纳米载体提高难溶性药物口服生物利用度的研究进展

纳米载体是药剂学备受关注的研究领域,作为一类新型给药系统,它能显著提高难溶性药物的溶解度、生物利用度和稳定性,且具有明显的缓释作用,因此得到了广泛的应用。目前常用于提高难溶性药物口服生物利用度的纳米载体有纳米脂质体、固体脂质纳米粒、纳米胶束、和纳米结晶等,它们的粒径、表面性质及其释药环境等是影响纳米载体药物口服吸收的主要因素。本文对纳米载体提高难溶性药物口服生物利用度的研究进展作一综述。     

Phytantriol and glyceryl monooleate cubic liquid crystalline phases as sustained‐release oral drug delivery systems for poorly water‐soluble drugs II. In‐vivo evaluation

Objectives Lipid‐based liquid crystals formed from phytantriol (PHY) and glyceryl monooleate (GMO) retain their cubic‐phase structure on dilution in physiologically relevant simulated gastrointestinal media, suggesting their potential application as sustained‐release drug‐delivery systems for poorly water‐soluble drugs. In this study the potential of PHY and GMO to serve as sustained‐release lipid vehicles for a model poorly‐water‐soluble drug, cinnarizine, was assessed and compared to that of an aqueous suspension formulation. Methods Small‐angle X‐ray scattering was used to confirm the nanostructure of the liquid‐crystalline matrix in the presence of the selected model drug, cinnarizine. Oral bioavailability studies were conducted in rats, and disposition of lipid and drug in segments of the gastrointestinal tract was determined over time. Differences in the digestibility and stability of formulations under digestion conditions were investigated using an in‐vitro lipolysis model. Key findings The oral bioavailability of cinnarizine using the PHY formulation was 41%, compared to 19% for the GMO formulation and 6% for an aqueous suspension. The PHY formulation provided a T_max for cinnarizine of 33 h, with absorption apparent up to 55 h after administration. In contrast, the T_max for the GMO formulation was only 5 h. The PHY formulation was retained in the stomach for extended periods of time, with 56% of lipid remaining in the stomach after 24 h, in contrast to less than 1% of the GMO formulation after 8 h, suggesting that gastric retention was a key aspect of the prolonged period of absorption, which correlated with the formulations' relative susceptibility to in‐vitro lipolysis and degradation. Conclusions PHY provides a dramatic sustained‐release effect for cinnarizine on oral administration, which is linked to gastric retention of the formulation and its ability to resist digestive processing. Poorly digested liquid crystal lipid formulations therefore offer a novel class of sustained‐release matrices for oral administration.     

Nanostructured materials in drug and gene delivery: a review of the state of the art

A wide variety of drug delivery systems have been developed, each with its own advantages and limitations, but the important goals of all of the systems are to enhance bioavailability, reduce drug toxicity, target to a particular organ, and increase the stability of the drug. The development of nanostructured drug carriers have grasped increased attention from scientific and commercial organizations due to their unique ability to deliver drugs and challenging molecules such as proteins and nucleic acids. These carriers present many technological advantages such as high carrier capacity, high chemical and biological stability, feasibility of incorporating both hydrophilic and hydrophobic substances, and their ability to be administered by a variety of routes (including oral, inhalational, and parenteral) to provide controlled/sustained drug release. Moreover, applications of nanoparticulate formulations in enhancing drug solubility, dissolution, bioavailability, safety, and stability have already been proven. In the view of their multifaceted applications, the present review aims to discuss and summarize some of the interesting findings and applications, methods of preparation, and characterization of various nanostructured carriers useful in drug delivery. Included in this discussion are polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, dendrimers, cyclodextrins, fullerenes, gold and silica nanoparticles, and quantum dots. Because there are likely to be new applications for nanoparticles in drug delivery, they are expected to solve many problems associated with the delivery of drugs and biomolecules through different delivery routes.     

Development and characterization of an atorvastatin solid dispersion formulation using skimmed milk for improved oral bioavailability

Atorvastatin has low aqueous solubility resulting in low oral bioavailability (12%) and thus presents a challenge in formulating a suitable dosage form. To improve the aqueous solubility, a solid dispersion formulation of atorvastatin was prepared by lyophilization utilising skimmed milk as a carrier. Six different formulations were prepared with varying ratios of drug and carrier and the corresponding physical mixtures were also prepared. The formation of a solid dispersion formulation was confirmed by differential scanning calorimetry and X-ray diffraction studies. The optimum drug-to-carrier ratio of 1:9 enhanced solubility nearly 33-fold as compared to pure drug. In vitro drug release studies exhibited a cumulative release of 83.69% as compared to 22.7% for the pure drug. Additionally, scanning electron microscopy studies suggested the conversion of crystalline atorvastatin to an amorphous form. In a Triton-induced hyperlipidemia model, a 3-fold increase in the lipid lowering potential was obtained with the reformulated drug as compared to pure drug. These results suggest that solid dispersion of atorvastatin using skimmed milk as carrier is a promising approach for oral delivery of atorvastatin.     

