Injectable Lipid-Based Depot Formulations: Where Do We Stand?

Spatially and time-resolved SAXS for monitoring dynamic structural transitions during in situ generation of non-lamellar liquid crystalline phases in biologically relevant media

Formation of high viscous inverse lyotropic liquid crystalline phases in situ upon exposure of low viscous drug-loaded lipid preformulations to synovial fluid provides a promising approach for design of depot formulations for intra-articular drug delivery. Rational formulation design relies on a fundamental understanding of the synovial fluid-mediated dynamic structural transitions occurring at the administration site. At conditions mimicking the in vivo situation, we investigated in real-time such transitions at multiple positions by synchrotron small-angle X-ray scattering (SAXS) combined with an injection-cell. An injectable diclofenac-loaded quaternary preformulation consisting of 72/8/10/10% (w/w) glycerol monooleate/1,2-dioleoyl-glycero-3-phospho-rac-(1-glycerol)/ethanol/water was injected into hyaluronic acid solution or synovial fluid. A fast generation of a coherent drug depot of inverse bicontinuous Im3m and Pn3m cubic phases was observed. Through construction of 2D spatial maps from measurements performed 60 min after injection of the preformulation, it was possible to differentiate liquid crystalline rich- and excess hyaluronic acid solution- or synovial fluid-rich regimes. Synchrotron SAXS findings confirmed that the exposure of the preformulation to the media leads to alterations in structural features in position- and time-dependent manners. Effects of biologically relevant medium composition on the structural features, and implications for development of formulations with sustained drug release properties are highlighted.

Application of solid lipid nanoparticles as a long-term drug delivery platform for intramuscular and subcutaneous administration: In vitro and in vivo evaluation

The purpose of this work was to evaluate solid lipid nanoparticles (SLNs) as a long acting injectable drug delivery platform for intramuscular and subcutaneous administration. SLNs were developed with a low (unsaturated) and high (supersaturated) drug concentration at equivalent lipid doses. The impact of the drug loading as well as the administration route for the SLNs using two model compounds with different physicochemical properties were explored for their in vitro and in vivo performance. Results revealed that drug concentration had an influence on the particle size and entrapment efficiency of the SLNs and, therefore, indirectly an influence on the C_max/dose and AUC/dose after administration to rats. Furthermore, the in vitro drug release was compound specific, and linked to the affinity of the drug compounds towards the lipid matrix and release medium. The pharmacokinetic parameters resulted in an increased t_max, t_1/2 and mean residence time (MRT) for all formulations after intramuscular and subcutaneous dosing, when compared to intravenous administration. Whereas, the subcutaneous injections performed better for those parameters than the intramuscular injections, because of the higher blood perfusion in the muscles compared with the subcutaneous tissues. In conclusion, SLNs extend drug release, need to be optimized for each drug, and are appropriate carriers for the delivery of drugs that require a short-term sustained release in a timely manner.

Nanoliposomal irinotecan (Nal-IRI)-based chemotherapy after irinotecan -based chemotherapy in patients with pancreas cancer

BACKGROUND

Nanoliposomal irinotecan (Nal-IRI) is a preferred second-line treatment for metastatic pancreas cancer. It is unclear, however, whether patients who had received irinotecan derive benefit.

METHODS

Medical records of metastatic pancreas cancer patients who had received irinotecan and then Nal-IRI were reviewed. The primary endpoint was overall survival after the initiation of Nal-IRI (an a priori threshold of >4 months defined success); adverse events and quotes from the medical record on decision-making were also recorded.

RESULTS

Sixty four patients met eligibility criteria with a median age of 65 years (range: 36, 80 years). The median overall survival from initiation of Nal-IRI was 5.1 months (95% confidence interval (CI): 4.3, 5.6 months). An exploratory comparison, based on no cancer progression with irinotecan versus progression, showed improved survival with Nal-IRI in the former group: 6.1 months (95% CI: 5.1, 9.3 months) versus 4.3 months (95% CI: 2.3, 4.8 months); p = 0.0006. Nal-IRI adverse events occurred as expected. Qualitative data illustrate several themes, including "limited treatment options," which appeared to drive the decision to prescribe Nal-IRI.

