Photocurable poly(ethylene glycol) as a bioink for the inkjet 3D pharming of hydrophobic drugs

Binder jetting and material extrusion are the two most common additive manufacturing techniques used to create pharmaceutical tablets. However, their versatility is limited since the powder component is present throughout the dosage forms fabricated by binder jet 3D printing and material extrusion 3D printing requires high operating temperatures. Conversely, material jetting allows for compositional control at a voxel level and can dispense material at room temperature. Unfortunately, there are a limited number of materials that are both printable and biocompatible. Therefore, the aim of this study was to engineer photocurable bioinks that are suitable for hydrophobic active pharmaceutical ingredients and have rapid gelation times upon visible light exposure. The resulting bioinks were comprised of poly(ethylene glycol) diacrylate (250 Da) as the crosslinkable monomer, Eosin Y as the photoinitiator, and methoxide-poly(ethylene glycol)-amine as the coinitiator. Additionally, poly(ethylene glycol) (200 Da) was added as a plasticizer to modulate the drug release profiles, and Naproxen was used as the model drug due to its high hydrophobicity. Various bioink formulations were dispensed into the bottom half of blank preform tablets - made via direct compression - using a piezoelectric nozzle, photopolymerized, and capped with the top half of the preform tablet to complete the pharmaceutical dosage form. Results from the release studies showed that drug release can be modulated by both the percent of poly(ethylene glycol) diacrylate in the formulation and the light exposure time used to cure the bioinks. These bioinks have the potential to expand the library of materials available for creating pharmaceutical tablets via inkjet printing with personalized drug dosages.

Numerical simulation of hot-melt extrusion processes for amorphous solid dispersions using model-based melt viscosity

Simulation of HME processes is a valuable tool for increased process understanding and ease of scale-up. However, the experimental determination of all required input parameters is tedious, namely the melt rheology of the amorphous solid dispersion (ASD) in question. Hence, a procedure to simplify the application of hot-melt extrusion (HME) simulation for forming amorphous solid dispersions (ASD) is presented. The commercial 1D simulation software Ludovic^® was used to conduct (i) simulations using a full experimental data set of all input variables including melt rheology and (ii) simulations using model-based melt viscosity data based on the ASDs glass transition and the physical properties of polymeric matrix only. Both types of HME computation were further compared to experimental HME results. Variation in physical properties (e.g. heat capacity, density) and several process characteristics of HME (residence time distribution, energy consumption) among the simulations and experiments were evaluated. The model-based melt viscosity was calculated by using the glass transition temperature (T_g) of the investigated blend and the melt viscosity of the polymeric matrix by means of a T_g-viscosity correlation. The results of measured melt viscosity and model-based melt viscosity were similar with only few exceptions, leading to similar HME simulation outcomes. At the end, the experimental effort prior to HME simulation could be minimized and the procedure enables a good starting point for rational development of ASDs by means of HME. As model excipients, Vinylpyrrolidone-vinyl acetate copolymer (COP) in combination with various APIs (carbamazepine, dipyridamole, indomethacin, and ibuprofen) or polyethylene glycol (PEG 1500) as plasticizer were used to form the ASDs.

Drug-eluting embolic microspheres for local drug delivery - State of the art

Embolic microspheres or beads used in transarterial chemoembolization are an established treatment method for hepatocellular carcinoma patients. The occlusion of the tumor-feeding vessels by intra-arterial injection of the beads results in tumor necrosis and shrinkage. In this short review, we describe the utility of using these beads as devices for local drug delivery. We review the latest advances in the development of non-biodegradable and biodegradable drug-eluting beads for transarterial chemoembolization. Their capability to load different drugs, such as chemotherapeutics and anti-angiogenic compounds with different physicochemical properties, like charge and hydrophilicity/hydrophobicity, are discussed. We specifically address controlled and sustained drug release from the microspheres, and the resulting in vivo pharmacokinetics in the plasma vs. drug distribution in the targeted tissue.

Application of matrix solid-phase dispersion followed by GC-MS/MS to the analysis of emerging contaminants in vegetables

A multiresidue method for the determination of 17 emerging contaminants in vegetables was developed based on ultrasound-assisted matrix solid-phase dispersion (MSPD). The analysis was performed using isotope dilution gas chromatography tandem mass spectrometry. In the development of the MSPD procedure, different parameters such as sonication and the type of sorbent or extraction solvent were assayed. Manual and in situ derivatization was assayed and the chromatographic response was higher when the reaction takes place in the injection port. The limits of detection obtained for the studied compounds were in the range of 0.1-0.4ngg(-1) for the different vegetables analyzed. The developed method was applied to vegetables obtained from several local markets. At least one of the organophosphates was detected in the analyzed samples at levels ranging from 0.6 to 4.6ngg(-1) and bisphenol A was detected in all the samples at concentration up to 16ngg(-1).

