Abstract
Dextromethorphan hydrobromide (DM) sustained release matrix pellets containing 10% w/w drug were prepared by an extrusion/spheronization technique. The effect of mixing different concentrations of ethyl cellulose (EC), hydroxypropyl methylcellulpse (HPMC K10), and Carbopol 934 with Avicel PH101 on the rheological properties of pellet wet mass was evaluated using mixer torque rheometry (MTR). The prepared pellets were characterized for size, drug content, and in-vitro DM release rate. The results showed that increasing the concentration of the hydrophobic polymer (EC) with Avicel PH101 decreased wet mass consistency, represented by mass mean line torque. Lower binder ratio was required for optimum wet massing, while mixing with swellable polymers (HPMC and Carbopol) caused a noticeable increase in both mean line torque and binder ratio. Combinations of HPMC and Carbopol at higher concentrations resulted in controlled in vitro release of DM from the prepared pellets. Furthermore, mathematical treatment of the in vitro release data of DM from the prepared pellets showed that all formulations except those containing 5% Carbopol plus 5% HPMC (F10) follow first order release. n values of these formulation were in the range of 0.09-0.40, which support an anomalous non-Fickian release.
Highlights
Pellets as a dosage form have several drug delivery and technological benefits in comparison to the conventional single-unit regimen
The results obtained by Ibrahim and Shazly (2014) revealed that diclofenac sodium release from pellets was governed by the molecular weight of PEG used, since increasing the molecular weight of PEG resulted in slowing the drug release rate from pellets, while increasing its concentration enhanced the release rate
Wet mass studies of Avicel PH101 mixed with different concentrations of ethyl cellulose (EC), HPMC, and Carbopol were conducted to determine the water/powder ratio required to attain a maximum torque value for powder wet massing prior to extrusion/spheronization procedures
Summary
Pellets as a dosage form have several drug delivery and technological benefits in comparison to the conventional single-unit regimen. Mahrous saves time and money by omitting the coating procedure (Ghali, Klinger, Schwartz, 1989) Such systems retard the penetration of aqueous fluids into the formulation and slow the rate of drug release. The results obtained by Ibrahim and Shazly (2014) revealed that diclofenac sodium release from pellets was governed by the molecular weight of PEG used, since increasing the molecular weight of PEG resulted in slowing the drug release rate from pellets, while increasing its concentration enhanced the release rate This was attributed to increasing the peak torque of pellet wet mass by increasing PEG molecular weight and lowering it by increasing PEG level. Bharag, Taka and Sakr (2006a) reported that extended-release DM matrix tablets were developed using HPMC K100LV/ methacrylic acid copolymer (Eudragit® L100-55) combination, and polyvinyl acetate–povidone (PVAP). The aim of the present study was to investigate the effect of different polymers on the dextromethorphan HBr matrix pellets wet massing properties, particle size and drug release rate
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