Lidocaine loaded nanostructured lipid carriers for prolonged local anesthesia: in vitro and in vivo studies

Advances in the use of local anesthetic extended-release systems in pain management

Pain management remains among the most common and largely unmet clinical problems today. Local anesthetics play an indispensable role in pain management. The main limitation of traditional local anesthetics is the limited duration of a single injection. To address this problem, catheters are often placed or combined with other drugs in clinical practice to increase the time that local anesthetics act. However, this method does not meet the needs of clinical analgesics. Therefore, many researchers have worked to develop local anesthetic extended-release types that can be administered in a single dose. In recent years, drug extended-release systems have emerged dramatically due to their long duration and efficacy, providing more possibilities for the application of local anesthetics. This paper summarizes the types of local anesthetic drug delivery systems and their clinical applications, discusses them in the context of relevant studies on local anesthetics, and provides a summary and outlook on the development of local anesthetic extended-release agents.

Design of Liposomal Lidocaine/Cannabidiol Fixed Combinations for Local Neuropathic Pain Treatment

The administration of drug fixed combinations by nanocarriers is a new attractive approach since it can allow improvements in both the skin penetration of cargo compounds and their synergistic effects. The cutaneous administration of lidocaine (LD) and cannabidiol (CBD) combination can be useful for the local treatment of neuropathic pain. In fact, these drugs might exert a complementary effect on pain acting on sodium and calcium channels. In this study, the feasibility to deliver this combination in the deeper layers of the skin using deformable liposomes was studied. Based on a study of the drug affinity for lipid components performed by DSC, CBD was loaded in the lipid bilayer for limiting the leakage, while LD was loaded in the inner core by a pH gradient method (G-liposomes) or after previous encapsulation in micelle (DiMiL). The effect of the presence of Tween 80 in the liposome membrane was also evaluated. DiMiL increased both the skin permeation and the retention in the dermis of CBD and LD with respect to G-liposomes (R_24dermis: 11.52 ± 2.4 against 4.51 ± 0.8 µg/cm² for CBD; 19.6 ± 2.9 against 3.2 ± 0.1 µg/cm² for LD). Moreover, both DiMiL and G-liposomes were more efficient than control formulations carrying free drugs in improving drug skin permeation. Interestingly, in the presence of a drug exerting a fluidizing effect such as CBD, the removal of Tween 80 from the composition led to an improved control of drug release and a higher extent of drug retention in the dermis layer.

Pain management with transdermal drug administration: A review

Pain management is an urgent issue to solve with complex mechanisms. Localized acute pain requires rapid and accurate delivery of drugs with less distribution in the blood circulation while chronic pain requires controlled release of drugs with long drug retention time. The transdermal route, a promising way with high patient compliance was known for painless delivery, long drug retention time, stable blood concentration, easily controlled dosage and release rate as well as the fewer side effects. This review presents transdermal route for pain management according to the different sites of action which drugs aim to reach, and illustrates different analgesic mechanisms, dosage forms, transdermal enhancements and clinical applications. In addition, the review concludes the difference of pain types and presents the future aims of pain management, thereby providing a reference for researches focusing on percutaneous analgesia.