[e-drug] Study of stability of medicines under tropical conditions

["Paul Newton" <newtonpaul100@yahoo.co.uk>]

E-DRUG: Study of stability of medicines under tropical conditions
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Dear Colleagues,

We are planning a long term study of the stability (active ingredient content, dissolution and identification of any degradation products) of medicines in the laboratory and in a hot and humid tropical field environment. The FDA/ICH guidelines (FDA Q1A(R2) Stability Testing of New Drug Substances and Products. www.fda.gov/CbER/gdlns/ichstab.pdf) give useful information for planning such studies in the laboratory and recommend that three different batches should be tested. However, we have been unable to find any recommendations as to the sample size required and how many dosage units per batch, such as tablets, should be removed at each time point for assays. Sample size calculations will depend on inter-tablet variability in degradation - information which is unavailable for the medicines we hope to test. If you are aware of any guidelines on sample sizes for such experiments we would be very grateful for the information.

With very best wishes,

Paul Newton

Microbiology Laboratory
Mahosot Hospital
Vientiane, Lao PDR 
e-mail: newtonpaul100@yahoo.co.uk