1 Fox W. Drug combinations and the bioavailability of rifampicin. Tubercle 1990a;71:241-245.

2 Fox W. Tuberculosis in India, past, present and future. Ind J Tuberc 1990b;37:175-213.

3 Buniva G, Pagani V, Carozzi A. Bioavailability of rifampicin capsules. Int J Clin Pharmacol, 1983;21:404-409.

4 Cavenaghi R. Rifampicin raw material characteristics and their effect on bioavailability. Bull Int Union Tuberc Lung Dis, 1989;64:36-37.

5 Laing R, Fourie B, Ellard G, Sesay M, Spinaci S, Blomberg B, Bryant D. Fixed-dose combination tablets for the treatment of tuberculosis. Report of an informal meeting held in Geneva Tuesday, 27 April 1999. Geneva: World Health Organization; 1999. WHO/CDS/CPC/TB/99.267.

6 Blomberg B, Evans P, Phanouvong S, Nunn P. Informal consultation on 4-drug fixed-dose combinations (4FDCs) compliant with the WHO model list of essential drugs. 15-17 August 2001. Geneva: World Health Organization; 2002: WHO/CDS/TB/2002.299.

7 Boman G, Lundgren P, Stjernstrom G. Mechanism of the inhibitory effect of PAS granules on the absorption of rifampicin: Adsorption of rifampicin by an excipient, bentonite. Eur J Clin Pharmacol, 1975;8:293-299.

8 Shishoo CJ, Shah SA, Rathod IS, Savale SS, Vora MJ. Impaired bioavailability of rifampicin in presence of isoniazid from fixed-dose combination (FDC) formulation. Int J Pharm, 2001;228:53-67.

9 Singh S, Mariappan TT, Sankar R, Sarda N, Singh B. A critical review of the probable reasons for the poor/variable bioavailability of rifampicin from anti-tubercular fixed-dose combination (FDC) products, and the likely solutions to the problem. Int J Pharm, 2001;228:5-17.

10 Acocella G. Human bioavailability studies. IUATLD Symposium “Quality control of anti-tuberculosis drugs”, Dubrovnik, 6 October 1988. Bull Int Union Tuberc Lung Dis, 1989;64:38-40.

11 Ellard GA, Fourie PB. Rifampicin bioavailability: a review of its pharmacology and the chemotherapeutic necessity for ensuring optimal absorption. Int J Tuberc Lung Dis, 1999;3:S301-S308.

12 Zak AF, Batuashvili TA, Shcedrin VI. Rifampicin preparations for internal use and their bioavailability. Antibiotiki, 1981;26:728-731.

13 McIlleron H, Wash P, Burger A, Folb P, Smith P. Widespread distribution of a single drug rifampicin formulation of inferior bioavailability in South Africa. Int J Tuberc Lung Dis, 2002;6:356-361.

14 Pelizza G, Nebuloni M, Ferrari P, Gallo GG. Polymorphism of rifampicin. Il Farmaco, 1977;32:471-481.

15 Yu LX, Furness MS, Raw A, Outlaw KPW, Nashaed NE, Ramos E, Miller SPF, Adams RC, Fang F, Patel RM, Holcombe FO Jr, Chiu Y, Hussain AS. Scientific consideration of pharmaceutical solid polymorphism in abbreviated new drug applications. Pharm Res, 2003;20:531-536.

16 Shishoo CJ, Shah SA, Rathod IS, Savale SS, Kotecha JS, Shah PB. Stability of rifampicin in dissolution medium in presence of isoniazid. Int J Pharm, 1999;190:109-123.

17 Mannisto P. Absorption of rifampicin from various preparations and pharmaceutic forms. Clin Pharmacol Ther, 1977;21:370-374.

18 Aspesi F. Dissolution testing. IUATLD Symposium “Quality control of anti-tuberculosis drugs”, Dubrovnik, 6 October 1988. Bull Int Union Tuberc Lung Dis, 1989;64:37-38.

19 Dressman JB, Amidon GL, Reppas C, Shah VP. Dissolution testing as a prognostic tool for oral drug absorption: immediate release dosage forms. Pharm Res, 1998;15:11-20.

20 Amidon GL, Lennernas H, Shah VP, Crison JR. A theoretical basis for a biopharmaceutic drug classification: the correlation of in vitro drug product dissolution and in vivo bioavailability. Pharm Res, 1995;12:413-420.

