Nanostructured Lipid Carrier (NLC) A Promising Drug Delivery for Transdermal Application
Skin application of pharmaceutical products is one of the methods used for drug administration. The problem of limited drug penetration via topical application makes searching for safe drug carriers that will provide an expected therapeutic effect of utmost importance. Research into safe drug carriers began with liposome structures, paving the way for work with nanocarriers, which currently play a large role as drug vehicles. Nanostructured lipid carriers (NLC) consist of blended solid and liquid lipids (oils) dispersed in an aqueous solution containing a surfactant. These carriers have many advantages: good biocompatibility, low cytotoxicity, high drug Content,they enhance a drug's stability and have many possibilities of application (oral, intravenous, pulmonary, ocular, dermal) The present study emphasize to evoke an interest in the current art of NLC by discussing the various parameter like need of NLC,types of lipid, drug used in various NLC formulation,characterization,skin occlusion, stability factor. This analysis indicates the possibility of using NLC for dermal and transdermal drug application. Key word:NLC,characterization ,lipids,stability,high speed homogenizer INTRODUCTION In the last decade, drug delivery research is clearly moving from the micro to the nanometer scale. In simple terms, a drug delivery system is defined as a formulation or a device that enables the introduction of a therapeutic substance in the body and improves its efficacy and safety by controlling the rate, time, and place of release of this substance in the body. The process of drug delivery includes the administration of the therapeutic product, the release of the active ingredients by the product, and the subsequent transport of the active ingredients across the biological membranes to the site of action.[1] The oral route is the most important and conventional method of drug administration. Unfortunately, oral drug delivery systems have many significant limitations, such as drug degradation in the gastrointestinal track (by enzymes, pH) pre systemic metabolism or toxic side effects. One of the methods which could overcome problems associated with the oral route is transdermal drug delivery (TDD) [2 3] Lipid based formulations as effective dermal vehicles for drugs Nanotechnology is a modern and rapidly evolving trend in dermal and transdermal drug delivery which includes several forms of nanocarriers such as liposomes, nanoemulsions, nanocrystals, polymeric nanoparticles, lipid nanocarriers and dendrimers. Lipid nanocarriers show essential advantages over conventional drug forms and they are formulated with biodegradable, non toxic and non irritant lipids. The small size (from 40 to 800 nm) of lipid nanocarriers allows to adhere them to the lipid film of SC and to increase the number of drug molecules that penetrate into deeper layers of the skin. Moreover, they demonstrate the occlusion effect, which results in increased skin hydration, thereby improving the absorption of the drug [4 5] Nano structured lipid Carriert (NLC) as New era for Topical Drug delivery Topical drug application has been introduced since long time to achieve several purposes on different levels (skin surface, epidermis, dermis and hypodermis) However, several problems have been reported with the conventional topical preparations e.g. low uptake due to the barrier function of the stratum corneum and absorption to the systemic circulation. A lot of research groups paid attention to the topical application of the SLN and NLC. Many features, which these carrier systems exhibit for dermal application of cosmetics and pharmaceutics, have been pointed out. SLN and NLC are composed of physiological and biodegradable lipids that show low toxicity. The small size ensures a close contact to the stratum corneum and can increase the amount of drug penetrated into the skin. Due to the occlusive properties of lipid nanoparticles, an increased skin hydration effect is observed. Furthermore, lipid nanoparticles are able to enhance the chemical stability of compounds sensitive to light, oxidation and hydrolysis.[74] FACTORS RESPONSIBLE FOR PENETRATION OF NLC FORMULATION THROUGH SKIN Many factors are responsible for drug penetration when topical application of NLC, such as concentration type of lipids and surfactants, NLC production method ,drug localization in the NLC .The mechanism of drug release from an NLC consists of diffusion and lipid particle degradation in the body [10] Drug release is affected by alteration from a highly disorganized lipid structure to one with more organized stable modifications. It is ideal to achieve controlled release from an NLC that is triggered by an impulse after application. Impulses for designing skin preparations with NLC can be temperature increase or water evaporation leading to changes in the lipid structure and,in consequence, to drug release. A drug release profile might be modified according to composition of the lipid matrix, surfactant concentration and production parameters. Laxmidhar sahoo /J. Pharm. Sci. Res. Vol. 12(4) 2020, 475 487