Lecture 2 - Pharmaceutics

Question 1

What is pharmaceutics?

Answer 1

The science of dosage design and its importance to patients

Question 2

In drug development, what does the first or discovery phase involve?

Answer 2

• Isolation or synthesis of a chemical entity which shows some specific pharmacological action and the serious toxicological effects
• Once the material chemically characterized it can be considered a drug and it enters the second phase of the development process

Question 3

What is the second phase in drug development? What does it involve?

Answer 3

It is the pharmaceutic phase. It involves:

• pharmaceutical characterization of the drug
• fabrication of a suitable dose form
• testing and evaluation of the finished product in terms of stability and bioavailability (how much gets to where it actually needs to be)

Question 4

Pharmaceutics is a broad term and encompasses several general areas. Name them

Answer 4

Physical pharmaceutics
Dosage form design
Fabrication
Microbiology

Question 5

How is physical pharmaceutics involved in pharmaceutics?

Answer 5

It’s an understanding of the basic physical chemistry necessary for the efficient design of a dosage form

Question 6

How is dosage form design involved in pharmaceutics?

Answer 6

It’s designing and formulating the medicine

Question 7

How is fabrication involved in pharmaceutics?

Answer 7

It’s the manufacture of the medicine on both small (compounding) and a large (pharmaceutical technology) scale

Question 8

How is microbiology involved in pharmaceutics?

Answer 8

The avoidance or elimination of microorganisms in the medicine

Question 9

Medicines are a combination of what?

Answer 9

They are a combination of the drug and a suitable delivery system; medicines are rarely the drug alone but also include additives (excipients) to make a delivery system

Question 10

Why is the delivery system of a drug important?

Answer 10

It provides a means of administering or introducing the drug into the body in a safe, efficient, reproducible and convenient manner. The selection of suitable additives is the process of formulation and the goal is to be able to get the drug from the dose form to the target tissues in the body

Question 11

There are three major considerations in the design of dosage form. Name them and explain their importance

Answer 11

1. The physicohemical properties of the drug.
2. Biopharmaceutical aspects such as how the route of administration affects the rate of extent of drug absorption into the body.
3. Therapeutic considerations of the disease state to be treated and the nature or situation of the patient.
   These considerations will dictate which dosage form is most appropriate, the specific route of administration and the frequency of dosing

Question 12

Name different routes of administrations (7)

Answer 12

Oral, rectal, topical, parenteral, respiratory, nasal, ophthalmic

Question 13

Name the dose forms of the oral route of administration

Answer 13

Solutions, syrups, suspensions, capsules and tablets

Question 14

Name the dose forms of the rectal route of administration

Answer 14

Suppositories, ointments and solutions

Question 15

Name the dose forms of the topical route of administration

Answer 15

Ointments, creams, pastes, lotions and transdermal

Question 16

Name the dose forms of the parenteral route of administration

Answer 16

Injections - solutions, suspensions, implants and emulsions

Question 17

Name the dose forms of the respiratory route of administration

Answer 17

Aerosols, inhalations and sprays

Question 18

Name the dose forms of the nasal route of administration

Answer 18

Solutions, sprays and powders

Question 19

Name the dose forms of the ophthalmic route of administration

Answer 19

Solutions, ointments and inserts

Question 20

What is preformulation

Answer 20

It is one of the first steps in formulating a dosage form. It is the preliminary gathering of information which will be needed to develop a formulation and to anticipate problems which will have to be dealt with in the design process

Question 21

Name the steps usually involved in preformulation

Answer 21

Assay development
Solubilty characteristics
Solid state characteristics
Stability

Question 22

Describe the assay development step in preformulation

Answer 22

Dosage formulation requires a method of measuring the drug both quantitatively and qualitatively. At least one of the methods will need to be stability-indicating

