Tablet Splitting of Antiepileptic Drugs in Pediatric Epilepsy: Potential Effect on Plasma Drug Concentrations

Concerns regarding tablet splitting: a systematic review

BACKGROUND

Tablet splitting can provide dose flexibility and cost savings; however, pharmaceutical representatives typically discourage the practice.

AIM

To identify and summarise all published concerns related to tablet splitting and to present the experimental evidence that investigates those concerns.

DESIGN & SETTING

Systematic review and qualitative synthesis of tablet-splitting concerns and evidence.

METHOD

Medline and EMBASE databases were searched over all years of publication for articles in English discussing the splitting of tablets. Eligible articles included original research, narrative reviews, systematic reviews, and expert opinion.

RESULTS

After removing duplicates, 1837 potentially relevant articles underwent dual review, whereupon 1612 articles were excluded based on title and abstract. After examination of 225 full texts, 138 articles were included (one systematic review, four narrative reviews, 101 original research articles, and 32 opinion articles). The described concerns included difficulty breaking tablets, loss of mass, weight variability, chemical instability, overly rapid dosing if sustained-release medications are split, non-compliance, and patient confusion resulting in medication errors. No substantive evidence was found to support concerns regarding loss of mass, weight variability, chemical instability, or non-compliance. Evidence does support some older adults struggling to split tablets without tablet splitters, and the inappropriateness of splitting sustained-release preparations, given the potential for alteration of the rate of drug release for some products.

CONCLUSION

With the exception of sustained-release tablets, which should not be split, and excepting those older people who may struggle to split tablets based on physical limitations, there is little evidence to support tablet-splitting concerns.

Formulation Optimization of Extemporaneous Oral Liquids Containing Naloxone and Propranolol for Pediatric Use

There is a need to develop dosage forms suitable for children to improve drug treatment. Extemporaneous compounding of drugs for children is one way to meet these needs. However, excipients generally considered as safe in adults may not be appropriate in dosage forms intended for children. The aim was to optimize the composition of two pediatric liquid preparations by substituting paraben as a microbiological preservative and ethanol as a solubilizer, with excipients more suitable for pediatric use. The oral liquids were Naloxone 1 mg/mL and Propranolol 10 mg/mL. Twelve different formulations were tested with propranolol and naloxone, respectively, during the screening process to select appropriate formulations. Sodium benzoate and glycerol were used as a preservative and solubilizer, respectively, and different pH of the formulations were evaluated. The formulations were characterized according to dispensed dose (dosing accuracy), viscosity and osmolality. The optimized formulations from the screening process were tested with two amounts of sodium benzoate and microbiological assays were performed. These formulations were shown to have satisfactory preservative properties and dosing accuracy. The results showed that the oral liquids could be prepared without the addition of solubilizer and with lower osmolality (naloxone), thus reducing the risk of gastrointestinal side effects.

Enabling modular dosage form concepts for individualized multidrug therapy: Expanding the design window for poorly water-soluble drugs

Multidrug dosage forms (aka combination dosage forms, polypills, etc.) create value for patients through reduced pill burdens and simplified administration to improve adherence to therapy. Enhanced flexibility of multidrug dosage forms would provide further opportunities to better match emerging needs for individualized therapy. Through modular dosage form concepts, one approach to satisfy these needs is to adapt multidrug dosage forms to a wider variety of drugs, each with a variety of doses and release profiles. This study investigates and technically explores design requirements for extending the capability of modular multidrug dosage form concepts towards individualization. This builds on our recent demonstration of independent tailoring of dose and drug release, which is here extended towards poorly water-soluble drugs. The challenging design requirement of carrying higher drug loads in smaller volumes to accommodate multiple drugs at their clinical dose is here met regarding dose and release performance. With a modular concept, we demonstrate high precision (<5% RSD) in dose and release performance of individual modules containing felodipine or naproxen in Kollidon VA64 at both a wide drug loading range (5% w/w and 50% w/w drug) and a small module size (3.6 mg). In a forward-looking design-based discussion, further requirements are addressed, emphasizing that reproducible individual module performance is predictive of dosage form performance, provided the modules are designed to act independently. Therefore, efforts to incorporate progressively higher drug loads within progressively smaller module volumes will be crucial to extend the design window further towards full flexibility of future dosage forms for individualized multidrug therapy.

Independent Tailoring of Dose and Drug Release via a Modularized Product Design Concept for Mass Customization

Independent individualization of multiple product attributes, such as dose and drug release, is a crucial overarching requirement of pharmaceutical products for individualized therapy as is the unified integration of individualized product design with the processes and production that drive patient access to such therapy. Individualization intrinsically demands a marked increase in the number of product variants to suit smaller, more stratified patient populations. One established design strategy to provide enhanced product variety is product modularization. Despite existing customized and/or modular product design concepts, multifunctional individualization in an integrated manner is still strikingly absent in pharma. Consequently, this study aims to demonstrate multifunctional individualization through a modular product design capable of providing an increased variety of release profiles independent of dose and dosage form size. To further exhibit that increased product variety is attainable even with a low degree of product modularity, the modular design was based upon a fixed target dosage form size of approximately 200 mm³ comprising two modules, approximately 100 mm³ each. Each module contained a melt-extruded and molded formulation of 40% w/w metoprolol succinate in a PEG1500 and Kollidon^® VA64 erodible hydrophilic matrix surrounded by polylactic acid and/or polyvinyl acetate as additional release rate-controlling polymers. Drug release testing confirmed the generation of predictable, combined drug release kinetics for dosage forms, independent of dose, based on a product’s constituent modules and enhanced product variety through a minimum of six dosage form release profiles from only three module variants. Based on these initial results, the potential of the reconfigurable modular product design concept is discussed for unified integration into a pharmaceutical mass customization/mass personalization context.

