C. Muthuselvi et al. / Elixir Vib. Spec. 95 (2016) 40673-40678 40673 Introduction The salicylate drug of acetylsalicylic acid is also called as aspirin. It can act as an effective analgesic to reduce the mild headache pain, toothache, muscle pain, and join pain [1]. Also, it behaves as an antipyretic drug to reduce fever and an anti– inflammatory medication which is capable of reducing swelling and redness associated with inflammation. The low doses of aspirin may be given to the patient immediately after a heart attack to reduce the risk of another heart attack or of the death of cardiac tissue [2–4]. Now a day, the effect of aspirin on colorectal cancer has been widely studied by the many researchers and they conclude that the regular use of aspirin reduces the long–term risk of Colorectal Cancer Risk (CRC) incidence and mortality [5]. Most of the drugs are delivered to patients in crystalline form [6]. The crystals of metal complexes with aspirin have been found to be some additional medical activities such as antiulcer, anticancer, antimutagenic and antioxidative in biological systems [7, 8]. In the present study, we are interested to grow the medicinal important aspirin drug crystal doping with the perchloric acid by vapor diffusion method. The grown crystals are characterized by the powder XRD, FT–IR, FT–Raman, UV– Visible spectroscopy, SEM and melting point studies. These results are compared with the pure aspirin drug crystal and they are summarized in the present study. Materials and Methods The raw materials used for crystallization (Aspirin, Perchloric acid and Ethanol) were purchased from the Merck India Ltd, Mumbai. Crystal growth by vapor diffusion method The aspirin crystals and aspirin–perchloric acid complex crystals were grown by using the vapor diffusion method. In this method, aspirin and perchloric acid were taken in the 1:1 stoichiometric ratio and they are dissolved in ethanol as a solvent in a small beaker (50 ml). This mixture is placed inside a larger beaker (250 ml) that contains a small volume of a solvent system (water) in which the sample is insoluble. The outer beaker was sealed. Vapor from the solvent of the inner beaker diffuses into the solution in the outer beaker, without disturbing the vessel causing the mixture to grow crystals. Since the rate of evaporation of ethanol slow, good quality crystals were formed after 5 weeks. The arrangement of vapor diffusion method is illustrated in Fig.1. The photographic view of the harvested colorless rectangular and needle shaped, aspirin and aspirin–perchloric acid complex crystals respectively are shown in Fig. 2. The molecular structures of pure aspirin and aspirin-perchloric acid complex crystals are depicted in Fig. 3. Figure 1: Arrangement of vapor diffusion method. Tele: +919487672735 E-mail address: muthuselviganesan100@gmail.com © 2016 Elixir All rights reserved ARTICLE INFO Article history: Received: 15 April 2016; Received in revised form: 25 May 2016; Accepted: 31 May2016; Keywords Vapor diffusion method, Aspirin – Perchloric acid complex, Powder XRD, FT – IR, FT – Raman, UV – Visible spectroscopy, SEM. Vapor Diffusion Growth and Characterization of Aspirin – Perchloric acid Complex Crystal C. Muthuselvi 1 , S. Pandiarajan 1 and R.V. Krishnakumar 2 1 Department of Physics, Devanga Arts College, Aruppukottai, 626 101, Tamilnadu, India. 2 Department of Physics, Thiagarajar College, Madurai, 625 009, Tamilnadu, India. ABSTRACT The aspirin–perchloric acid complex crystal is grown by the vapor diffusion method for the first time. The colorless needle shaped crystals are obtained after 5 weeks duration. These crystals are characterized by powder XRD, FT–IR, FT–Raman, UV–Visible spectroscopy, SEM and melting point studies to confirm the formation of complex crystal of aspirin –perchloric acid. The powder XRD, FT–IR and FT–Raman studies reveal the presence of perchloric acid with the medicinally important drug of aspirin in the complex form. The UV–Visible spectroscopy study shows that the optical window is found to be reduced in the presence of perchloric acid. But there is no change in the transparency of the both crystal in the visible region. The SEM analysis reveals the complex crystal has the distinct morphology in shape from the pure aspirin crystal. The melting point of complex crystal is found to be 110 ◦ C. Finally, these studies conclude that mixing of perchloric acid with aspirin changes the all physico-chemical properties of the pure drug compound of aspirin. The property change of aspirin–perchloric acid complex can be used to improve the medicinal activity of the drug compound in the biological systems. © 2016 Elixir All rights reserved. Elixir Vib. Spec. 95 (2016) 40673-40678 Vibrational Spectroscopy Available online at www.elixirpublishers.com (Elixir International Journal)