HPMC K15M and chitosan mixed matrices can be used to modify release rates in hydrophilic matrix tablets prepared by direct
compression. Incorporating the highly porous low-density copolymer (approximately 12%) in the matrix tablets provides densities
that were lower than that of the release medium. These tablets floated almost immediately upon contact with the release medium,
showing no lag times (unlike conventional floating systems) in floating behavior because low density is provided from the
beginning (t = 3 s). Extended floating times are achieved because of the air entrapped within the low-density copolymer particles, which
is only slowly removed from the system upon contact with the release medium. As expected, tablets without low density copolymer
(e.g., consisting of 40 mg polymer and 40 mg famotidine) sank to the bottom of the vessel showing no floating behavior. Faster
release of the drug from the hydrophilic matrix was probably a result of faster dissolution of the highly water-soluble drug
from the core and its diffusion out of the matrix forming the pores for entry of solvent molecules. Therefore, one can formulate
floating dosage forms that can show excellent floating lag times using low-density copolymer and achieve desired release profile.
James R. Benson (chairman, CEO, president), Nai-Hong Li (research director), and Finny Bhathena (representative in India)
of Polygenetics are acknowledged for their kind support of the research work.
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1. J.E.F. Reynolds, Martindale the Extra Pharmacopoeia (The Royal Pharmaceutical Society, London, 1996), pp. 1218–1220.
2. B.N. Singh and K.H. Kim, "Floating Drug Delivery Systems: An Approach to Oral Controlled Drug Delivery via Gastric Retention,"
J. Control. Release
63, 235–259 (2000).
3. M. Coffin and A. Parr, "Ranitidine Solid Dosage Form," US Patent 5 407 687, April 18, 1995.
4. S. Li et al., "Statistical Optimization of Gastric Floating System for Oral Controlled Delivery of Calcium," AAPS Pharm. Sci. Tech.
2, article 1 (2001).
5. S. Li et al., "Effect of HPMC and Carbopol on the Release and the Floating Properties of Gastric Floating Drug Delivery
System using Factorial Design," Int. J. Pharm.
253, 13–22 (2003).
6. F. Kedzierewicz et al., "Evaluation of Peroral Silicone Dosage Forms in Humans by Gamma Scintigraphy," J. Control. Release
58, 195–205 (1999).
7. S.S. Davis et al., "The Effect of Density on the Gastric Emptying of Single and Multiple-Unit Dosage Forms," Pharm. Res.
3, 208–213 (1986).
8. R. Groning and G. Heun, "Dosage Forms with Controlled Gastrointestinal Passage: Studies on the Absorption of Nitrofurantoin,"
Int. J. Pharm.
56, 111–116 (1989).
9. S. Arora et al., "Floating Drug Delivery Systems: A Review," AAPS Pharm Sci Tech.
6 (3), article 47, E372–E390 (2005).
10. G. Chawla and A. Bansal, "A Means to Address Regional Variability in Intestinal Drug absorption," Pharm. Technol.
27 (6), 50–68 (2003).
11. W. Müller and E. Anders, "Floating System for Oral Therapy," WO Patent 89/06956, 1989.
12. M. Jaimini, A.C. Rana, and Y.S. Tanwar, "Formulation and Evaluation of Famotidine Floating Tablets," Current Drug Deliv.
4, 51–55 (2007).
13. A. Streubel, J. Siepmann, and R. Bodmeier, "Floating Matrix Tablets based on Low-Density Foam Powder: Effects of Formulation
and Processing Parameters on Drug Release," Eur. J. Pharm. Sci.
18, 37–45 (2003).
14. A. Streubel, J. Siepmann, R. Bodmeier, "Floating Microparticles based on Low-Density Foam Powder," Int. J. Pharm.
241, 279–292 (2002).
15. M. Rosa, H. Zia, and T. Rhodes, "Dosing and Testing In Vitro of a Bioadhesive and Floating Drug Delivery System for Oral
Application," Int. J. Pharm.
105, 65–70 (1994).
16. P. Costa, J. Manuel, and S. Labao, "Modeling and Comparison of Dissolution Profiles," Eur. J. Pharm. Sci.
13, 123–133 (2002).
17. S. Baumgartner et al., "Physical and Technological Parameters Influencing Floating Properties of Matrix Tablets based
on Cellulose Ethers," STP Pharma Sci.
8, 285–290 (1998)
18. J. Timmermans and A. J. Moës, "How Well Do Floating Dosage Forms Float?" Int. J. Pharm.
62, 207–216 (1990). PT
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J.A. Raval, PhD,* is an assistant professor in the department of pharmaceutics and pharmaceutical technology at Shree S.K.
Patel College of Pharmaceutical Education and Research, Ganpat Universiy, Kherva-382711, Gujarat, India, tel. and fax 91 2762
. M.M. Patel is a principal at Kalol Institute of Pharmacy (Kalol, Gujarat, India). Nai-Hong Li is a research director at
Polygenetics (Los Gatos, CA). J.K. Patel is a principal at Nootan Pharmacy College (Visnagar, Gujarat, India).
*To whom all correspondence should be addressed.
Submitted: Dec. 15, 2008. Accepted: Feb. 19, 2009.