Radiolabeled Risperidone microSPECT/CT Imaging for Intranasal Implant Studies Development

The use of intranasal implantable drug delivery systems has many potential advantages for the treatment of different diseases, as they can provide sustained drug delivery, improving patient compliance. We describe a novel proof-of-concept methodological study using intranasal implants with radiolabeled risperidone (RISP) as a model molecule. This novel approach could provide very valuable data for the design and optimization of intranasal implants for sustained drug delivery. RISP was radiolabeled with 125I by solid supported direct halogen electrophilic substitution and added to a poly(lactide-co-glycolide) (PLGA; 75/25 D,L-Lactide/glycolide ratio) solution that was casted on top of 3D-printed silicone molds adapted for intranasal administration to laboratory animals. Implants were intranasally administered to rats, and radiolabeled RISP release followed for 4 weeks by in vivo non-invasive quantitative microSPECT/CT imaging. Percentage release data were compared with in vitro ones using radiolabeled implants containing either 125I-RISP or [125I]INa and also by HPLC measurement of drug release. Implants remained in the nasal cavity for up to a month and were slowly and steadily dissolved. All methods showed a fast release of the lipophilic drug in the first days with a steadier increase to reach a plateau after approximately 5 days. The release of [125I]I− took place at a much slower rate. We herein demonstrate the feasibility of this experimental approach to obtain high-resolution, non-invasive quantitative images of the release of the radiolabeled drug, providing valuable information for improved pharmaceutical development of intranasal implants.

Development of 3D-printed subcutaneous implants using concentrated polymer/drug solutions

Implantable drug-eluting devices that provide therapeutic cover over an extended period of time following a single administration have potential to improve the treatment of chronic conditions. These devices eliminate the requirement for regular and frequent drug administration, thus reducing the pill burden experienced by patients. Furthermore, the use of modern technologies, such as 3D printing, during implant development and manufacture renders this approach well-suited for the production of highly tuneable devices that can deliver treatment regimens which are personalised for the individual. The objective of this work was to formulate subcutaneous implants loaded with a model hydrophobic compound, olanzapine (OLZ) using robocasting - a 3D-printing technique. The formulated cylindrical implants were prepared from blends composed of OLZ mixed with either poly(caprolactone) (PCL) or a combination of PCL and poly(ethylene)glycol (PEG). Implants were characterised using scanning electron microscopy (SEM), thermal analysis, infrared spectroscopy, and X-ray diffraction and the crystallinity of OLZ in the formulated devices was confirmed. In vitro release studies demonstrated that all the formulations were capable of maintaining sustained drug release over a period of 200 days, with the maximum percentage drug release observed to be c.a. 60 % in the same period.

Metronidazole nanosuspension loaded dissolving microarray patches: An engineered composite pharmaceutical system for the treatment of skin and soft tissue infection

Bacteroides fragilis is one of the most common causative group of microorganisms that is associated with skin and soft tissue infections (SSTI). Metronidazole (MTZ) is the drug of choice used in the treatment of SSTI caused by the bacterium. However, owing to its physiochemical properties, MTZ have limited skin permeation, which render the drug unsuitable for the treatment of deep-rooted SSTIs. One strategy to overcome this limitation is to reformulate MTZ into nanosuspension which will then be loaded into dissolving microarray patches (MAPs) for the treatment of SSTIs caused by B. fragilis. Herein, we report for the first time on the preparation and optimisation of MAP loaded with MTZ nanosuspension (MTZ-NS). After screening a range of polymeric surfactants, we identified that Soluplus® resulted in the formation of MTZ-NS with the smallest particle size (115 nm) and a narrow PDI of 0.27. Next, the MTZ-NS was further optimised using a design of experiments (DoE) approach. The optimised MTZ-NS was then loaded into dissolving MAPs with varying MTZ-NS content. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and cell proliferation assays along with LIVE/DEAD™ staining on the 3T3L1 cell line showed that the MTZ-NS loaded dissolving MAPs displayed minimal toxicity and acceptable biocompatibility. In vitro dermatokinetic studies showed that the MTZ-NS loaded MAPs were able to deliver the nitroimidazole antibiotic across all strata of the skin resulting in a delivery efficiency of 95 % after a 24-hour permeation study. Lastly, agar plating assay using bacterial cultures of B. fragilis demonstrated that MTZ-NS loaded MAP resulted in complete bacterial inhibition in the entire plate relative to the control group. Should this formulation be translated into clinical practice, this pharmaceutical approach may provide a minimally invasive strategy to treat SSTIs caused by B. fragilis.

