Effect of Surface Coating with Magnesium Stearate via Mechanical Dry Powder Coating Approach on the Aerosol Performance of Micronized Drug Powders from Dry Powder Inhalers
- 988 Downloads
The objective of this study was to investigate the effect of particle surface coating with magnesium stearate on the aerosolization of dry powder inhaler formulations. Micronized salbutamol sulphate as a model drug was dry coated with magnesium stearate using a mechanofusion technique. The coating quality was characterized by X-ray photoelectron spectroscopy. Powder bulk and flow properties were assessed by bulk densities and shear cell measurements. The aerosol performance was studied by laser diffraction and supported by a twin-stage impinger. High degrees of coating coverage were achieved after mechanofusion, as measured by X-ray photoelectron spectroscopy. Concomitant significant increases occurred in powder bulk densities and in aerosol performance after coating. The apparent optimum performance corresponded with using 2% w/w magnesium stearate. In contrast, traditional blending resulted in no significant changes in either bulk or aerosolization behaviour compared to the untreated sample. It is believed that conventional low-shear blending provides insufficient energy levels to expose host micronized particle surfaces from agglomerates and to distribute guest coating material effectively for coating. A simple ultra-high-shear mechanical dry powder coating step was shown as highly effective in producing ultra-thin coatings on micronized powders and to substantially improve the powder aerosolization efficiency.
KEY WORDSaerosolization dry powder inhaler magnesium stearate mechanical dry powder coating salbutamol sulphate
Qi (Tony) Zhou acknowledges the financial support of Postgraduate Publications Award from Monash University. Miat S.p.A and Capsugel Australia are acknowledged for kind donations of Monodose inhalers and HPMC capsules, respectively.
- 4.Kretchme N, Faber HK. Lactose intolerance. Nutr Rev. 1972;30(11):260.Google Scholar
- 18.Rowe RC, Sheskey PJ, Quinn ME. Handbook of pharmaceutical excipients. 6th ed. London: Pharmaceutical Press; 2009. p. 434.Google Scholar
- 22.Zhou QT, Denman JA, Gengenbach T, Das S, Qu L, Zhang H, et al. Characterization of the surface properties of a model pharmaceutical fine powder modified with a pharmaceutical lubricant to improve flow via a mechanical dry coating approach. J Pharm Sci. 2011;100(8):3421–30.PubMedCrossRefGoogle Scholar
- 27.Kippax P, Morton DAV. Aerosolization analysis. Drug Deliv Technol. 2008;8(1):53–8.Google Scholar
- 31.Ikegami K, Kawashima Y, Takeuchi H, Yamamoto H, Mimura K, Mamose D, et al. A new agglomerated KSR-592 beta-form crystal system for dry powder inhalation formulation to improve inhalation performance in vitro and in vivo. J Control Release. 2003;88(1):23–33. doi: 10.1016/s0168-3659(02)00460-1.PubMedCrossRefGoogle Scholar