The effect of diethylene glycol monoethyl ether on skin penetration ability of diclofenac acid nanosuspensions

Simultaneously improving tabletability and solubility of diclofenac by cocrystallization with picolinamide

Diclofenac (DIC) is a nonsteroidal anti-inflammatory drug with poor tabletability and water solubility. In the present study, a new diclofenac-picolinamide cocrystal (DIC-PIC) was prepared to simultaneously improve its tabletability and solubility. The cocrystal was characterized using multiple techniques, such as X-ray diffraction, thermal methods and spectral analyses. The tabletability of DIC-PIC was significantly improved over DIC, which is attributed to the larger bonding area between crystals due to the higher plasticity of DIC-PIC, demonstrated by the lower in-die mean yield pressure, Py,i, of DIC-PIC (59.5 ± 0.6 MPa) than DIC (86.6 ± 1.4 MPa). The higher plasticity of DIC-PIC is consistent with the existence of a slip plane (001) in its crystal structure. The solubility of DIC-PIC is significantly higher than that of DIC (112 times higher in water and 22 times higher in pH = 6.8 buffer solution). Hence, the simultaneous improvement in tabletability and solubility of DIC-PIC overcomes two main barriers in developing DIC tablets, which makes it a promising candidate for developing a DIC tablet with improved performance.

Nanosuspension-Based Drug Delivery Systems for Topical Applications

Nanosuspensions have garnered recent attention as a promising strategy for mitigating the bioavailability challenges of hydrophobic drugs, particularly those characterized by poor solubility in both aqueous and organic environments. Addressing solubility issues associated with poorly water-soluble drugs has largely resolved the need to enhance drug absorption and bioavailability. As mucosal formulations and topical administration progress in the future, nanosuspension drug delivery, straightforward formulation techniques, and versatile applications will continue to be subjects of interest. Nanosuspensions have undergone extensive scrutiny in preparation for topical applications, encompassing ocular, pulmonary, and dermal usage. Among the numerous methods aimed at improving cutaneous application, nanocrystals represent a relatively recent yet profoundly intriguing approach. Despite the increasing availability of various nanosuspension products, primarily designed for oral administration, only a limited number of studies have explored skin permeability and drug accumulation in the context of nanosuspensions. Nevertheless, the scant published research unequivocally underscores the potential of this approach for enhancing cutaneous bioavailability, particularly for active ingredients with low to medium solubility. Nanocrystals exhibit increased skin adhesiveness in addition to heightened saturation solubility and dissolution rate, thereby augmenting cutaneous distribution. The article provides a comprehensive overview of nanosuspensions for topical application. The methodology employed is robust, with a well-defined experimental design; however, the limited sample size raises concerns about the generalizability of the findings. While the results demonstrate promising outcomes in terms of enhanced drug delivery, the discussion falls short of addressing certain limitations. Additionally, the references largely focus on recent studies, but a more diverse inclusion of historical perspectives could offer a more holistic view of the subject.

Advance and Challenges in the Treatment of Skin Diseases with the Transdermal Drug Delivery System

Skin diseases are among the most prevalent non-fatal conditions worldwide. The transdermal drug delivery system (TDDS) has emerged as a promising approach for treating skin diseases, owing to its numerous advantages such as high bioavailability, low systemic toxicity, and improved patient compliance. However, the effectiveness of the TDDS is hindered by several factors, including the barrier properties of the stratum corneum, the nature of the drug and carrier, and delivery conditions. In this paper, we provide an overview of the development of the TDDS from first-generation to fourth-generation systems, highlighting the characteristics of each carrier in terms of mechanism composition, penetration method, mechanism of action, and recent preclinical studies. We further investigated the significant challenges encountered in the development of the TDDS and the crucial significance of clinical trials.

