Profil farmakokinetika klomipramin tanpa dan dengan perlakuan vitamin C pada tikus dan manusia

SUWARSO, Edy, Promotor Prof.Dr. H. Lukman Hakim, MSc.,Apt

2004 | Disertasi | S3 Ilmu Farmasi

Telah dilaporkan sebelumnya bahwa pemberian vitamin C dosis tinggi (500 mg dan 1000 mg) pada terapi depresi endogen dengan klomipramin (75 mg/hari) menghasilkan perbaikan fisik dan mental penderita (Stoger et al., 1994). Berdasarkan laporan tersebut menarik untuk diteliti, apakah terdapat perubahan farmakokinetika klomipramin akibat praperlakuan vitamin C. Untuk mengungkap hal tersebut, digunakan dua pendekatan yaitu melalui penelitian praklinik dan klinik. Pada penelitian praklinik digunakan rancangan acak lengkap pola searah menggunakan tikus jantan Wistar (150 - 400 g). Sekelompok hewan tersebut dibagi 4 kelompok secara acak, masing- masing 6 ekor. Tikus pada kelompok kontrolO-D diberi klomipramin 15 mg/kg BB per oral, vitamin CO-D diberi vitamin C 50 mg/kg BB per oral selama 7 hari berturut-turut, kemudian diberi klomipramin seperti kontrolO-D. Tikus kontrolIV-D diberi klomipramin 15 mg/kg BB intravena, dan pada vitamin CIV-D diperlakukan sama dengan kontrolIV-D, tetapi sebelumnya diberi vitamin C seperti di atas. Darah (± 1 ml) diambil pada waktu-waktu tertentu dari vena lateralis ekor untuk analisis klomipramin utuh menggunakan Kromatografi Cair Kinerja Tinggi (KCKT). Untuk mempelajari pola ekskresi klomipramin, tikus diperlakuan sama seperti di atas, dan klomipramin utuh yang diekskresikan kedalam urin ditetapkan kadarnya dengan KCKT. Nilai- nilai parameter farmakokinetika diperoleh secara non kompartemental dan dianalisis dengan ANAVA (95 %). Pada studi klinik digunakan rancangan pola silang blok lengkap pada 12 sukarelawan sehat (usia 18 - 50 tahun) dari dua jenis kelamin. Pada kelompok kontrol, masing-masing diberi tablet Anafranil® (klomipramin 25 mg), dan setelah 2 minggu, subyek diberi vitamin C 500 mg (per oral) selama 7 hari berturut-turut sebelum diberi tablet Anafranil® (vitamin C 500S). Pada periode berikutnya (selang 2 minggu), subyek diberi vitamin C 1000 mg (per oral) selama 7 hari berturut-turut sebelum diberi tablet klomipramin 25 mg (vitamin C 1000S). Darah (± 7 ml) dan urin subyek dikumpulk an pada waktu-waktu tertentu untuk analisis klomipramin utuh menggunakan KCKT. Hasil penelitian praklinik menyatakan bahwa nilai Cmaks klomipramin (kontrolO-D) adalah 3371,83 ± 934,16 ng/ml dan pada kelompok vitamin C 2516,75 ± 679,38 ng/ml. Perlakuan vitamin C 50 mg/kg BB selama 7 hari berturut-turut