Soluplus®-based dissolving microarray patches loaded with colchicine: towards a minimally invasive treatment and management of gout

Considered as one of the most common inflammatory arthritis, gout is characterised by a sudden onset of severe joint pain. As the first-line drug of choice used in treating acute gout, colchicine (CLC) is hindered by poor gastrointestinal permeability as well as unfavourable gastrointestinal side effects. Herein, we present, for the first time, the preparation of microarray array patches (MAPs) made of a polymeric solubiliser, Soluplus®, loaded with CLC for its systemic delivery. The fabricated MAPs displayed acceptable mechanical properties and were capable of being inserted into the skin to a depth of ≈500 μm in full thickness ex vivo neonatal porcine skin, as evidenced by optical coherence tomography. In vitro dermatokinetic studies utilising full thickness neonatal porcine skin demonstrated that the CLC-loaded MAPs delivered CLC across all skin strata, resulting in a delivery efficiency of 73% after 24 hours. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and cell proliferation assays along with LIVE/DEAD™ staining on the 3T3-L1 cell line showed that the MAP formulation displayed minimal toxicity, with acceptable biocompatibility. Lastly, the anti-inflammatory properties of the formulation were evaluated using a THP-1 macrophage cell line. It was shown that treatment of THP-1 macrophages that are exposed to lipopolysaccharide (LPS) with CLC-loaded MAPs caused a significant (p < 0.05) reduction of TNF-α production, a pro-inflammatory cytokine typically associated with the early onset of acute gout. Accordingly, CLC-loaded MAPs could represent a new minimally-invasive alternative strategy for management of acute gout.

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.

3D-printed implantable devices with biodegradable rate-controlling membrane for sustained delivery of hydrophobic drugs

Implantable drug delivery systems offer an alternative for the treatments of long-term conditions (i.e. schizophrenia, HIV, or Parkinson’s disease among many others). The objective of the present work was to formulate implantable devices loaded with the model hydrophobic drug olanzapine (OLZ) using robocasting 3D-printing combined with a pre-formed rate controlling membrane. OLZ was selected as a model molecule due to its hydrophobic nature and because is a good example of a molecule used to treat a chronic condition schizophrenia. The resulting implants consisted of a poly(ethylene oxide) (PEO) implant coated with a poly(caprolactone) (PCL)-based membrane. The implants were loaded with 50 and 80% (w/w) of OLZ. They were prepared using an extrusion-based 3D-printer from aqueous pastes containing 36–38% (w/w) of water. The printing process was carried out at room temperature. The resulting implants were characterized by using infrared spectroscopy, scanning electron microscopy, thermal analysis, and X-ray diffraction. Crystals of OLZ were present in the implant after the printing process. In vitro release studies showed that implants containing 50% and 80% (w/w) of OLZ were capable of providing drug release for up to 190 days. On the other hand, implants containing 80% (w/w) of OLZ presented a slower release kinetics. After 190 days, total drug release was ca. 77% and ca. 64% for implants containing 50% and 80% (w/w) of OLZ, respectively. The higher PEO content within implants containing 50% (w/w) of OLZ allows a faster release as this polymer acts as a co-solvent of the drug.

