Polymorphic Forms of Lamivudine: Characterization, Estimation of Transition Temperature, and Stability Studies by Thermodynamic and Spectroscopic Studies

Table 1

Different solvent systems to prepare different crystal forms of lamivudine.

Solvent system	Form obtained	Shape
Water, Methanol,; Toluene + ethanol, Ethanol, DMF + methanol, 1,4-dioxane	Form I	elongated needles
Ethyl acetate, Dry ethanol, Acetonitrile, 2-propanol, Toluene, Dry methanol,; 1,4-dioxane + methanol + water	Form II	prismatic crystals
Heptane + 1-butanol; Hexane + n-propanol; Chloroform	Form III	fine needles