AVS 51st International Symposium
    Applied Surface Science Monday Sessions
       Session AS-MoP

Paper AS-MoP2
TOF-SIMS Investigation of Selected Excipients in Color Coated Placebo Tablets

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: X. Dong, Eli Lilly and Company
Authors: X. Dong, Eli Lilly and Company
C.A.J. Kemp, Eli Lilly and Company
Correspondent: Click to Email
Time of Flight-Secondary Ion Mass Spectrometry (TOF-SIMS) was applied to investigate the surface and cross-section of placebo tablets. Eight excipients, including lactose, hydroxypropyl cellulose (HPC), and microcrystalline cellulose (MCC) were examined, as well as color coat mixture and polishing material used in placebo tablets. The investigation of raw materials shows that HPC can be distinguished from other excipients based on its unique peaks present in positive ion TOF-SIMS spectra. Most peaks observed in the spectra of MCC were also detected in the spectra of lactose, which makes it difficult to distinguish MCC from lactose. The comparison between the spectra obtained from tablet surface and cross-section shows that the chemical composition of tablet surface is different from that of bulk. Mg, which comes from a polishing material used on the outside of the tablet, dominates placebo surface spectra, while Na, which is one of constitutes of several excipients, dominates the cross-section spectra. In addition, peaks corresponding to HPC were much more abundant in the surface spectra than in the cross-section spectra, comparing to peaks corresponding to MCC/lactose. The preliminary results suggest that HPC might migrate more easily to sample surface than MCC and lactose during the tablet manufacturing process. The possibility of surface contamination is relatively low, since HPC related peaks were consistently found in surface spectra of all placebo tablets examined, as well as one house drug tablet analyzed in previous work.