EBOJIELU GRACE

Background: Pharmaceutical manufacturing often relies on imported and synthetic binders, which can be costly and have variable availability. This study was aimed at evaluating starch from a locally sourced tuber, water yam (Dioscorea alata), as a cost-effective alternative. The study specifically compared the performance of native (unmodified) starch to pregelatinized water yam starch and corn starch. Methods: Starch was extracted from fresh Dioscorea alata tubers. A portion of this starch was then pregelatinized by forming a starch slurry of 50g of the extracted starch in 100ml of water and then heating it at 80ºc until a gel was formed. The gel was dried at 55ºF, converted back to powdered form and subjected to physicochemical characterization. Three distinct batches of 500mg paracetamol tablets were formulated using 0.5g/mL of corn starch, (2) native water yam starch, and (3) pregelatinized water yam starch as the binders. All tablet batches were evaluated for standard quality control parameters, including friability, disintegration time, and in-vitro dissolution. Results: All formulations using water yam starch (both native and pregelatinized) produced tablets with excellent mechanical strength, as indicated by friability values well below the 1.0% pharmacopeial limit. The disintegration test, however, revealed critical differences. The corn starch tablets failed, with a disintegration time of over 2 hours. The native water yam starch tablets also failed, at 43 minutes. In striking contrast, the tablets made with pregelatinized water yam starch passed with an excellent disintegration time of 60 seconds. The dissolution results directly reflected this: the corn starch and native starch batches failed to release the drug, while the pregelatinized batch met the standard. Conclusion: This study confirms that pregelatinization is an essential modification to unlock the potential of water yam starch. While native water yam starch acts as too strong a binder, pregelatinization transforms it into a highly effective, multifunctional excipient that provides both good binding and rapid disintegration. Pregelatinized Dioscorea alata starch is, therefore, a viable, locally sourced, and superior alternative to conventional binders like corn starch for immediate-release tablet formulations.