Document Detail


Study of the interaction between rifapentine and isoniazid under acid conditions.
MedLine Citation:
PMID:  16621412     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A well-known problem of anti-tuberculosis fixed-dose combination (FDC) products containing rifampicin (R) and isoniazid (H) is the fall in bioavailability, in particular of R, when two or more drugs are present together. The same has been ascribed to hydrolysis of R to 3-formylrifamycin (3-RIF) under stomach acid conditions and reaction of the latter with H to form isonicotinyl hydrazone (HYD). The objective of present study was to explore whether the same reaction occurred when H was present along with rifapentine (Rp), a newer long acting rifamycin, which is structurally similar to R. Clinical trials are currently undergoing for co-administration of Rp with H in patients who had completed 2 months of standard chemotherapy. For the purpose, first a validated HPLC method was developed for the separation of Rp and H, and the same was used for the study of interaction between the two drugs. Like R, Rp was also found to convert to 3-RIF in acid conditions, which reacted further with H to form HYD. The pH-rate profile was also similar in shape to that established with the combination of R and H; maximum decomposition occurred at pH 2, where Rp loss was to an extent of approximately 30%, while corresponding decomposition of H was approximately 9%. These values were similar to those reported for the combination of R (approximately 33%) and H (approximately 10%). Hence, the study suggests that co-administration of Rp and H should be avoided, like in case of R and H, and the two drugs should not be formulated directly into a single dosage form.
Authors:
Bhagwat Prasad; Hemant Bhutani; Saranjit Singh
Publication Detail:
Type:  Journal Article     Date:  2006-04-18
Journal Detail:
Title:  Journal of pharmaceutical and biomedical analysis     Volume:  41     ISSN:  0731-7085     ISO Abbreviation:  J Pharm Biomed Anal     Publication Date:  2006 Jun 
Date Detail:
Created Date:  2006-05-30     Completed Date:  2006-08-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8309336     Medline TA:  J Pharm Biomed Anal     Country:  England    
Other Details:
Languages:  eng     Pagination:  1438-41     Citation Subset:  IM    
Affiliation:
Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar 160062, Punjab, India.
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MeSH Terms
Descriptor/Qualifier:
Antitubercular Agents / chemistry*
Chromatography, High Pressure Liquid / methods
Drug Interactions
Hydrogen-Ion Concentration
Isoniazid / chemistry*
Rifampin / analogs & derivatives*,  chemistry
Chemical
Reg. No./Substance:
0/Antitubercular Agents; 13292-46-1/Rifampin; 54-85-3/Isoniazid; 61379-65-5/rifapentine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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