menurunkan nilai Cmaks sampai 25 % (p > 0,05). Pemberian vitamin C menurunkan nilai AUC0 - ~ klomipramin dibandingkan nilai AUC0 - ~ kontrolO-D, yaitu dari 1396,79 ± 233,50 (μg/ml).menit, menjadi 547,45 ± 93,91 (μg/ml).menit (p < 0,05). Pemberian klomipramin intravena menurunkan nilai AUC0 - ~ klomipramin ketika sebelumnya diberi vitamin C selama 7 hari xxx berturut-turut yaitu 1176,55 ± 50,18 (μg/ml).menit (kontrolIV-D), dan 689,35 ± 32,13 (μg/ml).menit (vitamin CIV-D; p > 0,05). Penurunan nilai Cmaks dan AUC0 - ~ disebabkan oleh peningkatan nilai kliren (CL; p < 0,05). Nilai CL klomipramin per oral 1,18 ± 0,09 ml/menit (kontrolO-D), namun setelah perlakuan vitamin C meningkat menjadi 2,84 ± 0,25 ml/menit (140,61 %). Pada pemberian klomipramin intravena nilai CL 3,27 ± 0,04 ml/menit (kontrolIV-D), meningkat secara bermakna setelah perlakuan vitamin C sebesar 5,89 ± 0,54 ml/menit (79,27 %). Nilai rasio ekstraksi hepatik (EH) klomipramin setelah perlakuan vitamin C baik per oral maupun intravena meningkat (p < 0,05), yaitu 0,06 ± 7,03.10-3 (kontrolO-D) menjadi 0,16 ± 8,43.10-3 (vitamin CO-D) dan kelompok kontrolIV-D 0,16 ± 6,15.10-3, kelompok vitamin CIV-D 0,33 ± 0,033. Feno mena di atas (peningkatan nilai EH 2x dari nilai kontrol) menunjukkan bahwa kemungkinan besar telah terjadi induksi enzim metabolik oleh vitamin C. Pada studi klinik, nilai Cmaks klomipramin kelompok kontrolS sebesar 482,17 ± 43,47 ng/ml, pada kelompok vitamin C 500S dan 1000S nilai Cmaks menjadi 201,85 ± 21,01 ng/ml, dan 124,21 ± 11,53 ng/ml. Perlakuan dua dosis vitamin C selama 7 hari berturut-turut menurunkan nilai Cmaks klomipramin (p < 0,05). Nilai AUC0 - ~ klomipramin setelah perlakuan vitamin C 500 mg turun menjadi 2037,54 ± 149,92 (ng/ml).jam dan berbeda secara bermakna dengan kelompok kontrolS {4434,53 ± 435,78 (ng/ml).jam; p < 0,05}, untuk kelompok vitamin C 1000S nilai AUC0 - ~ klomipramin 1305,00 ± 89,42 (ng/ml).jam terhadap nilai kelompok kontrolS (p < 0,05). Nilai EH meningkat setelah perlakuan vitamin C, kelompok kontrolS: 0,08 ± 7,43.10-3, kelompok vitamin C 500 S dan 1000S yaitu 0,16 ± 0,01, dan 0,25 ± 0,02. Nampak bahwa kapasitas metabolisme hepatik (dicerminkan oleh EH) meningkat 2 - 3x lipat akibat perlakuan vitamin C 500 dan 1000 mg. Nilai CL klomipramin kelompok kontrol 6239,58 ± 585,68 ml/jam dan kelompok vitamin C 500 S dan 1000S, CL meningkat menjadi 13142,04 ± 1113,15 ml/jam, dan 20079,34 ± 1241,20 ml/jam. Jadi pembersihan klomipramin dari tubuh lebih cepat 2 - 3x lipat dengan kehadiran vitamin C 500 dan 1000 mg.

