The structure and function of the skin details the individual components of the epidermis, dermis, and their roles in normal skin health. The individual cell types in the epidermis, the different epidermal layers, and the roles of the keratinocyte are explained. The epidermis and dermis, and their important relation to each other through the dermoepidermal junction are described. The dermal adnexal structures of hair follicles (pilosebaceous units), sweat glands, and nerves are all considered. The functions of skin and barrier function are also listed. Rare but important causes of disordered sweating (hyperhidrosis and hypohidrosis) are described. In addition, presentations of hyperhidrosis are discussed.

Structure and function of the skin

Solid lipid nanoparticles and nanostructured lipid carriers: A review emphasizing on particle structure and drug release

Alzheimer's disease is a neurological disorder that results in cognitive and behavioral impairment. Conventional treatment strategies, such as acetylcholinesterase inhibitor drugs, often fail due to their poor solubility, lower bioavailability, and ineffective ability to cross the blood-brain barrier. Nanotechnological treatment methods, which involve the design, characterization, production, and application of nanoscale drug delivery systems, have been employed to optimize therapeutics. These nanotechnologies include polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, microemulsion, nanoemulsion, and liquid crystals. Each of these are promising tools for the delivery of therapeutic devices to the brain via various routes of administration, particularly the intranasal route. The objective of this study is to present a systematic review of nanotechnology-based drug delivery systems for the treatment of Alzheimer's disease.

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Nanotechnology-based drug delivery systems for the treatment of Alzheimer's disease.

Solid lipid nanoparticles for nose to brain delivery of haloperidol: in vitro drug release and pharmacokinetics evaluation

Solid lipid nanoparticle is an efficient lipid based drug delivery system which can enhance the bioavailability of poorly water soluble drugs. Efavirenz is a highly lipophilic drug from nonnucleoside inhibitor category for treatment of HIV. Present work illustrates development of an SLN formulation for Efavirenz with increased bioavailability. At first, suitable lipid component and surfactant were chosen. SLNs were prepared and analyzed for physical parameters, stability, and pharmacokinetic profile. Efavirenz loaded SLNs were formulated using Glyceryl monostearate as main lipid and Tween 80 as surfactant. ESLN-3 has shown mean particle size of nm with a PDI value of 0.234, negative zeta potential, and 86% drug entrapment. In vitro drug release study has shown 60.6–98.22% drug release in 24 h by various SLN formulations. Optimized SLNs have shown good stability at 40°C 2°C and % relative humidity (RH) for 180 days. ESLN-3 exhibited 5.32-fold increase in peak plasma concentration () and 10.98-fold increase in AUC in comparison to Efavirenz suspension (ES).

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Enhanced Oral Bioavailability of Efavirenz by Solid Lipid Nanoparticles: In Vitro Drug Release and Pharmacokinetics Studies

Context: Transdermal formulations contain permeation enhancer which causes skin damage. Ceramide 2 is natural lipid found in stratum corneum (SC).Objective: Drug-loaded nanovesicles of ceramide-2, cholesterol, palmitic acid, cholesteryl sulfate were formulated and analyzed for physical and biological properties. Diclofenac was used as a model drug.Materials and method: The vesicles were prepared using the film hydration method and characterized for physical parameters, in vitro drug release, accelerated stability studies and formulated into gel. Respective gels were compared with a commercial formulation (CEG) and plain carbopol gel (CG) containing drug for ex vivo, in vivo drug permeation and anti-inflammatory activity.Results: The vesicles were stable with optimum physical parameters. DCG-1 showed 92.89% in vitro drug release. Ceramide vesicles showed drug release between 18 and 25 μg/cm2 whereas CG and CEG released 0.33 and 1.35 μg/cm2 drug, respectively. DCG-1 and CEG showed corresponding Cmax...

Preparation, characterization and permeation studies of a nanovesicular system containing diclofenac for transdermal delivery

Glyceryl monostearate based nanoparticles of mefenamic acid: Fabrication and in vitro characterization

Context: The vesicles based on skin lipid have a drug localization effect and its main lipid, ceramide provides protective and regenerative effects while oleic acid (OA) is a penetration enhancer, however, it causes slight irritation, so we have formulated formulation incorporating both of these to develop a transdermal formulation for better permeation.Objective: Present study investigated the preparation and characterization of physicochemical properties and permeation of nanovesicles of ceramide-2 containing OA and palmitic acid (PA) respectively and a commercial gel.Materials and methods: The vesicles were made using ceramide 2, cholesterol (Chol), cholesteryl sulfate (CS) and OA or PA, respectively, using film hydration method. The vesicles were characterized for physicochemical properties, ex vivo permeation using human skin and pharmacokinetic parameters and anti-inflammatory activity in rats.Results: The vesicles showed size at 102–125 nm while PDI was 0.11–0.13 and negative zeta potential...

