Are multisource levothyroxine sodium tablets marketed in Egypt interchangeable?

Area of Science:

• Pharmacology and Pharmaceutical Sciences
• Clinical Endocrinology
• Drug Quality and Bioequivalence

Background:

• Patient and physician-reported concerns regarding levothyroxine sodium (LT4) multisource tablet efficacy in Egypt.
• Need to investigate potential therapeutic variations among LT4 products available locally.

Purpose of the Study:

• To assess the clinical efficacy and pharmaceutical quality of different levothyroxine sodium tablet brands and sources.
• To explore correlations between in vitro dissolution profiles and in vivo clinical performance.

Main Methods:

• A 6-month multiple-dose clinical study involving 50 female patients with primary hypothyroidism.
• Administration of five different levothyroxine sodium tablet batches (two brands, three origins) purchased locally.
• Monitoring of thyroid stimulating hormone (TSH), total T4, and free T4 levels; in vitro dissolution testing according to pharmacopeial standards (BP/EP 2014 & USP 2014).

Main Results:

• Clinical and pharmaceutical data demonstrated significant inter-brand and inter-source variations in levothyroxine sodium tablet efficacy.
• In vitro dissolution testing results correlated with observed clinical outcomes, suggesting potential for quality control.

Conclusions:

• Multisource levothyroxine sodium tablets marketed in Egypt exhibit differences in efficacy.
• In vitro dissolution testing shows promise as a tool for identifying levothyroxine sodium tablets with suboptimal performance during their shelf life.