Combination of coating and injectable hydrogel depot to improve the sustained delivery of insulin

Development of Lacosamide-loaded In-Situ Gels through Experimental Design for Evaluation of Ocular Irritation In Vitro and In Vivo

Lacosamide (LCM) selectively increases the slow inactivation of voltage-gated sodium channels (VGSCs) and is a N-methyl D-aspartate acid (NMDA) receptor glycine site antagonist. Therefore, it can be used in dryness-related hyperexcitability of corneal cold receptor nerve terminals. Ocular in-situ gels remain in liquid form until they reach the target site, where they undergo a sol-gel transformation in response to specific stimuli. They can show mucoadhesive properties related to the polymer used and increase the residence time of the drug in the mucosa. In the presented study, ocular in-situ gel formulation of LCM, which has potential for use in ocular diseases and consists of hyaluronic acid and poloxamer 407 as polymers, was developed using cold method. The effect of formulation components on target product properties (pH, gelation temperature and viscosity) was evaluated by design of experiments (DoE) design. The optimized LCM-loaded in-situ gel had a pH value of 6.90 ± 0.01, showed pseudo-plastic flow with a viscosity of 562 ± 58 cP at 25°C, gelled at 33 ± 0.47°C, and released drugs via the Peppas-Sahlin mechanism. Ocular safety was confirmed via in vitro tests using two different cell lines (L929 and Arpe-19), along with in vivo Draize tests, histological examinations, and Hen's Egg Chario-Allontioc-Membrane (HET-CAM) analysis. In vitro studies confirmed the optimized LCM-loaded in-situ gel's suitability for ocular use, demonstrating long-acting effects through controlled release. In addition, ocular irritation and histological studies have supported that it will not show any toxic effect on the eye tissue.

Long-acting parenteral formulations of hydrophilic drugs, proteins, and peptide therapeutics: mechanisms, challenges, and therapeutic benefits with a focus on technologies

Despite being the most widely prescribed formulation, oral formulations possess several limitations such as low adherence, low bioavailability, high toxicity (in the case of anticancer drugs), and multiple-time administration requirements. All these limitations can be overcome by long-acting injectables. Improved adherence, patient compliance, and reduced relapse have been observed with long-acting formulation which has increased the demand for long-acting injectables. Drugs or peptide molecules with oral bioavailability issues can be easily delivered by long-acting systems. This review comprehensively addresses the various technologies used to develop long-acting injections with a particular focus on hydrophilic drugs and large molecules as well as the factors affecting the choice of formulation strategy. This is the first review that discusses the possible technologies that can be used for developing long-acting formulations for hydrophilic molecules along with factors which will affect the choice of the technology. Furthermore, the mechanism of drug release as well as summaries of marketed formulations will be presented. This review also discusses the challenges associated with the manufacturing and scale-up of the long-acting injectables.

Halofuginone-guided nano-local therapy: Nano-thermosensitive hydrogels for postoperative metastatic canine mammary carcinoma with scar removal

In female dogs, the highest morbidity and mortality rates cancer are the result of mammary adenocarcinoma, which presents with metastases in the lung. Other than early surgical removal, however, no special methods are available to treat mammary adenocarcinoma. Because human breast cancer and canine mammary carcinoma share clinical characteristics and heterogeneity, the canine model is a suitable spontaneous tumor model for breast cancer in humans. In this study, the physical swelling method was used to prepare halofuginone-loaded D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) polymer micelles nano-thermosensitive hydrogels (HTPM-gel). Furthermore, HTPM-gel was investigated via characterization, morphology, properties such as swelling experiment and in vitro release with reflecting its splendid nature. Moreover, HTPM-gel was further examined its capability to anti-proliferation, anti-migration, and anti-invasion. Ultimately, HTPM-gel was investigated for its in vivo anticancer activity in the post-operative metastatic and angiogenic canine mammary carcinoma. HTPM-gel presented spherical under transmission electron microscope (TEM) and represented grid structure under scanning electron microscope (SEM), with hydrodynamic diameter (HD) of 20.25 ± 2.5 nm and zeta potential (ZP) of 15.10 ± 1.82 mV. Additionally, HTPM-gel own excellent properties comprised of pH-dependent swelling behavior, sustained release behavior. To impede the migration, invasion, and proliferation of CMT-U27 cells, we tested the efficacy of HTPM-gel. Evaluation of in vivo anti-tumor efficacy demonstrates HTPM-gel exhibit a splendid anti-metastasis and anti-angiogenic ability, with exhibiting ideal biocompatibility. Notably, HTPM-gel also inhibited the scar formation in the healing process after surgery. In summary, HTPM-gel exhibited anti-metastasis and anti-angiogenic and scar repair features. According to the results of this study, HTPM-gel has encouraging clinical potential to treat tumors with multifunctional hydrogel.

