Influence of Bile Acids in Hydrogel Pharmaceutical Formulations on Dissolution Rate and Permeation of Clindamycin Hydrochloride

Clindamycin hydrochloride is a widely used antibiotic for topical use, but its main disadvantage is poor skin penetration. Therefore, new approaches in the development of clindamycin topical formulations are of great importance. We aimed to investigate the effects of the type of gelling agent (carbomer and sodium carmellose), and the type and concentration of bile acids as penetration enhancers (0.1% and 0.5% of cholic and deoxycholic acid), on clindamycin release rate and permeation in a cellulose membrane in vitro model. Eight clindamycin hydrogel formulations were prepared using a 23 full factorial design, and they were evaluated for physical appearance, pH, drug content, drug release, and permeability parameters. Although formulations with carbomer as the gelling agent exerted optimal sensory properties, carmellose sodium hydrogels had significantly higher release rates and permeation of clindamycin hydrochloride. The bile acid enhancement factors were higher in carbomer gels, and cholic acid exerted more pronounced permeation-enhancing effects. Since the differences in the permeation parameters of hydrogels containing cholic acid in different concentrations were insignificant, its addition in a lower concentration is more favorable. The hydrogel containing carmellose sodium as a gelling agent and 0.1% cholic acid as a penetration enhancer can be considered as the formulation of choice.

Terpenoid Hydrazones as Biomembrane Penetration Enhancers: FT-IR Spectroscopy and Fluorescence Probe Studies

Hydrazones based on mono- and bicyclic terpenoids (verbenone, menthone and carvone) have been investigated in vitro as potential biomembrane penetration enhancers. In this regard, liposomes composed of lecithin or cardiolipin as phospholipid phase components with incorporated fluorescence probes have been prepared using the thin-film ultrasonic dispersion method. The mean particle size of the obtained liposomes, established using laser diffraction, was found to be 583 ± 0.95 nm, allowing us to categorize them as multilamellar vesicles (MLVs) according to their morphology. Pursuant to fluorescence analysis, we may assume a reduction in microviscosity and, consequently, a decrease in the packing density of lecithin and cardiolipin lipids to be the major mechanism of action for terpenoid hydrazones 1–15. In order to determine the molecular organization of the lipid matrix, lipids were isolated from rat strata cornea (SCs) and their interaction with tested compounds was studied by means of Fourier transform infrared spectroscopy. FT-IR examination suggested that these hydrazones fluidized the SC lipids via the disruption of the hydrogen-bonded network formed by polar groups of SC constituents. The relationship between the structure of terpenoid hydrazones and their ability to enhance biomembrane penetration is discussed.

A Review on Chemical Permeation Enhancers used in the Formulation of Transdermal Drug Delivery System

Skin penetration enhancement technology is a rapidly evolving area that will greatly increase the quantity of transdermal drug delivery medications. Penetration enhancers are used to facilitate the movement of drugs through the skin barrier. Numerous methods exist for extending partition enhancement. The enhancers' contact with the polar head of the lipid groups is the potential means for increasing the penetration. Penetration enhancers improve the amount of free water molecules between the bilayer, leading to an improvement of the polar drug diffusion cross section. This article focuses on the different compounds assessed for improving penetration activity like sulphoxides, azones, pyrrolidones, alcohols and alkanols, glycols, surfactants and terpenes.

Nicotinic Amidoxime Derivate BGP-15, Topical Dosage Formulation and Anti-Inflammatory Effect

BGP-15 is a Hungarian-developed drug candidate with numerous beneficial effects. Its potential anti-inflammatory effect is a common assumption, but it has not been investigated in topical formulations yet. The aim of our study was to formulate 10% BGP-15 creams with different penetration enhancers to ensure good drug delivery, improve bioavailability of the drug and investigate the potential anti-inflammatory effect of BGP-15 creams in vivo. Since the exact mechanism of the effect is still unknown, the antioxidant effect (tested with UVB radiation) and the ability of BGP-15 to decrease macrophage activation were evaluated. Biocompatibility investigations were carried out on HaCaT cells to make sure that the formulations and the selected excipients can be safely used. Dosage form studies were also completed with texture analysis and in vitro release with Franz diffusion chamber apparatus. Our results show that the ointments were able to reduce the extent of local inflammation in mice, but the exact mechanism of the effect remains unknown since BGP-15 did not show any antioxidant effect, nor was it able to decrease LPS-induced macrophage activation. Our results support the hypothesis that BGP-15 has a potential anti-inflammatory effect, even if it is topically applied, but the mechanism of the effect remains unclear and requires further pharmacological studies.

