Dermatological products constitute a big segment of the pharmaceutical market. From conventional products to more advanced ones, a wide variety of dosage forms have been developed till current date. A representative of the advanced delivery means is carrier-based systems, which can load large number of drugs for treatment of dermatological diseases, or simply for cosmeceutical purposes. To make them more favorable for topical delivery, further incorporation of these carriers in a topical vehicle, such as gels or creams is made. Therefore in this review article, an overview is compiled of the most commonly encountered novel carrier based topical delivery systems; namely lipid based (nanoemulsions, microemulsions, solid lipid nanoparticles [SLNs] and nanostructured lipid carriers [NLCs]), and vesicular carriers (non-deformable, such as liposomes, niosomes, emulsomes and cerosomes, and deformable, such as transfersomes, ethosomes, transethosomes, and penetration enhancer vesicles), with special emphasis on those loaded in a secondary gel vehicle. A special focus was made on the commonly encountered dermatological diseases, such as bacterial and fungal infections, psoriasis, dermatitis, eczema, vitiligo, oxidative damage, aging, alopecia, and skin cancer.

In this study, oridonin-loaded long-circulating liposomes (LC-lipo@ORI) were prepared with the ethanol injection method. Its physicochemical properties and the morphology were characterized, and its stability and release profiles were evaluated. Furthermore, its antitumor effects were studied using two in vitro cell models of colon cancer and two tumor-bearing models in nude mice. The prepared LC-lipo@ORI was quasi-spherical, with a mean particle size of 109.55 ± 2.30 nm. The zeta potential was −1.38 ± 0.21 mV, the encapsulation efficiency was 85.79%±3.25%, and the drug loading was 5.87%±0.21%. In vitro release results showed that the cumulative release rate of LC-lipo@ORI at 12 h was 63.83%. However, ORI dispersion was almost completely released after 12 h. In vitro cytotoxicity results showed that, the inhibiting effects of LC-lipo@ORI on the proliferation of two types of colon cancer cells were apparently higher than those of ORI dispersion, whereas those of the blank carrier were not noticeable. In vivo studies confirmed that, the encapsulation of LC-lipo enhanced the inhibitory effects of ORI on tumor growth. These results indicated that LC-lipo@ORI a promising formulations for colon cancer treatment.

Previous evaluation of marketed acyclovir 5% creams using in vitro release testing (IVRT) and its correlation with the qualitative composition confirmed the discriminative characteristics of this methodology. This was in line with the principles of Topical drug Classification System (TCS). For the current research, experimental formulations were designed and prepared by applying controlled changes in manufacturing process, sources of raw materials, and amount of the excipients. The topical semisolids were representative for the four classes of TCS. The outcome of the IVRT and rheological assessments was evaluated in relation with the nature of the change and the functional role of the excipients. The variations in propylene glycol content from 5% to 40% impacted both the in vitro release rates (gradual decrease from 16.23 to 8.97 µg/cm2/min0.5) and the microstructural characteristics (proportional increase of yield stress from 17.98 to 46.40 Pa). The inert excipients e.g. cetostearyl alcohol or white soft paraffin altered majorly the rheological behavior, as their functionality is mainly related to vehicle properties. IVRT was discriminative for the microstructural differences induced by both categories of excipients according to TCS dichotomy. This simple, reliable, and reproducible test reflected the impact of difference in quantitative composition and characteristics of excipients.