Elucidating the Impact of Surfactants on the Performance of Dissolving Microneedle Array Patches

The need for biocompatible polymers capable of dissolving in the skin while exhibiting reasonable mechanical features and delivery efficiency limits the range of materials that could be utilized in fabricating dissolving microneedle array patches (MAPs). The incorporation of additives, such as surfactants, during microneedle fabrication might be an alternative solution to overcome the limited range of materials used in fabricating dissolving MAPs. However, there is a lacuna in the knowledge on the effect of surfactants on the manufacture and performance of dissolving MAPs. The current study explores the role of surfactants in the manufacture and performance of dissolving MAPs fabricated from poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) loaded with the model drugs, ibuprofen sodium and itraconazole. Three nonionic surfactants, Lutrol F108, Pluronic F88, and Tween 80, in solutions at varying concentrations (0.5, 1.0, and 2.0% w/w) were loaded into these dissolving MAPs. It was discovered that all of the dissolving MAPs that incorporated surfactant displayed a lower reduction in the microneedle height (≈10%) relative to the control formulation (≈20%) when subjected to a compressive force of 32 N. In addition, the incorporation of surfactants in some instances enhanced the insertion profile of these polymeric MAPs when evaluated using ex vivo neonatal porcine skin. The incorporation of surfactant into ibuprofen sodium-loaded dissolving MAPs improved the insertion depth of MAPs from 400 μm down to 600 μm. However, such enhancement was not apparent when the MAPs were loaded with the model hydrophobic drug, itraconazole. Skin deposition studies highlighted that the incorporation of surfactant enhanced the delivery efficiency of both model drugs, ibuprofen sodium and itraconazole. The incorporation of surfactant enhanced the amount of ibuprofen sodium delivered from 60.61% up to ≈75% with a majority of the drug being delivered across the skin and into the receptor compartment. On the other hand, when surfactants were added into MAPs loaded with the model hydrophobic drug itraconazole, we observed enhancement in intradermal delivery efficiency from 20% up to 30%, although this did not improve the delivery of the drug across the skin. This work highlights that the addition of nonionic surfactant is an alternative formulation strategy worth exploring to improve the performance and delivery efficiency of dissolving MAPs.

Development and characterization of a dry reservoir-hydrogel-forming microneedles composite for minimally invasive delivery of cefazolin

Cefazolin (CFZ) is one of the most extensively used cephalosporins. This antibiotic exerts its bactericidal activity by interfering with bacterial cell wall formation, leading to bacteriolysis. CFZ is highly polar, resulting in the drug having poor oral bioavailability. Accordingly, the antibiotic is administered via intramuscular or intravenous injections, which are both painful and invasive. Due to these limitations, there is an impetus to explore alternative drug delivery platforms which offer a minimally invasive approach to delivery CFZ into and across the skin. The current work presents the development of a composite pharmaceutical system composed of hydrogel-forming microneedles (MNs) in tandem with CFZ dry reservoirs. The hydrogel system was fabricated from Gantrez® S-97 and Carbopol® 974P NF crosslinked with PEG 10,000. Swelling kinetic studies showed that the hydrogel system developed was capable of achieving 4000% swelling in PBS pH 7.4. In addition, results from a solute diffusion study showed that CFZ was able to achieve ≈100% cumulative permeation across the swollen hydrogel film. When formulated into MNs, the hydrogel system was capable of breaching the stratum corneum, resulting in intradermal insertion of the hydrogel forming MNs into ex vivo neonatal porcine skin, as evidenced from optical coherence tomography. In addition, two different CFZ loaded dry reservoirs consisting of directly compressed tablets (DCT) and lyophilised (LYO) wafers were formulated and characterised. These dry reservoir systems showed fast dissolution, dissolving in phosphate buffer saline pH 7.4 in less than one minute. In vitro permeation studies, using full thickness ex vivo neonatal porcine skin were conducted. HPLC analysis demonstrated the dry reservoir combination consisting of DCT with hydrogel-forming MNs was capable of achieving up to 80 µg CFZ delivery into the epidermis within 2 hours of application. In addition, DCT reservoir coupled with hydrogel-forming MNs were able to deliver CFZ up to 1.8 mg into and across the skin at 24 hours. Should this system be translated into clinical practice, it may provide a minimally invasive strategy to administer CFZ for the treatment of infections such as septic arthritis, osteomyelitis and cellulitis.