Bentonite- and Palygorskite-Based Gels for Topical Drug Delivery Applications

Bentonite or palygorskite-based hydrogels have recently been suggested as a strategy to increase bioavailability and control the retention and release of therapeutic candidates. In this work, clay-based hydrogels loaded with diclofenac acid nanocrystals have been successfully designed and developed. The aim was to improve diclofenac solubility, its dissolution rate and to enhance its local bioavailability after topical application. For this purpose, diclofenac acid nanocrystals were prepared by wet media milling technology and then loaded into inorganic hydrogels based on bentonite and/or palygorskite. Diclofenac acid nanocrystals were characterized by morphology, size, and zeta potential. Moreover, rheological behavior, morphology, solid state, release studies, and in vitro skin penetration/permeation of diclofenac acid nanocrystals-loaded hydrogels were performed. The hydrogels were characterized by a crystalline structure, and demonstrated that the inclusion of diclofenac in clay-based hydrogels resulted in an increased thermal stability. The presence of both palygorskite and bentonite reduced nanocrystal mobility, and consequently its release and penetration into the skin. On the other hand, bentonite- or palygorskite-based hydrogels revealed great potential as an alternative strategy to enhance topical bioavailability of DCF nanocrystals, enhancing their penetration to the deeper skin layers.

Carboxylated superparamagnetic Fe3O4 nanoparticles modified with 3-amino propanol and their application in magnetic resonance tumor imaging

BACKGROUND

Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are of potential magnetic resonance imaging (MRI) contrast agents for tumor diagnosis. However, ultrasmall particle size or negative surface charge lead to relative short half-life which limit the utilization of USPIO for in vivo MRI contrast agents.

METHODS

Superparamagnetic Fe₃O₄ nanoparticles coated with polyacrylic acid (PAA)were synthetized, and modified by 3-amino propanol and 3-diethyl amino propyl amine. The characteristics of superparamagnetic Fe₃O₄ nanoparticles were investigated through transmission electron microscopy, X-ray diffraction analysis, Zata potential analysis, thermogravimetric analysis, and relaxation properties analysis. Magnetic resonance imaging animal experiment was performed.

RESULTS

The synthetized nanoparticles were irregular spherical, with small particle size, few agglomeration, and good dispersion in water. After modification, the potential fluctuation of nanoparticles was small, and the isoelectric point of nanoparticles changed to high pH. After 3-amino propanol modification, the weight loss of the curve from 820 to 940 °C was attributed to the decomposition of 3-amino propanol molecules on the surface. The T1 relaxation rate of nanoparticles changed little before and after modification, which proved that the modification didn't change the relaxation time. Brighter vascular images were observed after 3-amino propanol modification through measurement of magnetic resonance tumor imaging.

CONCLUSION

These data indicated the Fe₃O₄ nanoparticles modified by 3-amino propanol should be a better contrast agent in the field of magnetic resonance tumor imaging.

Altered Skin Permeation of Finasteride Using Clove Oil, Urea, and Lyophilized Powder of Grape Seed Extract

Purpose: Finasteride is a 5-alpha reductase inhibitor used to treat hair loss and acne. The skin permeation of finasteride is one of the main challenges associated with dermal drug delivery. One way to overcome the skin barrier is to use penetration enhancers. The purpose of this study was to investigate the effect of some penetration enhancers on finasteride permeability on the skin, as well as the effect of pretreatment time on their efficacy. Methods: In order to determine the effect of penetration enhancers on the skin permeability of finasteride, the skin was exposed to clove oil, urea, and lyophilized powder of grape seed extract (LPGSE) at different pretreatment times (2, 4 h), and then the permeability parameters were determined by passing the drug through the skin. Results: The results of this study showed that clove oil, urea, and LPGSE increased the transfer of finasteride from the skin. The highest rate of permeation was observed with clove oil (4 h), and the least permeability was observed with urea (4 h). Conclusion: Increasing the pretreatment time with clove oil and LPGSE increases the permeability of finasteride. Meanwhile, the increase in pretreatment time with urea reduces the penetration of finasteride from the skin due to reversible effects.

