Lecture 1(calculations)

Question 1

Initial Discovery of drug

Answer 1

New drugs (New Chemical Entities or NCE’s) can be discovered from natural sources or created synthetically

A potential NCE must be isolated, purified and synthesised before it can be developed

Step 1: Hit confirmation
Step 2: Hit explosion
Step 3: Lead generation & optimisation

Question 2

Pre formulation

Answer 2

The following factors must be characterised;

Particle size / Surface area
Solubility
Dissolution rate
Partition coefficient
Ionisation
Crystal properties
Stability

Question 3

Formulation Options

Answer 3

Tablets
Capsules
Creams
Injections
Patches
Inhalers
Oral solutions
Eye drops
Ear drops
Suppositories

Question 4

What happens in a clinical trial?

Answer 4

Phase I clinical trials are the first trials in humans to establish the safety, pharmacokinetics and pharmacodynamics.
Phase II clinical trials are carried out in patients to assess the efficacy and dose ranging of the drug.
Phase III clinical trials are carried out in larger numbers of patients to confirm efficacy and to demonstrate long-term safety and tolerance or to compare new formulations / drugs with existing treatments

The data are used to ascertain;
the physiological mechanisms of action of the drug (Pharmacology)
The side-effects of the drug (Toxicology)

Question 5

Marketing the drug

Answer 5

The purpose of marketing is “to reach customers and compel them to purchase, use and repurchase your product”

Market research will have already established there is a need for the product

Most POM-medicines are patented for a period of 10 years. After this time, rival manufacturers can legally make copies of the drug (generic copies)

Careful reformulation can lead to patent extension,

A manufacturer can sell considerably more OTC- or P-medicines by producing the same drug in different formulations

Question 6

units of mass

Answer 6

1 Kg = 1000 g
1 g
1 mg = 0.001 g
1 µg = 0.000001 g
1 ng = 0.000000001 g

Question 7

Formulation percentages

Answer 7

% literally means per hundred

% w/w weight in weight (m/m)

% w/v weight in volume

% v/v volume in volume

% v/w volume in weight

Remember 1 % = 1 g or mL per 100 g or mL

Question 8

Ratio Calculations

Answer 8

Expressed in 2 ways
A part(s) to X parts = X+A parts in total
B parts(s) in Y parts = Y parts in total

E.g.
2 parts to 8 parts = 2+8 = 10parts in total
2parts in 8 parts = 8 parts in total

Solubility described as 1 in X

Question 9

Question and response

Answer 9

Hard paraffin 4 parts
Soft paraffin 21 parts
Liquid paraffin 5 parts

To make 100 parts:

Therefore 100 / 30 x 4, 21 & 5 respectively

Hard paraffin 13.32 g
Soft paraffin 69.93 g
Liquid paraffin 16.65 g
To 2d.p.

Question 10

Parts per million

Answer 10

ppm
Very small conc of ingredient
Convention of 1ppm
w/v 1 g in 1,000,000 mL
w/w 1 g in 1,000,000 g
v/v 1 mL in 1,000,000 mL or 1 L in 1000,000 L