Permeability of Ibuprofen in the Form of Free Acid and Salts of L-Valine Alkyl Esters from a Hydrogel Formulation through Strat-M™ Membrane and Human Skin

This paper aimed to evaluate the effect of vehicle and chemical modifications of the structure of active compounds on the skin permeation and accumulation of ibuprofen [IBU]. In vitro permeation experiments were performed using human abdominal skin and Strat-M™ membrane. The HPLC method was used for quantitative determinations. The formulations tested were hydrogels containing IBU and its derivatives and commercial gel with ibuprofen. The results obtained indicate that Celugel® had an enhancing effect on the skin penetration of IBU. The average cumulative mass of [IBU] after 24 h permeation test from Celugel® formulation through human skin was over 3 times higher than for the commercial product. Three ibuprofen derivatives containing [ValOiPr][IBU], [ValOPr][IBU], and [ValOBu][IBU] cation were evaluated as chemical penetration enhancers. The cumulative mass after 24 h of penetration was 790.526 ± 41.426, 682.201 ± 29.910, and 684.538 ± 5.599 μg IBU cm−2, respectively, compared to the formulation containing unmodified IBU-429.672 ± 60.151 μg IBU cm−2. This study demonstrates the perspective of the transdermal hydrogel vehicle in conjunction with the modification of the drug as a potential faster drug delivery system.

Olive Oil Based Methotrexate Loaded Topical Nanoemulsion Gel for the Treatment of Imiquimod Induced Psoriasis-Like Skin Inflammation in an Animal Model

Psoriasis, a chronic inflammatory illness, is on the rise and is linked to several other life-threatening diseases. The primary goal of this study was to create a nanoemulsion gel loaded with methotrexate and olive oil (MTX NEG). The formulation was evaluated for physicochemical characterization, entrapment efficiency, drug release kinetics, skin permeation studies and stability tests. In addition, the efficacy of MTX NEG against psoriasis was tested using imiquimod-induced psoriasis in a rat model. The final optimized MTX NEG was developed with a particle size of 202.6 ± 11.59 nm and a PDI of 0.233 ± 0.01, with a 76.57% ± 2.48% average entrapment efficiency. After 20 h, the release kinetics predicted a 72.47% drug release at pH 5.5. FTIR findings demonstrated that the optimized MTX NEG formulation effectively fluidized both the epidermis and dermis of the skin, potentially increasing drug permeability and retention. The application of Tween 80 and PEG 400, on the other hand, significantly enhanced these effects, as these are well known penetration enhancers. After 24 h, an average of 70.78 ± 5.8 μg/cm2 of methotrexate was permeated from the nanoemulsion gel with a flux value of 2.078 ± 0.42 μg/cm2/h, according to permeation measurements. Finally, in vivo experiments on rabbit skin revealed that the increased skin penetration of methotrexate-loaded nanoemulsion gel was not due to structural alterations in intercellular lipid layers in the stratum corneum. In vivo antipsoriatic studies on rats revealed that MTX NEG produced a PASI decrease that was extremely similar and even better than the 91% reduction seen in the MTX tablet group. According to the pharmacokinetic profile, Cmax was 8.5 μg/mL, Tmax was 12 h, and t1/2 was 15.5 ± 2.37 h. These findings reinforce that MTX-NEG based on olive oil could be a possible treatment for psoriasis and could decrease the remission of psoriasis-like symptoms.

A Comprehensive Review on Natural Products as Chemical Penetration Enhancer

The drug delivery within the stratum corneum of the skin prevails a challenging area for the pharmaceutical field, especially to the formulation scientists. Several investigations revealed that the lipid domain, which is the integral component of the transport barrier, must be breached if it is to be delivered transdermally at an appropriate rate. In particular, transdermal drug delivery has intrigued researchers with multiple suggestions because multiple dosing or insufficient drug delivery or characteristics of various drugs often results in low therapeutic effects. The application of permeation or penetration enhancers may prolong the number of drugs that can be offered topically. The application of any natural permeation enhancer is innoxious over the artificial permeation enhancers. The natural permeation enhancers are investigated, so notably include essential oils, terpenes, terpenoids, fatty acid esters, etc., have a certain effect in the transdermal drug delivery system. Despite decades of investigation on the natural chemical penetration enhancer, the researchers could not establish the effectiveness of natural penetration enhancers clinically due to the lack of in vivo models. Several factors, like solubility, solvent selection, experimental models, etc., has restricted the application and development of natural penetration enhancers in topical drug delivery systems, especially in the patches. Therefore, further investigation needs to do on skin irritation to decide natural penetration enhancers controlling optimum enhancement effects with minimal skin irritation. This review gives a comprehensive literature survey on naturally obtained chemical penetration enhancers and their future possibilities. Keywords: Topical Drug delivery system, Natural products, Penetration enhancer, Stratum corneum, In vivo models.