Utility of certain nucleophilic aromatic substitution reactions for the assay of pregabalin in capsules

<p>Abstract</p> <p>Background</p> <p>Pregabalin (PG) is an anticonvulsant, analgesic and anxiolytic drug. A survey of the literature reveals that all the reported spectrophotometric methods are either don't offer high sensitivity, need tedious extraction procedures, recommend the measurement of absorbance in the near UV region where interference most probably occurs and/or use non specific reagent that don't offer suitable linearity range.</p> <p>Results</p> <p>Two new sensitive and simple spectrophotometric methods were developed for determination of pregabalin (PG) in capsules. Method (I) is based on the reaction of PG with 1,2-naphthoquinone-4-sulphonate sodium (NQS), yielding an orange colored product that was measured at 473 nm. Method (II) is based on the reaction of the drug with 2,4-dinitrofluorobenzene (DNFB) producing a yellow product measured at 373 nm. The different experimental parameters affecting the development and stability of the reaction product in methods (I) and (II) were carefully studied and optimized. The absorbance-concentration plots were rectilinear over the concentration ranges of 2-25 and 0.5-8 μg mL^-1for methods (I) and (II) respectively. The lower detection limits (LOD) were 0.15 and 0.13 μg mL^-1and the lower quantitation limits (LOQ) were 0.46 and 0.4 μg mL^-1for methods (I) and (II) respectively.</p> <p>Conclusion</p> <p>The developed methods were successfully applied to the analysis of the drug in its commercial capsules. The mean percentage recoveries of PG in its capsule were 99.11 ± 0.98 and 100.11 ± 1.2 (n = 3). Statistical analysis of the results revealed good agreement with those given by the comparison method. Proposals of the reaction pathways were postulated.</p

The impact of parallel regulatory–health technology assessment scientific advice on clinical development. Assessing the uptake of regulatory and health technology assessment recommendations

AimsThe parallel regulatory-health technology assessment scientific advice (PSA) procedure allows manufacturers to receive simultaneous feedback from both EU regulators and health technology assessment (HTA) bodies on development plans for new medicines. The primary objective of the present study is to investigate whether PSA is integrated in the clinical development programmes for which advice was sought.MethodsContents of PSA provided by regulators and HTA bodies for each procedure between 2010 and 2015 were analysed. The development of all clinical studies for which PSA had been sought was tracked using three different databases. The rate of uptake of the advice provided by regulators and HTA bodies was assessed on two key variables: comparator/s and primary endpoint.ResultsIn terms of uptake of comparator recommendations at the time of PSA in the actual development, our analysis showed that manufacturers implemented comparators to address both the needs of regulators and of at least one HTA body in 12 of 21 studies. For primary endpoints, in all included studies manufacturers addressed both the needs of the regulators and at least one HTA body.ConclusionsOne of the key findings of this analysis is that manufacturers tend to implement changes to the development programme based on both regulatory and HTA advice with regards to the choice of primary endpoint and comparator. It also confirms the challenging choice of the study comparator, for which manufacturers seem to be more inclined to satisfy the regulatory advice. Continuous research efforts in this area are of paramount importance from a public health perspective