Use of 3D Printing for the Development of Biodegradable Antiplatelet Materials for Cardiovascular Applications

Small-diameter synthetic vascular grafts are required for surgical bypass grafting when there is a lack of suitable autologous vessels due to different reasons, such as previous operations. Thrombosis is the main cause of failure of small-diameter synthetic vascular grafts when used for this revascularization technique. Therefore, the development of biodegradable vascular grafts capable of providing a localized and sustained antithrombotic drug release mark a major step forward in the fight against cardiovascular diseases, which are the leading cause of death globally. The present paper describes the use of an extrusion-based 3D printing technology for the production of biodegradable antiplatelet tubular grafts for cardiovascular applications. For this purpose, acetylsalicylic acid (ASA) was chosen as a model molecule due to its antiplatelet activity. Poly(caprolactone) and ASA were combined for the fabrication and characterization of ASA-loaded tubular grafts. Moreover, rifampicin (RIF) was added to the formulation containing the higher ASA loading, as a model molecule that can be used to prevent vascular prosthesis infections. The produced tubular grafts were fully characterized through multiple techniques and the last step was to evaluate their drug release, antiplatelet and antimicrobial activity and cytocompatibility. The results suggested that these materials were capable of providing a sustained ASA release for periods of up to 2 weeks. Tubular grafts containing 10% (w/w) of ASA showed lower platelet adhesion onto the surface than the blank and grafts containing 5% (w/w) of ASA. Moreover, tubular grafts scaffolds containing 1% (w/w) of RIF were capable of inhibiting the growth of Staphylococcus aureus. Finally, the evaluation of the cytocompatibility of the scaffold samples revealed that the incorporation of ASA or RIF into the composition did not compromise cell viability and proliferation at short incubation periods (24 h).

Poly(caprolactone)-based subcutaneous implant for sustained delivery of levothyroxine

This work aimed to develop a subcutaneous implant for prolonged delivery of LEVO to treat hypothyroidism. This could overcome challenges with patient compliance and co-administration and could improve treatment of this condition. For this purpose, implants were produced by solvent casting mixtures of poly(caprolactone) (PCL), poly(ethylene glycol) (PEG) and LEVO sodium. These implants contained mixtures of PCL of differing molecular weight, PEG and different LEVO sodium loadings (20% or 40% w/w). SEM images confirmed that the drug was evenly dispersed throughout the implant. In vitro release rates ranging from 28.37 ± 1.19 - 78.21 ± 19.93 µg/day and 47.39 ± 8.76 - 98.92 ± 4.27 µg/day were achieved for formulations containing 20% and 40% w/w drug loading, respectively. Implants containing higher amounts of low molecular weight PCL and 40% w/w of LEVO showed release profiles governed by zero order kinetics. On the other hand, implants containing higher amounts of high molecular weight PCL showed a release mechanism governed by Fickian diffusion. Finally, two representative formulations were tested in vivo. These implants were capable of providing detectable LEVO levels in plasma during the entire duration of the experiments (4 weeks) with LEVO plasma levels ranging between 5 and 20 ng/mL.

Bioadhesive-Thermosensitive In Situ Vaginal Gel of the Gel Flake-Solid Dispersion of Itraconazole for Enhanced Antifungal Activity in the Treatment of Vaginal Candidiasis

