Vijay Kumar Singh1, Bharat Bhusan Subudhi2. 1. a Columbia Institute of Pharmacy , Tekari , Raipur , Chhattisgarh , India and. 2. b School of Pharmaceutical Sciences, Siksha O Anusandhan University , Bhubaneswar , Odisha , India.
Abstract
BACKGROUND INFORMATION: Methotrexate (MTX), an anticancer drug of choice, has poor permeability across blood-brain barrier (BBB) making it unsuitable for brain tumor application. Its brain availability and scope of application was improved by preparation of reversible conjugate with lysine by capitalizing the endogenous transport system of lysine at BBB. METHODS: To enhance its delivery to brain, MTX was reversibly conjugated with l-Lysine by an amide linkage. It was characterized by advanced spectroscopy techniques including IR, NMR and MS. Furthermore, conjugate was assessed for stability, toxicity and drug release ability. In vivo distribution studies were done by radioscintigraphy study using 99mTc radioisotope. RESULTS: The structure of prodrug was confirmed by 1H-NMR, 13C-NMR and Mass. The m/e (mass to charge ratio) fragment was found at [M + H] 711.32 in Mass spectra. Stability and metabolic studies suggested that conjugate was stable at physiological pH (in Phosphate buffer pH 7.4 t1/2 is 70.25 ± 2.17 h and in plasma t1/2 is 193.57 ± 2.03 min) and circulated adequately to release MTX slowly in brain. In vivo biodistribution study showed that prodrug significantly increased the level of MTX in brain when compared with pharmacokinetic parameter of parent drug. CONCLUSION: The brain permeability of MTX was enhanced significantly by this conjugate.
BACKGROUND INFORMATION: Methotrexate (MTX), an anticancer drug of choice, has poor permeability across blood-brain barrier (BBB) making it unsuitable for brain tumor application. Its brain availability and scope of application was improved by preparation of reversible conjugate with lysine by capitalizing the endogenous transport system of lysine at BBB. METHODS: To enhance its delivery to brain, MTX was reversibly conjugated with l-Lysine by an amide linkage. It was characterized by advanced spectroscopy techniques including IR, NMR and MS. Furthermore, conjugate was assessed for stability, toxicity and drug release ability. In vivo distribution studies were done by radioscintigraphy study using 99mTc radioisotope. RESULTS: The structure of prodrug was confirmed by 1H-NMR, 13C-NMR and Mass. The m/e (mass to charge ratio) fragment was found at [M + H] 711.32 in Mass spectra. Stability and metabolic studies suggested that conjugate was stable at physiological pH (in Phosphate buffer pH 7.4 t1/2 is 70.25 ± 2.17 h and in plasma t1/2 is 193.57 ± 2.03 min) and circulated adequately to release MTX slowly in brain. In vivo biodistribution study showed that prodrug significantly increased the level of MTX in brain when compared with pharmacokinetic parameter of parent drug. CONCLUSION: The brain permeability of MTX was enhanced significantly by this conjugate.
Entities:
Keywords:
Amino acid transport system; brain delivery; conjugates; lysine; methotrexate