Needle-Free Jet Injectors and Nanosuspensions: Exploring the Potential of an Unexpected Pair

Needle-free liquid jet injectors are medical devices used to administer pharmaceutical solutions through the skin. Jet injectors generate a high-speed stream of liquid medication that can puncture the skin and deliver the drug to the underlying tissues. In this work, we investigated the feasibility of using liquid jet injectors to administer nanosuspensions, assessing the impact of the jet injection on their pharmaceutical and physicochemical properties. For this purpose, the model drug diclofenac was used to prepare a set of nanosuspensions, stabilized by poloxamer 188, and equilibrated at different pHs. The hydrodynamic diameter and morphology of the nanocrystals were analyzed before and after the jet injection across porcine skin in vitro, together with the solubility and release kinetics of diclofenac in a simulated subcutaneous environment. The efficacy of the jet injection (i.e., the amount of drug delivered across the skin) was evaluated for the nanosuspension and for a solution, which was used as a control. Finally, the nanosuspension was administered to rats by jet injector, and the plasma profile of diclofenac was evaluated and compared to the one obtained by jet injecting a solution with an equal concentration. The nanosuspension features were maintained after the jet injection in vitro, suggesting that no structural changes occur upon high-speed impact with the skin. Accordingly, in vivo studies demonstrated the feasibility of jet injecting a nanosuspension, reaching relevant plasma concentration of the drug. Overall, needle-free jet injectors proved to be a suitable alternative to conventional syringes for the administration of nanosuspensions.

Ultradeformable vesicles: concepts and applications relating to the delivery of skin cosmetics

Skin aging is a phenomenon resulting in reduced self-confidence, thus becoming a major factor in social determinants of health. The use of active cosmetic ingredients can help prevent skin aging. Transfersomes are well known to be capable of deeply penetrating the dermis. This scoping review provides an insight into transfersomes and their prospective use in anti-aging cosmetics. Numerous reports exist highlighting the successful skin delivery of therapeutic agents such as high-molecular-weight, poorly water soluble and poorly permeable active ingredients by means of transfersomes. Moreover, in vitro and in vivo studies have indicated that transfersomes increase the deposition, penetration and efficacy of active ingredients. However, the use of transfersomes in the delivery of active cosmetic ingredients is limited. Considering their similar physicochemical properties, transfersomes should possess considerable potential as a delivery system for anti-aging cosmetics.

Dissolvable microneedles based on Panax notoginseng polysaccharide for transdermal drug delivery and skin dendritic cell activation

This work explored the feasibility of using biological polysaccharide to fabricate dissolvable microneedles (MNs) for the purpose of transdermal drug delivery and skin dendritic cell (DC) activation. Panax notoginseng polysaccharide (PNPS), a naturally derived immunoactive macromolecule, was used to fabricate dissolvable MNs. The prepared PNPS MNs showed a satisfactory mechanical strength and a skin penetration depth. By Franz diffusion cell assay, the PNPS MNs demonstrated a high transdermal delivery amount of model drugs. Furthermore, with the assistance of MNs, PNPS easily penetrated across the stratum corneum and target ear skin DCs, activating the maturation and migration of immunocytes by increasing the expressions of CD40, CD80, CD86, and MHC II of skin DCs. Consequently, the matured DCs migrated to the auricular draining lymph nodes and increased the proportions of CD4+ T and CD8+ T cells. Thus, PNPS might be a promising biomaterial for transdermal drug delivery, with adjuvant potential.

Pharmaceutical nanocrystals: A promising approach for improved topical drug delivery

The barrier function of skin and non-optimal physicochemical properties of drug present a challenge to skin penetration of many drugs, thus motivating the development of novel drug delivery systems. Recently, nanocrystal-based formulations have been investigated for topical drug delivery and demonstrated improved skin penetration. This review highlights barriers in skin penetration, current techniques to improve topical delivery and application of nanocrystals in conquering obstacles for topical delivery. Nanocrystals can improve delivery through the skin by mechanisms like higher concentration gradient across skin resulting in increased passive diffusion, hair follicle targeting, diffusional corona and adhesion to skin. This would be of interest for formulation scientists for product development of molecules that are 'difficult-to-deliver' topically.