The aim of this study is, preparing various dendrimeric formulations of oxaliplatin and investigating their properties. First of all, the solubility enhancement capabilities of polyamidoamine (PAMAM) G3.5 and PAMAM G4.5 dendrimers were investigated. The results showed that oxaliplatin solubility mostly increasing linearly with dendrimer concentration. Additionally, the increase was more notable in PAMAM G4.5 dendrimers. Then, drug–dendrimer complexes were prepared in different mediums, since the medium used can affect the amount of drug-loaded to dendrimers. Prepared complexes were examined for loading capacity and loading efficiency. It was found that PAMAM G4.5 dendrimers can complex with 2- to 5-fold more oxaliplatin than PAMAM G3.5. Finally, oxaliplatin was modified to a platinum (IV) compound to prepare chemical drug–dendrimer conjugates. Ester bonds were established by Steglich esterification through the hydroxyl group of modified oxaliplatin and the carboxyl groups of the dendrimers. The formulations were characterized by UV, IR, NMR spectroscopy, and dynamic light scattering techniques. PAMAM G3.5 conjugate was further evaluated for the cytotoxicity test. The IC50 value of PAMAM G3.5 conjugate was found as 0.72 µM. For unmodified oxaliplatin, this value was 14.03 µM. As a result, a dendrimer-based drug delivery system that has been found promising for further improvement has been developed successfully.

In recent years, the hydrophobic active substances have led researchers to develop new formulations to enhance bioavailability and dissolution rate; brinzolamide, a lipophilic drug belongs to carbonic anhydrase inhibitors, which cause reduction of intraocular pressure in patients suffering from glaucoma. Currently, the marketed product of brinzolamide is in the form of ocular drops; nonetheless, the conventional drops provide decreased therapeutic efficacy owing to their low bioavailability and pulsed drug release. Thus, the development of novel ocular formulations such as topical microemulsions is of high importance. In this work, the preparation of new microemulsions containing brinzolamide (0.2, 0.5 and 1% w/w) and comprised from isopropyl myristate, tween 80 and span 20 and Cremophor EL was performed. The obtained microemulsions were further characterized for their physicochemical properties. In addition, Fourier Transformed-Infrared spectroscopy was used touate the compatibility of active ingredients and components. In vitro release studies along with kinetic modeling were performed using the dialysis membrane method in simulated tear fluid. Bioadhesion studies were performed using Texture analysis. Finally, in vitro ocular irritation based on EpiOcular™ Eye Irritation Test and cytocompatibility studies was performed to examine any possible harm on ocular cells and predict in vivo safety profile.

A combination of doxorubicin (DOX) and small interfering RNA (siRNA) is proven effective for the reverse of multidrug resistance. However, rapid degradation and poor cellular internalization of siRNA hinder their synergistic action. To improve the combination effect, asparagine–glycine–arginine peptide (NGR) -modified nanobubbles (NBs) containing cell-penetrating peptide (CPP) decorated DOX and CPP decorated c-myc siRNA were constructed. Diameters of these NBs were about 245 nm and zeta potentials were about −3 mV. Encapsulation efficiencies (EE) of DOX exceeded 80%. Release of DOX could be triggered by ultrasound (US) since above 80% DOX was released from NBs after sonication while less than 5% DOX was discharged without treatment of US. These NBs were considered stable during 24 h since the decrease of particle size was no more than 10 nm, variances of EE were less than 5%, and changes of transmission (ΔT) were less than 3%. More drugs in formulation decorated with CPP and NGR were accumulated in the tumor when combined with sonication. The evident synergistic action of DOX, siRNA, NBs, and US was verified in mice with strong antitumor efficacy. Taken together, NGR-modified NBs containing CPP-DOX and CPP-siRNA are able to realize time- and spatial-controlled drug delivery and show potential application prospects.

In this study, the aerogel technology was used to prepare pulmonary drug carriers consisting of alginate and alginate–hyaluronic acid by an emulsion gelation technique and supercritical CO2 drying. During the preparation process, the emulsification rate and inner phase viscosity were varied to control the diameter of aerogel microspheres. Results showed that the aerogel microspheres were highly porous (porosity > 98%) with low densities in the range between 0.0087 and 0.0634 g/cm3 as well as high surface areas between 354 and 759 m2/g. The obtained microspheres showed aerodynamic diameter below 5 µm making them suitable for pulmonary drug delivery. An in vitro drug release study with the model drug sodium naproxen was conducted and a non-Fickian drug release mechanism was observed, with no significant difference between the release profiles of alginate and alginate–hyaluronic acid microspheres. During the emulsion gelation step, the feasibility of using the capillary number to estimate the largest stable droplet size in the emulsions was also studied and it was found that using this number, the droplet size in the emulsions may well be predicted.

