Search

In the European Union, bioequivalence (BE) for narrow therapeutic index (NTI) drugs is currently demonstrated when the 90% confidence interval for the ratio of the population geometric means of the test and reference products for AUC, and in some cases for Cmax, falls within the acceptance range of 90.00% to 111.11%. However, meeting this requirement results in an increased difficulty of demonstrating BE and a need for clinical trials with larger subject sample sizes, especially for medium-to-high variability drugs. To address this challenge, a scaled average BE based on the reference product within-subject variability for narrowing the acceptance range of NTI drugs was recently proposed. However, this approach showed increased type I error (T1E), especially close to the cut-off point between the unscaled and scaled portions of the method. Based on simulations, this limitation can be overcome by predefining the protocol the path to be followed: either the fixed 90.00–111.11% acceptance range approach or the previously proposed scaled average BE approach with a slight adjustment of the one-sided significance level α to 0.042 for a 2 × 3 × 3 partial replicate design and without a lower cut-off point. This results in a mixed approach allowing to reduce the sample size whilst not inflating the T1E. [ABSTRACT FROM AUTHOR]

The current regulatory criterion for bioequivalence of narrow therapeutic index (NTI) drugs in the European Union requires that the 90% confidence interval for the ratio of the population geometric means of the test product compared with the reference for area under the plasma concentration‐time curve (AUC), and in certain cases maximum plasma drug concentration (Cmax), to be included within the tighter acceptance range of 90.00–111.11%. As a consequence, sponsors need to recruit a higher number of subjects to demonstrate bioequivalence and this may be seen as increasing the burden for the development of generics. This "one‐size‐fits‐all" criterion is particularly questionable when the within‐subject variability of the reference product is moderate to high. As an alternative, we propose a further refined statistical approach where the acceptance range is narrowed based on the within‐subject variability of the reference product of the NTI drug, similar to the one used for widening the standard 80.00–125.00% acceptance range for highly variable drugs. The 80.00–125.00% acceptance range is narrowed, only if the within‐subject variability is lower than 30%, down to the current NTI acceptance range of 90.00–111.11% when the within‐subject variability is 13.93% or lower. Examples within the current European Medicines Agency list of NTI drugs show a considerable reduction in required sample size for drugs like tacrolimus and colchicine, where the predicted within‐subject variability is 20–30%. In these cases, this approach is less sample size demanding without any expected increase in the therapeutic risks, since patients treated with reference products with moderate to high within‐subject variability are frequently exposed to bioavailability differences larger than 10%. [ABSTRACT FROM AUTHOR]

The bioequivalence of a new ibuprofen 600‐mg film‐coated tablet obtained by roller compaction was studied in a crossover study with 22 healthy volunteers. Bioequivalence was analyzed based on (a) the S‐enantiomer, (b) the R‐enantiomer, and (c) the sum of both enantiomers (representing the results of an achiral assay). The bioequivalence conclusion for ibuprofen products should be based not only on AUC and Cmax but also on tmax since tmax is related to the onset of action. However, it is not possible to ensure if bioequivalence has been demonstrated for tmax as regulators have not defined the acceptance range for the difference between medians of tmax in those cases, where tmax is clinically relevant. In this study, it was possible to conclude bioequivalence for tmax based on S‐ibuprofen, though this conclusion might be questioned if the decision is based on R‐ibuprofen or the achiral method. [ABSTRACT FROM AUTHOR]

Background: In Spain the price of all ibuprofen 600 mg tablet generic products is the same due to reimbursement existing rules so for the patient there is not any economic incentive to choose a particular one. Bearing in mind that the quality of generic products should be similar, it could be questioned if differences in patient preferences evaluated as sales could be related to differences on their pharmaceutical properties. The aims of this work were to study the variability on the pharmaceutical characteristics of marketed bioequivalent tablet formulations and its impact on patient preferences. Methods: Thirty-six batches corresponding to fourteen different generic products were chosen among the best-selling products of the Spanish market in the years 2011 and 2015 and were compared to the reference product. The effect on patient preferences of six variables was studied through a multivariate analysis. The first two variables were marketing characteristics: 1) years in the market and 2) the number of other generic products marketed by the same manufacturer, which could be related to the size and service provided by the manufacturer. The other four variables studied were pharmaceutical tablet properties: 3) mean weight, 4) hardness, 5) disintegration, and 6) dissolution. A multiple linear regression analysis was performed to identify the effect on sales of the six variables studied. Results: The disintegration time was the most significant (P=0.018) factor affecting the sales of Ibuprofen tablets which may be related to the onset of action. Conclusion: The faster the tablet disintegration, the higher its sales. Two possible explanations are suggested: 1) the most specialized ibuprofen tablet manufacturer considers fast disintegration as a key parameter and/or 2) habitual consumers of ibuprofen can detect small differences on the onset of action among different marketed formulations. In this work, all marketed ibuprofen tablets comply with the pharmacopoeia specifications. [ABSTRACT FROM AUTHOR]

Context: Teicoplanin is a glycopeptide antibiotic consisting of a combination of different active components. Clinical equivalence between different batches of this drug is not guaranteed by the present pharmacopeial specification of chemical composition based on an HPLC chromatogram. Objective: To test a modification of this specification and to evaluate independent compositions recently published in the literature. Materials and methods: The expectable area under the plasma curve of each batch has been estimated based on its chemical composition as described in a former paper. Batch-comparisons are based on ratios between the area of the test batch and the area of a reference. Results and discussion: The modification of this specification recently proposed by the European Medicines Agency (EMA) has been tested confirming its goodness. A new acceptance range of AUC variation, rounding −10% to +15%, has been obtained. It is narrower than the current interval of the pharmacopeial specification. Concerning the generic batches that have been studied, the majority of differences with the reference is lower than ±10%. Variations in the compositions of the reference product have been observed to influence the results and a control criteria are proposed. Conclusion: The variability of the pharmacokinetic performance of teicoplanin can be better controlled with this new proposal of composition specification given by EMA. [ABSTRACT FROM AUTHOR]

Context: Teicoplanin is a fermentative antibiotic consisting of several active components that contribute similarly to the antibacterial activity, but exhibit different pharmacokinetic properties. Differences in systemic exposure between batches of teicoplanin are possible within pharmacopeial specifications as the proportion of subcomponents may vary from batch to batch. Objective: The aim of this paper is to study the possible modification of the present pharmacopeial specification for teicoplanin composition to ensure an a priori pharmacokinetic equivalence between all pharmacopoeial-compliant batches. Methods: The expectable whole Area Under the Curve (AUC) of plasma levels of teicoplanin was predicted for different experimental batches and also for the theoretical extreme batches within pharmacopeial specifications. Calculations were done based on the AUC of each teicoplanin active subcomponent. Subsequently, the equivalence between a generic teicoplanin and a reference drug product was investigated by means of the ratio of AUCs. Results: Batches under study, complying with current pharmacopoeial specifications, showed a maximum predicted difference in AUC slightly larger than 40%. The observed variability in teicoplanin compositions surpasses the conventional ±5% specification used for drugs obtained by chemical synthesis, but no 5% differences have been observed for any of the AUC means of the reference product when compared with the whole pooled data. Discussion and conclusion: Alternative specifications of actives composition can be defined to ensure that all batches complying with the pharmacopoeia are inside ±10% interval between them. [ABSTRACT FROM AUTHOR]