Drug-Excipients Compatibility Studies in Proniosomal Formulation: A Case Study with Resveratrol

Proniosomal drug delivery system is one of the advancements in nanotechnology. Similarly to traditional dosage forms, chemical and physical compatibility of proniosomes components with the active ingredient(s) is a key step in the preformulation process of such systems. In this work, the compatibility of resveratrol with selected excipients in the development of proniosomal formulation was investigated by thermal and spectroscopic techniques. To evaluate the drug-excipient compatibility, different techniques such as differential scanning calorimetric study, attenuated total reflectance Fourier transform infrared spectroscopy study and powder X-ray diffraction were adopted. The results showed that the excipients used in the formulation were compatible with resveratrol.

Effect of Manual Grinding on Diclofenac Acid Nanocrystals: A Chemico-Physical Investigation

X-ray Powder Diffraction, Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimeter were used to study the effect of the manual grinding in an agate mortar of the diclofenac acid polymorphs HD1 and HD2. In particular, we have tried to highlight how the HD2 form is more sensitive than the HD1 to the grinding process to achieve a nanometric crystal size. HD1 shows no change, while in the case of the HD2, changes in the molecular conformation and the formation of a new metastable form of the polymorph are observed after grinding.

Etodolac nanosuspension based gel for enhanced dermal delivery: in vitro and in vivo evaluation

AIM

The objective of this study was to develop dermal nanosuspension (NS) based gel formulation of etodolac (ETD).

METHODS

Etodolac nanosuspension (ETD-NS) was prepared by wet milling method and dispersed in hydroxypropyl methylcellulose (NS-HPMC) or hydroxyethyl cellulose (NS-HEC) gels. Rheologic and mechanical properties were investigated. In vitro and ex vivo permeability studies were performed. Topical anti-inflammatory and analgesic activity were evaluated in regard to carrageenan-induced inflammatory paw oedema and radiant heat tail-flick method, respectively.

RESULTS

The ETD-NS with approximately 190 nm particle size (PS), 0.16 polydispersity index (PDI), and -15 mV zeta potential (ZP) values were obtained. The work of bioadhesion values of NS-HEC and NS-HPMC gels were 0.229 mJ/cm² for both gels. Dermal permeation of ETD from NS-HEC gel (7.18%) was found significantly higher than the NS-HPMC gel (4.56%). Enhanced anti-inflammatory and analgesic activity of NS-HEC gels were observed in comparison with micronised ETD.

CONCLUSIONS

ETD-NS based gel formulation is promising for topical delivery of ETD.

Nanosuspensions and Microneedles Roller as a Combined Approach to Enhance Diclofenac Topical Bioavailability

Topical application of the anti-inflammatory drug diclofenac (DCF) reduces the severity of systemic unwanted effects compared to its oral administration. A number of transdermal formulations are available on the market and routinely used in clinical and home-care settings. However, the amount of DCF delivered across the skin remains limited and often insufficient, thus making the oral route still necessary for achieving sufficient drug concentration at the inflamed site. In attempting to improve the transdermal penetration, we explored the combined use of DCF nanosuspensions with a microneedle roller. Firstly, DCF nanosuspensions were prepared by a top-down media milling method and characterized by spectroscopic, thermal and electron microscopy analyses. Secondly, the pore-forming action of microneedle rollers on skin specimens (ex vivo) was described by imaging at different scales. Finally, DCF nanosuspensions were applied on newborn pig skin (in vitro) in combination with microneedles roller treatment, assessing the DCF penetration and distribution in the different skin layers. The relative contribution of microneedle length, nanosuspension stabilizer and application sequence could be identified by systemically varying these parameters.

Safety assessment of the pharmacological excipient, diethylene glycol monoethyl ether (DEGEE), using in vitro and in vivo systems

BACKGROUND

Diethylene glycol monoethyl ether (DEGEE) is widely used as a solubilizer in cosmetics as well as in oral, topical, transdermal and injectable pharmaceutical formulations. Due to the unavailability of detailed toxicological studies on DEGEE, the Scientific Committee on Consumer Products (SCCP) found its toxicological reports to be unsatisfactory, comprising only summaries. Also, a few reports have raised concern on the use of DEGEE as it might cause damage to the kidneys.