Ceramide-2 nanovesicles for effective transdermal delivery: development, characterization and pharmacokinetic evaluation

Context: Ibuprofen is an important NSAID, however, it can cause GI disturbances when given orally, and employment of transdermal route will require permeation enhancer causing skin injury. Objective: Drug-loaded nanovesicles of ceramide-2, cholesterol, palmitic acid, and cholesteryl sulfate (ICVG) were formulated and analyzed for physicochemical and permeation properties. Materials and method: Vesicles were formulated using film hydration method and physicochemical parameters, in vitro drug release, and stability were assessed. Further, nanovesicle gels were evaluated against plain gel containing drug (CG) for ex vivo/in vivo drug permeation and anti-inflammatory activity. Results: The developed formulations showed optimal physicochemical profile and ICV-1 gave 97.24% drug release. Drug permeation was between 17.32 and 33.12 μg/cm2 for ICVG formulations and 0.27 μg/cm2 for CG. ICVG-1 and CG showed Cmax of 9.6 and 0.7 μg/ml at 8 and 4 h. ICVG-1 showed 19.9 times higher AUC than CG. Edema inhibition...

Development of a new nanovesicle formulation as transdermal carrier: Formulation, physicochemical characterization, permeation studies and anti-inflammatory activity

PURPOSE The purpose of the study was formulation development, optimization and evaluation of a Self-Emulsifying Drug Delivery System (SEDDS) of Simvastatin (SIM) for improvement in dissolution and bioavailability of SIM. Solubility enhancement of Biopharmaceutical Classification System (BCS) Class-II drugs is a burning topic and attracting various publications and patents regarding different strategies employed for improvement of dissolution viz., USOO5340591A (Solid dispersion), US005472954A, US005646131A (complexation), USOO5858410A (Nanosuspensions), USOO5874029A (micronization) US2008.00095O2A1 (Solid composites), US2008O146640A1 (Prodrug) US 2009001 1009 A1 (nanocapsules), etc. Methods: SEDDS was prepared on the basis of solubility studies employing Capmul MCM EP as lipid and Cremophor ELP as surfactant. Box-Behnken design was implemented for optimization by using lipid concentration, surfactant concentration and mixing time as dependent variables and their impact was observed on particle size, poly dispersity index (PDI) and drug released in 15min. Optimized formulation was evaluated for particle size, PDI, zeta potential, emulsification time, transmittance, invitro drug release and in situ Single-Pass Intestinal Perfusion (SPIP) studies. RESULTS For optimized formulation, OF1 value of particle size, PDI, zeta potential, emulsification time, transmittance and percent in-vitro release were 162±14.32nm, 0.19±0.01, -22.3 ±1.1mV, 93±3.11 sec, 99.45±4.35 % and 99.43± 5.6 % in 30 min respectively. In-situ SPIP studies were performed on Wistar rats and the value of predicted fraction absorbed for humans was found to be 0.98. CONCLUSION SIM SEDDS was successfully developed and evaluated for in-vitro & in-vivo parameters. All the evaluated parameters were in tolerable limits. In vitro release studies from optimized formulation, OF1, exhibited maximum drug release when compared to SIM API and marketed preparation. Moreover, the predicted value of fraction absorbed (Fa) in humans by in-situ SPIP method was also in agreement with in-vitro dissolution studies thus, confirming SEDDS as a suitable drug delivery system for solubility enhancement of SIM.

Self-Emulsifying Drug Delivery System of Simvastatin: Formulation Development, Optimization by Box- Behnken Design, In-Vitro and In-Situ Single-Pass Intestinal Perfusion (SPIP) Studies.

Yatendra Kumar

Papers

Preparation, characterization and permeation studies of a nanovesicular system containing diclofenac for transdermal delivery

Glyceryl monostearate based nanoparticles of mefenamic acid: Fabrication and in vitro characterization

Ceramide-2 nanovesicles for effective transdermal delivery: development, characterization and pharmacokinetic evaluation

Development of a new nanovesicle formulation as transdermal carrier: Formulation, physicochemical characterization, permeation studies and anti-inflammatory activity

Self-Emulsifying Drug Delivery System of Simvastatin: Formulation Development, Optimization by Box- Behnken Design, In-Vitro and In-Situ Single-Pass Intestinal Perfusion (SPIP) Studies.