Development and evaluation of nitrendipine loaded solid lipid nanoparticles: influence of wax and glyceride lipids on plasma pharmacokinetics

Nitrendipine is an antihypertensive drug with poor oral bioavailability ranging from 10 to 20% due to the first pass metabolism. For improving the oral bioavailability of nitrendipine, nitrendipine loaded solid lipid nanoparticles have been developed using triglyceride (tripalmitin), monoglyceride (glyceryl monostearate) and wax (cetyl palmitate). Poloxamer 188 was used as surfactant. Hot homogenization of melted lipids and aqueous phase followed by ultrasonication at temperature above the melting point of lipid was used to prepare SLN dispersions. SLN were characterized for particle size, zeta potential, entrapment efficiency and crystallinity of lipid and drug. In vitro release studies were performed in phosphate buffer of pH 6.8 using Franz diffusion cell. Pharmacokinetics of nitrendipine loaded solid lipid nanoparticles after intraduodenal administration to conscious male Wistar rats was studied. Bioavailability of nitrendipine was increased three- to four-fold after intraduodenal administration compared to that of nitrendipine suspension. The obtained results are indicative of solid lipid nanoparticles as carriers for improving the bioavailability of lipophilic drugs such as nitrendipine by minimizing first pass metabolism.     

Physical chemical considerations of lipid-based oral drug delivery--solid lipid nanoparticles

Of all the methods employed by formulators when presented with the task of improving oral bioavailability, the use of lipid assemblies is perhaps the least understood. Nonetheless, lipid-based formulations, and in particular solid lipid nanoparticles (SLN), show great promise for enhancing the oral bioavailability of some of the most poorly absorbed compounds. The physical/chemical characteristics of lipid-based systems are highly complex because of the existence of a variety of lipid assembly morphologies, the morphology-dependent solubility of drug, the interconversion of assembly morphology as a function of time and chemical structure, and the simultaneous lipid digestion. The present work will center on recent studies of the relevant physicochemical characteristics of SLN, most notably solubility of the drug in the lipid matrix, location of the drug in the aggregate, drug release properties of the aggregate, and particle size stability. Strengths and weaknesses of the lipid assemblies, in particular solid lipid nanoparticles, in promoting drug delivery by the oral route for systemic or Peyer's patch uptake will be highlighted, and possible future research pathways will be suggested.     

Fabrication and Evaluation of Curcumin-loaded Nanoparticles Based on Solid Lipid as a New Type of Colloidal Drug Delivery System

Curcumin has very broad spectrum of biological activities; however, photodegradation, short half-life and low bioavailability have limited its clinical application. Curcumin-loaded solid lipid nanoparticles were studied to overcome these problems. The aim of this study was to optimize the best formulation on curcumin-loaded solid lipid nanoparticles. Emulsion-evaporation and low temperature-solidification technique was applied with monostearin as lipid carriers. The single factor analysis and orthogonal design were used to optimize formulation and various parameters were investigate. By the optimisation of a single factor analysis and orthogonal test, the particles size, polydispersity index, zeta potential, encapsulation efficiency and drug loading capacity of the optimised formulation were 99.99 nm, 0.158, −19.9 mV, 97.86%, and 4.35%, respectively. The differential scanning calorimetry and X-ray diffraction analysis results demonstrated new structure was formed in nanoparticles. The release kinetics in vitro demonstrated curcumin-loaded solid lipid nanoparticles can control drug release. These studies confirmed that curcumin-loaded solid lipid nanoparticles could be prepared successfully with high drug entrapment efficiency and loading capacity. Curcumin-loaded solid lipid nanoparticles may be a promising drug delivery system to control drug release and improve bioavailability.     

