View by Category

Loading...

PPT – DRUG STABILITY PowerPoint presentation | free to view - id: 24b892-YjRkZ

The Adobe Flash plugin is needed to view this content

About This Presentation

Write a Comment

User Comments (0)

Transcript and Presenter's Notes

- DRUG STABILITY KINETICS
- General Outline
- Definition of drug stability and drug kinetics
- Importance of studying kinetics
- Basic math principles
- Drug kinetics reaction orders
- Determination of reaction orders
- Shelf life and half life
- Overage
- Degradation pathways
- Influence of packaging on drug stability
- Influence of temperature on drug stability
- Influence of catalysts on drug stability

1

- Definition of drug stability and drug kinetics
- Stability
- It is defined as the study of the extent

to which the properties - of a drug substance or drug product remain within

specified limits at - certain temperature. Properties may be physical,

chemical, - microbiological, toxicological or performance

properties such as - disintegration and dissolution.
- Drug Kinetics
- It is defined as how drug changes with time

i.e., study of rate - of change. Many drugs are not chemically stable

and the - principles of chemical kinetics are used to

predict the time span for - which a drug (pure or formulation) will maintain

its therapeutic - effectiveness or efficacy at a specified

temperature.

2

- Importance of studying kinetics
- It determines
- Stability of drugs (t1/2)
- Shelf life ((t0.9)
- Expiration date
- Stability of drugs (t1/2)
- The half life (t1/2) is defined as the time

necessary for a - drug to decay by 50 (e.g., From 100 to 50, 50

to 25, 20 to - 10)
- Shelf life (t0.9)
- It is defined as the time necessary for the

drug to decay to - 90 of its original concentration.

3

- Basic Math principles
- i) The straight Line
- General equation Y mx b
- Y dependent variable
- m slope
- X independent variable
- b intercept
- also
- Ordinate dependent variable axis
- abscissa independent variable axis

4

m slope ?Y / ?X

5

- Advantages of use of straight line
- Easier to determine parameters (slope and

intercept) - Simultaneous determination of two parameters (m

b) - Logarithms
- (a) Common log (base10)
- log 100 log 102 2
- log 1000 log 103 3
- (a) Natural log (base e 2.72)
- In 100 In ex
- In 100 In 2.72x 4.61

6

- Relation between Log and Ln
- Ln X 2.303 Log X
- Rules for calculating with Log
- log (a . b) log a log b
- log (a / b) log a - log b
- log an n log a
- log ex X
- (iii) Differentiation
- Determination of the rate of change ( slope

in graph)

7

Straight Line

Slope m ?Y / ?X constant

8

Curve

Slope is not constant but function of X Slope

1st derivative of y with respect to X

9

Rules of differentiation y axn

dy/dx anxn-1 e.g., y x2

dy/dx 2x y n eax dy/dx an

eax e.g., y 3e-2x dy/dx

-6e-2x y ln x dy/dx

1/x y 1/x dy/dx -

1/x2 y ex dy/dx ex

Example y 10 x3 2 x2 5x 5

dy/dx 30 x2 4 x 5

10

(iv) Integration Determination of area under

the curve i.e., sum or amount.

a

b

AUC

Where Y is the function of the graph b

upper limit a Lower limit Rules of

Integration

- Example
- Determine the area under the curve for the

relationship - y mx b, upper limit a and Lower limit 0

(No Transcript)

- If you do not know the equation of the line you

can use the trapezoidal - rule to calculate the area under curve (AUC)
- 4) Order of Reactions
- Law of mass action
- The rate of a reaction is proportional to the

molar concentrations of the reactants each raised

to power equal to the number of molecules

undergoing reaction. - a A b B

Product - Rate a Aa .Bb
- Rate K Aa .Bb
- Order of reaction sum of exponents
- Order of A a and B b
- Then Overall order a b

- Example
- The reaction of acetic anhydride with ethyl

alcohol to form ethyl acetate and water - (CH3 CO)2 2 C2H5OH 2 CH3

CO2 C2H5 H2O - Rate K (CH3 CO)2 O . C2H5OH2
- Order for (CH3 CO)2 O is 1st order
- Order for C2H5OH2 is 2nd order
- Overall order of reaction is 3rd Order

- Types of reaction orders
- Zero order reaction
- It is a reaction where reaction rate is not

dependent on the concentration of material i.e

concentration is not changing (i.e. negligible

amount of change). - Example Fading of dyes

Equation for zero order a A k

Product (P) Rate - dc/dt K c0 - dc/dt

k dc - k dt co Initial

concentration ct Concentration at time

t

18

C

T

Units of the rate constant K c co

Kt K co c /t K Concentration / time

mole / liter . second M. sec-1

19

- Determination of t1/2
- Let c co /2 and t1/2 t
- substitute in equation
- c co k t
- t1/2 co / 2K
- Note Rate constant (k) and t1/2 depend on co
- Determination of t0.9
- Let c 0.9 co and t t0.9
- substitute in equation
- c co k t
- t90 t0.9 0.1 co / k

