Advancing oral drug delivery: The science of fast dissolving tablets (FDTs)
The field of oral drug delivery has witnessed significant advancements, with a focus on developing innovative formulations to address challenges associated with traditional dosage forms, especially for patients with difficulties in swallowing. Fast Dissolving Tablets (FDTs) have emerged as a promising class of tablets designed to rapidly disintegrate or dissolve in saliva, providing a convenient and patient-friendly alternative for various populations.
This article explores the unique properties, advantages, and potential applications of FDTs, emphasizing their role in overcoming challenges posed by conventional oral drug delivery systems. FDTs offer rapid dissolution within 15-120 seconds in the buccal cavity, facilitating direct absorption through the buccal mucosa and ensuring quick therapeutic effects. This characteristic proves particularly beneficial for individuals facing swallowing challenges, such as pediatric and geriatric patients, or those with conditions like dysphagia.
Recognizing the significance of FDTs, the European Pharmacopoeia (EP) has officially recognized them as “oral dissolving tablets,” highlighting their acceptance in both academic and industrial settings. The article delves into the anatomical and physiological characteristics of the oral cavity, shedding light on the buccal epithelium, oral mucosa vascularization, and salivary flow, which play crucial roles in drug absorption.
The ideal features of FDTs include rapid dissolution or disintegration, high drug load capacity, masking of bitter taste, positive mouth feel, ease of transport, and reduced sensitivity to environmental factors. The advantages of FDTs extend to their administration for patients unable to swallow, convenient treatment for bedridden and mobile patients, enhanced mouth feel and taste masking, ease of administration, and precise dosing.
Table 1: Commonly used Superdisintegrants in FDTs [61]
| Superdisintegrant | Mechanism | Particle size | Nature |
|---|---|---|---|
| Crospovidone | Both wicking and swelling | Particle size100μm | Crosslinked homopolymer of Nvinyl- 2-pyrrolidone |
| SSG | Uptake of water followed by fast and massive swelling | Insoluble in water. Particle size 140 mesh | Cross–linked low substituted Carboxymethyl–ether of polyglucopyranose |
| CCS | Swelling | Insoluble in water. Particle size- 200 mesh | Cross–linked form of CMC |
| Derivatives of acrylic acid | Wicking action | Dispersed in cold water, insoluble in organic solvents | Poly(acrylic acid) highly porous hydrogel |
| Sodium alginate | Swelling | Slowly solubilized in water, hygroscopic characteristics | Sodium salt of the alginic acid |
| NS-300 | Wicking type | Particle size –106 μm | Carboxy methyl cellulose (CMC) |
| Effervescent mixture | Effervescence | Crystalline nature | Sodium bicarbonate, citric acid, sodium salt of alginic acid, tartaric acid |
| L-HPC | Both wicking and swelling | Particle size– 106μm | Low hydroxylpropyl cellulose |
| ECG-505 | Swelling type | Particle size– 106μm | Calcium salt of CMC |
Despite their advantages, FDTs come with limitations, including issues related to mechanical strength, hygroscopic nature, brittleness, and challenges with bitter drugs or unpleasant odors. Overcoming these challenges requires a careful formulation approach to balance rapid disintegration with mechanical strength and taste masking.
The article also discusses the salient characteristics of Fast Dissolving Dosage Forms (FDDDS) and various techniques for preparing FDTs, such as freeze-drying, tablet molding, and spray drying. Additionally, it explores the role of non-invasive drug delivery systems in addressing pharmaceutical industry needs, including improving drug half-life, solubility/stability, and bioavailability.
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Shubhrat Maheshwari, Aditya Singh, Aditya Varshney, Anurag Sharma, Advancing oral drug delivery: The science of fast dissolving tablets (FDTs), Intelligent Pharmacy, 2024, ISSN 2949-866X, https://doi.org/10.1016/j.ipha.2024.01.011.
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