Question 23

Describe the solubility characteristics step in preformulation

Answer 23

In most cases, the drug needs to dissolve before it can be absorbed into the body.
Need to determine water solubility, partition coefficient and dissolution characteristics; if ionizable functional groups are present, need to know pKa and possible salt forms; may need information about solubility in other solvents (alcohol, propylene glycol and glycerin)

Question 24

Describe the solid state characteristics step in preformulation

Answer 24

For solid dose forms in particular we need to know crystalline properties and polymorphism, flow and compression properties, particle size and melting point

Question 25

Describe the stability step in preformulation

Answer 25

For all dose forms, we need to know the nature of degradation; effect of temperature, pH, light and oxygen compatibility, hydroscopicity and vapor pressure

Question 26

Name some of the problems that may be dealt with in the preformulation phase

Answer 26

Poor water solubility of the drug The drug may degrade in stomach acid or be affected by digestive enzymes The drug may degrade when in solution or exposed to light, heat or oxygen

Question 27

Define pharmaceutical care

Answer 27

A patient-centered, outcomes-oriented pharmacy practice that requires the pharmacist to work in concert with the patient and other involved health-care providers to promote health, to prevent disease and to assess, monitor, initiate and modify medication use to assure that drug therapy regimes are safe and effective

Question 28

What is the roles and responsibilities of a pharmacist with regards to pharmaceutics?

Answer 28

Pharmacists must ensure that the prescribed medication is appropriate, that the dose is correct and that the correct medication is dispensed and appropriately labeled

Question 29

What is the roles and responsibilities of a pharmacist with regards to the patient or caregiver?

Answer 29

Pharmacists must ensure the patient or caregiver understands: - the purpose of the medication and the goals and timelines of the therapy and what to do if the goals are not being met - what the dose of the medication is, how to ensure and administer it and what the meanings of any auxiliary labels are - possible adverse effects and what to do should any of these occur - the proper storage conditions for the medication

Question 30

Pharmaceutics converging with pharmaceutical care can best be illustrated with some examples. Name them

Answer 30

Compounding, compatibility, stability, problem solving,

Question 31

Describe how compounding can be involved with pharmaceutics converging with pharmaceutical care

Answer 31

In some situations, an appropriated dose form is not commercially available so the pharmacist may be called upon to extemporaneously prepare a suitable dose form. The pharmacist must be concerned and knowledgeable about stability and bioavailability of compounded product

Question 32

Give some examples of how compounding can be involved with pharmaceutics converging with pharmaceutical care

Answer 32

The patient may not be able to take a solid oral dose form such as a capsule or tablet and so a liquid preparation such as a suspension may be compounded. The dose forms commercially available are of an inappropriate strength. A capsule dose form is often prepared in these cases

Question 33

Describe how compatibility can be involved with pharmaceutics converging with pharmaceutical care

Answer 33

Occasionally there is an advantage to mixing drugs together before administration but there may be issues of incompatibility or when mixing the drugs leads to solubility or stability problems. By understanding the chemical nature of the drugs and how the manufacturer them, the pharmacist will have some insight regarding whether it is acceptable to mix these together

Question 34

Describe how stability can be involved with pharmaceutics converging with pharmaceutical care

Answer 34

Some drug products are stored at reduced temperature to increase the shelf-life of the product. Occasionally a product is stored under different conditions and must make a judgment as to whether the product is still suitable for use. Although we would always want to be conservative, our training in pharmaceutics can give us an informed basis on which to make that judgment

Question 35

Describe how problem solving can be involved with pharmaceutics converging with pharmaceutical care

Answer 35

Parenteral nutrition is providing nutrition intravenously to patients that are unable to eat. The mixtures contain amino acids, carbohydrates, electrolytes, fat emulsion, vitamins and trace minerals. Combinations of phosphate and calcium can form water-insoluble salt but by the use of pH adjustment and managing the proportions of phosphate to calcium this problem can be avoided. A problem arose with PN solutions used for premature neonates where the cannula (plastic needle) sometimes became plugged with an insoluble material which was eventually identified as calcium phosphate