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The aim of this work was to develop, optimize and characterize a silymarin-laden polyvinylpyrrolidone (PVP)-polyethylene glycol (PEG) polymeric composite to resolve low aqueous solubility and dissolution rate problem of the drug. A number of silymarin-laden polymeric formulations were fabricated with different quantities of PVP K-30 and PEG 6000 by the solvent-evaporation method. The effect of PVP K-30 and PEG 6000 on the aqueous solubility and dissolution rate was investigated. The optimized formulation and its constituents were characterized using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) techniques. Both the PEG 6000 and PVP K-30 positively affected the aqueous solubility and dissolution rate of the drug. In particular, a formulation consisting of silymarin, PVP K-30 and PEG 6000 (0.25/1.5/1.5, w/w/w) furnished the highest solubility (24.39±2.95 mg/mL) and an excellent dissolution profile (~100% in 40 min). The solubility enhancement with this formulation was ~1150-fold as compared to plain silymarin powder. Moreover, all the constituents existed in the amorphous state in this silymarin-laden PVP-PEG polymeric composite. Accordingly, this formulation might be a promising tool to administer silymarin with an enhanced effect via the oral route.

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Background: Gallic acid (GA-3,4,5-trihydroxybenzoic acid), a phenolic phytochemical, is a ubiquitous secondary metabolite found in most plants, with appreciable concentrations in grapes seed, rose flowers, sumac, oak and witch hazel. GA often results from the hydrolysis of terpenes and the polyphenol tannic acid. Applications: It exhibits powerful antioxidant, anti-inflammatory, antimicrobial, and anti-cancer activities. Most intriguing benefit has been reported to be on the skin. Due to these beneficial properties, GA and its derivatives (e.g. lipid-soluble phenols such as synthetic gallic esters aka gallates) have been extensively used as an adjuvant in a number of therapeutic formulations, as a substitute of hydrocortisone in children with atopic dermatitis (AD) and other skin conditions (hyperpigmentation, wound healing), and as a cosmetic ingredient. GA has a USFDA GRAS status (generally recognized as safe), exhibiting fairly low systemic toxicity and associated mortality at acute doses in many experimental models. Despite anti-skin aging benefits obtained with relatively safe GA formulations, few cases of gallate-induced skin allergic have been reported in humans. Therefore, approaches to improve the bioavailability and biodegradability of this poor-water soluble and non-biodegradable phenolic compound are warranted. Purpose: This review has focused on the recently reported biological activities pertaining to the skin as well as the pharmacological properties of GA and its derivatives with special emphasis on its use in (nano-) cosmetic formulations. Since this is an evolving area of research, an adequate emphasis has been placed upon advantages and disadvantages of various nanoformulations.

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Microsponge refers to a highly cross-linked particle system with a capacity to adsorb (like a dry sponge) pharmaceutical materials. There are various methods available to prepare microsponge formulations, in this study we used quasi emulsion-solvent diffusion method with a combination of hydrophobic (ethyl cellulose) and hydrophilic (hydroxypropyl methylcellulose) polymers mediated via Tween 80 and polyvinyl alcohol. Various ratios and amounts of the polymers and surfactants were used to prepare microsponge formulations using ketoprofen as a model drug and extensively characterised. Our results, for the first time, indicate successful and optimised formulation with desired pharmaceutical characteristics using a combination of hydrophobic and hydrophilic polymers.

A surface-attached silymarin-loaded solid dispersion with improved dissolution profile and enhanced oral bioavailability was formulated using silymarin, polyvinylpyrrolidone (PVP) and Tween 80 in water. In this solid dispersion, hydrophilic PVP was adhered onto the surface of crystalline drug rendering silymarin hydrophilic without changing its crystallinity. The drug solubility from the optimised solid dispersion prepared with silymarin/PVP/Tween 80 at the weight ratio of 5/2.5/2.5 increased by almost 650-fold compared to drug powder. The drug was physically and chemically stable in the solid dispersion for at least 6 months. Moreover, the solid dispersion enhanced the oral bioavailability of the drug in rats by almost 3-fold compared to the commercial product. The silymarin-loaded solid dispersion also exhibited advanced hepatoprotective bioactivity against CCl4-induced liver damage compared to silymarin or the commercial product. Thus, this silymarin-loaded solid dispersion would be useful for the enhancement of oral bioavailability and hepatoprotective activity of poorly water-soluble silymarin.