# \[e-drug\] Differences in shelve lives of same medicine (4)

**URL:** <https://talk.edrugplus.org/t/e-drug-differences-in-shelve-lives-of-same-medicine-4/20577>\
**Category:** e-drug\
**Created:** [September 27, 2004, 4:10pm UTC](https://talk.edrugplus.org/t/e-drug-differences-in-shelve-lives-of-same-medicine-4/20577 "2004-09-27T16:10:59Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Emeje\_Martins](https://avatars.discourse-cdn.com/v4/letter/e/aca169/32.png) [@Emeje\_Martins](https://talk.edrugplus.org/u/Emeje_Martins)\
**Post date:** [September 27, 2004, 4:10pm UTC](https://talk.edrugplus.org/t/e-drug-differences-in-shelve-lives-of-same-medicine-4/20577/1 "2004-09-27T16:10:59Z")

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E-DRUG: Differences in shelve lives of same medicine (4)  
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Dear e-druggers,

A particular drug should not have differences in its  
shelve life, no matter the method of testing.

However,the same drug can be presented as  
different dosage forms, and the other constituents of  
these dosage forms could affect the stability and  
shelve life of the active(drug). This is the reason  
only highly experienced experts should carry out these  
type of studies.

Martins,  
Nat.Inst. for Pharm.Res.  
Abuja,  
Nigeria.  
martinsemeje@yahoo.com

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**Author:** ![KAZEEM\_BABATUNDE](https://avatars.discourse-cdn.com/v4/letter/k/bbce88/32.png) [@KAZEEM\_BABATUNDE](https://talk.edrugplus.org/u/KAZEEM_BABATUNDE)\
**Post date:** [September 28, 2004, 10:35am UTC](https://talk.edrugplus.org/t/e-drug-differences-in-shelve-lives-of-same-medicine-4/20577/2 "2004-09-28T10:35:54Z")

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E-DRUG: Differences in shelve lives of same medicine (5)  
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Hello E-Druggers,

This issue has been adequately dealt with by comments  
from respected e-druggers. But I want to just add that  
we should be clear exactly about what we are dealing  
with.

Is it Half life or shelf life?

A Drug ESSENTIALLY do not have different half lives but a  
single drug can different shelf lives depending on  
formulation factors and storage factors. Furthermore,  
formulation factors and drug designing strategies  
(which manipulate drug structures)can be used to slow  
down or delay release of a drug or improve its tissue  
penetration and persistence.

But essentially formulation factors will account for  
two different formulations containing the same active  
ingredient to have different shelf lives.

Kazeem Babatunde Yusuff  
Dept. of Clinical Pharmacy  
Faculty of Pharmacy  
University of Ibadan  
Nigeria  
yusuffkby@yahoo.co.uk

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**Author:** ![stein](https://avatars.discourse-cdn.com/v4/letter/s/5f8ce5/32.png) [@stein](https://talk.edrugplus.org/u/stein)\
**Post date:** [September 28, 2004, 4:12pm UTC](https://talk.edrugplus.org/t/e-drug-differences-in-shelve-lives-of-same-medicine-4/20577/3 "2004-09-28T16:12:37Z")

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E-DRUG: Differences in shelf lives of same medicine (6)  
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dear E-druggers,

Shelf life is the time from production/delivery to expiry date.  
Minimum shelf life is often specified in tender conditions.  
Expiry dates often refer to certain storage conditions.

The expiry date on the package is not the date when the medicine doesn't have full effect anymore. The expiry date is when the manufacturer stops having full responsibility for the pharmaceutical quality of the medicine in the package.

Different manufacturers may use different excipients and packaging materials, and use different production methods. Testing methods may vary. Both manufacturers and regulatory authorities may have varying focus and views (and morals) in these things.

All these things can have influence on expiry date.

Manufacturers may also have different tactics. Some think that short shelf lives (and more outdated packages) make larger sales. Others think that long shelf life gives the company good reputation.

Counterfeit medicines have expiry date on the packages.

So expiry dates are never 'The Truth' about the quality of medicines.

Expiry dates should be evaluated with professional knowledge and common sense.

regards

Stein Lyftingsmo  
Hospital Pharmacy of Elverum  
Norway  
www.lyftingsmo.no  
stein@lyftingsmo.no