Performance Evaluation And Application Research Of Novel Enteric Coating Material

Aim:pH adjusting agent,plasticizer and anti-sticking agent often are added into enteric polyacrylic acid resin which can not be used for coating directly.And coating operation is cumbersome and difficult to control the quality of coating.This paper aims to develop a novel enteric coating premix and investigate its physical-chemical features and applications.Methods:The methyl methacrylate/ethyl acrylate(1:1)polymer powder was synthesized by emulsion polymerization.The viscosity of polymer powder,loss on drying,residue on ignition,acid value,heavy metals,arsenic salt content,enteric performance,infrared spectra and the glass transition temperature were investigated.pH adjusting agent,anti-sticking agent and plasticizer were added to the aqueous phase to prepare the enteric coating solution.Free film was prepared by casting technique and spraying.The effects of pH adjusting agent amounts and adding methods on the liquid particle size and viscosity of enteric coating solution were investigated.The influence of anti-sticking agent amounts on the viscosity of enteric coating solution were investigated.The effects of plasticizers kinds and amounts on the liquid particle size,viscosity,spreadability and film-forming ability of enteric coating solution were investigated,as well as stability,acid resistance and mechanical properties of the free film to optimize coating solution formulation.Spray drying was used to prepare the enteric coating premix witn the optimium formulation of the coating solution.A type fully-formulated enteric coating systems was prepared with TEC and B type fully-formulated enteric coating systems was prepared with optimium complex vitamin.Microscope was used to observe the microstructure of the enteric coating premix.Angle of repose was used as the index to study the flowability.Particle size and viscosity of coating solution were used as index to study the effects of stirring time on re-dispersibility.Metformin hydrochloride and aspirin were used as model drug and prepared AB fully-formulated enteric coating systems were used as coating materials to prepare enteric tablets by spin coating pan.Minimum coating weight gains were screened by measured 2h anti-acidity ratio and the application effects of two fully-formulated enteric coating systems were evaluated.Results:The prepared polymer was white homogeneous powder and had proper Viscosity of the polymer powder,loss on drying,residue on ignition,acid value,heavy metals,arsenic salt content and enteric performance,which were consistent with the standards of the Europe Pharmacopeia.The IR spectra showed its 1640 cm-1 C=C stretching vibration disappeared,indicating a more complete polymerization.The glass transition temperature of the polymer powder was 127.4 ?,indicating plasticizers and other ingredients should be added to satisfy the need of enteric coating.When the dosage of pH adjusting agents,anti-sticking agents and plasticizers are 1.3%,20%and 10%of the polymer content,the viscosity of the coating liquid was(56.214±65)mpa.s,particle size was(236.2±17.07)nm,film forming temperature was about 20 ?,which meet the requirements of coating.When the plasticizer was TEC and aqueousVE:liposoluble VE= 1:1(w/w),the viscosity particle size and film forming properties of the coating solution were consistent with the requirements of coating.Among them,the mechanical properties of the coating film is better when used TEC as the plasticizer:tensile strength was(53.27±18.52)N/cm2,elongation was(164.99±19.33)%and Young's modulus was(0.87±0.28)Gpa.The plasticizer leakage ratio of free film was lower and anti-acidity was better when used aqueous:lipid VE=1:1(w/w)as the plasticizer:plasticizer leakage ratio was(45.02±8.74)%and permeability constant was(291.721?58.981)g.mm.L.m-2.mol-1.h-1.The angle of repose were(48.52±0.58)°and(42.0±0.50)° of the prepared A and B fully-formulated enteric coating systems.The particle sizes of coating solution were 486.2nm and 383.4nm,and the viscosities were 64.0mpa.s and 40.5mpa.s after 0.5h magnetic stirring,which satisfy the requirements coating.The prepared metformin hydrochloride enteric-coated tablets minimal weight gains of the cores coated surface lettering and no lettering were 13.50%and 7.30%,which basically satisfy the requirements of enteric coating.The minimum coating weight gain of prepared aspirin enteric-coated tablets with AB two kinds of fully-formulated enteric coating systems were 7.30%and 6.80%,indicating a similar effect of the two fully-formulated enteric coating systems in pratical applications.Conclusion:The prepared AB two kinds of novel fully-formulated enteric coating systems had good film-forming properties,anti-acidity,mechanical properties,convenience of use,and good coating effects.They have broad application prospects.