21 Lobenberg R, Amidon GL. Modern bioavailability and biopharmaceutics classification system. New scientific approaches to international regulatory standards. Eur J Pharm Biopharm, 2000;50:3-12.

22 Martinez MN, Amidon GL. A mechanistic approach to understanding the factors affecting drug absorption: a review of fundamentals. J Clin Pharmacol, 2002;42:620-643.

23 Panchagnula R, Agrawal S. Biopharmaceutics and pharmacokinetics in variable bioavailability of rifampicin. Int J Pharm, 2003;in press.

24 Bolton S. Sample size and power In: Pharmaceutical statistics: Practical and clinical applications. 2nd Ed. Bolton S ed. New York: Marcel Dekkar Inc. 1990:187-209.

25 Davis SS, Illum L. Drug delivery systems for challenging molecules. Int J Pharm, 1998;176:1-8.

26 Devane J. Oral drug delivery technology: Addressing the solubility/permeability paradigm. Pharm Tech, 1998;68-80.

27 Waterbeemd, H.V. The fundamental variables of the biopharmaceutics classification system (BCS): a commentary. Eur. J. Pharm. Sci, 1998;7:1-3.

28 Wilding, I.R. Evolution of the Biopharmaceutics Classification System (BCS) to oral Modified Release (MR) formulations; what do we need to consider? Eur. J. Pharm. Sci, 1999:8;157-159.

29 Dressman, J., Butler, J., Hempenstall, J. and Reppas, C. The BCS: Where do we go from here? Pharm. Tech, 2001;July:68-76.

30 Sen H, Jindal KC, Deo KD, Gandhi KT. An improved process for preparation of four-drug anti-tubercular fixed-dose combination. International patent no. WO 02/087547 A1, 2002.

31 Zwolska Z, Augustynowicz-Kopec E, Niemirowska-Mikulska. The pharmacokinetic factors and bioavailability of rifampicin, isoniazid and pyrazinamide fixed in one dose capsule. Acta Pol Pharm, 2002;59:448-452.

32 Agrawal S, Kaur KJ, Singh I, Bhade SR, Kaul CL, Panchagnula R. Assessment of bioequivalence of rifampicin, isoniazid and pyrazinamide in a four drug fixed-dose combination with separate formulations at the same dose levels. Int J Pharm, 2002;233:169-177.

33 Agrawal S, Singh I, Kaur KJ, Bhade SR, Kaul CL, Panchagnula R. Bioequivalence assessment of rifampicin, isoniazid and pyrazinamide in a fixed-dose combination of rifampicin, isoniazid, pyrazinamide and ethambutol vs. separate formulations at the same dose levels. Int J Clin Pharmacol Ther, 2002;40:474-481.

34 Panchagnula R, Kaur KJ, Singh I, Kaul CL. Bioequivalence of rifampicin when administered as a fixed-dose combined formulation of four drugs versus separate formulations. Methods Find Exp Clin Pharmacol, 2000;22:689-694.

35 Nyazema NZ, Rabvukwa P, Gumbo J, Ndudzo P, Chitemerere C. Bioavailability of rifampicin in a separate formulation and fixed-dose combination with isoniazid: a case for a fixed-dose combination (FDC) for the treatment of tuberculosis. Cent Afr J Med, 1999;45:141-144.

36 Panchagnula R, Kaur KJ, Singh I, Kaul CL. The WHO simplified study protocol in practice: investigation of combined formulations supplied by the WHO. Int J Tuberc Lung Dis, 1999;3:S336-S342.

37 McIlleron H, Gabriels G, Smith PJ, Fourie PB, Ellard GA. The development of a standardized screening protocol for the in vivo assessment of rifampicin bioavailability. Int J Tuberc Lung Dis, 1999;3:S329-S335.

38 Pillai G, Fourie P, Padayatchi N, Onyebujoh P, McIlleron H, Smith P, Gabriels G. Recent bioequivalence studies on fixed-dose combination anti-tuberculosis drug formulations available on the global market. Int J Tuberc Lung Dis, 1999;3:S309-S316.

39 Pahkla R, Lambert J, Ansko P, Winstanley P, Davis PD, Kiivet RA. Comparative bioavailability of three different preparations of rifampicin. J Clin Pharm Ther, 1999;24:219-225.