CONCLUSION

Nal-IRI might be considered in pancreas cancer patients who had received irinotecan, particularly in the absence of disease progression with the latter.

Liquid Crystalline Phases for Enhancement of Oral Bioavailability

Liquid crystalline phases (LCPs) are generated upon lipolysis of ingested lipids in the gastrointestinal tract. The breaking off and subsequent evolution of LCPs produce more advanced vesicular and micellar structures which facilitate oral absorption of lipids, as well as co-loaded drug entities. Owing to sustained or controlled drug release, bioadhesiveness, and capability of loading drugs of different properties, LCPs are promising vehicles to implement for enhancement of oral bioavailability. This review aims to provide an overview on the classification, preparation and characterization, in vivo generation and transformation, absorption mechanisms, and encouraging applications of LCPs in enhancement of oral bioavailability. In addition, we comment on the merits of LCPs as oral drug delivery carriers, as well as solutions to industrialization utilizing liquid crystalline precursor and preconcentrate formulations.

Self-injectable extended release formulation of Remdesivir (SelfExRem): A potential formulation alternative for COVID-19 treatment

There has been a growing and evolving research to find a treatment or a prevention against coronavirus 2019 (COVID-19). Though mass vaccination will certainly help in reducing number of COVID-19 patients, an effective therapeutic measure must be available too. Intravenous remdesivir (RDV) was the first drug receiving Food and Drug Administration (FDA) approval for the treatment of COVID-19. However, in a pandemic like COVID-19, it is essential that drug formulations are readily available, affordable and convenient to administer to every patient around the globe. In this study, we have developed a Self-injectable extended release subcutaneous injection of Remdesivir (SelfExRem) for the treatment of COVID-19. As opposed to intravenous injection, extended release subcutaneous injection has the benefits of reducing face-to-face contact, minimizing hospitalization, reducing dosing frequency and reducing overall health care cost. SelfExRem was developed using a biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA), dissolved in a biocompatible vehicle. Six different batches were formulated using 2 different grades of low molecular weight PLGA and 3 different PLGA concentration. The force of injection of various polymeric solutions through 23–30-gauge needles were analyzed using a TA.XTplus texture analyzer. The time required for injection was evaluated both manually and by using an autoinjector. In vitro release of all the batches were carried out in 1% v/v tween 80 in phosphate buffer saline. The study indicated that SelfExRem developed with 15% w/v PLGA (75:25) provided a steady release of drug for 48 h and may be a breakthrough approach for the treatment of COVID-19.

The Phospholipid Research Center: Current Research in Phospholipids and Their Use in Drug Delivery

This review summarizes the research on phospholipids and their use for drug delivery related to the Phospholipid Research Center Heidelberg (PRC). The focus is on projects that have been approved by the PRC since 2017 and are currently still ongoing or have recently been completed. The different projects cover all facets of phospholipid research, from basic to applied research, including the use of phospholipids in different administration forms such as liposomes, mixed micelles, emulsions, and extrudates, up to industrial application-oriented research. These projects also include all routes of administration, namely parenteral, oral, and topical. With this review we would like to highlight possible future research directions, including a short introduction into the world of phospholipids.

Biomedical Applications of Multifunctional Polymeric Nanocarriers: A Review of Current Literature

Polymeric nanomaterials have become a prominent area of research in the field of drug delivery. Their application in nanomedicine can improve bioavailability, pharmacokinetics, and, therefore, the effectiveness of various therapeutics or contrast agents. There are many studies for developing new polymeric nanocarriers; however, their clinical application is somewhat limited. In this review, we present new complex and multifunctional polymeric nanocarriers as promising and innovative diagnostic or therapeutic systems. Their multifunctionality, resulting from the unique chemical and biological properties of the polymers used, ensures better delivery, and a controlled, sequential release of many different therapeutics to the diseased tissue. We present a brief introduction of the classical formulation techniques and describe examples of multifunctional nanocarriers, whose biological assessment has been carried out at least in vitro. Most of them, however, also underwent evaluation in vivo on animal models. Selected polymeric nanocarriers were grouped depending on their medical application: anti-cancer drug nanocarriers, nanomaterials delivering compounds for cancer immunotherapy or regenerative medicine, components of vaccines nanomaterials used for topical application, and lifestyle diseases, ie, diabetes.