Non-phospholipid vesicles as carriers for peptides and proteins: production, characterization and stability studies

Liquid crystalline phases that are stable in excess water, formed using lipids such as glyceryl monooleate (GMO) and oleyl glycerate (OG), are known to provide a sustained release matrix for poorly water soluble drugs in vitro, yet there has been no report of the use of these materials to impart oral sustained release behaviour in vivo. In the first part of this study, in vitro lipolysis experiments were used to compare the digestibility of GMO with a second structurally related lipid, oleyl glycerate, which was found to be less susceptible to hydrolysis by pancreatic lipase than GMO. Subsequent oral bioavailability studies were conducted in rats, in which a model poorly water soluble drug, cinnarizine (CIN), was administered orally as an aqueous suspension, or as a solution in GMO or OG. In the first bioavailability study, plasma samples were taken over a 30 h period and CIN concentrations determined by HPLC. Plasma CIN concentrations after administration in the GMO formulation were only sustained for a few hours after administration while for the OG formulation, the plasma concentration of cinnarizine was at its highest level 30 h after dosing, and appeared to be increasing. A second study in which CIN was again administered in OG, and plasma samples taken for 120 h, revealed a T_max for CIN in rats of 36 h and a relative oral bioavailability of 344% when compared to the GMO formulation (117%) and the aqueous suspension formulation (assigned a nominal bioavailability of 100%). The results indicate that lipids that form liquid crystalline structures in excess water, may have application as an oral sustained release delivery system, providing they are not digested rapidly on administration.     

Bioavailability enhancement of a poorly water-soluble drug by solid dispersion in polyethylene glycol-polysorbate 80 mixture

Oral bioavailability of a poorly water-soluble drug was greatly enhanced by using its solid dispersion in a surface-active carrier. The weakly basic drug (pK(a) approximately 5.5) had the highest solubility of 0.1mg/ml at pH 1.5, < 1 microg/ml aqueous solubility between pH 3.5 and 5.5 at 24+/-1 degrees C, and no detectable solubility (< 0.02 microg/ml) at pH greater than 5.5. Two solid dispersion formulations of the drug, one in Gelucire 44/14 and another one in a mixture of polyethylene glycol 3350 (PEG 3350) with polysorbate 80, were prepared by dissolving the drug in the molten carrier (65 degrees C) and filling the melt in hard gelatin capsules. From the two solid dispersion formulations, the PEG 3350-polysorbate 80 was selected for further development. The oral bioavailability of this formulation in dogs was compared with that of a capsule containing micronized drug blended with lactose and microcrystalline cellulose and a liquid solution in a mixture of PEG 400, polysorbate 80 and water. For intravenous administration, a solution in a mixture of propylene glycol, polysorbate 80 and water was used. Absolute oral bioavailability values from the capsule containing micronized drug, the capsule containing solid dispersion and the oral liquid were 1.7+/-1.0%, 35.8+/-5.2% and 59.6+/-21.4%, respectively. Thus, the solid dispersion provided a 21-fold increase in bioavailability of the drug as compared to the capsule containing micronized drug. A capsule formulation containing 25 mg of drug with a total fill weight of 600 mg was subsequently selected for further development. The selected solid dispersion formulation was physically and chemically stable under accelerated storage conditions for at least 6 months. It is hypothesized that polysorbate 80 ensures complete release of drug in a metastable finely dispersed state having a large surface area, which facilitates further solubilization by bile acids in the GI tract and the absorption into the enterocytes. Thus, the bioavailability of this poorly water-soluble drug was greatly enhanced by formulation as a solid dispersion in a surface-active carrier.     

Simvastatin Solid Lipid Nanoparticles for Oral Delivery: Formulation Development and In vivo Evaluation

Solid lipid nanoparticles have been increasingly utilised for improving oral bioavailability of drugs. Simvastatin is biopharmaceutical class 2 drug with poor oral bioavailability of 5%. In the present study, simvastatin solid lipid nanoparticles were successfully prepared by hot melt emulsification process and optimised with respect to surfactant and lipid concentration, and drug loading. The nanoparticles were characterised for entrapment efficiency, particle size, morphology, crystallinity and thermal behavior. Optimised formulations prepared from solid lipids glyceryl behenate and glyceryl palmitostearate containing Tween 80 as surfactant exhibited satisfactory entrapment efficiencies above 96% and mean particle size below 200 nm. The electron micrographs indicated that lipid nanocarriers were almost spherical in appearance. X-ray diffraction and differential calorimetric studies proved that the drug was amorphised in the lipid matrix and did not crystallise out. To improve the physical as well as chemical stability of formulations, dry adsorbed nanoparticles were prepared by evaporative drying method using a carrier. The adsorbed nanoparticles demonstrated good flow properties and satisfactory reconstitution properties. Pharmacodynamic studies of simvastatin solid lipid nanoparticles revealed improved reduction in total cholesterol values as compared to pure drug powder indicating improved bioavailability.     