Subdivision of modified-release tablets: state-of-the-art and future perspectives

Tablet splitting is a practice disseminated among health professionals for dose adjustments, swallowing facilitation or even treatment cost reduction. Nevertheless, tablets not designed for this purpose cause imprecise dosage and stability loss with important therapeutic repercussions. Novel technologies of modified drug release tablets have come to market including new materials and innovative production processes, for example, polymeric matrix, orodispersible, 3D printing, MUPs, etc. The heterogeneity and complexity of these tablets go well beyond a traditional gastroresistant coating tablet, making orientations on the practice of tablet subdivision difficult. This editorial aims to provide a critical and up-to-date evaluation of this scenario based on the most recent studies involving the subdivision of modified-release tablets.

The Effects of Fillers and Binders on the Accuracy of Tablet Subdivision

The effects of excipients on the accuracy of tablet subdivision are severely underinvestigated. In this study, placebo tablets were prepared using a combined mixture design of fillers and binders to evaluate the effect of these excipients on subdivision accuracy. The responses assessed were mass loss, mass variation, tablet fragmentation, and increased friability. Dicalcium phosphate dihydrate (DCP) gave rise to more uniform and denser tablets than microcrystalline cellulose (MCC), thus resulting in greater subdivision accuracy. The binder type, hydroxypropylcellulose (HPC) or polyvinylpyrrolidone (PVP), did not affect the subdivision of DCP tablets. On the contrary, the structural similarity between HPC and MCC led to improved subdivision accuracy for MCC tablets. A less accurate subdivision was observed in tablets prepared with a DCP-MCC combination; this finding could be attributed to irregular binder distribution in this matrix. An optimized response was built using desirability analysis. This study helps to illuminate the relationship between fillers and binders to guide formulation scientists in the development of tablets with better subdivision performance.

Comparison of Treatment Response Achieved by Tablet Splitting Versus Whole Tablet Administration of Levothyroxine in Patients with Thyroid Cancer

Objectives

TSH suppression by Levothyroxine consumption is a mainstay of thyroid cancer treatment. Tablet-splitting is a worldwide approach in dose adjustment in patients. However, it is highly recommended to evaluate the validity of tablet splitting for each distinctive drug by clinical trials before routinely using tablet halves in clinical practice. In this study we compared the effect of 150 µg dose of Levothyroxine by use of a100 and a 50 µg tablets or one and half 100 µg tablets in Differentiated thyroid cancer (DTC) patients.

Methods

One hundred DTC patients treated with one and half 100 µg Levothyroxine tablets were randomly divided into two groups. The first group continued taking medication as before and the second group received the same daily dose by taking one 100 and one 50 microgram Levothyroxine tablets. The mean changes in TSH and T3 levels and patients weight were compared between the groups.

Results

91 patients completed the study. Levothyroxine consumption pattern, age, gender distribution, weight and TSH levels were comparable between groups at the beginning of the study. The mean change of body weights, serum levels of T3 and TSH showed no significant difference between groups in different time points during the study (P>0.05).

Conclusion

This study showed similar efficacy of tablet splitting and two tablets administration for Levothyroxine; however, patients preferred two tablets at the end of the study. It can be concluded that tablet splitting can be used as an alternative way when the 50 µg tablet is not available.

Comparative Effect of Divided Doses of Adult Solid and Liquid Oral Formulations of Antiepileptic Drugs in the Management of Pediatric Epilepsy

Objective:

To compare the differences in the efficacy and safety of the commonly prescribed AEDs in the management of epilepsy in children when using divided doses of adult solid oral formulations (DDSF) with the liquid oral formulations (LFs).

Materials and Methods:

Patients who had one or more seizures per month and prescribed with DDSF were recruited. Initially the patients were continued on DDSF for 4 months following which they were switched over to LF for the subsequent 4 months. Seizure frequencies and adverse drug effects (ADRs) were recorded every month for 8 months and plasma AED levels were estimated at the end of 4^th and 8^th months.

Results:

A total of 200 patients completed the study protocol. The median seizure frequencies per month with DDSF and LF were: partial seizures (20.5, 9.0; P < 0.001), generalized tonic-clonic seizures (6.5, 2.0; P < 0.001), myoclonic seizures (58.5, 29.0; P < 0.001). Mean plasma drug levels ± SD (μg/ml) with DDSF and LF were: sodium valproate (48.2 ± 13.7, 69.1 ± 16.3; P < 0.001), phenytoin sodium (5.0 ± 2.4, 12.8 ± 3.8; P < 0.001), carbamazepine (4.5 ± 2.0, 11.5 ± 4.8; P < 0.001) and phenobarbitone (14.1 ± 5.2, 25.4 ± 12.3, P < 0.001). The incidence of treatment emergent ADRs was poor scholastic performance (25.5%), behavioral problems and dizziness/sedation (21.0%), somnolence/sleep disorders (19.5%).

Conclusion:

Patients treated with LF had better seizure control and optimal therapeutic drug levels and less adverse effects when compared to DDSF.