Do Thickening Agents Used in Dysphagia Diet Affect Drug Bioavailability?

Computer-aided optimization of carbidopa/levodopa orally disintegrating tablets

OBJECTIVE

This study aimed to optimize the formulation of carbidopa/levodopa orally disintegrating tablets (ODTs) in order to improve their disintegration performance, and facilitate easier medication intake for Parkinson's patients.

METHOD

The response surface methodology (RSM) was used to optimize the formulation, with the content of cross-linked polyvinylpyrrolidone (PVPP), microcrystalline cellulose (MCC), and mannitol (MNT) as independent variables, and disintegration time as the response parameter. Python was utilized to model Carr Indices and mixing time to determine the suitable mixing time. Direct compression (DC) was used for the preparation of ODTs.

RESULT

The optimization process resulted in the following values for the independent variables: 7.04% PVPP, 22.02% MCC, and 16.21% MNT. By optimizing the mixing time using Python, it was reduced to 14.19 min. The ODTs prepared using the optimized formulation and a mixing time of 14.19 min exhibited disintegration times of 16.74 s in vitro and 17.63 s in vivo. The content uniformity of levodopa and carbidopa was found to be 100.83% and 99.48%, respectively.

CONCLUSION

The ODTs optimized using RSM and Python demonstrated excellent disintegration performance, leading to a decrease in the time the drug exists in solid form in the oral cavity. This improvement in disintegration time reduced the difficulty of swallowing for patients and enhanced medication compliance, while still ensuring that ODTs prepared by DC had sufficient mechanical strength to meet storage and transportation requirements.

Modified medication use in dysphagia: the effect of thickener on drug bioavailability-a systematic review

INTRODUCTION

Dysphagia is associated with long-term conditions including strokes, dementia, Parkinson's disease and frailty. Dysphagia affects 30-40% of the population aged over 65 years-old. Adults with dysphagia often experience long-term conditions requiring multiple medications (often > 5) to manage these. The thickening of liquids is a common compensatory strategy in dysphagia management. Studies suggest that immersion in thickened liquids affects medicines' solubility in vitro. Clinicians and pharmacists are unaware of the pharmacokinetic/therapeutic effects of thickened liquids on oral medicines. We conducted a systematic review of existing literature on thickeners' effects on drug bioavailability.

METHODOLOGY

We performed a literature search of MEDLINE & EMBASE. Search terms included: dysphagia/thickened diet (EMBASE only)/ bioavailability or absorption of medicines or pharmacokinetics; excluded: NG feeds/animal studies.

STUDIES INCLUDED

all genders, countries, > 18 years, community and hospital settings. PRISMA guidance was followed.

RESULTS

Five hundred seventy results were found, and 23 articles identified following the reference list review. Following an abstract and full-text review, 18 were included. Most articles evaluated thickeners on dissolution profiles in-vitro, with a few investigating in-vivo. Most studies were single-centre prospective studies identifying that thickeners generally affect dissolution rates of medications. Few studies assessed bioavailability or used clinical outcomes.

CONCLUSION

Dysphagia and polypharmacy are common in older adults, but little is known about the effects of altering liquid viscosity on the therapeutic effect of most medications. Further larger-scale studies are required to evaluate the therapeutic impact of thickener, on a bigger range of medications, factoring in other variables such as type of thickener, viscosity of thickener and duration of immersion.

The Adverse Effects and Events of Thickened Liquid Use in Adults: A Systematic Review

PURPOSE

Practice pattern studies suggest that liquid modification is currently a primary strategy used by speech-language pathologists to manage dysphagia; however, the breadth of negative consequences associated with their use is not well understood. The purpose of this review was to summarize the evidence on adverse events and effects of thickened liquid (TL) use in adults.

METHOD

Six databases were searched in February 2022: EMBASE, MEDLINE (PubMed), Speechbite, AMED, AgeLine, and CINAHL. Articles were included if they compared adults receiving different TL viscosities and discussed at least one adverse event or effect of consuming TLs. Articles were excluded if they were review articles, rehabilitation studies, rheological analyses, not in English, or not peer reviewed. Screening and data extraction were completed by two independent reviewers. Risk of bias was assessed using Cochrane tools.

RESULTS

Thirty-three studies (N = 4,990 participants across all studies) were eligible for inclusion (2,405 unique records screened). Reported adverse events included dehydration (n = 5), pneumonia (n = 4), death (n = 2), urinary tract infection (n = 1), and hospitalization (n = 1); adverse effects included reduced quality of life (n = 18), aspiration (n = 12), reduced intake (n = 8), increased residue (n = 4), and reduced medication bioavailability (n = 2). Results were mapped on to codes and domains of the International Classification of Functioning, Disability and Health.

CONCLUSIONS

A range of adverse outcomes associated with TL use were identified. Adverse outcomes should be monitored and reported in dysphagia research. Given current research evidence, it is vital for clinicians to weigh the risks and benefits of TL use to mitigate potential adverse outcomes.