Rationale for ibuprofen co-administration with antacids: Potential interaction mechanisms affecting drug absorption

Ibuprofen is a widely used NSAID which is often co-administered with antacids because of its gastro-irritant effects. Literature data suggest that antacid interactions may increase or decrease the drug's absorption rate and onset of action and that the interaction may be formulation specific. In the present study, literature data on ibuprofen absorption were evaluated in order to gain insight into the nature of the in vivo effect. Solubility determinations in reactive media containing magnesium or aluminium and dissolution studies in the presence of antacid suspension were performed in an attempt to simulate in vitro the effects observed in vivo. The results obtained indicate that magnesium hydroxide enhances ibuprofen solubility, dissolution and bioavailability, while aluminium hydroxide has a retarding effect. Solubility studies indicated formation of a soluble solid ibuprofen phase in the presence of Mg2+, in contrast, an insoluble ibuprofen salt was formed with Al3+. The introduction of magnesium based antacid suspension into the dissolution media resulted in a formulation specific increase in drug dissolution rate with the most pronounced effect observed for the slowest release tablet formulation. The results obtained indicate the potential for in vitro studies to predict physicochemical interactions that are likely to influence drug absorption rate in vivo.     

Candesartan cilexetil loaded solid lipid nanoparticles for oral delivery: characterization,pharmacokinetic and pharmacodynamic evaluation

Abstract

Candesartan cilexetil (CC) is used in the treatment of hypertension and heart failure. It has poor aqueous solubility and low oral bioavailability. In this work, CC loaded solid lipid nanoparticles (CC-SLNs) were developed to improve the oral bioavailability. Components of the SLNs include either of trimyristin/tripalmitin/tristearin, and surfactants (Poloxamer 188 and egg lecithin E80). The CC loaded nanoparticles were prepared by hot homogenization followed by ultrasonication method. The physicochemical properties, morphology of CC-SLNs were characterized, the pharmacokinetic and pharmacodynamic behaviour of CC-SLNs were evaluated in rats. Stable CC-SLNs having a mean particle size of 180–220?nm with entrapment efficiency varying in between 91–96% were developed. The physical stability of optimized formulation was studied at refrigerated and room temperature for 3 months. Further, freeze drying was tried for improving the physical stability. DSC and XRD analyses indicated that the drug incorporated into SLN was in amorphous form but not in crystalline state. The SLN-morphology was found to be nearly spherical by electron microscopic studies. Pharmacokinetic results indicated that the oral bioavailability of CC was improved over 2.75-fold after incorporation into SLNs. Pharmacodynamic study of SLNs in hypertensive rats showed a decrease in systolic blood pressure for 48?h, while suspension showed a decrease in systolic blood pressure for only 2?h. Taken together, these effects are due to enhanced bioavailability coupled with sustained action of CC in SLN formulation. Thus, the results conclusively demonstrated the role of CC-SLNs for a significant enhancement in oral bioavailability along with improved pharmacodynamic effect.     

Encapsulation of poorly soluble basic drugs into enteric microparticles: a novel approach to enhance their oral bioavailability

Poorly water soluble basic drugs are very sensitive to pH changes and following dissolution in the acidic stomach environment tend to precipitate upon gastric emptying, which leads to compromised or erratic oral bioavailability. In this work, we show that the oral bioavailability of a model poorly soluble basic drug (cinnarizine) can be improved by drug encapsulation within highly pH-responsive microparticles (Eudragit L). The latter was prepared by emulsion solvent evaporation which yielded discrete spherical microparticles (diameter of 56.4 ± 6.8 μm and a span of 1.2 ± 0.3). These Eudragit L (dissolution threshold pH 6.0) microparticles are expected to dissolve and release their drug load at intestinal conditions. Thus, the enteric microparticles inhibited the in vitro release of drug under gastric conditions, despite high cinnarizine solubility in the acidic medium. At intestinal conditions, the particles dissolved rapidly and released the drug which precipitated out in the dissolution vessel. In contrast, cinnarizine powder showed rapid drug dissolution at low pH, followed by precipitation upon pH change. Oral dosing in rats resulted in a greater than double bioavailability of Eudragit L microparticles compared to the drug powder suspension, although C_max and T_max were similar. The higher bioavailability with microparticles contradicts the in vitro results. Such an example highlights that although in vitro results are an indispensable tool for formulation development, an early in vivo assessment of formulation behaviour can provide better prediction for oral bioavailability.     

