Download (hons) course year iv june 201

UNIVERSITY OF MALTA
MEDICAL SCHOOL
FACULTY OF MEDICINE AND SURGERY
DEPARTMENT OF PHARMACY
B.PHARM (HONS) COURSE YEAR IV
JUNE 2013 SESSION OF EXAMINATIONS
PHR 4308
PHARMACEUTICS IV
SAMPLE PAPER
Duration: 3 hours
Section A: Answer ALL questions
Question 1
(a) Give the Noyes-Whitney equation as applied to dissolution rate.
(4 marks)
(b) How does particle size relate to the dissolution rate of a solid dosage form?
(2 marks)
Question 2
(a) With reference to transdermal preparations, how does skin structure relate to the passage of drug
through the skin?
(2 marks)
(b) Give an example of a transdermal drug delivery system. What are the advantages in the use of
this preparation over other dosage forms of the same active ingredient?
(2 marks)
Question 3
(a) Describe factors influencing release of active ingredient from an extended release oral preparation
formulated as an insoluble matrix system.
(3 marks)
(b) How do plasma drug concentrations administered through an osmotic pump extended release oral
preparation compare to an intravenous infusion administration? Draw a sketch of plasma drug
concentration versus time for the two dosage forms.
(2 marks)
Question 4
(a) What are desirable characteristics of radionuclides used in PET?
(2 marks)
(b) Describe the use of the sodium iodide-131 and include the type of radioactive decay for this
radiopharmaceutical.
(3 marks)
Question 5
(a) Describe the problems encountered with the use of proteins as drugs.
(3 marks)
(b) List 6 desired properties for identifying proteins suitable for development as drugs.
(3 marks)
Question 6
(a) What is meant by (i) iontophoresis and (ii) sonophoresis?
(2 marks)
(b) What are the advantages of pegylated dosage forms?
(2 marks)
Section B: Answer ALL questions
1. Self Inspection is a necessary tool used in the area of GDP.




How often should such audits take place?
(2 marks)
Discuss the designation of responsibility for self inspection.
(3 marks)
Which qualifications are necessary in order to act as an auditor?
(4 marks)
List the major areas which should be included in the written procedures for an internal audit.
(5 marks)
2. List the main areas addressed by the GMP Guidelines, briefly stating how each contributes towards
ensuring quality in the manufacturing process.
(16 marks)
Section C: SELECT ONE QUESTION (20 MARKS EACH QUESTION)
A scientific calculator may be used.
QUESTION 1
(a) A new drug is found to be ineffective after it has decomposed by 30%. The original
concentration of the one sample is 5.0 mg/ml. When assayed 20 months later, the
concentration was found to be 4.2mg/ml. Assuming that the drug decomposition is first
order, what should be the expiry date on the label? What is the half life of this
product?
(3,1 marks)
For first order decomposition
For the half life
A = Ao .e -kt
t1/2 = 0.693/k
(b)
kf

