"Formulation Optimization and In Vitro Evaluation of Sustained Release Desvenlafaxine Succinate Tablets with Natural Polymers"

Background: Desvenlafaxine succinate is a serotonin–norepinephrine reuptake inhibitorwidely prescribed for the management of major depressive disorder. Due to its relativelyshort biological half-life, sustained-release formulations are desirable to maintain therapeuticdrug levels, reduce dosing frequency, and improve patient compliance.Objective: The present study aimed to develop and evaluate sustained-release matrix tabletsof desvenlafaxine succinate using natural polymers and to investigate the influence ofpolymer type and concentration on drug release behavior.Methods: Sustained-release matrix tablets were prepared by direct compression usingxanthan gum, guar gum, and acacia gum at different drug-to-polymer ratios (1:2, 1:3, and1:4). The prepared formulations were evaluated for pre-compression and post-compressionparameters, including flow properties, hardness, friability, weight variation, thickness, anddrug content. In vitro dissolution studies were performed using USP Type II dissolutionapparatus in distilled water and phosphate buffer (pH 6.8). Swelling behavior and releasecharacteristics were also investigated.Results: All formulations exhibited acceptable physicochemical properties with drug contentranging from 96.24% to 99.13%, hardness between 4.8 and 6.4 kg/cm2, and friability valuesbelow 1%, indicating satisfactory tablet quality. Dissolution studies demonstrated thatpolymer type and concentration significantly influenced drug release. Formulationscontaining xanthan gum and guar gum exhibited superior release-retarding propertiescompared with acacia gum. Among the investigated formulations, DFX3 (drug: xanthan gum,1:4) showed a controlled release profile with 91.90% drug release after 12 h, while DFG2demonstrated comparable sustained-release behavior. Swelling studies revealed thatincreasing polymer concentration enhanced water uptake and gel layer formation, resulting inprolonged drug release.Conclusion: The study successfully demonstrated the feasibility of developing sustained-release desvenlafaxine succinate matrix tablets using natural polymers. Xanthan gumexhibited the most effective release-retarding capability among the polymers investigated.The optimized formulation provided sustained drug release for up to 12 h and showeddissolution behavior comparable to the marketed sustained-release product, indicating itspotential as an effective oral controlled-release delivery system.