Abstract Famotidine is an effective new H2 receptor antagonist. Famotidine is a specific, long acting H2 receptor antagonist. It is indicated for the treatment of duodenal ulcer, gastric ulcer, GERD and Zollinger-Ellison Syndrome. Since its introduction for the treatment of acid related disorders in 1985, an estimated 18.8 million patients worldwide have been treated with famotidine. In this study 40 mg famotidine tablets were formulated and coated with two different coating materials i.e. HPMC and opadry white, to check the effect of these coating materials on the bioavailability of famotidine tablets. In vitro techniques like disintegration test and dissolution test were used to evaluate famotidine tablets. Disintegration test was performed on both the formulations. Mean disintegration time for formulation 1 was found to be 5 minutes and mean disintegration time for formulation 2 was 3 minutes. The results of dissolution after 120 minutes for formulation 1 showed release up to 100.01% and the formulation 2 was released up to 100.05%. For in vivo evaluation these two formulations were administered to eight normal human subjects with one week washout period. Blood samples were collected and plasma was obtained and analysized by HPLC. Pharmacokinetic parameters of formulation 1 were Cmax 0.97±0.47 μg/ml, tmax was 1.68±0.37 hours, AUC 3.97±1.61 μg.h/ml, AUMC 13.35±5.97 μg.h2/ml, MRT 2.27±0.55 hours, Ke 0.394±0.052, T1/2 1.97 ±0.38 hours, Vd 5.78±4.45 L/Kg, Vss 1.92±0.68 L/Kg, Cl 2.08±0.08 ml/h/Kg and for formulation 2 these values were 1.64±1.02 μg/ml, 1.5±0.46 hours, 10.07±0.21 μg.h/ml, 11.06±0.64 μg.h2/ml, 2.38±0.99 hours, 0.394±0.07, 1.97±0.69 hours, 6.309±2.72 L/Kg, 1.61±0.118 L/Kg, 1.76±0.037 ml/h/Kg respectively. Statistical analysis was performed and it was found that the formulation 2 which was coated with opadry white was more bioavailable than formulation 1 which was coated with HPMC. It was also concluded that coating materials affect the bioavailability of Famotidine tablets. Özet Famotidin yeni, etkili, spesifik ve uzun etkili bir H2 reseptör antagonistidir. Zollinger-Ellison Sendromu, GERD, gastrik ülser ve duedonal ülser tedavisinde kullanilmaktadir. 1985 yilinda asitlerle ilgili rahatsizliklarin tedavisi için tanitildigindan beri Dünya’da tahminen 18.8 milyon hasta famotidin ile tedavi edilmistir. Bu çalismada, kaplama materyallerinin famotidin tabletlerinin biyoyararliligi üzerine olan etkilerinin arastirilmasi amaciyla, 40 mg lik famotidin tabletleri HPMC ve opadry white gibi 2 farkli kaplama materyalleri ile kaplanmis ve formule edilmistir. Famotidin tabletlerinin degerlendirilmesinde dagilma ve dissolusyon gibi in-vitro teknikler kullanilmistir. Dagilma testi her iki formulasyona da uygulanmistir. Birinci formulasyon için dagilma süresi 5 dakika, ikinci formulasyon için ise 3 dakika bulunmustur. Birinci formulasyon için 120 dakika sonrasindaki dissolusyon degeri % 100.01, ikinci formulasyon için ise % 100.05 olarak bulunmustur. In-vivo degerlendirme için bu iki formulasyon 6normal insana bir haftalik temizlenme (washout) süreleri dikkate alinarak verilmistir. Bu kisilerin kan ve plazma örnekleri HPLC de analiz edilmistir. Birinci formulasyonun farmakokinetik parametreleri sirasiyla; Cmax: 0.97±0.47 μg/ml, tmax: 1.68±0.37 saat, AUC: 3.97±1.61 μg.h/ml, AUMC: 13.35±5.97 μg.h2/ml, MRT: 2.27±0.55 saat, Ke: 0.394±0.052, T1/2: 1.97±0.38 saat, Vd: 5.78±4.45 L/Kg, Vss: 1.92±0.68 L/Kg, Cl: 2.08±0.08 ml/h/Kg olarak tespit edilmistir. Ikinci formulasyon için ise ayni parametreler sirasiyla; Cmax: 1.64±1.02 μg/ml, tmax: 1.5±0.46 saat, AUC: 10.07±0.21 μg.h/ml, AUMC: 11.06±0.64 μg.h2/ml, MRT: 2.38±0.99 saat, Ke: 0.394±0.07, T1/2: 1.97±0.69 saat, Vd: 6.309±2.72 L/Kg, Vss: 1.61±0.118 L/Kg, Cl: 1.76±0.037 ml/h/Kg seklinde tespit edilmistir. Uygulanan istatistiksel analizlere göre opadry white ile kaplanmis olan ikinci formulasyonun, HPMC ile kaplanmis olan birinci formulasyona göre biyoyararliliginin daha iyi oldugu anlasilmistir. Ayrica, kaplama materyallerinin famotidin tabletlerinin biyoyararliligini etkiledigi sonucuna varilmistir.

Keywords: Famotidine, Bioavailability, Pharmacokinetics, HPMC, Opadry White