THE PHARMACOKENETICS OF LEVOFLOXACIN IN HEALTHY RABBIT TREATED WITH ANTACID

THE PHARMACOKENETICS OF LEVOFLOXACIN IN HEALTHY RABBIT TREATED WITH ANTACID Aniek Setiya Budiatin, Weni Kristanti, Suharjono Departement of Clinical Pharmacy. Airlangga University School of Pharmacy. Surabaya. ABSTRACT The effect of antacid (Antasida DOEN) 14 ml/ kg BW which containing polyvalent cation Mg (OH) 2 and Al(OH) 3 on the absorption of levofloxacin were examined in healthy rabbit. Twelve subjects were administered 23 mg/ml kg BW levofloxacin alone. On day 8 the six subjects were administered antacid and levofloxacin concomitant and the other were administered antacid two hours after levofloxacin. There were statistically significant different in pharmacokinetic parameter produced by administration with antacid concomitant but the other one were not significant different. There were C max and AUC decrease (p<0.05) but increase was not significant different (p>0.05) for administration concomitant and but the other one were C max, AUC and smaller than control but not significant different (p>0.05). The different had apparent effect on the plasma concentrations of levofloxacin and was determined with spectrofluorometric.antacid may reduce the absorption of levofloxacin, the extent of this interaction appears to increase as time between administration of two drugs decreases. Keyword: levofloxacin, Mg (OH) 2 and Al(OH) 3, antacid, spetrofluorometric Correspondence: Aniek Setiya Budiatin, Departement of Clinical Pharmacy, Airlangga University School of Pharmacy, Jl Dharmawangsa Dalam, Surabaya, phone. 62-31-5033710 INTRODUCTION Levofloxacin (fig. 1) is fluoroquinolone antibiotic and is the 1 ofloxacin isomer, more active 8 128 times against positive and negative microorganism than d- ofloxacin, and twice more potent than rasemat form (Fish and Chow, 1997). Levofloxacin were used for treatment disease : GIT, respiratory tract up and down; urinary tract, skin infection, which inhibit DNA synthesis as a potential antibacterial. Plasma concentrations in healthy volunteers reach a mean peak drug plasma concentrations (C max ) of approximately 2.8 and 5.2 mg/l within 1 to 2 hours after oral administration of levofloxacin 250 and 500 mg tablets, respectively. The oral absorption is very rapid and complete, the bioavailability of oral levofloxacin approaches 100% and it little affected by administration with food (Fish and Chow, 1997). Figure1. Levofloxacin Figure 2. Ciprofloxacin In separate study, the effect of antacid, sucralfat; food, H 2 receptor antagonist on fluoroquinolon interaction was examined (Radanst et al. 1992). The interactions with aluminum and magnesium containing antacid with fluoroquinolones (siprofloxacin, Figure 2), resulting in significantly decrease absorption when administered concurrently (Fish and Chow 1997). A measure such as does not adequately describe situations in which double peaking may occur or which prolonged absorption is observed. Antacid (Mg (OH) 2 and Al(OH) 3) is widely used for a variety of indications (duodenal ulcer disease, dyspepsia, saur stomach) (McEvoy 2002). The probably that levofloxacin will be given to patients receiving long term therapy with antacid/h 2 blocker is high. Since antacid affect oral absorption of variety of 264