It has been previously reported that pretreatment with high doses of vitamin C (500 and 1000 mg) to patients with endogenous depression treated with clomipramine causes physical and mental improvement of the patients (Stoger et al., 1994). The report then created an idea to uncover the pharmacokinetic phenomenon behind the improvement of therapy with clomipramine. To do that, two approaches have been used, namely preclinical and clinical trials. A completely randomized design was employed in the preclinical study using male Wistar rats (150 to 400 g). The rats were divided randomly into four groups in which each contained 6 rats. The rats in the controlO-D group were each given a per oral dose of clomipramine (15 mg/kg BW), whereas those in vitamin CO-D group were treated with vitamin C (50 mg/kg BW; per oral) for 7 consecutive days before the administration of clomipramine as in control. The rats in controlIV-D were given clomipramine 15 mg/kg BW intravenously, whereas those in vitamin CIV-D were treated the same as those in controlIV-D but with previous treatment with vitamin C as done before. Blood (± 1 ml) samples were withdrawn at various interval from the tail vein for an High Performance Liquid Chromatographic (HPLC) analysis of unchanged clomipramine. In order to study the urinary excretion of clomipramine, the drug treatments were performed as above, but the clomipramine-containing urine was collected for HPLC analysis of unmetabolized clomipramine. ANAVA (95 %) was used to analyze the obtained non compartmental parameter values. A completely cross-over design was employed during the clinical trials in 12 healthy volunteers (aging 18 - 50 years) of both sexes. To each subject in control group was administered Anafranil® tablet (containing 25 mg clomipramine), and following a 2 weeks washed-out period, the same subjects were each given 500 mg buffered vitamin C tablet for 7 consecutive days (vitamin C 500S group) before they were each given Anafranil® tablet. The next period, after 2 weeks washed-out, the subjects received 1000 mg buffered vitamin C tablets for 7 days (vitamin C 1000S group) and Anafranil® tablets were orally administered as above. Blood (± 7 ml) and urine samples were then collected at various time intervals for analysis of unmetabolized clomipramine in serum and urine by an HPLC method. The preclinical studies have revealed that Cmax values of clomipramine (per oral) were 3371.83 ± 934.16 ng/ml (control) and 2516.75 ± 679.38 ng/ml (vitamin C treated rats). It is obvious that 7 days treatment with vitamin C has decreased the Cmax value up to 25 % in the rats (p > 0.05). This decrease was also found for the AUC0 - ~ of clomipramine where initial values was 1396.79 ± xxxii 233.50 (μg/ml).minute and following the vitamin C treatments, the AUC0 - ~ became 547.45 ± 93.91 (μg/ml).minute. Identical results were also obtained with intravenous clomipramine after the rats were treated with vitamin C; initial AUC0 - ~ value of 1176.55 ± 50,18 (μg/ml).minute has decreased to 689.35 ± 32.13 (μg/ml).minute when 7 days of vitamin C were given before clomipramine (p > 0.05). The CL of oral clomipramine was initially 1.18 ± 0.09 ml/minute (control) and increased to 2.84 ± 0.25 ml/minute (or 140.61 % rise) after treatments with vitamin C for 7 days. This increase in CL also occurred when clomipramine was given intravenously, i.e. from 3.27 ± 0.04 ml/minute (control) to 5.89 ± 0.54 ml/minute after vitamin C , or an increase of 79.27 %. A parameter of metabolism (i.e. EH) has changed significantly, from 0.06 ± 7.03 x 10-3 (oral clomipramine control) to 0.16 ± 8.43 x 10-3 (oral clomipramine with vitamin C), or from 0.16 ± 6.15 x 10-3 (intravenous clomipramine control) to 0.33 ± 0.033 (intravenous clomipramine with vitamin C). A two- fold increase in EH value of clomipramine may have affected the metabolic clearance of clomipramine as seen in the enhancement of total CL, and the decreases of Cmax and AUC0 - ~ of the antidepressant. As clomipramine is mostly metabolized in the liver, these findings give a strong indication that vitamin C has induced the metabolic enzymes of clomipramine. Studies with human subjects resulted the same phenomena as those in the rats. There was obviously a dose-dependent decrease in Cmax values of clomipramine, from 482.17 ± 43.47 ng/ml (control) to 201.85 ± 20.01 ng/ml (with 500 mg oral vitamin C), and to 124.21 ± 11.53 ng/ml (with 1000 mg oral vitamin C; p < 0.05). The same is true for the AUC0 - ~ values {(ng/ml).hour}, i.e. from 4434.53 ± 435.78 (control) to 2037.54 ± 149.92 (after 500 mg oral vitamin C), or 1305.00 ± 89.42 (after 1000 mg oral vitamin C; p < 0.05). The EH values of clomipramine in the subjects have enhanced from 0.08 ± 7.43 x 10-3 (control) to 0.16 ± 0.01 (after 500 mg oral vitamin C), and to 0.25 ± 0.02 (after 1000 mg oral vitamin C). The dose-dependent increases in the metabolic parameter (EH) have resulted in the increases of metabolic or total clearance (CL) of clomipramine, i.e. from 6239.58 ± 585.68 ml/hour (control) to 13142.04 ± 1113.15 ml/hour (after 500 mg oral vitamin C), and to 20079.34 ± 1241.20 ml/hour (after 1000 mg oral vitamin C). These data reveal that there is a 2 - 3 fold increase in both EH and CL values of clomipramine following a 7 days treatments with vitamin C.

Kata Kunci : Farmakokinetika Klomipramin,Vitamin C, clomipramine, vitamin C, metabolism capacity, rats, humans.