Natural–Synthetic Binary Superdisintegrant Systems in Orodispersible Tablets

Abstract

Fexofenadine hydrochloride is a second-generation, non-sedating H1-receptor antagonist prescribed for seasonal allergic rhinitis and chronic idiopathic urticaria. Despite BCS Class III status with high solubility and low permeability, conventional tablets have Tmax of 1–3 hours and require water for swallowing, which delays symptom relief and limits use in pediatric, geriatric, and dysphagic patients. Fast dissolving tablets (FDTs) that disintegrate within 30 seconds in the oral cavity without water enable rapid onset via pregastric absorption and improve compliance. This review analyzes formulation of fexofenadine HCl FDTs using a binary superdisintegrant system of natural mucilage from Plantago ovata, Lepidium sativum, Moringa oleifera, or Ocimum basilicum and synthetic crospovidone. Natural mucilage provides rapid water uptake and three-dimensional swelling with swelling index 15–25 mL/g, generating disruptive hydrostatic force, while crospovidone functions by wicking with high capillary activity and porosity, ensuring water penetration without gel formation. The synergistic combination at 4–10% w/w mucilage plus 2–8% w/w crospovidone achieves disintegration time 12–28 seconds, wetting time under 40 seconds, and more than 90% drug release in 5 minutes. Direct compression with mannitol as cooling diluent, microcrystalline cellulose PH 102 as binder, aspartame as sweetener, magnesium stearate as lubricant, and talc as glidant produces tablets with hardness 3–4 kg/cm² and friability below 0.8%. Bitter taste of fexofenadine is masked by a mannitol–aspartame–menthol combination. Challenges of mucilage hygroscopicity, microbial load, and batch variation are addressed through co-processing, moisture control below 10%, and gamma irradiation. QbD via 3² factorial design identifies mucilage: crospovidone ratio and compression force as critical parameters. This natural–synthetic binary system meets IP 2022 and USFDA FDT criteria and offers a cost-effective, biocompatible platform for rapid management of allergic symptoms.

Keywords: Fexofenadine HCl; Fast dissolving tablets; Natural mucilage; Crospovidone; Binary superdisintegrants; Plantago ovata; Taste masking; Allergy.