Development and characterization of solid oral dosage form incorporating candesartan nanoparticles

Sparingly water-soluble drugs such as candesartan cilexetil offer challenges in developing a drug product with adequate bioavailability. The objective of the present study was to develop a tablet dosage form of candesartan cilexetil incorporating drug nanoparticles to increase its saturation solubility and dissolution rate for enhancing bioavailability while reducing variability in systemic exposure. The bioavailability of candesartan cilexetil is dissolution limited following oral administration. To enhance bioavailability and overcome variability in systemic exposure, a nanoparticle formulation of candesartan cilexetil was developed. Candesartan cilexetil nanoparticles were prepared using a wet bead milling technique. The milled nanosuspension was converted into solid intermediate using a spray drying process. The nanosuspensions were characterized for particle size before and after spray drying. The spray dried nanoparticles were blended with excipients for tableting. The saturation solubility and dissolution characteristics of the nanoparticle formulation were investigated and compared with commercial candesartan cilexetil formulation. The drug nanoparticles were evaluated for solid-state transitions before and after milling. This study demonstrated that tablet formulation incorporating drug nanoparticles showed significantly faster rate of drug dissolution in a discriminating dissolution medium as compared to commercially available tablet formulation. Systemic exposure studies in rats indicated a significant increase in the rate and extent of drug absorption.     

口服固体自微乳化给药系统的研究进展

目的对新近发展的固体自微乳化给药系统（S-SMEDDS）文献进行综述。方法查阅近年国内外相关文献并进行归纳和总结。结果对固体自微乳的载体、固化技术以及缓控释制剂进行了探讨,为研究水难溶性药物的生物利用度及适合药物释放特性的S-SMEDDS技术提供相关参考。结论固体自微乳化系统可以显著提高难溶性药物的口服生物利用度,且兼顾了液态自微乳和固体制剂二者的优势,是一个极具潜力的新型制剂。     

Pharmacokinetic evaluation of oral fenofibrate nanosuspensions and SLN in comparison to conventional suspensions of micronized drug

An increasing number of newly developed drugs show bioavailability problems due to poor water solubility. Formulating the drugs as nanosuspensions may help to overcome these problems by increasing saturation solubility and dissolution velocity. In the present study the bioavailability of the poorly soluble fenofibrate following oral administration was investigated in rats. Four formulations were tested: a nanosuspension type DissoCube(R), one solid lipid nanoparticle (SLN) preparation and two suspensions of micronized fenofibrate as reference formulations, one suspension in sirupus simplex and a second in a solution of hydroxyethy-cellulose in physiological saline. Both colloidal drug delivery systems showed approximately two-fold bioavailability enhancements in terms of rate and extent compared to the reference formulations. No significant differences were found in AUC(0-22 h) as well as in C(max) and t(max) between the two colloidal delivery systems. In conclusion, nanosuspensions may be a suitable delivery system to improve the bioavailability of drugs with low water solubility.     

Solid lipid nanoparticles loading candesartan cilexetil enhance oral bioavailability: in vitro characteristics and absorption mechanism in rats

Candesartan cilexetil (CC) is widely used for the treatment of hypertension and heart failure, but it shows very poor aqueous solubility and very low oral absorption. In this work, CC-loaded solid lipid nanoparticles (CLNs) were successfully developed to improve the oral bioavailability. The physicochemical properties of CLNs were characterized, and the pharmacokinetic behavior of CLNs was evaluated in rats. CLNs exhibited nanometer-sized spherical particles with high entrapment efficiency (91.33%). The absorption of CLNs in the stomach was only 2.8% of that in intestine. Moreover, CLNs could be internalized into the enterocytes and then transported into the systemic circulation via the portal circulation and intestinal lymphatic pathway. The pharmacokinetic results indicated that the oral bioavailability of candesartan was obviously improved over 12-fold after incorporation into solid lipid nanoparticles. These results demonstrated that solid lipid nanoparticles have great potential for increasing oral bioavailability of lipophilic drugs such as CC. FROM THE CLINICAL EDITOR: Candesartan cilexetil is a potent angiotensin receptor inhibitor with low bioavailability due to poor aqueous solubility. In this work, solid lipid nanoparticles were used to improve the oral bioavailability 12-fold compared to standard preparation in rats, suggesting that a similar approach might be effective in future human applications.     

