Nano-strategies for advancing oral drug delivery: Porous silicon particles and cyclodextrin encapsulation for enhanced dissolution of poorly soluble drugs

Development of novel active pharmaceutical ingredients (API) for oral use often face challenges due to low bioavailability. Nanoparticle-based drug delivery systems and cyclodextrin (CD) encapsulation offer promising solutions by enhancing API solubility or dissolution rates. Porous silicon nanoparticles have shown potential to encapsulate APIs in their amorphous form within the pores, improving their dissolution rates compared to crystalline counterparts. A novel synthesis approach, circumventing the expensive and tedious synthesis from Si wafer material, has been developed using centrifugal Chemical Vapor Deposition (cCVD). Herein, various cCVD Si particles were evaluated for their ability to enhance the dissolution rate of the model drugs celecoxib (CEL), phenytoin (PHT), griseofulvin (GRI), diclofenac (DCF) and naproxen (NAP). Our findings demonstrate increased dissolution rates of all tested APIs when formulated with cCVD Si particles, compared to free API in pH 7.4 or pH 2.0. Particle characteristics were largely retained after loading, and the solid state of the loaded APIs were evaluated using Differential Scanning Calorimetry (DSC). Dissolution kinetics were influenced by the particle properties, mass loading and API characteristics. Loading of CD-CEL, -GRI and -DCF complexes into the cCVD Si particles showed a potential for further enhanced dissolution rates, representing the first reported investigation of this combination. In conclusion, the cCVD Si particles are promising for improving the dissolution rate of poorly soluble drugs, potentially due to precipitation of amorphous or metastable forms. Further enhancements were observed upon loading CD-drug complexes, thereby offering promising strategies for optimizing drug bioavailability.