The Effect of the Wet Granulation Process on Drug Dissolution

The Influence of the Intergranular Superdisintegrant Performance on New Drotaverine Orodispersible Tablet Formulations

The main objective of this study consists in establishing the influence of the intergranular superdisintegrant on the specific properties of drotaverine hydrochloride fast-dissolving granules (DROT-FDGs) and orodispersible tablets (DROT-ODTs). The orodispersible tablets were obtained by the compression of the FDGs and excipient mixture with an eccentric tableting machine. To develop DROT-ODTs, two types of superdisintegrant excipients in different concentrations (water-soluble soy polysaccharides (SSP) (1%, 5%) and water-insoluble soy polysaccharides-Emcosoy® STS IP (EMCS) (1%, 3%, 5%)) were used, resulting in five formulations (D1-D5). The DROT-FDGs and the DROT-ODTs were subjected to pharmacotechnical and analytical evaluation. All the orodispersible tablets obtained respect the quality requirements in terms of friability (less than 1%), crushing strength (ranging between 52 N for D2 and 125.5 N for D3), and disintegration time (<180 s). The in vitro release of drotaverine from ODTs showed that all formulations presented amounts of active substance released greater than 85% at 10 min. The main objective, developing 30 mg DROT-ODTs for children aged between 6 and 12 years by incorporating the API in FDGs, was successfully achieved.

Applying Biopharmaceutical Classification System criteria to predict the potential effect of Cremophor® RH 40 on fexofenadine bioavailability at higher doses

Aim: To study the impact of various permeability enhancers on fexofenadine bioavailability. Furthermore, to predict the potential effect of Cremophor^® RH 40 on fexofenadine pharmacokinetics at higher doses using Biopharmaceutical Classification System criteria. Experimental methods: The effect of the dose increase (60-360 mg) on the dissolution and permeability behavior of fexofenadine-Cremophor RH 40 formulations was studied in humans. The Biopharmaceutical Classification System criteria of the drug was determined. Results & conclusion: Cremophor RH 40 improved the dissolution and bioavailability of fexofenadine. The pharmacokinetics increased linearly with the dose increase. Absorption number (A_n) was significantly increased after addition of Cremophor RH 40 in comparison to an unprocessed drug. Similar A_n values were observed throughout the same dose range. The dose number (D₀) values were <1 whereas, all the dissolution number (D_n) values were >1 at the same dose level.

To Evaluate the Effect of Solvents and Different Relative Humidity Conditions on Thermal and Rheological Properties of Microcrystalline Cellulose 101 Using METHOCEL™ E15LV as a Binder

The solvent used for preparing the binder solution in wet granulation can affect the granulation end point and also impact the thermal, rheological, and flow properties of the granules. The present study investigates the effect of solvents and percentage relative humidity (RH) on the granules of microcrystalline cellulose (MCC) with hydroxypropyl methyl cellulose (HPMC) as the binder. MCC was granulated using 2.5% w/w binder solution in water and ethanol/water mixture (80:20 v/v). Prepared granules were dried until constant percentage loss on drying, sieved, and further analyzed. Dried granules were exposed to different percentage RH for 48 h at room temperature. Powder rheometer was used for the rheological and flow characterization, while thermal effusivity and differential scanning calorimeter were used for thermal analysis. The thermal effusivity values for the wet granules showed a sharp increase beginning 50% w/w binder solution in both cases, which reflected the over-wetting of granules. Ethanol/water solvent batches showed greater resistance to flow as compared to the water solvent batches in the wet granule stage, while the reverse was true for the dried granule stage, as evident from the basic flowability energy values. Although the solvents used affected the equilibration kinetics of moisture content, the RH-exposed granules remained unaffected in their flow properties in both cases. This study indicates that the solvents play a vital role on the rheology and flow properties of MCC granules, while the different RH conditions have little or no effect on them for the above combination of solvent and binder.

The role of intra- and extragranular microcrystalline cellulose in tablet dissolution

The objective of this study was to examine the influence of intra- and extragranular microcrystalline cellulose (MCC) on drug dissolution from tablets made by high-shear granulation. Granulations were made in a Littleford Model W-10-B (10-liter) mixer and dried in a fluid bed dryer (Niro Inc.). A Plackett-Burman screening design and 2(3) factorial design were employed to study how drug type, MCC (intra- or extra-), filler type (lactose or dicalcium phosphate), disintegrant type (sodium starch glycolate or croscarmellose sodium) and level, proportion of magnesium stearate, and impeller speed affect tablet hardness, disintegration time, and dissolution. Two model drugs were chosen based on their solubility: metoprolol tartrate (solubility > 1000 mg/ml) and hydrochlorothiazide (solubility = 1.05 mg/ml). Tablets were compressed to the same target weight (dose) and similar tablet hardness. In some cases, dissolution testing was also carried out on the loose granules. The intra-extragranular distribution of MCC was found critical to the compactibility and initial dissolution rates from these tablets. Intragranular MCC reduced drug dissolution, the effect being most marked in the case of the slightly soluble hydrochlorothiazide. For formulations containing intragranular MCC, the granulating fluid level on tablet dissolution was also important, since an increase in fluid level resulted in slower drug dissolution from both the loose granules and the tablets compressed from them. Conversely, extragranular MCC tended to increase both dissolution rates and compactibility. It may be concluded that the appropriate distribution of MCC between and within granules may optimize both dissolution and compactibility without changing overall tablet composition.