RESUMEN
The rapid onset of action of nifedipine causes a precipitous reduction in blood pressure leading to adverse effects associated with reflex sympathetic nervous system (SNS) activation, including tachycardia and worsening myocardial and cerebrovascular ischemia. As a result, short acting nifedipine preparations are not recommended. However, importantly, there are no modified release preparations of nifedipine authorised for paediatric use, and hence a paucity of clinical studies reporting pharmacokinetics data in paediatrics. Pharmacokinetic parameters may differ significantly between children and adults due to anatomical and physiological differences, often resulting in sub therapeutic and/or toxic plasma concentrations of medication. However, in the field of paediatric pharmacokinetics, the use of pharmacokinetic modelling, particularly physiological-based pharmacokinetics (PBPK), has revolutionised the ability to extrapolate drug pharmacokinetics across age groups, allowing for pragmatic determination of paediatric plasma concentrations to support drug licensing and clinical dosing. In order to pragmatically assess the translation of resultant dissolution profiles to the paediatric populations, virtual clinical trials simulations were conducted. In the context of formulation development, the use of PBPK modelling allowed the determination of optimised formulations that achieved plasma concentrations within the target therapeutic window throughout the dosing strategy. A 5 mg sustained release mini-tablet was successfully developed with the duration of release extending over 24 h and an informed optimised dosing strategy of 450 µg/kg twice daily. The resulting formulation provides flexible dosing opportunities, improves patient adherence by reducing frequent administration burden and enhances patient safety profiles by maintaining efficacious levels of consistent drug plasma levels over a sustained period of time.
RESUMEN
The total number of paediatric formulations available only account for a small proportion of the full therapeutic plethora required to effectively treat paediatrics and, therefore, the availability of high quality medicines designed specifically for children remains an ongoing challenge. Currently, the World Health Organisation (WHO) report that around 50% of medication issued for long-term conditions are not taken as advised, whilst it has also been established that, in general practice, around one tenth of medicines prescribed for children are either off-label or unlicensed. Such off-label and unlicensed use is owing to the considerable anatomical and physiological differences observed between paediatric subsets. Identifying such differences, is essential for better informing paediatric drug development and assisting regulatory reviews, whilst ensuring safe and effective therapeutic concentrations of pharmacological substances. Points covered: The review discusses factors affecting the safety, toxicity and efficacy of paediatric drug delivery systems. The research highlights features of the gastrointestinal tract and reports anatomical and physiological differences between paediatrics and adults. Additionally, differences observed in paediatric pharmacokinetic profiles (absorption, distribution, metabolism and elimination) due to physiological differences are also discussed. Furthermore, this review considers the advantages and limitations of current paediatric specific dosage forms available and assesses the acceptability of innovative small flexible solid oral dosage forms. Lastly, this review highlights factors affecting paediatric medicine adherence and acceptability and discusses the techniques available to overcome barriers associated with non-adherence.
Asunto(s)
Uso Fuera de lo Indicado , Pediatría , Adulto , Niño , Formas de Dosificación , Humanos , Preparaciones FarmacéuticasRESUMEN
Owing to considerable differences observed in anatomy and physiology between paediatric subsets, it has been well established that children respond to drugs differently compared to adults. Furthermore, from a formulation perspective, there is a distinct challenge to develop a dosage form that is capable of safely, accurately, and reliably delivering the dose across the whole paediatric population. Orally disintegrating mini-tablets (ODMT) have widely been considered as an age-appropriate formulation option that possess the ability for adequate dose flexibility, avoids swallowing difficulties, and exhibits superior stability due to its solid state. Within this study, two strengths (0.5 mg and 2 mg) of carvedilol ODMT formulations were developed using an excipient composition and load that is appropriate for paediatric use. The formulations demonstrated adequate mechanical strength (>20 N) and fast disintegration times (<30 s). Dissolution profiles observed were robust and comparable to the marketed conventional tablet formulation across various parts of the gastrointestinal (GI) tract in both the fed and fasted state, signifying appropriate efficacy, quality, and performance. As such, the formulations developed in this study show potential to address the need of an 'age-appropriate' formulation of carvedilol, as highlighted by the European Medicines Agency (EMA) Inventory of the Needs for Paediatric Medicine.
RESUMEN
The development of age appropriate paediatric formulations, particularly those suitable for young children, presents challenges with only limited knowledge available on the acceptability of different medicines and how this affects medication adherence. This publication describes studies conducted at Alder Hey Children's Hospital, Liverpool, UK with the aim of determining which factors relating to dose form and organoleptic properties of a medicinal product influence medication adherence in chronically ill children. The research was conducted in two phases comprising 70 chronically ill children aged between 3 and 11 years, 70 primary caregivers, and 33 hospital clinical and technical staff. Phase one, the CHIMP study (children's medication preferences), investigated children's preferences in terms of the organoleptic properties of medicines, and factors which influence these preferences and medication adherence. The data generated in the CHIMP study was used to construct a Medication Adherence Prediction Tool (MedAPT), in the form of a questionnaire, which was the subject of a second study (MedAPT), to qualify the prediction tool, in which adherence predictions derived from children and primary caregiver's questionnaire response data were statistically evaluated against adherence measurement generated from pharmacy medication refill data. The developed MedAPT questionnaire correctly predicted medication adherence/non-adherence in 79.4% of children. It is envisaged that, following further confirmation of the MedAPT as a prediction tool, this may be used in clinical practice as a predictor of adherence, and as a means of focussing resources and interventions to address non-adherence.