Abstract
The aim of the present study was to prepare and characterize controlled-release matrix tablets of zidovudine using hydrophilic HPMC K4 M or Carbopol 934 alone or in combination with hydrophobic ethyl cellulose. Release kinetics was evaluated by using USP XXIV dissolution apparatus No.2 (paddle) type. Scanning electron microscopy was used to visualize the effect of dissolution medium on matrix tablet surface. The in vitro results of controlled – release zidovudine tablets were compared with conventional marketed tablet Zidovir. The in vitro drug release study revealed that HPMC K4 M or Carbopol 934 preparation was able to sustain the drug release near to 6 hours. Combining HPMC K4 M or Carbopol 934 with ethyl cellulose sustained the drug release for nearly 12 h. The in vitro evaluation showed that the drug release may be by diffusion along with erosion. Results suggest that the developed controlled-release tablets of zidovudine could perform therapeutically better than marketed dosage forms, leading to improve efficacy, controlling the release and better patient compliance.
Highlights
HIV (Human ImmunodeÞciency Virus) is a virus that causes AIDS (Acquired ImmunodeÞciency Syndrome), a health condition in which a person is affected by a series of diseases because of poor immunity
The hydrophilic polymers, HPMC K4 M or Carbopol 93410 selected in the present study provide pH-independent drug release to oral dosage forms that can be used for formulating the sustained-release dosage forms
The drug release was slower from the tablets containing HPMC K4 M as compared with that from marketed tablets (Þg. 2)
Summary
HIV (Human ImmunodeÞciency Virus) is a virus that causes AIDS (Acquired ImmunodeÞciency Syndrome), a health condition in which a person is affected by a series of diseases because of poor immunity. The main limitation to therapeutic effectiveness of AZT is its dose-dependent hematological toxicity, low therapeutic index, short biological half-life, and poor bioavailability. It is rapidly absorbed from the gastrointestinal tract (GIT) exhibiting a peak plasma concentration of 1.27 μM. Number of studies shows the use of hydrophilic matrices to formulate the controlled release dosage forms of different drugs[2,3,4,5,6,7,8,9] Because of their simplicity and cost-effectiveness, hydrophilic gel matrix tablets are widely used for oral controlled release dosage forms. In the present investigation, an attempt has been made to formulate the controlled – release matrix tablets of AZT using hydrophilic matrix material (HPMC K4 M or Carbopol 934) in combination with hydrophobic ethyl cellulose[4,11,12]
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