Fabrication of carboxymethyl cellulose-based thermo-sensitive hydrogels and inhibition of corneal neovascularization

Corneal neovascularization (CNV) is a common multifactorial sequela of anterior corneal segment inflammation, which could lead to visual impairment and even blindness. The main treatments available are surgical sutures and invasive drug injections, which could cause serious ocular complications. To solve this problem, a thermo-sensitive drug-loaded hydrogel with high transparency was prepared in this study, which could achieve the sustained-release of drugs without affecting normal vision. In briefly, the thermo-sensitive hydrogel (PFNOCMC) was prepared from oxidized carboxymethyl cellulose (OCMC) and aminated poloxamer 407 (PF127-NH2). The results proved the PFNOCMC hydrogels possess high transparency, suitable gel temperature and time. In the CNV model, the PFNOCMC hydrogel loading bone morphogenetic protein 4 (BMP4) showed significant inhibition of CNV, this is due to the hydrogel allowed the drug to stay longer in the target area. The animal experiments on the ocular surface were carried out, which proved the hydrogel had excellent biocompatibility, and could realize the sustained-release of loaded drugs, and had a significant inhibitory effect on the neovascularization after ocular surface surgery. In conclusion, PFNOCMC hydrogels have great potential as sustained-release drug carriers in the biomedical field and provide a new minimally invasive option for the treatment of neovascular ocular diseases.

Injectable systems for long-lasting insulin therapy

Insulin therapy is the mainstay to treat diabetes characterizedd by hyperglycemia. However, its short half-life of only 4-6 min limits its effectiveness in treating chronic diabetes. Advances in recombinant DNA technology and protein engineering have led to several insulin analogue products that have up to 42 h of glycemic control. However, these insulin analogues still require once- or twice-daily injections for optimal glycemic control and have poor patient compliance and adherence issues. To achieve insulin release for more than one day, different injectable delivery systems including microspheres, in situ forming depots, nanoparticles and composite systems have been developed. Several of these delivery systems have advanced to clinical trials for once-weekly insulin injection. This review comprehensively summarizes the developments of injectable insulin analogs and delivery systems covering the whole field of injectable long-lasting insulin technologies from prototype design, preclinical studies, clinical trials to marketed products for the treatment of diabetes.

In-situ Gels for Brain Delivery: Breaching the Barriers

The blood-brain barrier (BBB) regulates blood and chemical exchange in the central nervous system. It is made up of brain parenchyma capillary endothelial cells. It separates the interstitial cerebrospinal fluid from the circulation and limits brain drug entry. Peptides, antibodies, and even tiny hydrophilic biomolecules cannot flow across the BBB due to their semi-permeability. It protects the brain from poisons, chemicals, and pathogens, and blood cells penetrate brain tissue. BBB-facilitated carrier molecules allow selective permeability of nutrients such as D-glucose, L-lactic acid, L-phenylalanine, L-arginine, and hormones, especially steroid hormones. Brain barriers prevent drug molecules from entering, making medication delivery difficult. Drugs can reach specific brain regions through the nasal cavity, making it a preferred route. The in-situ gels are mucoadhesive, which extends their stay in the nasal cavity, allows them to penetrate deep and makes them a dependable way of transporting numerous medications, including peptides and proteins, straight into the central nervous system. This approach holds great potential for neurological therapy as they deliver drugs directly to the central nervous system, with less interference and better drug release control. The brain affects daily life by processing sensory stimuli, controlling movement and behaviour, and sustaining mental, emotional, and cognitive functioning. Unlike systemic routes, the nasal mucosa is extensively vascularized and directly contacts olfactory sensory neurons. Compared to the systemic circulation, this improves brain bioavailability of medications. Drugs can be delivered to the brain using in-situ gel formulations safely and efficiently, with a greater therapeutic impact than with traditional techniques.

