Thermal studies on natural polysaccharide

To characterize thermal property of natural gums obtained from the seeds of Diospyros melonoxylon (D. melonoxylon) Roxb, Buchanania lanzan (B. lanzan) spreng and Manilkara zapota (M. zapota) (Linn.) P. Royen syn. Natural gums were thermally characterized using differential scanning calorimetry (DSC), differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA) under nitrogen atmosphere. Major thermal transitions as well as activation energies of the major decomposition stages were determined. Elemental analysis was performed in order to determine the composition of carbon, hydrogen, nitrogen and sulfur. DSC traces indicated a major intense exothermic transition (around 200 °C) followed by weaker exotherm(s). Thermogravimetric analysis showed two phase of weight loss. The first phase has minor weight loss in samples is attributed to the loss of adsorbed and structural water of biopolymers or due to desorption of moisture as hydrogen bound water to the saccharide structure. The second weight loss event may be attributed to the polysaccharide decomposition. The initial decomposition temperature (IDT) was calculated from thermograms obtained of TGA, seed Polysaccharide of D. melonoxylon (IDT 221.21 °C), B. lanzan (IPDT 170.4 °C) and M. zapota (IPDT 178.6 °C) were obtained. According to the integral procedural decomposition temperature (IPDT) values calculated based on the TGA thermograms; D. melonoxylon (IPDT 563.3 °C), B. lanzan (IPDT 598.1 °C) and M. zapota (IPDT 600.6 °C) were obtained respectively. The elemental analysis study shows that the isolated natural Polysaccharides consist of certain percentage of carbon, nitrogen, sulphur and hydrogen in all the gums. The results of the present investigation reveal that the natural gums are thermally stable and these gums can be used as release modifiers in various dosage forms.