Quality by Design (QbD)-Based Development and Optimization of a Polyherbal Nanoformulation of Gymnema Sylvestre, Trigonella Foenum-Graecum and Momordica Charantia for Multitargeted Management of Type 2 Diabetes Mellitus

Abstract

Type 2 diabetes mellitus (T2DM) is a multifactorial metabolic disorder characterized by insulin resistance, progressive pancreatic beta-cell dysfunction, persistent hyperglycemia, abnormal lipid metabolism, oxidative stress and an increased risk of microvascular and macrovascular complications. The present study was designed to develop and optimize a polyherbal nanoformulation containing standardized extracts of Gymnema sylvestre, Trigonella foenum-graecum and Momordica charantia using a Quality by Design (QbD) approach. The three herbs were selected because their phytoconstituents may act through complementary mechanisms including inhibition of intestinal carbohydrate-digesting enzymes, improvement of glucose utilization, modulation of insulin secretion/sensitivity and attenuation of oxidative stress. Hydroalcoholic extracts were standardized using gymnemic acids, 4-hydroxyisoleucine and charantin as respective phytochemical markers. Chitosan-tripolyphosphate nanoparticles were prepared using ionic gelation. A Quality Target Product Profile (QTPP) and critical quality attributes (CQAs) were established, followed by risk assessment. Chitosan concentration (X1), sodium tripolyphosphate concentration (X2) and sonication time (X3) were optimized using a three-factor Box-Behnken design. Particle size, polydispersity index and entrapment efficiency were considered primary responses. In the illustrative optimized dataset, the nanoformulation exhibited a mean particle size of approximately 181 nm, PDI of 0.212, positive zeta potential of +28.7 mV and overall marker entrapment efficiency of 82.4%. A biphasic and sustained phytoconstituent release pattern was observed over 24 h. The optimized nanoformulation showed greater inhibitory activity against alpha-glucosidase and alpha-amylase than the unencapsulated polyherbal blend. In an illustrative high-fat-diet/streptozotocin-induced T2DM model, the nanoformulation produced progressive reductions in fasting blood glucose and improvements in HbA1c, insulin resistance and lipid parameters relative to untreated diabetic controls. QbD-based optimization provided a systematic relationship between formulation/process variables and nanoparticle performance and established a preliminary design space and control strategy. These findings support further experimental investigation of standardized polyherbal chitosan nanoparticles as a multitarget phytopharmaceutical delivery platform. However, pharmacokinetic studies, long-term toxicological assessment, batch-to-batch botanical standardization and appropriately designed clinical trials are required before therapeutic conclusions can be made.