Fabrication and Characterization of Risperidone Implants as an Extended Antipsychotic Delivery System, Exploring the Role of Excipients

Reservoir-Type Subcutaneous Implantable Devices Containing Porous Rate Controlling Membranes for Sustained Delivery of Risperidone

Implantable drug delivery systems are crucial for achieving sustained delivery of active compounds to specific sites or systemic circulation. In this study, a novel reservoir-type implant combining a biodegradable rate-controlling membrane with a drug-containing core prepared using direct compression techniques is developed. The membrane is composed of poly(caprolactone) (PCL), and risperidone (RIS) served as the model drug. Characterization of both membranes and direct compressed pellets includes hardness testing, optical coherence tomography, mercury intrusion porosimetry, and surface morphology observation. In vitro release studies of RIS reveal that higher drug loading in the pellets extended-release duration up to 70 days when incorporated into membranes with four layers. Increasing the number of membrane layers slows the release rate further, ranging from 70 to 170 days depending on membrane thickness. Biocompatibility studies demonstrate that these implantable devices are non-toxic and biocompatible with cells in vitro. In vivo studies conduct in male Wistar rats demonstrate sustained release of RIS, with plasma levels showing a significant increase post-implantation at a relatively constant rate for up to 49 days. These results indicate that the developed implants have the potential to provide long-acting drug delivery to the systemic circulation.

Development of intranasal implantable devices for schizophrenia treatment

In this work the preparation and characterisation of intranasal implants for the delivery of risperidone (RIS) is described. The aim of this work is to develop better therapies to treat chronic conditions affecting the brain such as schizophrenia. This type of systems combines the advantages of intranasal drug delivery with sustained drug release. The resulting implants were prepared using biodegradable materials, including poly(caprolactone) (PCL) and poly(lactic-co-glycolic acid) (PLGA). These polymers were combined with water-soluble compounds, such as poly(ethylene glycol) (PEG) 600, PEG 3000, and Tween® 80 using a solvent-casting method. The resulting implants contained RIS loadings ranging between 25 and 50%. The obtained implants were characterised using a range of techniques including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflectance-Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). Moreover, in vitro RIS release was evaluated showing that the addition of water-soluble compounds exhibited significant faster release profiles compared to pristine PCL and PLGA-based implants. Interestingly, PCL-based implants containing 25% of RIS and PLGA-based implants loaded with 50% of RIS showed sustained drug release profiles up to 90 days. The former showed faster release rates over the first 28 days but after this period PLGA implants presented higher release rates. The permeability of RIS released from the implants through a model membrane simulating nasal mucosa was subsequently evaluated showing desirable permeation rate of around 2 mg/day. Finally, following in vitro biocompatibility studies, PCL and PLGA-based implants showed acceptable biocompatibility. These results suggested that the resulting implants displayed potential of providing prolonged drug release for brain-targeting drugs.

Polymeric implants with drug-releasing capabilities: a mapping review of laboratory research

PURPOSE

To provide a systematic map of the nature and extent of preclinical research concerning drug-releasing polymeric implants.

SIGNIFICANCE

By summarizing available data, this mapping review can guide the development of new drug-delivery devices.

METHODS

In-vitro studies assessing drug-delivery implants were reviewed. A study protocol was registered at Open Science Framework. The association of polymers with prominent drugs, manufacturing processes, geometries, treatments, and anatomical locations was assessed using the VOSviewer software. The release periods were also evaluated.

RESULTS

A total of 423 articles, published between 1975 and 2020, were included and grouped into a framework with nine main categories. More than half of studies were published between 2010 and 2020. Among 201 individual polymers or combinations, the most investigated were PLGA, PCL, PLA, Silicone (SIL), EVA, and PU. Similarly, from 232 individual drugs or combinations, the most prominent were dexamethasone (DEX; anti-inflammatory), paclitaxel (PTX; anticancer), fluoruracil (anticancer), ciprofloxacin (CFX) hydrochloride (antibiotic), and gentamicin (GS; antibiotic). A total of 51 manufacturing processes were encountered, of which the most reported were solvent evaporation, compression molding (CM), extrusion (EX), electrospinning (ELS), and melt molding (MM). Among 38 implant geometries, cylinder (CIL) was the most prominent, followed by disk, square film, circular film (FCIR), and undefined film. Release times varied greatly, although the majority of articles ranged between 5 and 300 d.

CONCLUSIONS

Drug-delivery implants were highly heterogeneous due to its applicability for multiple health conditions. Most implants were made of PLGA and most drugs assessed presented anti-inflammatory, antibiotic, or anticancer effects. Solvent evaporation and CIL were the most prominent manufacturing process and geometry, respectively.

Fabrication of long-acting insulin formulation based on poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles: preparation, optimization, characterization, and in vitro evaluation

The purpose of this research was the fabrication, statistical optimization, and in vitro characterization of insulin-loaded poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanoparticles (INS-PHBV-NPs). Nanopar-ticles were successfully developed by double emulsification solvent evaporation method. The NPs were characterized for particle size, entrapment efficiency (EE%), and polydispersity index (PDI). The NPs also were characterized by scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and circular dichroism (CD). The optimum conditions were found to be 1.6% polyvinyl alcohol (PVA), 0.9% of PHBV, and 15 mg/ml of insulin with the aid of the Box-Behnken experimental design results. The optimized NPs showed spherical shape with particle size of 250.21 ± 11.37 nm, PDI of 0.12 ± 0.01, and with EE% of 90.12 ± 2.10%. In vitro drug release pattern followed Korsmeyer-Peppas model and exhibited an initial burst release of 19% with extended drug release of 63.2% from optimized NPs within 27 d. In conclusion, these results suggest that INS-PHBV-NPs could be a promising candidate for designing an injectable sustained release formulation for insulin.