tPA, streptokinase is characterized by:
- Higher fibrin specificity and shorter systemic effect
- Lower cost and less fibrin specificity
- Higher molecular weight and oral bioavailability
- Immunity to antibodies in all patients
Correct Answer: Lower cost and less fibrin specificity
Q16. Major commercial advantage of streptokinase production is:
- Extremely high price making it profitable
- Complex manufacturing making regulation easier
- Low production cost and established manufacturing processes
- Complete absence of immunogenicity
Correct Answer: Low production cost and established manufacturing processes
Q17. Which diluent is recommended for reconstituting lyophilized streptokinase?
- Sterile water for injection
- Absolute ethanol
- 10% acetic acid
- Mercurochrome solution
Correct Answer: Sterile water for injection
Q18. Activity of streptokinase is usually expressed in which units?
- Milligrams per milliliter (mg/mL)
- International Units (IU)
- Degrees Celsius
- Moles per liter (M)
Correct Answer: International Units (IU)
Q19. A sensitive laboratory marker of systemic fibrinolysis after streptokinase is:
- Serum creatinine
- D-dimer
- Fasting blood glucose
- Total bilirubin
Correct Answer: D-dimer
Q20. Typical pharmaceutical dosage form of commercial streptokinase is:
- Oral tablets
- Topical cream
- Lyophilized powder for injection
- Transdermal patch
Correct Answer: Lyophilized powder for injection
Q21. Which processing approach best increases long-term stability of streptokinase?
- Lyophilization with appropriate stabilizers
- Storage in aqueous solution at 30°C
- Exposure to UV light for sterilization
- Addition of proteases to formulation
Correct Answer: Lyophilization with appropriate stabilizers
Q22. Which preservative practice is recommended for parenteral streptokinase products?
- Add benzyl alcohol to multi-dose vials routinely
- Avoid preservatives in single-dose lyophilized vials
- Use parabens to extend in-use time indefinitely
- Store reconstituted product at room temperature for weeks
Correct Answer: Avoid preservatives in single-dose lyophilized vials
Q23. Which chromogenic substrate is commonly used in chromogenic assays for plasmin activity related to streptokinase?
- S-2251 (H-D-Val-Leu-Lys-pNA)
- p-nitrophenyl phosphate for alkaline phosphatase
- Methyl orange for titration
- Bradford reagent for protein
Correct Answer: S-2251 (H-D-Val-Leu-Lys-pNA)
Q24. Which factor most increases immunogenicity of streptokinase preparations?
- Use of human recombinant expression systems
- Repeated dosing in the same patient
- Lyophilization with stabilizers
- Proper cold-chain storage
Correct Answer: Repeated dosing in the same patient
Q25. Recombinant production of streptokinase offers which key advantage?
- Guaranteed absence of antigenicity in all patients
- Consistent quality, higher yields and controlled impurities
- Elimination of need for potency assays
- Ability to be administered orally
Correct Answer: Consistent quality, higher yields and controlled impurities
Q26. Most critical quality-control parameter before release of streptokinase batch is:
- Colour of the vial cap
- Potency/activity (IU) per vial
- Size of external packaging
- Melting point of the freeze-dried cake
Correct Answer: Potency/activity (IU) per vial
Q27. If reconstituted streptokinase is not used immediately, recommended practice is:
- Store at 2–8°C for the minimal validated in-use period
- Leave at room temperature for 72 hours
- Add preservative and reuse for multiple patients
- Freeze at −20°C for later use
Correct Answer: Store at 2–8°C for the minimal validated in-use period
Q28. Hypotension during streptokinase infusion is primarily due to:
- Excessive sodium load in formulation
- Bradykinin and cytokine-mediated vasodilation
- Direct myocardial depression
- Blockade of beta-adrenergic receptors
Correct Answer: Bradykinin and cytokine-mediated vasodilation
Q29. Which statement about streptokinase is FALSE?
- It forms a complex with plasminogen to activate plasmin
- It is itself a serine protease enzyme
- It can induce antibody formation on repeated exposure
- It is less fibrin-specific than tPA
Correct Answer: It is itself a serine protease enzyme
Q30. Typical shelf-life of properly stored lyophilized streptokinase at 2–8°C is approximately:
- 1 week
- 6 months
- 2 years
- 10 years
Correct Answer: 2 years
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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