الفهرس 
SofosbuvirOnly 14 pages are availabe for public view
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Abstract
Hepatitis C virus infection is a global life-threatening problem, affecting around 170 million people worldwide. Sofosbuvir is a direct acting antiviral (DAA) approved for chronic hepatitis C treatment. In-vitro studies defined sofosbuvir as a substrate for P-gp, thus its absorption may be influenced by concurrent administration of P-gp inducers and P-gp inhibitors. If a drug is a substrate for P-gp, the possibility for herbal medicine interaction which contain constituents that may cause powerful P-gp induction or inhibition is expected to be high. These Herb-drug interactions can potentiate the risk of toxicity or decrease the efficacy of treatment. Garlic and ginkgo biloba extracts are widely used herbal medicines that exhibit hepatoprotective activities. The garlic sulfur containing constituents mainly induce P-gp activity. A number of studies have shown that ginkgo biloba as a probable P-gp inhibitor through an interaction with both P-gp substrate binding site and ATP binding site. The present study aimed to investigate the possible interactions between either aged garlic extract or ginkgo biloba extract with the directly acting antiviral drug sofosbuvir through targeting P-gp and to investigate the possible renal and hepatotoxicities in rats by measuring liver and kidney markers as well as histopathological examinations for liver and kidney sections.
The present study was divided into two parts:
1. Evaluation of sofosbuvir and GS-331007 pharmacokinetics following single oral administration of sofosbuvir with verapamil, aged garlic extract and ginkgo biloba extract (repeated administration) by LC-MS/MS.
Rats were randomly divided into four groups (six animals per group) and treated for 14 days as follows: saline by gastric tube, verapamil (15mg/kg, PO), aged garlic extract (120mg/kg, PO) and ginkgo biloba extract (25mg/kg, PO) followed by single dose of sofosbuvir (40mg/kg, PO). At the end of the experiment, diet was prohibted for 12 h and water was freely accessed. Rats were given a single dose of sofosbuvir then blood samples were collected from the sinus plexus into heparinized 1.5 ml polythene tubes at Zero, 0.5, 1, 2, 4, 8, 12 and 24 hours. Samples were centrifuged at 4000 x g. The blood samples (500µL) were collected for each time interval for all rats and after separation, plasma samples were stored at -80ºC until analysis. Animals were sacrificed and intestinal tissues were excised and stored at -80ºC for assessment of P-gp expression using quantittive real-time polymerase chain reaction (PCR) and for assessment of P-gp levels using enzyme-linked immunosorbent assay (ELISA). The pharmacokinetic parameters for sofosbuvir and GS-331007 were estimated using the validated Kinetica® 5.1 SP1 software.
The assessed parameters:
1. Determination of sofosbuvir and GS-31007 at different time intervals in rats plasma
2. Validation parameters for determination of sofosbuvir and GS-331007 by LC- MS/MS
3. Pharmacokinetic parameters
4. P-glycoprotein (P-gp) expression/levels
2. Evaluation of toxicity for aged garlic and ginkgo biloba extracts with sofosbuvir in rats.
Rats were randomly divided into five groups (six animals per group) and treated for 14 days as follows: saline by gastric tube (control), saline followed by single dose of sofosbuvir (40mg/kg, PO), verapamil (15mg/kg, PO) followed by single dose of sofosbuvir (40mg/kg, PO), aged garlic extract (120mg/kg, PO) followed by single dose of sofosbuvir (40mg/kg, PO) and ginkgo biloba extract (25mg/kg, PO) followed by single dose of sofosbuvir (40mg/kg, PO). Blood samples were collected from sinus plexus to test liver and kidney functions. All rats in each group were anesthized and sacrificed 24h after a single sofosbuvir dose. Liver and kidney tissues were dissected out for histopathological examination.
The assessed parameters:
1. Hepatotoxicity markers
1.1. Alanine aminotransferase (ALT) using colorimetric method
1.2. Aspartate aminotransferase (AST) using colorimetric method
2. Nephrotoxicity markers
2.1. Blood urea nitrogen (BUN) using colorimetric method
2.2. Serum creatinine using colorimetric method
3. Histopatholoical Examination
3.1. Hematoxylin and Eosin for tissue staining then examination using full HD microscopic imaging system ICC50 camera.
The findings of the present study can be summarized as follows:
1. Evaluation of sofosbuvir and GS-331007 pharmacokinetics following single oral administration of sofosbuvir with verapamil, aged garlic extract and ginkgo biloba extract (repeated administration) by LC-MS/MS.
• Pretreatment of rats with verapamil (15mg/kg) for 14 days resulted in significant increase of sofosbuvir Cmax.
• Pretreatment with ginkgo biloba extract and verapamil significantly increased sofosbuvir half life (t1/2).
• The clearance of sofosbuvir was significantly increased following pretreatment with 120mg/kg of aged garlic extract and was significantly decreased following pretreatment with 15mg/kg of verapamil.
• Pretreatment with aged garlic extract caused sinificant decrease of sofosbuvir AUC(0-t) while pretreatment with ginkgo biloba extract and verapamil caused significant increase of sofosbuvir AUC(0-t).
• The pharmacokinetic parameters of GS-331007 indicated that pretreatment of rats with verapamil (15mg/kg), aged garlic extract (120mg/kg) and ginkgo biloba extract (25mg/kg) for 14 days resulted in no significant change of AUC(0-t), Cmax, t1/2 and clearance of GS-331007.
• P-gp expression/levels were significantly increased following pretreatment with aged garlic extract (120mg/kg) and were significantly decreased following pretreatment with verapamil (15mg/kg). There was non-significant inhibition of P-gp expression following pretreatment with ginkgo biloba extract (25mg/kg).
2. Evaluation of toxicity for aged garlic and ginkgo biloba extracts with sofosbuvir in rats.
• There was no significant change in liver enzymes or kidney markers between all groups followed by the concomitant administration of aged garlic extract and ginkgo biloba extract with sofosbuvir.
• Besides, aged garlic extract and ginkgo biloba extract showed normal morphological features of hepatic parenchyma with fewer degenrated hepatocytes and normal morphological features of renal parenchyma with sporadic records of degenrative tubular changes in few tubular epithelial cells.