A novel approach to a fine particle coating using porous spherical silica as core particles

An Overview of Taste-Masking Technologies: Approaches, Application, and Assessment Methods

It is well-known that plenty of active pharmaceutical ingredients (API) inherently possess an unpleasant taste, which influences the acceptance of patients, especially children. Therefore, manufacturing taste-masked dosage forms has attracted a lot of attention. This review describes in detail the taste-masking technologies based on the difference in the taste transmission mechanism which is currently available. In particular, the review highlights the application of various methods, with a special focus on how to screen the appropriate masking technology according to the properties of API. Subsequently, we overviewed how to assess taste-masking efficacy, guiding researchers to rationally design taste-masking formulations.

Mannitol Is a Good Anticaking Agent for Spray-Dried Hydroxypropyl-Beta-Cyclodextrin Microcapsules

Agglomeration is an undesirable phenomenon that often occurs in spray-dried microcapsules powder. The objective of this work is to determine the best solution for spray-dried hydroxypropyl-β-cyclodextrin (HP-β-CD) microcapsules from four anticaking agents, namely calcium stearate (CaSt), magnesium stearate (MgSt), silicon dioxide (SiO₂), and mannitol (MAN), and to explore their anticaking mechanisms. Our results showed that MAN was found to be the superior anticaking agent among those tested. When the MAN ratio is 12%, the microcapsules with a special Xanthium-type shape had higher powder flowability and lower hygroscopicity and exhibited good anticaking properties. Mechanism research revealed that CaSt, MgSt, and SiO₂ reduce hygroscopicity and caking by increasing the glass transition temperature of the microcapsules, while MAN prevents the hydroxyl group of HP-β-CD from combining with water molecules in the air by a crystal outer-layer on the microcapsule surface.

Fundamental evaluation and optimization of porous spherical silica for developing functional fine particles via fluidized bed coating

Particle coating, a taste-masking technique for drugs, is limited by its long manufacturing time, which is caused by the decrease in the spray rate required to prevent particle agglomeration. Mesoporous silica particles, which have a high surface area and pore sizes in the range of 2-50 nm, possess high surface free energy; they have attracted significant interest for numerous applications in adsorption, separation, and catalysis and drug delivery. A form of mesoporous silica, microbead silicate, can prevent particle aggregation because of its good water absorbency and drying properties. Hence, it has been suggested to be applicable for particle coating. This study evaluated the physical properties and drug release capability of microbead silicate with different pore sizes. Although microbead silicate with small pores displayed a rapid drug release profile, drug release was incomplete. Contrastingly, microbead silicate with large pores achieved complete drug release even with high drug loading. Furthermore, in the case of 100% layering, the porosity of microbead silicate was maintained, thus sufficiently preventing aggregation due to the prevention of formation of liquid bridging of the coating solution. These results suggest that using microbead silicate with large pores for particle coating enables complete drug release while improving manufacturability.

Application of the Modified Tangential Spray-Fluidized Bed to Produce Nonpareils from Primary Crystals

Coating of fine primary drug particles by a fluidized bed processor has been reported to be potentially challenging. This work aimed to develop a spray layering process to produce nonpareils by a side spray fluid bed with swirling air flow. The first part examined the effects of various parameters for producing lactose nonpareils by using Box-Behnken design. The factors considered were atomizing air pressure, spray rate, and fluidizing air temperature. This was followed by an in-depth investigation on the effects of inlet airflow rate, air temperature, and spray rate on properties of the product, in addition to process optimization. The results indicated a negative correlation between atomizing air pressure and D₉₀ (particle size at 90th percentile in the cumulative undersize plot) as well as span (size distribution). Temperature had a positive correlation with D₉₀ and span while spray rate affected span. Both atomizing air pressure and temperature correlated negatively with span. It was also found that spray rate negatively affected roundness at different coat weight gain levels across the study design space. Inlet airflow rate was found to correlate negatively with roundness at 15%, w/w coat weight gain. The mean useful yield of the optimized runs was about 91%. In the second part of this study, the metformin hydrochloride crystals as starter seeds were converted into nearly spherical shaped spheroids with 1:1 crystals to coat weight deposition over a processing time of about 3.5 h. The processor studied shows promise for direct spheronization of crystals into spherical seeds.

Evaluation of coat uniformity and taste-masking efficiency of irregular-shaped drug particles coated in a modified tangential spray fluidized bed processor

OBJECTIVE

To explore the feasibility of coating irregular-shaped drug particles in a modified tangential spray fluidized bed processor (FS processor) and evaluate the coated particles for their coat uniformity and taste-masking efficiency.

METHODS

Paracetamol particles were coated to 20%, w/w weight gain using a taste-masking polymer insoluble in neutral and basic pH but soluble in acidic pH. In-process samples (5, 10 and 15%, w/w coat) and the resultant coated particles (20%, w/w coat) were collected to monitor the changes in their physicochemical attributes.

RESULTS

After coating to 20%, w/w coat weight gain, the usable yield was 81% with minimal agglomeration (< 5%). Some aerodynamic modifications to particle shape and surface morphology were observed for the in-process samples with 5 and 10% coat compared with the uncoated particles. A 15%, w/w coat was optimal for inhibiting drug release in salivary pH with subsequent fast dissolution in simulated gastric pH.

CONCLUSION

The FS processor shows promise for direct coating of irregular-shaped drug particles with wide size distribution. The coated particles with 15% coat were sufficiently taste masked and could be useful for further application in orally disintegrating tablet platforms.