Intrauterine drug delivery systems are specialized intrauterine devices (IUDs/IUS) engineered to provide controlled, local drug delivery directly to the uterine cavity. This concise overview for B.Pharm students highlights device design, biocompatible polymers (PDMS, EVA, PLGA), release mechanisms (diffusion-controlled reservoir, matrix erosion), pharmacokinetics (high uterine concentration, low systemic exposure), clinical applications (contraception, treatment of menorrhagia, emergency contraception with copper IUD), manufacturing, sterilization, analytical testing (HPLC, in vitro release), and regulatory/biocompatibility considerations. Emphasis is on formulation strategies, rate‑controlling membranes, stability, and common complications to prepare you for exams and practical formulation work. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What best defines an intrauterine drug delivery system (IUD/IUS)?
- A device placed in the uterine cavity to release drug locally over time
- An oral tablet designed to target uterine tissue
- A transdermal patch that releases hormones systemically
- An intramuscular depot injection for long‑term contraception
Correct Answer: A device placed in the uterine cavity to release drug locally over time
Q2. Which is a primary advantage of intrauterine drug delivery compared with systemic therapy?
- Higher systemic plasma concentrations
- Reduced systemic side effects due to localized delivery
- Faster renal clearance of the drug
- Elimination of the need for device sterilization
Correct Answer: Reduced systemic side effects due to localized delivery
Q3. Which combination of materials is commonly used in commercial levonorgestrel IUS devices?
- Silicone elastomer reservoir with a polyethylene frame
- Polyvinylchloride matrix without a frame
- Pure PLGA biodegradable ring without elastomer
- Glass reservoir with stainless steel frame
Correct Answer: Silicone elastomer reservoir with a polyethylene frame
Q4. How does a copper IUD primarily exert its contraceptive effect?
- Systemic inhibition of ovulation via hormone release
- Local release of copper ions that impair sperm motility and viability
- Slow release of antibiotics to prevent fertilization
- Electrical stimulation of the endometrium to prevent implantation
Correct Answer: Local release of copper ions that impair sperm motility and viability
Q5. Which release mechanism predominantly describes many hormone-releasing IUS devices?
- Diffusion-controlled reservoir release through a rate‑controlling membrane
- Complexation followed by ion exchange in the uterine fluid
- Immediate bolus release followed by zero release
- Gas-driven pulsatile ejection of drug
Correct Answer: Diffusion-controlled reservoir release through a rate‑controlling membrane
Q6. Which biodegradable polymer is most commonly studied for intrauterine biodegradable implants?
- Poly(lactic-co-glycolic acid) (PLGA)
- Polyethylene terephthalate (PET)
- Polydimethylsiloxane (PDMS)
- Polyvinyl acetate (PVA)
Correct Answer: Poly(lactic-co-glycolic acid) (PLGA)
Q7. Which kinetic model describes constant drug release independent of drug concentration?
- First‑order kinetics
- Higuchi model (square‑root time diffusion)
- Zero‑order kinetics
- Korsmeyer–Peppas with n > 1 only
Correct Answer: Zero‑order kinetics
Q8. What is the primary clinical indication for levonorgestrel intrauterine systems?
- Contraception and long‑term pregnancy prevention
- Treatment of systemic bacterial infections
- Management of osteoporosis
- Prevention of sexually transmitted infections
Correct Answer: Contraception and long‑term pregnancy prevention
Q9. Which IUD is the preferred option for emergency contraception when inserted within 5 days after unprotected intercourse?
- Levonorgestrel IUS (hormonal)
- Copper IUD (e.g., ParaGard)
- Progestin implant in the arm
- Combined oral contraceptive emergency dose
Correct Answer: Copper IUD (e.g., ParaGard)
Q10. Which of the following is a relatively common complication following IUD insertion?
- Device expulsion
- Permanent infertility in all users
- Immediate systemic toxicity requiring dialysis
- Daily severe allergic reactions in most patients
Correct Answer: Device expulsion
Q11. Which sterilization method is often avoided for drug‑loaded polymeric IUS because it can degrade the drug or polymer?
- Gamma irradiation
- Ethylene oxide (EtO) sterilization
- Moist heat autoclaving (steam sterilization)
- Low-temperature plasma sterilization
Correct Answer: Moist heat autoclaving (steam sterilization)
Q12. Which analytical test is essential during development to characterize release behavior of an IUS?
- In vitro drug release testing under validated conditions
- Blood glucose monitoring
- Urine dipstick for protein
- Centrifugation sedimentation rate
Correct Answer: In vitro drug release testing under validated conditions
Q13. Which polymer is commonly used as a rate‑controlling membrane in reservoir IUS formulations?
- Ethylene‑vinyl acetate (EVA)
- Polyvinyl chloride (PVC) without plasticizer
- Polyethylene glycol (PEG) liquid matrix
- Gelatin capsule coating
Correct Answer: Ethylene‑vinyl acetate (EVA)
Q14. What is the active hormone in most hormonal intrauterine systems used for contraception?
- Levonorgestrel
- Estradiol
- Testosterone
- Dexamethasone
Correct Answer: Levonorgestrel
Q15. Which mathematical model describes diffusion‑controlled release with a square‑root time dependence?
