Lipid-based systems as promising approach for enhancing the bioavailability of poorly water-soluble drugs

Low oral bioavailability as a consequence of low water solubility of drugs is a growing challenge to the development of new pharmaceutical products. One of the most popular approaches of oral bioavailability and solubility enhancement is the utilization of lipid-based drug delivery systems. Their use in product development is growing due to the versatility of pharmaceutical lipid excipients and drug formulations, and their compatibility with liquid, semi-solid, and solid dosage forms. Lipid formulations, such as self-emulsifying (SEDDS), self-microemulsifying SMEDDS) and self-nanoemulsifying drug delivery systems (SNEDDS) were explored in many studies as an efficient approach for improving the bioavailability and dissolution rate of poorly water-soluble drugs. One of the greatest advantages of incorporating poorly soluble drugs into such formulations is their spontaneous emulsification and formation of an emulsion, microemulsion or nanoemusion in aqueous media. This review article focuses on the following topics. First, it presents a classification overview of lipid-based drug delivery systems and mechanisms involved in improving the solubility and bioavailability of poorly water-soluble drugs. Second, the article reviews components of lipid-based drug delivery systems for oral use with their characteristics. Third, it brings a detailed description of SEDDS, SMEDDS and SNEDDS, which are very often misused in literature, with special emphasis on the comparison between microemulsions and nanoemulsions

High-shear wet granulation of SMEDDS based on mesoporous carriers for Improved carvedilol solubility

Mesoporous carriers are a convenient choice for the solidification of self-microemulsifying drug delivery systems (SMEDDS) designed to improve the solubility of poorly water-soluble drugs. They are known for high liquid load capacity and the ability to maintain characteristics of dry, free-flowing powders. Therefore, five different mesoporous carriers were used for the preparation of carvedilol-loaded SMEDDS granules by wet granulation methods—in paten (manually) and using a high-shear (HS) granulator. Granules with the highest SMEDDS content (63% and 66% of total granules mass, respectively) and suitable flow properties were obtained by Syloid® 244FP and Neusilin® US2. SMEDDS loaded granules produced by HS granulation showed superior flow characteristics compared to those obtained manually. All SMEDDS granules exhibited fast in vitro release, with 93% of carvedilol releasing from Syloid® 244FP-based granules in 5 min. Upon compaction into self-microemulsifying tablets, suitable tablet hardness and very fast disintegration time were achieved, thus producing orodispersible tablets. The compaction slightly slowed down the carvedilol release ratenevertheless, upon 1 h (at pH 1.2) or 4 h (at pH 6.8) of in vitro dissolution testing, the amount of released drug was comparable with granules, confirming the suitability of orodispersible tablets for the production of the SMEDDS loaded single unit oral dosage for

A comparative study of lipid-based drug delivery systems with different microstructure for combined dermal administration of antioxidant vitamins

Antioxidant vitamins have been proven to be highly efficient in treatment of skin impaired by oxidative stress, but challenges regarding stability and skin penetration limit their therapeutic effect. Lipid-based drug delivery systems offer great potential for overcoming these drawbacks. This work aimed to identify the most promising system for combined antioxidant therapy. A comparative assessment of several systems, containing the same ingredients but differing in their microstructure, was therefore performed. Namely, microemulsions (MEs) of both types (W/O and O/W) and lyotropic liquid crystals (LLCs), simultaneously loaded with vitamin C or ascorbyl palmitate and vitamin E, were assessed. Stability, antioxidant capacity (DPPH assay), and release (Franz diffusion cells) of the vitamins incorporated was examined. The results obtained were supported with the systems’ thermal and rheological (rotational and oscillatory tests) evaluation. In addition, biological acceptability (MTS assay) of the systems studied was investigated. The findings demonstrate that the microstructure of MEs and LLCs studied has a decisive impact on the stability, antioxidant activity, and release of the vitamins incorporated. The highest stability was preserved in LLCs for both pairings, with vitamins C and E being a more stable combination. LLCs also provided suitable vitamins’ antioxidant activity and release characteristics. In addition, the system exhibited preferable rheological features for dermal administration. Furthermore, cytotoxicity studies on a keratinocyte cell line demonstrated the highest biocompatibility for LCCs with the cell proliferation being greater than 85%. In conclusion, LLCs were confirmed as the most favorable lipid-based drug delivery system for combined antioxidant treatment

Encapsulation of natural antioxidant resveratrol in liposomes

Liposomes have been shown to be suitable systems for encapsulation and preserving the health-beneficial properties of a wide range of biological active ingredients such as resveratrol (RSV). The aim of this study was to encapsulate RSV in liposomes, with a goal to achieve the extended release and improved stability of RSV. Multilameral liposomes were prepared by means of two different methods: thin film method (TF) and proliposome method (PRO). In both methods, the ratio between added RSV and phospolipon 90G (P90G) was 1:20 w/w. Extrusion and sonication were applied in order to obtain unilameral liposomes. Both methods were efficient in capturing RSV within the microparticles, thus encapsulation efficiency had high values (92,9% in case of TF and 97,4% in case of PRO). The size reduction of liposomes resulted with particles of the average diameter ranged between 120 and 270 nm. Antioxidative activity was retained at a high level (approximately 95%). Franz diffusion cell was used for release studies and diffusion of RSV was monitored for 6h. According to the results, liposomes appeared to be suitable vehicles for encapsulation of resveratrol where PRO is particularly useful for encapsulation of antioxidants