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Hydroxypropyl Methylcellulose (HPMC) polymer chains exhibit distinct performance characteristics based on molecular weight distributions. The E15, E5, and K4M designations reference specific viscosity ranges measured as 2% aqueous solutions at 20°C. HPMC E15 demonstrates a molecular weight range of 26,000-30,000 g/mol, while E5 falls within 20,000-24,000 g/mol, and K4M between 80,000-120,000 g/mol. These variations directly influence polymer chain entanglement, solution viscosity, and film-forming capabilities. Unlike standardized chemical formulas, manufacturers control molecular architecture through cellulose etherification processes, where reaction time and temperature determine chain length. Batch-to-batch consistency remains paramount, with pharmaceutical-grade HPMC maintaining molecular weight tolerances within ±5%.
Molecular weight directly dictates functional performance across applications. Higher molecular weight polymers like HPMC K4M generate viscosities exceeding 80,000 mPa·s at 2% concentrations, creating robust hydrogel matrices for extended-release tablets. In contrast, lower molecular weight HPMC E5 (4,000-7,000 mPa·s) enables rapid dissolution in immediate-release formulations. Thermal gelation points demonstrate similar dependence – HPMC E15 transitions at 60-65°C while K4M gels near 70-75°C. Performance data reveals HPMC E15's unique balance: 28,000±2000 g/mol molecular weight delivers optimal mucoadhesion strength (45-50 mN/cm²) and sustained dissolution profiles, with 85% API release within 8 hours compared to E5's 90% release within 2 hours.
Chain entanglement governed by molecular weight creates quantifiable performance differences. Water penetration rates through HPMC matrices show logarithmic decreases as molecular weight increases – HPMC K4M exhibits permeability coefficients of 4.5×10⁻⁷ cm²/s versus E15's 8.2×10⁻⁷ cm²/s. Solution rheology follows power-law behavior where intrinsic viscosity [η] relates to molecular weight (M) via the Mark-Houwink equation: [η] = K·Ma. Exponents for HPMC range between 0.6-0.9 based on substitution patterns. Gelation strength measurements reveal fracture stress values correlate linearly with molecular weight – HPMC K4M matrices withstand 8.5 kPa compression forces before failure, while E15 withstands 6.2 kPa and E5 manages 3.8 kPa. These physicochemical relationships determine functionality across therapeutic delivery systems.
Manufacturer | Grade | Molecular Weight (g/mol) | Viscosity (mPa·s) | Methoxy Content (%) | Hydroxypropoxy Content (%) |
---|---|---|---|---|---|
Ashland | E15 | 26,000-30,000 | 13,500-16,500 | 28-30 | 7-12 |
Dow Chemical | E5 | 20,000-24,000 | 4,000-7,000 | 29-31 | 8-11 |
Shin-Etsu | K4M | 80,000-120,000 | 75,000-140,000 | 20-24 | 7-12 |
Lotte Fine Chemical | E15 | 27,500±1,500 | 14,800-15,600 | 27-29 | 9-10 |
Specialized manufacturing processes enable molecular weight targeting within ±3% tolerance through controlled cellulose depolymerization. Manufacturers achieve customized viscosity profiles by regulating etherification reactor pressure and alkali catalyst concentrations. For sustained-release tablet coatings, blends of HPMC E15 and K4M (40:60 ratio) create matrices with tailored diffusion coefficients of 1.8×10⁻⁶ cm²/s. In construction applications, molecular weight reduction treatments produce low-viscosity HPMC variants (1,500-3,500 g/mol) that accelerate cement hydration while maintaining water retention capabilities exceeding 95%. These modifications allow adjustment of dissolution rates from rapid-disintegrating (≥85% API release within 30 minutes) to delayed-release profiles (≤10% release after 2 hours gastric simulation).
Ophthalmic solutions utilizing HPMC E15 (MW:28,500±500) demonstrate 240% viscosity enhancement over saline with 4-minute corneal residence time improvements. In controlled-release tablets containing HPMC K4M, dissolution testing shows precise linear release kinetics (R²=0.99) over 12 hours. Tile adhesives modified with HPMC E5 exhibit wetting time reductions to 18 seconds (vs. 43 seconds for standard formulations) due to optimized molecular weight and surface tension effects. Construction mortar trials confirm 100 ppm HPMC E15 additions improve compressive strength retention by 19.5% under dry conditions. The pharmaceutical industry increasingly specifies molecular weight-controlled HPMC grades, with contract manufacturing organizations reporting 31% reduction in dissolution profile deviations when implementing molecular weight-selective sourcing protocols.
Precise hpmc e15 molecular weight
specifications between 26,000-30,000 g/mol satisfy strict pharmaceutical monograph requirements where viscosity tolerances must not exceed ±10% of label claim. For immediate-release applications demanding faster hydration, hpmc e5 molecular weight (20,000-24,000 g/mol) provides superior disintegration efficiency. Extended-release formulations consistently employ hpmc k4m molecular weight grades (80,000-120,000 g/mol) to achieve near-zero-order API release kinetics. Validation protocols now incorporate molecular weight verification through gel permeation chromatography, with pharmacopeial standards requiring Mw/Mn polydispersity indices below 1.8 for pharmaceutical-grade materials. Current industry data indicates molecular weight-controlled HPMC reduces tablet coating defects by 47% compared to viscosity-classified materials alone.
(hpmc e15 molecular weight)
A: The molecular weight of HPMC E15 typically ranges from 20,000 to 60,000 g/mol. It varies based on the specific manufacturer and viscosity grade.
A: HPMC E5 has a lower molecular weight than E15, averaging about 10,000-30,000 g/mol. This difference affects its viscosity and solubility in formulations.
A: HPMC K4M has a higher molecular weight, often between 60,000 and 120,000 g/mol. This aligns with its high-viscosity grade for controlled-release applications.
A: Molecular weight variations arise from polymerization differences and substitution degrees. For instance, E15 is medium-viscosity, while K4M has a higher weight for thicker gels.
A: Molecular weight is measured via methods like size exclusion chromatography (SEC). For HPMC E15, viscosity tests indirectly indicate weight based on 2% aqueous solution standards.