CB February 2017
CH5011 Data Handling Coursework
Answer both questions. Total marks: 100
Phenytoin is an anti-epileptic drug. It is a weak acid with a pKa of 8.1 The unionised form is insoluble, and will form a precipitate. Consequently when infusing intravenously (IV) it is important to avoid this from happening.
A pharmacist prepares a phenytoin solution for IV infusion; commonly the pH of infusion solutions is pH 5.0 A colleague suggests they should consider changing the pH of the solution to avoid precipitation.
Using the Henderson-Hasselbalch equation, determine a possible pH range which could be used, also bearing in mind any risks to the patient.
A patient with clinical depression is given a dose of 75mg of imipramine, and plasma samples taken at various time intervals are analysed.
The data obtained are shown in Table 1.
Table 1. Plasma concentrations of imipramine.
Plasma Concentration (Cp) /mg L-1
a) On semi-log (i.e. log Y axis) graph paper, plot the data above, and label accordingly (hint – it will be a straight line as it follows first order kinetics).
b) Estimate the initial plasma concentration Cp(0) at time zero.
c) …and using this, calculate the volume of distribution for imipramine.
d) What does this tell us about the distribution of the drug to the tissues, and what might we infer concerning imipramine’s physicochemical nature?
e) Why can Vd be a useful parameter for a prescriber?
f) From your graph, estimate the half-life of the drug in this patient.
(This is best done by find the time which elapses between one concentration, and half of that concentration).
g) Now calculate the clearance of drug X in this person.
h) Explain in words what your answer to (g) means.
Formulae for Q2:
VD = Q/Cp(0) t½=0.693 x VD/CL
VD = volume of distribution
Q = dose
Cp(0) = plasma concentration at time zero.
CL = clearance
t½ = half-life
Our Service Charter
Excellent Quality / 100% Plagiarism-FreeWe employ a number of measures to ensure top quality essays. The papers go through a system of quality control prior to delivery. We run plagiarism checks on each paper to ensure that they will be 100% plagiarism-free. So, only clean copies hit customers’ emails. We also never resell the papers completed by our writers. So, once it is checked using a plagiarism checker, the paper will be unique. Speaking of the academic writing standards, we will stick to the assignment brief given by the customer and assign the perfect writer. By saying “the perfect writer” we mean the one having an academic degree in the customer’s study field and positive feedback from other customers.
Free RevisionsWe keep the quality bar of all papers high. But in case you need some extra brilliance to the paper, here’s what to do. First of all, you can choose a top writer. It means that we will assign an expert with a degree in your subject. And secondly, you can rely on our editing services. Our editors will revise your papers, checking whether or not they comply with high standards of academic writing. In addition, editing entails adjusting content if it’s off the topic, adding more sources, refining the language style, and making sure the referencing style is followed.
Confidentiality / 100% No DisclosureWe make sure that clients’ personal data remains confidential and is not exploited for any purposes beyond those related to our services. We only ask you to provide us with the information that is required to produce the paper according to your writing needs. Please note that the payment info is protected as well. Feel free to refer to the support team for more information about our payment methods. The fact that you used our service is kept secret due to the advanced security standards. So, you can be sure that no one will find out that you got a paper from our writing service.
Money Back GuaranteeIf the writer doesn’t address all the questions on your assignment brief or the delivered paper appears to be off the topic, you can ask for a refund. Or, if it is applicable, you can opt in for free revision within 14-30 days, depending on your paper’s length. The revision or refund request should be sent within 14 days after delivery. The customer gets 100% money-back in case they haven't downloaded the paper. All approved refunds will be returned to the customer’s credit card or Bonus Balance in a form of store credit. Take a note that we will send an extra compensation if the customers goes with a store credit.
24/7 Customer SupportWe have a support team working 24/7 ready to give your issue concerning the order their immediate attention. If you have any questions about the ordering process, communication with the writer, payment options, feel free to join live chat. Be sure to get a fast response. They can also give you the exact price quote, taking into account the timing, desired academic level of the paper, and the number of pages.