Synthesis and characterization of ascorbic acid-layered double hydroxide via co-precipitation method and its control release properties with various types of aqueous media / Muhammad Helmie Hairudin

Ascorbic acid (ASA) or also known as vitamin C was successfully intercalated between Zn-Al layered double hydroxide, Zn-Al-LDH inorganic host is synthesiz by co-precipitation method at pH 7.0 ±0.5 and Zn and Al molar ratio of 4. Both PXRD and FTIR result confirm that the ASA was successfully intercalated into the Zn-Al-LDH interlayer. The X-Ray diffraction pattern showed that the expansion of basal spacing from 8.9 Å in the Zn-Al-LDH change to 11.7 Å is because of intercalation of ASA occur into the Zn-AL-LDH (intercalation of ASA into ZN-Al-LDH). The most importance feature in FTIR spectrum for Zn-Al-ASA is the dissapearences of nitrate absorption band (at 1351cm-1) and the presence new band at 1613cm-1 , due to the presence of C=C alkene, which confirms the intercalation of ASA in the ionic form in the interlayer of the LDH. CHNS analysis, the loading percentage of ASA into LDH is determined to be 27 % at the concentration of ASA 0.9 M CHNS analysis indicates that only 0.3 % of nitrogen present at. The percentage saturated released of the ASA is in order of phosphate > carbonate > chloride with percentage saturated released 92 %, 64 % and 42 % respectively. This study shows that the Zn-Al-layered double hydroxide can use used as a host for controlled released formulation.