| Summary: | Lamivudine (3TC), Nevirapine (NVP) and Zidovudine (AZT) is indicated as part of
antiretroviral combination therapy for the treatment of Human Immunodeficiency
Virus (HIV) infected adults and children who present clinical or immunological
evidence of progression of the disease. Current dosage forms of these drugs in
single or dual-therapy include tablets, coated tablets and oral solutions.
Three problem areas are currently experienced with the above mentioned dosage
forms. Firstly tablets and coated tablets, although they provide good stability and
therefore shelf life, cannot be easily administered to children and geriatrics due to the
fact that they cannot swallow tablets. Oral solutions on the other hand can be easily
administered to children and geriatrics but provides poor stability and shelf life
especially in harsh African conditions. Thirdly, according to UNICEF,
extemporaneous preparation of pediatric suspensions from solid adult dosage forms
can reduce the stability of the drugs as well as the bioavailability.
The aim of this study was to formulate a novel dosage form that will provide a
solution for the above-mentioned problems.
Combinations of the three drugs were formulated in a dispersible or chewable tablet.
Preformulation studies were carried out to determine the compatibility of the drugs
and the excipients used in the formulae. Four batches of tablets were manufactured,
each containing a different amount of the three drugs mentioned above, in
accordance with WHO requirements. Accelerated stability tests were carried out at
different temperatures and degrees of humidity to determine the stability of the drugs
in the dosage form. Physical tests that were carried out on the tablets include assay,
hardness, friability, loss on drying, disintegration time, dissolution and uniformity of
mass, diameter and thickness.
Initial studies revealed that 3TC were the least stable of the three drugs in watery
solutions. 3TC was least stable in a solution at a high pH (NaOH in water), it was
more stable at a lower pH (HCI in water) and most stable at neutral conditions
(Water). NVP was also less stable at lower pH conditions in solution. The dosage
form complied with requirements for rapid disintegration and palatability in solution.
The dosage form can be classified as a dispersible as well as a chewable tablet. === Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
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