Folia Medica Indonesiana Vol. 44 No. 4 October December 2008 : 264-268 agents, the effect of administration of antacid on the absorption of ciprofloxacin was studied (Radanst et al, 1992), Therefore studies were perform to determined the effect of antacid administration on the oral absorption of levofloxacin in healthy rabbits. MATERIAL AND METHODS Levofloxacin was a kind gift of PT Kimia Farma. Methanol (HPLC gradient) was purchased from JT Baker, Antacida DOEN was a kind gift of First Medipharma, Dipotassium hydrogenphosphate and Phosphoric acid 85% were purchased from Merck (Darmstadt, Germany), Double distilled Water was obtained from PT. Ikapharmindo Putramas (Indonesia). Heparin 500 unit/ml, Ammonium molybdat were purchased from Fluka AG, Citric acid was purchased from Riedel-de Häen, Xylol was obtained from Brataco Chemika, Acetonitril was purchased from Riedel-de Häen, Hitachi F-4000 Spectrofluorometer (Japan) was used for fluorometric measurements, Direct Reading Micro Balance LM -20 Libror, Ultrasonic Cleaner Sakura US-10E, Centrifuge Hettich, Protofix 32, Thermolyne Barnstead type 370, glassware and injection syringe. Stock solutions containing 1 μg/ ml of each levofloxacin was prepared in methanol. Working standard solutions containing 100-0 ng/ml was prepared by suitable dilution of the stock solutions with methanol. The experimental animals were Australian Rabbit from Batu Malang, weight 2.5 kg. antacide 14 mg/ kg BW of rabbit, 70 mg/ml oral solution form and levofloxacin 23 mg/ml kg BW of rabbits (Paget 1964). The twelve rabbits were fast overnight before drug administration and 2 hours after the dose was administered. Water was allowed ad libitum 10 ml. Blood sample (2ml) were collected with injection syringe 2.5 cc containing anticoagulant via ear of marginal venous. Samples were collecting in a vacuum test tube. Blood samples were obtained immediately before and 5, 10, 20, 30,45,, 75,,, 300 minutes after ingestion of the orally administered formulation.. Plasma was harvested and samples were stored at -20 0 C until assayed. Plasma concentration of levofloxacin was determined by spectrofluorometric. The assay was linier over the calibration range 100 to 0 ng/ml (El-Kommos et al, 2003) One milliliter aliquot volumes of standard or sample solutions were transferred into 10-ml calibrated flask. One milliliter of the ammonium molybdenum solution (7.5 μg /ml) was added and ph was adjusted to 3.5 using 1 ml of Teorell and Stenhagen buffer solution. The volume was completed with methanol. The relative fluorescence intensity of resulting solutions was measured against reagent blanks treated similarly at the excitation and emission maxima specified for levofloxacin. (El-Kommos et al. 2003) Five milliliter of plasma were deproteinized by the addition of 10 ml acetonitrile, centrifuged at 4000 rpm for 5 minutes. One milliliter of clear supernatant was spiked with 1 ml of drug stock solution. The mixture was then extracted with 2 portions; each of 5 ml chloroform. The chloroformic extract was collected, evaporated on a boiling water bath, then appropriate dilutions were made to obtain drug solutions containing 100, 300 and 500 ng/ ml, then general procedure was followed. The twelve rabbits were the same treatment as levofloxacin alone, and the day 8, six rabbits were administered antacid and levofloxacin concomitant and the other one were administered antacid 2 hours after levofloxacin (El-Kommos et. al., 2003). The pharmacokinetic analysis of plasma concentration of levofloxacin were determined using spectrofluorometric method. The assay had a dynamic range of 10 to ng/ml (El-Kommos et al. 2003).. The maximum plasma concentration of levofloxacin (C max ) and earliest time at which C max occurred ( ) were estimated directly from the experimental data. The intensity under the plasma concentration-time curve from time zero to the last time (t) plasma levofloxacin was measurable (AUC 0-300 ) was estimated by the linier trapezoidal approximation (Shargel 2005). Student s t tests with 95% confidence limits were used to examine pair-wise differences between the groups. Value of p<0.05 were considered to be statistically significant (Santosa et al 2005). RESULTS The mean plasma levofloxacin concentration-time curves for the administered antacid and levofloxacin concomitant groups were significant different, C max, AUC and (Figure 3, Table 1: with treatment 6 rabbits number 1 until 6) and the administered antacid two hours after levofloxacin were not significant different (Figure 4, Table 2, with treatment 6 rabbits number 7 until 12). 265

Table 1. Summary of pharmacokinetic parameter of the administered antacid and levofloksasin concomitant (treatment rabbits number 1 until 6) Rabbit number 1 2 3 4 5 6 Mean ± SD T max 75.00 16.43 Control (µg/ ml) minute (µg.minute/ml) 4.21 754.10 3.29 484.48 2.27 494.00 4.59 985.17 3.96 497.83 2.08 415.08 3.40 1.04 5.11 219.62 30 135.00 59.24 C max (µg/ ml) 1.19 1.24 1.34 2.10 0. 2.43 1.53 0.59 AUC0-300 minute (µg.minute/ml) 225.47 216.77 276.64 491.13 156.51 306.80 278.89 116.21 Control 1 1 Time Figure 3. Curve concentration (µg/ml) vs time, I = were administered levofloxacin and antacid concomitant Table 2. Summary of pharmacokinetic parameter of the administered antacid 2 hours after levofloxacin (treatment 6 rabbits number 7 until 12) Rabbit number 7 8 9 10 11 12 Mean ± SD 65..0 12..25 Control (µg/ ml) minutes (µg.minute/ ml) 1.79 336.59 4.05 630.54 3.21 6.19 2.31 447.16 2.46 424.99 0.67 143.71 2.09 0.94 431.53.14 70.00 24.49 (µg/ ml) menit (µg.minute/ ml) 1.75 356.38 2.26 488.18 3.43 518.38 2.79 8.46 1.85 352.72 1.20 263.21 2.21 0.80 431.22 128.25 266