The poor solubility of itraconazole (ITZ) has limited its efficacy in the treatment of vaginal candidiasis. Accordingly, the improvement of ITZ solubility using a solid dispersion technique was important to enhance its antifungal activity. Besides, as the purpose of this research was to develop local-targeting formulations, bioadhesive-thermosensitive in situ vaginal gel combined with the gel-flake system was found to be the most suitable choice. To obtain optimum solubility, entrapment efficiency, and drug-loading capacity, optimization of solid dispersion (SD) and gel-flake formulations of ITZ was performed using a composite central design. The results showed that the optimized formulation of SD-ITZ was able to significantly enhance its solubility in both water and simulated vaginal fluid to reach the values of 4.211 ± 0.23 and 4.291 ± 0.21 mg/mL, respectively. Additionally, the optimized formulation of SD-ITZ gel flakes possessed desirable entrapment efficiency and drug-loading capacity. The in situ vaginal gel containing SD-ITZ gel flakes was prepared using PF-127 and PF-68, as the gelling agents, with the addition of hydroxypropyl methylcellulose (HPMC) as the mucoadhesive polymer. It was found that the obtained in situ vaginal gel provided desirable physicochemical properties and was able to retain an amount of more than 4 mg of ITZ in the vaginal tissue after 8 h. Importantly, according to the in vivo antifungal activity using infection animal models, the incorporation of the solid dispersion technique and gel-flake system in the formulation of the bioadhesive-thermosensitive in situ vaginal gel led to the most significant decrease of the growth of Candida albicans reaching <1 log colony-forming units (CFU)/mL or equivalent to <10% of the total colony after 14 days, indicating the improvement of ITZ antifungal activity compared to other treated groups. Therefore, these studies confirmed a great potential to enhance the efficacy of ITZ in treating vaginal candidiasis. Following these findings, several further experiments need to be performed to ensure acceptability and usability before the research reaches the clinical stage.

New and sensitive HPLC-UV method for concomitant quantification of a combination of antifilariasis drugs in rat plasma and organs after simultaneous oral administration

A combination treatment comprising ivermectin (IVM), albendazole (ABZ) and doxycycline (DOX) is often prescribed for lymphatic filariasis patients. Nevertheless, there has not been an analytical method established and documented to determine these compounds simultaneously. Herein, we report a new high-performance liquid chromatographic method coupled with a UV detector (HPLC-UV) to quantify these drugs in plasma and organs. This developed analytical method was validated according to the International Conference on Harmonization (ICH) and US Food and Drug Administration (FDA) guidelines. The validated method was successfully employed to analyze IVM, ABZ along with its metabolites (albendazole sulfoxide (ABZ-OX) and albendazole sulfone (ABZ-ON)), and DOX in the plasma and organs of Wistar rats after simultaneous oral administration. An Xselect CSH™ C₁₈ HPLC column was utilized as a stationary phase, with a mobile phase consisting of 0.1% v/v trifluoracetic acid in water and acetonitrile with a run time of 20 min. The calibration curves in biological samples were found to be linear across the concentration range of 0.01-5 μg mL^-1 for IVM, ABZ and ABZ metabolites, and 0.025-10 μg mL^-1 for DOX with an R value ≥0.998 in each case. The validated method was found to be selective, precise and accurate. Finally, the method developed in this study was deployed to assess the pharmacokinetic profiles and biodistribution of the combination of drugs after oral administration to Wistar rats. The validated HPLC-UV method in this study provides an extensive range of prospective applications for pharmacokinetic-based studies, therapeutic drug monitoring and toxicology.

Fused deposition modelling for the development of drug loaded cardiovascular prosthesis

Cardiovascular diseases constitute a number of conditions which are the leading cause of death globally. To combat these diseases and improve the quality and duration of life, several cardiac implants have been developed, including stents, vascular grafts and valvular prostheses. The implantation of these vascular prosthesis has associated risks such as infection or blood clot formation. In order to overcome these limitations medicated vascular prosthesis have been previously used. The present paper describes a 3D printing method to develop medicated vascular prosthesis using fused deposition modelling (FDM) technology. For this purpose, rifampicin (RIF) was selected as a model molecule as it can be used to prevent vascular graft prosthesis infection. Thermoplastic polyurethane (TPU) and RIF were combined using hot melt extrusion (HME) to obtain filaments containing RIF concentrations ranging between 0 and 1% (w/w). These materials are capable of providing RIF release for periods ranging between 30 and 80 days. Moreover, TPU-based materials containing RIF were capable of inhibiting the growth of Staphylococcus aureus. This behaviour was observed even for TPU-based materials containing RIF concentrations of 0.1% (w/w). TPU containing 1% (w/w) of RIF showed antimicrobial properties even after 30 days of RIF release. Alternatively, these methods were used to prepare dipyridamole containing TPU filaments. Finally, using a dual extrusion 3D printer vascular grafts containing both drugs were prepared.

