MPharm Master of Pharmacy Master of Pharmacy: Pharmaceutical Formulations and Dosage Forms 2 — Questions and Answers
Question 1: Which mechanism governs drug release from an osmotic pump tablet (OROS)?
- Diffusion through a rate-controlling membrane
- Osmotic pressure driving fluid in and drug solution out through a laser-drilled orifice (Correct answer)
- Erosion of a wax matrix
- Ion-exchange resin complexation
Correct answer: Osmotic pressure driving fluid in and drug solution out through a laser-drilled orifice
OROS tablets use osmotic pressure to draw water in, building pressure that pushes drug solution out through a precision orifice at a controlled rate.
Question 2: What is the primary purpose of a plasticizer in film-coated tablets?
- Increase drug solubility
- Reduce polymer brittleness and improve film flexibility (Correct answer)
- Act as a colorant
- Prevent microbial growth
Correct answer: Reduce polymer brittleness and improve film flexibility
Plasticizers (e.g., PEG, triethyl citrate) lower the glass transition temperature of coating polymers, making the film flexible and resistant to cracking.
Question 3: A suppository base that melts at body temperature but is immiscible with water is classified as:
- Water-soluble base (PEG)
- Fatty or oleaginous base (cocoa butter) (Correct answer)
- Emulsifying base (Witepsol)
- Hydrophilic gel base (glycerinated gelatin)
Correct answer: Fatty or oleaginous base (cocoa butter)
Cocoa butter is the classic fatty base that melts near 37 °C and does not mix with rectal fluids, releasing drug by melting rather than dissolution.
Question 4: Which type of emulsion is preferred for intravenous parenteral nutrition lipid emulsions?
- Water-in-oil (W/O)
- Oil-in-water (O/W) (Correct answer)
- Multiple W/O/W
- Microemulsion
Correct answer: Oil-in-water (O/W)
IV lipid emulsions are O/W type so the aqueous continuous phase is miscible with blood, preventing fat embolism.
Question 5: In hot-melt extrusion (HME), the primary role of the process is to:
- Granulate particles by wet agglomeration
- Disperse drug molecularly in a polymer carrier to form a solid dispersion (Correct answer)
- Coat pellets with an enteric polymer
- Dry granules by fluidized-bed technology
Correct answer: Disperse drug molecularly in a polymer carrier to form a solid dispersion
HME uses heat and mechanical shear to embed drug molecules within a thermoplastic polymer matrix, producing an amorphous solid dispersion that enhances solubility.
Question 6: The HLB value required to stabilize an O/W emulsion typically falls in the range of:
- 1–6
- 7–9
- 8–18 (Correct answer)
- 18–20
Correct answer: 8–18
Emulsifiers with HLB 8–18 are hydrophilic enough to orient at the oil-water interface and stabilize O/W emulsions.
Question 7: Which excipient class is used in orally disintegrating tablets (ODTs) to achieve rapid disintegration without water?
- Sustained-release polymers (HPMC)
- Super-disintegrants (croscarmellose sodium) (Correct answer)
- Enteric coatings (Eudragit L)
- Wax matrix formers (carnauba wax)
Correct answer: Super-disintegrants (croscarmellose sodium)
Super-disintegrants like croscarmellose sodium swell rapidly upon contact with saliva, breaking the tablet apart within 30 seconds.
MPharm Master of Pharmacy Master of Pharmacy: Pharmaceutical Formulations and Dosage Forms 2
Which mechanism governs drug release from an osmotic pump tablet (OROS)?