20

- (b) First order reaction
- The most common pharmaceutical reactions e.g

drug absorption -

drug degradation - The reaction rate of change is proportional to

drug concentration i.e. - drug conc. is not constant.
- a A

k Product (P) - Rate - dc/dt K c1
- Equation

21

C co e ktDifficult to determine slope

lnco

lnc lnco kt Slope c1 c2 / t1 t2 Slope

-k

C

Lnc

Log co

Log c log co kt / 2.303 Slope c1 c2 / t1

t2 Slope -k / 2.303

Logc

Or use semi log paper

22

Semi log paper Slope -K / 2.303

Slope log c1 log c2 / t1 t2 NOT c1 c2 /

t1 t2 Units of K lnc lnco Kt K ( lnco

lnc ) / t Unit time-1

23

- Determination of t1/2
- Let t t1/2 and c co /2
- substitute in ln c ln co Kt
- t1/2 ln 2/ K 0.693 / K
- K units 0.693 / t1/2 time-1
- Determination of t0.9
- Let t t0.9 c 0.9 co
- substitute in ln c ln co Kt
- t0.9 0.105 / K and K 0.105/ t0.9

24

- Example A drug degrades according to the

following - Time (min.) Conc. ()
- 0 100
- 1 65.6
- 2 43.0
- 3 28.19
- 4 18.49
- 10 1.50
- Plot c against t on semi log paper and determine

slope, K and t1/2

25

Solution log 28.195 1.45 and log 1.5

0.176 slope 1.45 0.176 / 3 10 1.27 /

-7 - 0.181 Equation log c log co Kt /

2.303 slope -K/ 2.303 - 0.181 - K /

2.303 K 0.417 min-1 t1/2 0.693 / K t1/2

0.693 / 0.417 1.66 minute

26

- Special Case
- Apparent zero order of reaction
- In aqueous suspensions of drugs, as the dissolved
- drug decomposes more drug dissolve to maintain

drugconcentration - i.e. drug concentration kept constant, once all

undissolved drug is - dissolved, rate becomes first order.
- Another special case Pseudo 1st order
- When we have two components, one of which is

changing appreciably from its initial

concentration and the other is present in excess

that it is considered constant or nearly

constant. - Note In first order reactions, neither K or nor

t1/2 is dependent on - concentration

27

- (c) 2nd Order reaction
- When you have two components reacting with

each - other or one component reacting with itself.

- 2nd order graph

Units of K 1/C 1/Co Kt K (1/C - 1/Co)

/ t K M-1. sec -1

i.e, K is dependent on initial drug

concentration. Half life t1/2 1 /

KCo Shelf life t0.9 0.11 / KCo

About PowerShow.com

PowerShow.com is a leading presentation/slideshow sharing website. Whether your application is business, how-to, education, medicine, school, church, sales, marketing, online training or just for fun, PowerShow.com is a great resource. And, best of all, most of its cool features are free and easy to use.

You can use PowerShow.com to find and download example online PowerPoint ppt presentations on just about any topic you can imagine so you can learn how to improve your own slides and presentations for free. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world. Or use it to create really cool photo slideshows - with 2D and 3D transitions, animation, and your choice of music - that you can share with your Facebook friends or Google+ circles. That's all free as well!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

You can use PowerShow.com to find and download example online PowerPoint ppt presentations on just about any topic you can imagine so you can learn how to improve your own slides and presentations for free. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world. Or use it to create really cool photo slideshows - with 2D and 3D transitions, animation, and your choice of music - that you can share with your Facebook friends or Google+ circles. That's all free as well!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

presentations for free. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world. Or use it to create really cool photo slideshows - with 2D and 3D transitions, animation, and your choice of music - that you can share with your Facebook friends or Google+ circles. That's all free as well!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

Recommended

«

/ »

Page of

«

/ »

disablevideo

Promoted Presentations

Related Presentations

Page of

Page of

CrystalGraphics Sales Tel: (800) 394-0700 x 1 or Send an email

Home About Us Terms and Conditions Privacy Policy Contact Us Send Us Feedback

Copyright 2015 CrystalGraphics, Inc. — All rights Reserved. PowerShow.com is a trademark of CrystalGraphics, Inc.

Copyright 2015 CrystalGraphics, Inc. — All rights Reserved. PowerShow.com is a trademark of CrystalGraphics, Inc.

The PowerPoint PPT presentation: "DRUG STABILITY" is the property of its rightful owner.

Do you have PowerPoint slides to share? If so, share your PPT presentation slides online with PowerShow.com. It's FREE!

Committed to assisting Ksu University and other schools with their online training by sharing educational presentations for free