Understanding syringeability and injectability of high molecular weight PEO solution through time-dependent force-distance profiles

Opioid medications play a vital role in treating moderate to severe pain. Unfortunately, many drug misusers and abusers attempt to alter the formulations or properties of these drugs by manipulation, (e.g., crushing, chewing, smoking, snorting, injecting). The intravenous (IV) route is most dangerous to abusers, as the drugs directly enter the circulatory system and produce intense euphoria. To obtain a full understanding of the impact of syringe factors (e.g., needle gauge size, needle length, syringe barrel size), on the ease of injection, we undertook a comprehensive assessment of syringeability and injectability of manipulated abuse-deterrent formulations (ADFs). A texture analyzer-based testing method was developed for the measurement of the resistance force of pulling, holding, and pushing phases of injections. Results showed that the finer needle gauge sizes required higher injection force to withdraw drug solutions. In addition, the syringed liquid volume was highly dependent on needle gauge size, holding time, and sample viscosity. In most cases, a lower needle gauge number and a longer holding time increased the syringed volume. Needle length was highly correlated to injection force (R² = 0.99). Using longer needles to inject drug solution requires greater force. Furthermore, large barrel size was correlated to pushing force (R² = 0.99); thus, increasing the difficulty of pushing the plunger of a large syringe with one hand. Finally, relationships between injection force, sample viscosity, and testing conditions were elucidated using a mathematical model, which could be used in the future to assess and predict injection force of solution samples.

Preparation and evaluation of in - situ gels containing hydrocortisone for the treatment of aphthous ulcer

Aphthous ulcers are painful sores that may occur in the mouth's mucous membrane and are the most common type of oral lesions. The present research is aimed to develop in-situ gel of hydrocortisone for the treatment of aphthous ulcers. Temperature induced in-situ gels were prepared by using various concentrations of methylcellulose. The prepared formulations were evaluated for the conversion of sol-gel transition temperature or gelation temperature, gelling capacity, pH, viscosity, syringeability, spreadability, drug content, In vitro and ex vivo studies. The gelation temperatures of the prepared formulations were found to be in the range of 32-39 ​°C. The formulations exhibited fairly uniform drug content (76.40-94.7%) and pH was found to be 6.8. In vitro drug release was carried out for 8 ​h using phosphate buffer as a diffusion medium. In-situ gel formulation containing 1% w/v of methylcellulose as a gel base prolonged the drug release up to 8 ​h and showed sustained release behaviour. Via these, in-situ gel formulations, the release kinetics of the drug was first order. Finally, it can be inferred that in-situ gel formulation containing 1% w/v of methylcellulose facilitates prolonged drug release, extended drug residence period, which in turn improves the bioavailability of drugs. The short-term stability studies were carried out and no substantial changes were observed.

Injectability as a function of viscosity and dosing materials for subcutaneous administration

Injectability is a term related to the ease of parenteral administration of a dosing solution, and includes dose preparation, dose administration, ergonomics related to these procedures, pain of injection, and other adverse events at the injection site. This article focuses on force measurements related to injectability, namely: force to expel syringe contents (expulsion force - a mimic for in vivo injection force), needle-penetration force, and needle-bending force, and these results are supplemented by expulsion time measurements with 18 participants, as well as injections in a porcine model. Based on the expulsion time measurements, where 80 N injection force was found to be difficult for most people, we consider the maximum acceptable injection force to be 40 N, and recommend targeting no more than 20 N, especially if the configuration may be used in an autoinjector or similar device. The injectability of antisense oligonucleotide solutions was assessed to determine optimal dosing materials (among those evaluated) for a variety of solution viscosities. Dosing materials varied in syringe inner diameter, needle inner diameter, needle length, and needle wall thickness: standard-wall vs. thin-wall. In general, short (6-8 mm) thin-wall needles are recommended as a way to improve patient perception and comfort during subcutaneous dose administration.

Risk based in vitro performance assessment of extended release abuse deterrent formulations

High strength extended release opioid products, which are indispensable tools in the management of pain, are associated with serious risks of unintentional and potentially fatal overdose, as well as of misuse and abuse that might lead to addiction. The issue of drug abuse becomes increasingly prominent when the dosage forms can be readily manipulated to release a high amount of opioid or to extract the drug in certain products or solvents. One approach to deter opioid drug abuse is by providing novel abuse deterrent formulations (ADF), with properties that may be viewed as barriers to abuse of the product. However, unlike regular extended release formulations, assessment of ADF technologies are challenging, in part due to the great variety of formulation designs available to achieve deterrence of abuse by oral, parenteral, nasal and respiratory routes. With limited prior history or literature information, and lack of compendial standards, evaluation and regulatory approval of these novel drug products become increasingly difficult. The present article describes a risk-based standardized in-vitro approach that can be utilized in general evaluation of abuse deterrent features for all ADF products.

Bone critical defect repair with poloxamine-cyclodextrin supramolecular gels

The aim of this study was to evaluate the osteoinductive capacity of a poloxamine (Tetronic(®) 908, T) and α-cyclodextrin (αCD) supramolecular gel (T-CD) as scaffold in a critical size defect in rat calvaria. The T-CD gel was evaluated solely and after being loaded with simvastatin (SV) and bone morphogenetic protein (BMP-2) separately and in combinations in order to reduce the doses of the active substances. Three doses of SV (7.5, 75, 750 μg) and two doses of BMP-2 (3 and 6 μg) were tested. The histology and histomorphometrical analysis showed improved bone repair with T-CD compared to T, probably due to better release control of both SV and BMP-2. In addition, as T-CD eroded more slowly than poloxamine alone, it remained longer in the defect site. Although synergism was not obtained with BMP-2 and SV, according to the observed regeneration of the defect, the dose of BMP-2 and SV can be reduced to 3 μg and 7.5 μg, respectively.

Effect of liposomes on rheological and syringeability properties of hyaluronic acid hydrogels intended for local injection of drugs

The aim of this work was to thoroughly study the effect of liposomes on the rheological and the syringeability properties of hyaluronic acid (HA) hydrogels intended for the local administration of drugs by injection. Whatever the characteristics of the liposomes added (neutral, positively or negatively charged, with a corona of polyethylene glycol chains, size), the viscosity and the elasticity of HA gels increased in a lipid concentration-dependent manner. Indeed, liposomes strengthened the network formed by HA chains due to their interactions with this polymer. The nature and the resulting effects of these interactions depended on liposome composition and concentration. The highest viscosity and elasticity were observed with liposomes covered by polyethylene glycol chains while neutral liposomes displayed the lowest effect. Despite their high viscosity at rest, all the formulations remained easily injectable through needles commonly used for local injections thanks to the shear-thinning behavior of HA gels. The present study demonstrates that rheological and syringeability tests are both necessary to elucidate the behavior of such systems during and post injection. In conclusion, HA liposomal gels appear to be a promising and versatile formulation platform for a wide range of applications in local drug delivery when an injection is required.