- Higuchi model
- Zero‑order model
- Michaelis–Menten kinetics
- Cmax‑Tmax empirical model
Correct Answer: Higuchi model
Q16. How does the US FDA generally classify a drug‑releasing intrauterine system?
- As a combination product (drug‑device combination)
- Purely as a Class I medical device without drug considerations
- As a food supplement
- As a biologic product
Correct Answer: As a combination product (drug‑device combination)
Q17. A typical copper IUD consists of a copper wire wound around which base material frame?
- Polyethylene frame
- Glass frame
- Stainless steel frame only
- PLGA biodegradable frame
Correct Answer: Polyethylene frame
Q18. Compared to systemic hormonal therapy, intrauterine delivery usually results in which tissue/plasma concentration profile?
- Higher uterine tissue concentration and lower systemic plasma levels
- Lower uterine and higher systemic concentrations
- Equal uterine and plasma concentrations
- No detectable drug in uterine tissue
Correct Answer: Higher uterine tissue concentration and lower systemic plasma levels
Q19. Which analytical technique is most appropriate for quantifying levonorgestrel released from an IUS during stability and release testing?
- High‑performance liquid chromatography (HPLC)
- Gram staining
- Polarimetry for chirality only
- Simple pH paper testing
Correct Answer: High‑performance liquid chromatography (HPLC)
Q20. Which clinical factor increases the risk of IUD expulsion?
- Insertion immediately postpartum (within minutes of delivery)
- Insertion in a post‑menopausal woman only
- Using a device sterilized by EtO
- Placing the device under ultrasound guidance
Correct Answer: Insertion immediately postpartum (within minutes of delivery)
Q21. For biodegradable intrauterine implants composed of PLGA, the main degradation mechanism is:
- Hydrolytic cleavage of ester bonds
- Photodegradation by uterine light exposure
- Oxidative cleavage by systemic enzymes only
- Evaporation of the polymer chains
Correct Answer: Hydrolytic cleavage of ester bonds
Q22. Which formulation parameters directly influence the drug release rate from a reservoir IUS?
- Membrane thickness, drug solubility in membrane, and temperature
- Tablet hardness and friability only
- Oral bioavailability and gastric pH
- Patient diet and sleep patterns only
Correct Answer: Membrane thickness, drug solubility in membrane, and temperature
Q23. In a reservoir intrauterine system, what is typically the rate‑limiting step for drug release?
- Permeation through the rate‑controlling membrane
- Rapid dissolution in systemic circulation
- Enzymatic metabolism in the ovaries
- Renal excretion of unchanged drug
Correct Answer: Permeation through the rate‑controlling membrane
Q24. Which condition is a contraindication to IUD insertion?
- Active pelvic inflammatory disease (PID)
- Controlled hypothyroidism
- Remote history of treated bacterial vaginosis only
- Well‑controlled asthma
Correct Answer: Active pelvic inflammatory disease (PID)
Q25. Which polymer name corresponds to the common silicone elastomer used in IUS devices?
- Polydimethylsiloxane (PDMS)
- Polyvinylpyrrolidone (PVP)
- Polyacrylic acid (PAA)
- Polycaprolactone (PCL)
Correct Answer: Polydimethylsiloxane (PDMS)
Q26. After IUD insertion, a routine follow‑up exam should include which practical check?
- Verification of IUD strings by pelvic examination
- Fasting blood glucose test
- MRI of the pelvis for everyone
- Biopsy of endometrium in all patients
Correct Answer: Verification of IUD strings by pelvic examination
Q27. In vitro release testing of IUS is best performed under which condition to ensure proper sink conditions?
- Using a large volume of release medium with agitation to maintain sink conditions
- Using a minimal medium volume without agitation
- In solid state without any medium to mimic dryness
- Only in human volunteers without in vitro testing
Correct Answer: Using a large volume of release medium with agitation to maintain sink conditions
Q28. Which statement is TRUE regarding IUDs and sexually transmitted infections (STIs)?
- IUDs do not protect against STIs and may increase PID risk if STI is present at insertion
- IUDs provide reliable protection against chlamydia and gonorrhea
- Levonorgestrel IUS is approved to prevent HIV transmission
- Copper IUDs sterilize the uterine cavity against all microbes
Correct Answer: IUDs do not protect against STIs and may increase PID risk if STI is present at insertion
Q29. Levonorgestrel released from an intrauterine system primarily acts by which local effects?
- Thickening cervical mucus and causing endometrial suppression
- Direct bactericidal action in the uterus
- Increasing systemic estrogen to prevent ovulation
- Stimulating uterine contractions to expel ova
Correct Answer: Thickening cervical mucus and causing endometrial suppression
Q30. Which regulatory and safety evaluation is essential for intrauterine drug devices prior to approval?
- Biocompatibility testing according to ISO 10993 standards
- Only taste masking studies
- Mandatory oral bioavailability studies in all subjects
- Daily skin patch testing for all users
Correct Answer: Biocompatibility testing according to ISO 10993 standards
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.
Mail- Sachin@pharmacyfreak.com