A
B
kb
The above expression represents a reversible reaction in its simplest form. Both forward and
backward reactions are first order processes.
When A was converted reversibly to B, the equilibrium constant, K, was established
experimentally to be 6.3.
The concentrations of compound A was measured spectroscopically at regular intervals of
time. It was however required to dilute the first aliquot 10 times in order to fall within the
spectroscopic range. The initial reading was 0.05 moles/litre.
(i) Calculate the initial concentration of Ao and Aeqm
The integrated rate expression for the reversible reaction is
Log Ao - Aeqm
A
-
Aeqm
=
kf + kb
2.303
t
( 1, 2 marks)
(ii) Analysis of the data gave a slope of - 0.02min-1.
From the slope and the value of K, calculate the forward and backward reaction rates.
( 2,2 marks)
(c) What is understood by a reaction susceptible to specific acid-base catalysis?
(3 marks)
The pH-rate profile of cefotaxime sodium at an ionic strength of 1.0 shows slopes of -1, zero,
+1 within the pH ranges 0-4, 4-7, 7-10 respectively.
(i) Give a sketch showing this profile and state what kind of catalysis presumably occurs at
each of the three pH ranges?
(3,3 marks)
QUESTION 2
(a)
Phenobarbital has a solubility of 0.1%w/v in water and a solubility of 12.5%w/v in alcohol.
How many ml of each would be required to prepare 170ml of hydroalcoholic solution of
Phenobarbital containing 0.08 g/ml Phenobarbital?
(2,2 marks)
Given the equations below with all symbols having the usual meaning.
f1 + f 2 = 1
and
f1 = log ( S2 / ST )
log ( S2/S1 )
(b)
In suspensions, the Sedimentation volume, F and the degree of flocculation  are defined by
the equations below.
Explain how the appearance of a suspension changes as F ranges from less than 1, to 1, to
greater than 1.
Explain your answer in terms of Vu, Vo, V, F, F and  and support your answer with
sketches.
F = Vu / Vo
and
 = F / F = Vu / V
( 2,2,2,2 marks)
(c)
What is the primary aim of the emulsifying agents?
(1 marks)
Two groups of emulsifying agents are given below. Explain, with the use of sketches where
required, how each group fulfils this primary aim.
(i) Surface-active agents
(ii) Finely divided particles
(4 marks)
(3 marks)
QUESTION 3
This procedure is relevant to questions a and b
A tabletting procedure by a wet granulation process involves the following steps:
Step 1 Preblending the dry ingredients
Step 2 Addition of the granulating liquid.
Step 3 Kneading and/or mixing
Step 4 Milling of the wet granules.
Step 5 Drying the granules.
Step 6 Milling the dried granules.
Step 7 Second blending stage-mixing the milled granules with lubricants, glidants and
disintegrants
Step 8 Compression of the granules to form tablets
(a)
Describe what happens during step 2 and step 3 the powder and the granulating liquid
progressively undergo
agglomeration,
(4 marks)
agglomeration break-down,
(4 marks)
reagglomeration,
(2 marks)
paste formation.
(1 mark)
(b)
Explain fully the function of lubricants, glidants and disintegrants added in step7.
(2, 2, 2 marks)
(c)
The main stages in the manufacture of hard gelatin capsules are the following:
Step 1 Preparation of the gelatin solution and placing this in a jacketed stirred hopper.
Step 2 Dipping of the pinbars and spinning of the pin bars.
Step 3 Capsule drying.
Step 4 Capsule removal and assembly.
Step 5 Capsule inspection and sorting.
Step 6 Capsule printing and packaging.
What occurs in Step 3 during capsule drying.
(3 marks)
Section D: Answer ALL questions
Question 1
For each incorrect answer in this question, 0.25 marks will be deducted.
Unanswered questions will attract 0 marks.
1) Listeria monocytogenes is resistant to all cephalosporins.
2) A cephamycin is a cephalosporin that has a methoxy group at position ‘7’ of the cephem
nucleus.
3) The loss of the carboxyl group at position ‘4’ of the cephem nucleus by esterification does
not in itself result in any loss of activity of the compound.
4) The cephalosporins owe their cidal effect to their activity on the pre-formed murein of the
bacterial cell wall.
5) A drug of choice for treating genital chlamydiosis is ceftriaxone.
6) Extended spectrum beta-lactamases (ESBLs) confer remarkable resistance to all
cephalosporins, with the exception of the cephamycins.
7) Local strains of Neisseria gonorrhoeae are fully sensitive to ciprofloxacin.
8) Levofloxacin has useful anti-streptococcal and anti-enterococcal activity; it is, hence,
particularly indicated in penicillin allergic patients.
9) Levofloxacin has an oral bioavailability of ca 70%.
10) Fluoroquinolones do not penetrate prostatic tissue well.
11) Rifampicin inhibits DNA-dependent RNA polymerase.
12) Rifampicin is highly active against Staph. aureus, Myco. tuberculosis, Myco. leprae and
Brucella melitensis.
13) Rifampicin can be generally used on its own since mutational resistance is unlikely to occur.
14) Rifampicin is a microbistatic antibiotic.
15) INAH can cause an age-dependent hepatitis.
16) The toxicity of INAH can be reduced by concomitant administration of vitamin B12.
17) Vancomycin is a lipoglycopeptide.
18) Vancomycin but not teicoplanin can cause the Red Man Syndrome.
19) The Red Man Syndrome is due to a hypersensitivity reaction to the antibiotic.
20) Ca 20% of all community strains of Staph. aureus are MRSAs.
(0.5 marks each)
Question 2
(1) Write short notes on caspofungin.
(10 marks)