Dosage forms exam 1 stability 3

Chemical kinetics equations

Rate= +/- dC/dT Concentration over time

rate=k (a+b)[A][B]
Reaction rates depend on

Temperature
Order of the reaction

Sum of the exponents
What are the greatest interest of reactions?

Zero, first and second (mainly zero and first)
In First order Rate is proportional to

Concentration
For first order reaction, plot of integrated Ln C vs T... (lnC=lnCo-K1t)the slope is what?

-K1
Example of pseudo first order degradation

Ester Hydrolysis
Pseudo first order equation

-dCE/dt= kCE
Zero Order equation

-dC/dt=kC^0
Zero order graph equation
C=Co-kot
- Co is intercept
- slope is ko
To maintain constant concentration for zero order

There is a resevoir of drug to replac the drug that is lost to decomposition
Effects of pH on degradation rate

Protons and hydroxyl ions can catalyze reactions (Ester hydrolysis)
Max stability is located where at the graph?

Where log k is at its lowest.
Temperature affect on degradation rates.... 10 Celcius increase causes

2-5 fold decay rate increase
Arrhenius equation

k=Ae^-Ea/RT
Arrhenius used to predict

Shelf life for normal conditions
Ampicillin freezing causes

Pockets of increased conc. causeing increased degradation rate
buffers in solution when freezing

Can alter pH during freezing process.

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swynocker

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Dosage forms exam 1 stability 3

Description

Stability 3

Updated

2010-10-27T05:42:42Z

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