Changes in the Mechanical Properties of Alginate-Gelatin Hydrogels with the Addition of Pygeum africanum with Potential Application in Urology

New hydrogel materials developed to improve soft tissue healing are an alternative for medical applications, such as tissue regeneration or enhancing the biotolerance effect in the tissue-implant–body fluid system. The biggest advantages of hydrogel materials are the presence of a large amount of water and a polymeric structure that corresponds to the extracellular matrix, which allows to create healing conditions similar to physiological ones. The present work deals with the change in mechanical properties of sodium alginate mixed with gelatin containing Pygeum africanum. The work primarily concentrates on the evaluation of the mechanical properties of the hydrogel materials produced by the sol–gel method. The antimicrobial activity of the hydrogels was investigated based on the population growth dynamics of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923, as well as the degree of degradation after contact with urine using an innovative method with a urine flow simulation stand. On the basis of mechanical tests, it was found that sodium alginate-based hydrogels with gelatin showed weaker mechanical properties than without the additive. In addition, gelatin accelerates the degradation process of the produced hydrogel materials. Antimicrobial studies have shown that the presence of African plum bark extract in the hydrogel enhances the inhibitory effect on Gram-positive and Gram-negative bacteria. The research topic was considered due to the increased demand from patients for medical devices to promote healing of urethral epithelial injuries in order to prevent the formation of urethral strictures.

Recent advances in polymeric transdermal drug delivery systems

Transdermal delivery has proven to be one of the most favorable methods among novel drug delivery systems. Since drugs administered by transdermal delivery systems avoid the gastrointestinal tract, and thus avoid conversion by the liver, the likelihood of liver dysfunction and gastrointestinal tract irritation as side effects is low. Drug delivery through the skin has other advantages, such as maintaining an effective rate of drug delivery over time, a steady rate of circulation, and the benefits of a passive delivery system and diffusion. Transdermal drug delivery is achieved using patches which consist of different and specific layers. In the last few decades, many types of patches have been approved worldwide, such as medical plasters, which have been generally applied to the skin for localized diseases. Such patches can be traced back to ancient China (around 2000 BCE) and are the early precursors of today's transdermal patches. With the help of effective design, materials, manufacturing, and evaluation, a large number of drugs can now be administered using this valuable advanced technology. This study reviews different types of polymer patches, their advantages and disadvantages, and different studies related to transdermal drug delivery methods, and the advantages and disadvantages of each method. Different mechanisms of transdermal drug delivery system with patches are also discussed.

Formulation strategies to modulate drug release from poloxamer based in situ gelling systems

Introduction: Poloxamer based in situ gelling systems offer numerous advantages in drug delivery; however, their application as prolonged-release delivery platforms is limited mainly due to their weak mechanical properties and the interconnected aqueous network causing fast gel erosion and drug diffusion.Area covered: The focus of this review is to provide an insightful discussion on the formulation strategies that can be employed to sustain/prolong the drug release from poloxamer based in situ gelling systems. The review also outlines the formulation factors, influencing drug release from these systems.Expert opinion: The nature, composition, and concentration of poloxamers are the most critical factors in defining the rate of drug release from an in situ gelling matrix. Hydrophobic gel matrices have compact micellar arrangements resulting in slow diffusion and erosion. Depending on the intended clinical application, gel characteristics can be modulated, either by physical blending or by chemical crosslinking with additive materials, to slow release and improve residence time at the administration site. Incorporating drug-loaded particles into poloxamer gels sustains drug release by creating multiple rate-limiting release barriers. Chemical modification of poloxamers appears to be a promising strategy to obtain prolonged sustained release for parenteral application without compromising the rheological properties of the formulation.