Use of lipophilic and hydrophilic polymers in production of sustained release zinc sulfate tablets

Zinc sulfate administered to correct zinc deficiency. Its oral administration has shown serious digestive side effects and sometimes it has led to the lack of use it. The main aim of the present study was to use lipophilic and hydrophilic polymers in production of sustained release zinc sulfate tabletsover an extended period of time.
Sustained release (SR) zinc sulfate tablets were prepared using either lipophilic-based matrix or hydrophilic matrix system or natural polymers by either hot-fusion (HF) granulation or direct compression (DC) method. Physical and chemical features of provided SR tablets including hardness, friability, and weight variation, disintegration time, swelling index, content uniformity and drug release behavior were evaluated. The drug concentration was assayed by an atomic absorption spectrophotometer at 213.8 nm.
Most of the prepared formulations showed acceptable physicochemical properties. Among 30 formulations, SR tablets with lipophilic matrix-based showed more predictable release profiles compared to tablets prepared based on hydrophilic or natural matrixes. Tablets containing carnauba wax showed slower release while tablets with hydrogenated castor oil represented faster release profile. A few lipophilic matrix tablets containing zinc sulfate (110 mg), beeswax (or carnauba wax) and Avicel (or Emcompress) were selected as the optimum formulations showing release profiles based on USP criteria for lipophilic-based SR tablets. The mean dissolution time (MDT) and dissolution efficiency (DE8%) of selected formulations were 1.69-1.95 hr and 69.3-71.8%, respectively. Tablet hardness and granule size had no effects on release rate. The drug release kinetic followed Higuchi model.
Lipophilic based SR tablets of zinc sulfate is suggested as an alternative for capsule or syrup of the drug whichhave digestive side effects.