Enhancing intradermal delivery of tofacitinib citrate: Comparison between powder-loaded hollow microneedle arrays and dissolving microneedle arrays

Autoimmune-mediated inflammatory skin diseases, such as psoriasis, alopecia areata, and vitiligo, have been reported as the 4th leading cause of nonfatal disease burden worldwide. This is mainly related to the poor quality of life experienced by these patients. Although topical and systemic steroids represent the most common treatment, the variability in success rates and side effects often lead to treatment discontinuation. Recent off-label clinical studies using oral Janus Kinase (JAK) inhibitors (e.g., ruxolitinib, tofacitinib, baraticinib) have shown promising results. However, frequent side effects, such as infections and blood clots have been reported. Therefore, the aim of this research was to enhance the intradermal delivery of tofacitinib citrate with MN arrays. Using crosslinked hydrogels containing modifying agents (urea, sorbitol and sodium chloride), hollow MN arrays were fabricated and then loaded with tofacitinib citrate. Their efficiency in intradermal delivery of tofacitinib was compared with dissolving MN arrays and a control (Aqueous cream BP), using neonatal porcine skin. Despite the fact that the hydrogel was only present on the outer surface, hollow MN arrays showed comparable resistance to compression values and insertion capabilities to dissolving MN arrays. Although hollow MN arrays containing NaCl in the formulation led to slightly higher depositions of tofacitinib in epidermis and dermis of neonatal porcine skin when compared to a control cream, dissolving MN arrays showed superiority in terms of tofacitinib deposition in the dermis. Indeed, at 24 h of the study, control cream and dissolving MN arrays delivered 143.98 ug/cm² and 835 ug/cm² of drug in the dermis, respectively, confirming the enhanced intradermal drug delivery capacity of MN arrays and their potential for treatment of autoimmune skin diseases.

Poly(caprolactone)-Based Coatings on 3D-Printed Biodegradable Implants: A Novel Strategy to Prolong Delivery of Hydrophilic Drugs

Implantable devices are versatile and promising drug delivery systems, and their advantages are well established. Of these advantages, long-acting drug delivery is perhaps the most valuable. Hydrophilic compounds are particularly difficult to deliver for prolonged times. This work investigates the use of poly(caprolactone) (PCL)-based implant coatings as a novel strategy to prolong the delivery of hydrophilic compounds from implantable devices that have been prepared by additive manufacturing (AM). Hollow implants were prepared from poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVA) using fused filament fabrication (FFF) AM and subsequently coated in a PCL-based coating. Coatings were prepared by solution-casting mixtures of differing molecular weights of PCL and poly(ethylene glycol) (PEG). Increasing the proportion of low-molecular-weight PCL up to 60% in the formulations decreased the crystallinity by over 20%, melting temperature by over 4 °C, and water contact angle by over 40°, resulting in an increased degradation rate when compared to pure high-molecular-weight PCL. Addition of 30% PEG to the formulation increased the porosity of the formulation by over 50% when compared to an equivalent PCL-only formulation. These implants demonstrated in vitro release rates for hydrophilic model compounds (methylene blue and ibuprofen sodium) ranging from 0.01 to 34.09 mg/day, depending on the drug used. The versatility of the devices produced in this work and the range of release rates achievable show great potential. Implants could be specifically developed in order to match the specific release rate required for a number of drugs for a wide range of conditions.