In the current study erythropoietin (EPO) loaded trimethyl chitosan/tripolyphosphate nanoparticles-embedded in a thermosensitive hydrogel was prepared. The influence of the main experimental factors on the properties of EPO-loaded nanoparticles were evaluated using a two-factors central composite design and the optimized formulation was then freeze dried. Sodium dodecyl sulfate-page and circular dichroismspectroscopy were used to confirm the structural stability of EPO following encapsulation and freeze drying. Rheological properties, and the release rate of EPO from the hydrogel were examined. Mean particle size, zeta potential, and entrapment efficiency of the optimized EPO-loaded nanoparticles were confirmed 151.5 ± 16 nm, 11.5 ± 1.8 mV, and 78.5 ± 5.9%, respectively. The hydrogel containing nanoparticles existed as a solution at room temperature converted to a semisolid upon increasing the temperature to 35 ± 1.2 °C and demonstrated controlled release of EPO for more than 10 days. The stability of EPO in the hydrogel system was further investigated using in vivo biological activity assay and the result revealed relative potency of 0.85 as calibrated with standard EPO. Finally, a single injection of the EPO-loaded nanoparticles-embedded in the hydrogel administered to Sprague-Dawley rats resulted in elevated reticulocytes for about 20 days compared to control group received blank hydrogel.

α-Mangostin-loaded mucoadhesive nanoparticles (NPs) were prepared for colon-targeted drug delivery against colorectal cancer cells using pH-dependent composite mucoadhesive NPs. Chitosan (CS) and thiolated chitosan (TCS) were used to form the NPs, following by genipin (GP) crosslinking and the surface modification by Eudragit® L100 (L100). The particle size, morphologies and characteristics of NPs were observed. The α-mangostin loading and release patterns were investigated. In vitro mucoadhesive properties were examined by the wash-off method. In addition, the anti-tumour activity was tested on colorectal cancer cells. The results showed that NPs were slightly oblong in shape with particle size ranging between 300 and 900 nm. The small size of NPs was found with TCS and larger NPs were observed by GP and L100 process. However, GP and L100 provided an increase in α-mangostin loading, limited the release of α-mangostin in the upper gastrointestinal tract, and enhanced α-mangostin delivery to the colon. The TCS-based NPs with GP and L100 exhibited strong mucoadhesion to colon mucosa, more than uncoated-NPs and CS-based NPs. Moreover, NPs exhibited the anti-tumour activity. Therefore, the mucoadhesive TCS-based NPs could be a promising candidate for a controlled-release drug delivery system of α-mangostin to the colon.

Due to their light consistency and good spreadability, aqueous foams are considered as convenient and highly accepted drug carrier systems that are of great importance in the field of topical drug delivery. The production of a stable, easy to dose, preferably environmentally harmless foam formulation is challenging. Therefore, foam characterisation requires a complex approach: several tests are to be performed throughout the formulation. Our study primarily aims to investigate the quality attributes of propellant-free foam-forming additives. Throughout the research, we focused on acquiring knowledge about the properties of pharmaceutical excipients suitable for foam formulations and their effect on foam characteristics. Not only were the relative foam density, actuated foam weight and the foam collapse tendencies studied, but also the initial liquid properties. Along with surface tension determination, bubble-forming experiments were carried out. The bubble size and rate of formation, standardised by using a texture analyser, were followed by image analysis. Analysing the bubble-forming properties of dilute surfactant solutions allows assumptions on the properties of foam formed from the more concentrated solutions. The size and number of bubbles in the produced foams are related to the kinetics of single bubble formation. For comparison, commercially available medicated foams were studied.