Folia Medica Indonesiana Vol. 44 No. 4 October December 2008 : 264-268 Control 2 2 Time Figure 4. Curve concentration (µg/ml) vs time, 2 = were administered antacid 2 hours after levofloxacin DISCUSSION To determine the effect of timing on absorption of antacid and levofloxacin administered of single 23 mg / kg BW dose of levofloxacin to 12 healthy rabbits in two-way crossover study, levofloxacin was given alone or combined with ether an magnesium/aluminum containing antacid 14 ml /kg BW; the timing of antacid and levofloxacin administration was varied (concomitant and antacid 2 hours after levofloxacin). The literature describing reduced absorption of fluoroquinolones due to antacid administration to patients and volunteers is most extensive for ciprofloxacin (Figure 5) where in the gastro intestinal region the complex chelate form of antacid (metal = Mg and Al) and ciprofloxacin couldn t absorbed, the structure of levofloxacin (Figure 3) was similar with ciprofloxacin (Figure 4) (Brighty et al. 2000; Nix et al. 1989;) so the effect was same. Antacid was given with levofloxacin concomitant decreased the mean C max and the mean area under the concentration-vs-time curve (AUC 0-300) of levofloxacin 55.29 %, 53.91 % significant different (p<0.05) (Santosa et al, 2005) respectively and increased % but not significant different (p>0.05) (Table 1 and figure 3). Administration of the antacid 2 hours after levofloxacin decrease but not significant different in C max 5.74 % and AUC 0-300 0.07 % (p> 0.05) respectively and increased 0.77 % but not significant different (p> 0.05). The inhibition of absorption can be significant and potentially lead to the failure of the treatment, even when levofloxacin dose are separated from antacid dose by more than 2 hours (Radanst et al 1992). Oxo group Carboxil group Insoluble complex of levofloxacin-metal Figure 5. Levofloxacin and metal complex form the reaction similar with Ciprofloxacin (Nix et al., 1989; Brighty et al, 2000) 267

CONCLUSION There were statistically significant different in pharmacokinetic parameter produced by administration with antacid concomitant but the other one were not significant different. There were C max and AUC decrease(p<0.05) but increase was not significant different (p>0.05) for administration concomitant and but the other one were C max, AUC and smaller than control but not significant different (p>0.05). It s suggested that levofloxacin dose are separated from antacid dose by more than 2 hours. REFERENCES Brighty, Katherine, E. Gootz, Thomas D, 2000, Chemistry and mechanism of action of the quinolone antibacterials, in VT Andriole (ed), The Quinolones, Academic Press, London, pp. 43-44. El-Kommos, ME, Saleh, GA, El-Gizawi, SM, Abou- Elwafa, MA 2003, Spectrofluorometric determination of certain quinolone antibacterials using metal chelation, Talanta, vol.. pp. 1033-1050 Evans, G 2004, A Handbook of Bioanalysis and Drug Metabolism, USA: CRC Press, pp 26 Fish, DN, Chow, AT 1997, The clinical pharmacokinetics of levofloxacin, Pubmed, vol. 32, no. 2, pp. 101-119. McEvoy, GK 2002, AHFS Drug Information, American Society Of Health System Pharmacists, pp. 788-7. Nix, DE, Watson, WA, Lenes ME, Frost, RW, Krol, G, Goldstein, H, Lettieri, J, Schentag, JJ 1989, Effects of aluminium and magnesium antacids and ranitidine on the absorption of ciprofloxacin, Clin Pharmacol Ther, no. 46, pp. 700-705. Paget, GE. and Barnes, JE 1964, Toxicity test, in DR Laurence, AL Bacharach, Evaluation of Drugs Activities: Pharmacometrics, vol. I, Academic Press, London, pp. 161. Radanst, JM, Marchbanks CR, Dudley, MN, 1992, Interaction of fluoroquinolones with other drugs: mechanism, variability, clinical significance and management, Clinical Infectious Disease, vol. 14, no. 13, pp. 272-282. Santosa, PB and Ashari, 2005, Analisis Statistik dengan Microsoft Excel dan SPSS, 1st edn, Andi Offset, Yogyakarta, pp. -62. Shargel, L, Wu Pong, Susana, Yu, ABC 2005, Applied Biopharmaceutics and Pharmacokinetics, 5th edn, The McGraw-Hill Companies, Inc., Boston, pp. 453-477, 488. 268