Levetiracetam synergises with common analgesics in producing antinociception in a mouse model of painful diabetic neuropathy

Painful diabetic neuropathy is difficult to treat. Single analgesics often have insufficient efficacy and poor tolerability. Combination therapy may therefore be of particular benefit, because it might provide optimal analgesia with fewer adverse effects. This study aimed to examine the type of interaction between levetiracetam, a novel anticonvulsant with analgesic properties, and commonly used analgesics (ibuprofen, aspirin and paracetamol) in a mouse model of painful diabetic neuropathy. Diabetes was induced in C57BL/6 mice with a single high dose of streptozotocin, applied intraperitoneally (150 mg/kg). Thermal (tail-flick test) and mechanical (electronic von Frey test) nociceptive thresholds were measured before and three weeks after diabetes induction. The antinociceptive effects of orally administered levetiracetam, analgesics, and their combinations were examined in diabetic mice that developed thermal/mechanical hypersensitivity. In combination experiments, the drugs were co-administered in fixed-dose fractions of single drug ED50 and the type of interaction was determined by isobolographic analysis. Levetiracetam (10-100 mg/kg), ibuprofen (2-50 mg/kg), aspirin (5-75 mg/kg), paracetamol (5-100 mg/kg), and levetiracetam-analgesic combinations produced significant, dose-dependent antinociceptive effects in diabetic mice in both tests. In the tail-flick test, isobolographic analysis revealed 15-, and 19-fold reduction of doses of both drugs in the combination of levetiracetam with aspirin/ibuprofen, and paracetamol, respectively. In the von Frey test, approximately 7- and 9-fold reduction of doses of both drugs was detected in levetiracetam-ibuprofen and levetiracetam-aspirin/levetiracetam-paracetamol combinations, respectively. These results show synergism between levetiracetam and ibuprofen/aspirin/paracetamol in a model of painful diabetic neuropathy and might provide a useful approach to the treatment of patients suffering from painful diabetic neuropathy.

Cyclooxygenase inhibition and rosuvastatin-induced vascular protection in the setting of ischemia-reperfusion: A human in vivo study

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG Co-A) reductase inhibitors have preconditioning effects involving up-regulation of cyclooxygenase (COX)-2. We investigated the effect of selective and non-selective COX inhibition on rosuvastatin-mediated protection against ischemia-reperfusion (IR)-induced endothelial dysfunction in the human forearm. Healthy volunteers (n=66) were allocated to placebo, acetylsalicylic acid (ASA) 81mg daily, ASA 325mg daily, celecoxib 200mg twice daily or 400mg ibuprofen four times daily, each administered for 5 to 7days. On the last day of study drug therapy, subjects received a single dose of 40mg rosuvastatin. Twenty-four hours later flow-mediated dilation (FMD) of the radial artery was evaluated before and after IR. In the placebo group, FMD was similar before and after IR (8.1±1.0 vs 7.2±0.8%; P=NS) indicating a significant protective effect of rosuvastatin. There was also no effect of IR on FMD in the ASA 81mg group (6.7±0.6 vs 6.1±0.7%; P=NS). In contrast, following IR there was a significant decrease in FMD in the ASA 325mg group (7.2±0.8 vs 3.3±0.7%, P<0.001), the celecoxib group (7.3±1.5 vs 2.6±1.5%, P<0.01) as well as the ibuprofen group (6.8±0.7 vs 2.6±0.8%; P<0.01). Therefore, nonselective COX inhibition with ASA 325mg and ibuprofen completely inhibit the protective effects of rosuvastatin in the setting of IR injury, as does therapy with the specific COX-2 antagonist celecoxib. In contrast, therapy with low dose ASA (81mg daily) does not have such inhibitory effects.

Antinociceptive and anti-inflammatory activity of Sambucus palmensis link, an endemic Canary Island species

ETHNOPHARMACOLOGICAL RELEVANCE

Sambucus palmensis Link is an endemic species of the Canary Islands, popularly known as "Saúco canario". This species has wide use in folk medicine practice on the islands, especially as analgesic and anti-inflammatory. So the aim of our study is to evaluate the antinociceptive and anti-inflammatory activity of an aqueous extract of this species.

MATERIALS AND METHODS

Three aqueous extract doses (35, 52.5 and 70 mg/kg) were orally administered to laboratory Swiss mice obtained from the Central Animal House of La Laguna University. Writhing responses induced by phenylquinone, formalin induced paw pain response, tail-flick test and paw edema induced by carrageenan were evaluated in this work.

RESULTS

Oral pretreatment with 52.5 and 70 mg/kg Sambucus palmensis aqueous extract significantly reduced the writhing number induced by phenylquinone injection (61.64 and 89.04% respectively), and the pain response in the first (36.67 and 38.89%) and second (57.28 and 70.1%) phases respectively of the formalin test. Sambucus palmensis had a very slight effect on tail-flick test and inhibited moderately the edema formation induced by carrageenan in mice.

CONCLUSIONS

These data show for the first time that Sambucus palmensis has a significant antinociceptive effect that seems to be more peripherical than central. Sambucus palmensis also displays a moderate anti-inflammatory activity in an acute inflammation model. These results support the widespread use of Sambucus palmensis in popular medicine to treat pain and inflammation.