OBJECTIVE

Safety assessment of DEGEE using in vitro and in vivo models.

METHODS

In vitro effects of DEGEE (0.5-25 mg/ml) were assessed in the HEK293 human embryonic kidney cells. In vivo effects were evaluated after single acute exposure of DEGEE via intraperitoneal route in Swiss albino mice and further, a 28 days subchronic exposure study was conducted where DEGEE was administered orally, once daily.

RESULTS

DEGEE was cytotoxic to HEK293 cells, and an IC50 of 15 mg/ml was established. An increase in the intracellular levels of ROS and alteration in the mitochondrial membrane potential led to nuclear fragmentation and induction of apoptosis in these cells. Survival rate of animals administered intraperitoneally with a single acute dose of 1000 mg/kg DEGEE was 100% with no significant changes in the behavioural and histological parameters. However, the dose of 3000 mg/kg and above led to total mortality within 14 days of acute exposure. Subchronic oral exposure of 500-2000 mg/kg DEGEE showed no significant changes in the hematological, biochemical and histopathological parameters.

CONCLUSIONS

The in vitro findings indicate that the nephrotoxic potential of DEGEE cannot be ruled out. The results of the in vivo studies reveal that the degree of toxic effects shown by DEGEE varies, depending on the dose, duration of exposure and routes of administration. Therefore, the present findings are of relevance and thorough studies should be conducted before using this substance in clinical formulations. Graphical abstract Evaluation of the toxic potential of Diethylene glycol monoethyl ether.

In Vitro Drug Dissolution/Permeation Testing of Nanocarriers for Skin Application: a Comprehensive Review

This review highlights in vitro drug dissolution/permeation methods available for topical and transdermal nanocarriers that have been designed to modulate the propensity of drug release, drug penetration into skin, and permeation into systemic circulation. Presently, a few of USFDA-approved in vitro dissolution/permeation methods are available for skin product testing with no specific application to nanocarriers. Researchers are largely utilizing the in-house dissolution/permeation testing methods of nanocarriers. These drug release and permeation methods are pending to be standardized. Their biorelevance with reference to in vivo plasma concentration-time profiles requires further exploration to enable translation of in vitro data for in vivo or clinical performance prediction.

Review of Modern Techniques for the Assessment of Skin Hydration

Skin hydration is a complex process that influences the physical and mechanical properties of skin. Various technologies have emerged over the years to assess this parameter, with the current standard being electrical probe-based instruments. Nevertheless, their inability to provide detailed information has prompted the use of sophisticated spectroscopic and imaging methodologies, which are capable of in-depth skin analysis that includes structural and composition details. Modern imaging and spectroscopic techniques have transformed skin research in the dermatological and cosmetics disciplines, and are now commonly employed in conjunction with traditional methods for comprehensive assessment of both healthy and pathological skin. This article reviews current techniques employed in measuring skin hydration, and gives an account on their principle of operation and applications in skin-related research.

Chitosan/beidellite nanocomposite as diclofenac carrier

Chitosan (CS) and purified sodium beidellite (Na-Bd) were used to obtain a nanocomposite able to carry anionic pharmaceutical ingredients. Diclofenac sodium (DS) was chosen as a model drug and was loaded by intercalation solution technique. Solid state characterization of the resultant hybrids was performed, including X-ray diffraction, Fourier transformed infrared spectroscopy, Thermal analysis and high resolution transmission electron microscopy coupled with energy dispersive X-Ray analysis. Drug loading capacity and encapsulation efficiency were quantified by measuring equilibrium concentration by UV-Vis spectroscopy at 276 nm. Solid-state characterization of the samples confirmed both chemical and physical interaction of DS with the nanocomposites. High drug loading along with a modified cumulative release of the drug in simulated intestinal fluid was obtained. The developed clay/polymer hybrids can act as potential candidates for the design of modified dosage forms of anionic drugs.