A controlled release matrix using a mixture of hydrophilic and hydrophobic polymers

The influence of the composition and charges of the acrylic resins, the hydrophilic polymer, and the other excipients on the release rate of drug from the matrices.

“…The percent of drug release was 97% at stirring speed of 50 rpm after eight hours. These results may be due to both of the eroding and diffusion effect of this medium on the swollen matrices of NaCMC (1,23). While the release rate of the drug was 64% at the same stirring speed when the dissolution medium was simulated gastric fluid at pH ≈ 1.2 after eight hours.…”

“…From the results obtained it was observed that as the percent of the hydrophilic NaCMC increased the release rate of drug decreased , these findings may be because of ;The ability of the hydrophilic polymer to swell and absorb an extra amount of the dissolution medium with a result of reducing or controlling the drug release [8][9][10]21]; The slowly erosion or attrition of the hydrophilic NaCMC from the tablets which resulted in a decrease of drug release [1, 18 -20] ; Propranolol hydrochloride is a cationic drug and NaCMC is an anionic polymer so, they may form a complex which decrease the drug release, these phenomena were reported in many studies when the anionic surfactants and the cationic drugs were used to prepare controlled release matrices, [1,13]; The cationic ammonium groups in the Eudagit RL100 make it slightly cationic polymer which may enhance the complex formation and reinforce the decrease of the drug release [19]; The amount of the soluble ammonium groups in the Eudragit RL100 increased the penetration of the dissolution medium into the matrices and increases the swellability of the tablet which decreases the release rate of the drug [19].…”

“…Most of these studies focused on the mechanisms of the drug release from the hydrophobic matrices may be because of. Disintegration of the tablets [1,19]; Attrition (erosion) of the tablets [18 -20]; Destruction of the matrices [1,19,27]; the release rate of the drug from the hydrophilic matrices was mainly due to the swelling and sometimes due to the erosion and destruction of the tablets when the formulation is a mixture of the hydrophobic /hydrophilic polymers. [8 -10, 1-4] In the formula F1 with 10 % lactose, the tablets were disintegrated within two hours and the entire drug was released, while in the formulations F2 and F3 the tablets were disintegrated within three hours and the entire drug was released, inspite of the least solubility of lactose in comparison with sorbitol and dextrose [11].…”

“…The polymers are widely used in the preparation of controlled release matrices due to their simplicity, safety and it should be economical use [1][2][3][4]. Among these polymers celluloses have been extremely popular in controlling the release rate of soluble drug from solid dosage form.…”

“…Among these polymers celluloses have been extremely popular in controlling the release rate of soluble drug from solid dosage form. The ease of compression, their ability to accommodate large amount of drugs and the minimum processing variables on the release rate are the main reasons for their popularity [1][2]. Sodium carboxymethylcellulose is a widely used polymer, due to its availability in a range of viscosity grades and good swelling and erosion characteristics, which can be used to modulate the release of various drugs [5 -10].…”