Development, Evaluation, and Pharmacokinetic Assessment of Polymeric Microarray Patches for Transdermal Delivery of Vancomycin Hydrochloride

Methicillin-resistant Staphylococcus aureus (MRSA) can cause harmful and potentially deadly infections. Vancomycin remains the first-line antibiotic treatment for MRSA-derived infections. Nevertheless, as a peptide drug, it is poorly absorbed when administered orally because of its high molecular weight and low permeability in the gastrointestinal tract and is therefore administered intravenously for the treatment of systemic diseases. In order to circumvent some of the many drawbacks associated with intravenous injection, other routes of drug delivery should be investigated. One of the strategies which has been employed to enhance transdermal drug delivery is based on microarray patches (MAPs). This work, for the first time, describes successful transdermal delivery of vancomycin hydrochloride (VCL) using dissolving MAPs (DMAPs) and hydrogel-forming MAPs (HFMAPs). VCL was formulated into DMAPs and reservoirs [film dosage forms, lyophilized wafers, and compressed tablets (CSTs)] using excipients such as poly(vinyl pyrrolidone), poly(vinyl alcohol), sodium hyaluronate, d-sorbitol, and glycerol. In this study, HFMAPs were manufactured using aqueous blends containing poly(methylvinyl ether-co-maleic acid) cross-linked by esterification with poly(ethylene glycol). The VCL-loaded CSTs (60% w/w VCL) were the most promising reservoirs to be integrated with HFMAPs based on the physicochemical evaluations performed. Both HFMAPs and DMAPs successfully delivered VCL in ex vivo studies with the percentage of drug that permeated across the neonatal porcine skin recorded at 46.39 ± 8.04 and 7.99 ± 0.98%, respectively. In in vivo studies, the area under the plasma concentration time curve from time zero to infinity (AUC_0-∞) values of 162.04 ± 61.84 and 61.01 ± 28.50 μg h/mL were achieved following the application of HFMAPs and DMAPs, respectively. In comparison, the AUC_0-∞ of HFMAPs was significantly greater than that of the oral administration control group, which showed an AUC_0-∞ of 30.50 ± 9.18 μg h/mL (p < 0.05). This work demonstrates that transdermal delivery of VCL is feasible using DMAPs and HFMAPs and could prove effective in the treatment of infectious diseases caused by MRSA, such as skin and soft tissue infections, lymphatic-related infections, and neonatal sepsis.

The measurement properties of the five-item International Index of Erectile Function (IIEF-5): a Dutch validation study

Erectile dysfunction (ED), affecting men worldwide, is associated with worse mental health. The severity of ED as well as the effect of its treatment can be assessed using valid self-reported outcome measures. A widely used measure is the International Index of Erectile Function short form (IIEF-5) which is not yet validated in Dutch. The objective of this study was to translate the IIEF-5 into Dutch and to investigate its reliability and validity to provide a useful evaluation tool. The IIEF-5 was translated into Dutch following standardized forward-backward procedures. To conduct this observational study, men with symptoms of ED completed the Dutch IIEF-5 at inclusion, 1 week later, and 6 months after inclusion. A population-based sample (reference group) completed the IIEF-5 once. The quality domains reliability and validity were addressed by testing the measurement properties internal consistency, reliability, measurement error, and content validity. Data of 82 patients and 253 reference group participants were analyzed. Internal consistency was adequate with Cronbach's alpha of 0.94 in both patient and reference group. In patients, the test-retest reliability was adequate with an intra-class correlation coefficient for agreement of 0.88. A floor effect was present in the patient group (42%), though not in the reference group (3%). There was no ceiling effect in patients (0%), while this was present in the reference group (17%). Analysis of responsiveness was not possible due to the limited number of patients receiving treatment. The Dutch IIEF-5 is a reliable and valid measure to determine severity of symptoms of ED. This evaluation tool is valuable for clinical use and interpreting results across international clinical studies. The context of a patient's sexual life is, however, indispensable and should be taken into account.