Effect of the lubricant magnesium stearate on changes of specific surface area of directly compressible powders under compression

During compression, powders fragment, plastically deform, and/or may behave both ways. Different profiles ofspecific surface area changes have been shown in several studies for many powders. In this study, the effect of alubricant on the specific surface area of a powder was studied during the consolidation process of the powder as anattempt to clarify the behavior of powders under compression. Changes in specific surface areas of Starch [Rice starch],cellulose [Avicel[R]PH102], spray dried lactose [Zeparox[R]], and dibasic calcium phosphate [Emcompress[R]] werestudied using gas adsorption technique. Magnesium stearate was used as a lubricant. Specific surface area of plasticallydeforming materials; cellulose, and starch was clearly affected by the addition of lubricants. Spray dried lactosecombined both fragmenting and plastically deforming behavior in its consolidation under compression and its specificsurface area was slightly affected by the addition of lubricant. Specific surface area of fragmenting material; Dibasiccalcium phosphate was not affected by the addition of a lubricant

effects of capsule fill weight and drug/carrier blend ratio on the aerosolization of a model drug from a spinhaler

The purpose of this work was to examine the effect of capsule fill weight and drug/carrier blend ratio of fluorescein isothiocyanate [FITC]-Dextran used as a model drug on the aerosolization performance from Spinhaler[TM]. Micronised FITC-Dextran was tumbled with modified alpha-lactose monohydrate in the ratio of 1:25 and 4:22. Factorial design experiments were carried out to test capsule fill weights of 26 and 104 mg for aerosolization using Andersen cascade impactor [ACI]. Powders were characterised in terms of particle size distribution, morphology and thermal properties. Fine particle fraction based on loaded dose [FPF[Total]] was increased significantly from 14.9 to 23.1% when the blend ratio was increased from 1:25 to 4:22 [fill weight of 26 mg]. The Device retention of FIT-Dextran was reduced as the fill weight and /or blend ratio increased. Mass median aerodynamic diameter [MMAD] of FITC-Dextran decreased slightly but significantly [from 3.59 to 3.27micro m] with the increase in blend ratio for the fill weight 26 mg. Therefore the increase in the capsule fill weight and /or drug: carrier blend ratio improves the aerosolization performance. The effect of blend ratio was however greater compared to fill weight

study of the effect of jet milling process with or without pre-treatment on aerosolisation characteristics of FITC-dextran particles

In vitro aerosolisation studies from a Spinhaler[TM] into the Andersen Cascade Impactor [ACI] of fluorescein isothiocyanate [FITC] -Dextran M. Wt. 4,400 [model drug] produced by different techniques were carried out. Three techniques, namely; micronisation, freeze-drying followed by micronisation and spray-drying followed by micronisation, were used to produce FITC-Dextran samples of similar particle sizes [Volume Median Diameter [VMD] =5.7micro m] which, yet, differ in their surface characteristic. The measured Specific Surface Areas [SSAs] of FITC-Dextran were different, which indicated different surface characteristics. Wadell's shape factor was calculated to provide measurement for the particles' shape. Device retention after aerosolisation was similar for the three formulations as it was high, which is a characteristic of Spinhaler[TM]. However, the dispersion of each of the aerosolised blends were distinctly different from the others, as it was noticed that the micronised FITC-Dextran performed better than the remaining samples. The results were explained on the basis that porous particles of the micronised FITC-Dextran, as indicated by the SSA and the use of electron microscope, are light in weight, and therefore would have lower inertia; allowing them by this to remain longer in the airstream before impaction

Development of sustained release Ibuprofen Alginate gel beads

In this work, attempts have been done to produce a sustained release drug delivery system using ibuprofen-loaded alginate gel beads. Ibuprofen. as other NSAIDs, may cause gastric irritation; therefore, if it was possible to decrease its release in the stomach, this would increase the compliance of the patients. Sodium alginate/ibuprofen ratio plays an important role in the release characteristics of ibuprofen. Using sodium alginate/ibuprofen ratio of 1:4 or more has shown zero- order release kinetics in pH 6.8 simulated intestinal fluid. Release studies in pH 1.2 have shown very limited percentage release of ibuprofen; less than 15%. Adding different excipients to the different formulae will produce regular and spherical beads but will also affect the release of the drug. Therefore, it is important to investigate the effect of excipients on the release characteristics upon adding them to the formula. The release of ibuprofen can be controlled by adjusting the Sodium alginate/ibuprofen ratio or by adding excipients