40 Padgoankar KA, Revankar SN, Bhatt AD, Vaz JA, Desai ND, D’Sa S, Shah V, Gandewar K. Comparative bioequivalence study of rifampicin and isoniazid combinations in healthy volunteers. Int J Tuberc Lung Dis, 1999;3:627-631.

41 Gurumurthy P, Ramchandran G, Vijayalakshmi S, Kumar AK, Venkatesan P, Chandrasekaran V, Vijayasekaran V, Kumaraswami V, Prabhakar R. Bioavailability of rifampicin, isoniazid and pyrazinamide in a triple drug formulation: comparison of plasma and urine kinetics. Int J Tuberc Lung Dis, 1999;3:119-125.

42 Panchagnula R, Singh I, Kaur KJ, Kaul CL. Bioequivalence of rifampicin from two drugs fixed-dose combined formulation compared to separate formulations. Methods Find Exp Clin Pharmacol, 1999;21:625-628.

43 Zofia Z, Niemirowska-Mikulsa H, Augustynowicz-kopec E, Stambrowska A. Results of examination in healthy volunteers of rifampicin and isoniazid bioavailability from Polish two-drug combination capsules of rifamazid used for tuberculosis treatment. Pneumonol Alergol Pol, 1998;66:198-206.

44 Zwolska Z, Niemirowska-Mikulska H, Augustynowicz-Kopec E, Walkiewicz R, Stambrowska H, Safinowska A, Grubek-Jaworska H. Bioavailability of rifampicin, isoniazid and pyrazinamide from fixed-dose combination capsule. Int J Tuberc Lung Dis, 1998;2:824-830.

45 Schall R, Muller FO, Duursema L, Groenewoud G, Hundt HK, Middle MV, Mogilnicka EM, Swart KJ. Relative bioavailability of rifampicin, isoniazid and ethambutol from a combination tablet vs. concomitant administration of a capsule containing rifampicin and a tablet containing isoniazid and ethambutol. Arzneinittelforschung, 1995;45:1236-1239.

46 Chouchane N, Barre J, Toumi A, Tillement JP, Benakis A. Bioequivalence study of two pharmaceutical forms of rifampicin capsules in man. Eur J Drug Metab Pharmacokinet, 1995;20:315-320.

47 Jindal KC, Chaudhary RS, Singal AK, Gangwal SS, Khanna S. Effect of particle size on the bioavailability and dissolution rate of rifampicin. Ind Drugs, 1995;32:100-105.

48 Acocella G, Luisetti M, Grassi GG, Peona V, Pozzi V, Grassi C. Bioavailability of isoniazid, rifampicin and pyrazinamide (in free combination or fixed-triple formulation) in intermittent antituberculosis chemotherapy. Monaldi Arch Chest Dis, 1993;48:205-209.

49 Garg SK, Chakrabarti A, Panigrahi D, Sharma M, Talwar P, Kumar N, Sharma PL. Comparative bioavailability and in-vitro antimicrobial activity of two different brands of rifampicin. Eur J Drug Metab Pharmacokinet, 1991;16:223-229.

50 Schaberg T, Lode H. Pharmacokinetic aspects of tuberculosis therapy with a fixed combination of rifampicin, isoniazid and pyrazinamide. Z Gesamte Inn Med, 1991;46:276-279.

51 Acocella G, Novis A, Gialdroni-Grassi G, Grassi C. Comparative bioavailability of isoniazid, rifampin, and pyrazinamide administered in free combination and in a fixed triple formulation designed for daily use in antituberculosis chemotherapy. I. Single-dose study. Am Rev Respir Dis, 1988;138:882-885.

52 Acocella G, Conti R, Luisetti M, Pozzi E, Grassi C. Pharmacokinetic studies on antituberculosis regimens in humans. I. Absorption and metabolism of the compounds used in the initial intensive phase of the short course regimens: Single administration study. Am Rev Respir Dis, 1985;132:510-515.

53 Garnham JC, Taylor T, Turner P, Chasseaud LF. Serum concentrations and bioavailability of rifampicin and isoniazid in combination. Br J Clin Pharmacol, 1976;3:897-902.

54 Boman G. Serum concentration and half-life of rifampicin after simultaneous oral administration of aminosalicylic acid or isoniazid. Eur J Clin Pharmacol, 1974;7:217-225