Polymer-surfactant nanoparticles for sustained release of water-soluble drugs

Poor drug encapsulation efficiency and rapid release of the encapsulated drug limit the use of nanoparticles in biomedical applications involving water-soluble drugs. We have developed a novel polymer-surfactant nanoparticle formulation, using the anionic surfactant Aerosol OT (AOT) and polysaccharide polymer alginate, for sustained release of water-soluble drugs. Particle size of nanoparticles, as determined by atomic force microscopy and transmission electron microscopy, was in the range of 40-70 nm. Weakly basic molecules like methylene blue, doxorubicin, rhodamine, verapamil, and clonidine could be encapsulated efficiently in AOT-alginate nanoparticles. In vitro release studies with basic drug molecules indicate that nanoparticles released 60-70% of the encapsulated drug over 4 weeks, with near zero-order release during the first 15 days. Studies with anionic drug molecules demonstrate poorer drug encapsulation efficiency and more rapid drug release than those observed with basic drugs. Further studies investigating the effect of sodium concentration in the release medium and the charge of the drug suggest that calcium-sodium exchange between nanoparticle matrix and release medium and electrostatic interaction between drug and nanoparticle matrix are important determinants of drug release. In conclusion, we have formulated a novel surfactant-polymer drug delivery carrier demonstrating sustained release of water-soluble drugs.     

PLGA nanoparticles for the oral delivery of nuciferine: preparation,physicochemical characterization and in vitro/in vivo studies

This article reports a promising approach to enhance the oral delivery of nuciferine (NUC), improve its aqueous solubility and bioavailability, and allow its controlled release as well as inhibiting lipid accumulation. NUC-loaded poly lactic-co-glycolic acid nanoparticles (NUC-PLGA-NPs) were prepared according to a solid/oil/water (s/o/w) emulsion technique due to the water-insolubility of NUC. PLGA exhibited excellent loading capacity for NUC with adjustable dosing ratios. The drug loading and encapsulation efficiency of optimized formulation were 8.89?±?0.71 and 88.54?±?7.08%, respectively. NUC-PLGA-NPs exhibited a spherical morphology with average size of 150.83?±?5.72?nm and negative charge of ?22.73?±?1.63?mV, which are suitable for oral administration. A sustained NUC released from NUC-PLGA-NPs with an initial exponential release owing to the surface associated drug followed by a slower release of NUC, which was entrapped in the core. In addition, ～77?±?6.67% was released in simulating intestinal juice, while only about 45.95?±?5.2% in simulating gastric juice. NUC-PLGA-NPs are more efficient against oleic acid (OA)-induced hepatic steatosis in HepG₂ cells when compared to naked NUC (n-NUC, *p < 0.05). The oral bioavailability of NUC-PLGA-NPs group was significantly higher (**p < 0.01) and a significantly decreased serum levels of total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), as well as a higher concentration of high-density lipoprotein cholesterol (HDL-C) was observed, compared with that of n-NUC treated group. These findings suggest that NUC-PLGA-NPs hold great promise for sustained and controlled drug delivery with improved bioavailability to alleviating lipogenesis.     

Lipid nanoparticles: Different preparation techniques,characterization, hurdles,and strategies for the production of solid lipid nanoparticles and nanostructured lipid carriers for oral drug delivery

The bioavailability of an orally administered drug primarily depends on its solubility in the GIT and its permeability across cell membranes. Also, a drug in solution form is preferred for conducting pharmacological, toxicological and pharmacokinetic studies during the drug development stage. Thus, poor water solubility not only limits a drug’s biological application but also challenges its pharmaceutical development. The use of lipid nanoparticles (LNs) in pharmaceutical technology has been reported for several years due to its important in green chemistry for several reasons specifically for its biochemical as “green” materials and biochemical processes as green processes that can be very environmentally friendly. Also, the physiological/physiologically related lipids (GRAS) made LNs usually enhance the drug absorption in the GIT. Hence, the pathways for absorption, metabolism, and transportation are present in the body, which may contribute to a large extent to the bio-fate of the lipidic carrier. Moreover, the LNs improves the mucosal adhesion and increases their GIT residence time. The LNs with a solid matrix are two types: solid lipid nanoparticle (SLN) and nanostructured lipid carrier (NLC). Also, their hydrophobic core provides a suitable environment for entrapment of hydrophobic drugs to improve its bioavailability. This review highlights and discusses the simple and easily scaled-up novel SLN and NLC along with their different production techniques, hurdles, and strategies for the production of LNs, characterization, lyophilization and drug release. Also, this review summarizes the research findings reported by the different researchers regarding the different method of preparation, excipients and their significant findings.