3D-Printed Products for Topical Skin Applications: From Personalized Dressings to Drug Delivery

3D printing has been widely used for the personalization of therapies and on-demand production of complex pharmaceutical forms. Recently, 3D printing has been explored as a tool for the development of topical dosage forms and wound dressings. Thus, this review aims to present advances related to the use of 3D printing for the development of pharmaceutical and biomedical products for topical skin applications, covering plain dressing and products for the delivery of active ingredients to the skin. Based on the data acquired, the important growth in the number of publications over the last years confirms its interest. The semisolid extrusion technique has been the most reported one, probably because it allows the use of a broad range of polymers, creating the most diverse therapeutic approaches. 3D printing has been an excellent field for customizing dressings, according to individual needs. Studies discussed here imply the use of metals, nanoparticles, drugs, natural compounds and proteins and peptides for the treatment of wound healing, acne, pain relief, and anti-wrinkle, among others. The confluence of 3D printing and topical applications has undeniable advantages, and we would like to encourage the research groups to explore this field to improve the patient’s life quality, adherence and treatment efficacy.

Solubility and Partition Coefficient of Salicylamide in Various pH Buffer Solutions

The solubility and partition coefficient are essential physicochemical parameters in developing a pharmaceutical dosage form of medicine. In addition, these parameters help to predict the absorption of an active compound in oral or topical dosage forms. Salicylamide, an active ingredient available in oral and topical dosage forms, is a weak acid (pKa 8.2) and is sparingly soluble in water. Meanwhile, its solubility and partition coefficients are influenced by the pH of the environment. The Henderson-Hasselbalch equation is used to predict solubility-pH and partition-pH profiles at various pH solutions. This study aims to determine salicylamide's solubility and partition coefficient in various pH (2–11). Both tests were carried out in various pH buffer solutions (at a concentration of 0.02 M and 0.2 ionic strength) in a water bath shaker at a temperature of 37 ± 0.5 °C. In addition, the salicylamide content was determined using the UV spectrophotometer method at the maximum wavelength at each pH. The results showed that the solubility increased at pH 2–10, while the partition coefficient value decreased. On the other hand, at pH 11, there was an increase in the number of ionized species, but the solubility decreased.

Recent advancement in topical drug delivery for psoriasis: Clinical Pertinence and Potential Market

: Psoriasis is an immune-mediated chronic skin inflammation. This disease can be associated with several manifestation like red flaks, silver scale, patches, plaques and silvery-white squams. Approximately 70% of the patients treated with topical dosage forms have a mild-to-moderate form of psoriasis, whereas a moderate-to-severe form of psoriasis is treated with systemic, photo, and biological therapies. Considering the big fraction that topicals cover, we present the current market potential, clinical relevance, and recent advances in the topical delivery of the drug for psoriasis. Though we witnessed several advancements in the recent few decades, delivering new immunomodulatory and biological molecules for topical psoriatic treatment have been proved efficient and safe option for the large percentage of patients for whom systemic therapy is not indicated. This article enumerates the promising topical dosage forms at present under assessment for their clinical pertinence. The competency of conventional topicals to reach and transform the world market is enumerated in terms of their success rate after proving the clinical pertinence against psoriasis. However, the entrance of novel drug delivery systems based advanced topical products in the global market is highly anticipated as they have immense potential to precedent tremendous impact on psoriasis treatment in near future.

Topical application of Apremilast in the treatment of mild to moderate psoriasis

Mild to moderate psoriasis is highly prevalent in about 80% of the global psoriatic population. Current available treatment options for mild to moderate psoriasis are topical dosage forms and are associated variety of setbacks. To address these setbacks, Apremilast topical gels, 2% & 4%, w/w were developed, and a clinical proof of concept study (POC) was performed to establish efficacy and safety. A single centre randomized, double-blind, placebo-controlled study was conducted with apremilast topical gels 2% & 4% w/w in adult mild to moderate psoriatic patients for 12 weeks. The efficacy of the gels was evaluated by comparing the PASI scores before and after treatment of 12 weeks. Both gels exhibited a significant reduction in PASI values when compared with baseline PASI scores. An average percentage inhibition of PASI with test products, i.e. 2% and 4% w/w Apremilast topical gels, are about 46.8% and 34.6%, respectively, after 12 weeks of treatment. The results confirm that the apremilast topical gels are a good option for the treatment of mild to moderate psoriasis and have to be explored further.

Topical Lipid Based Drug Delivery Systems for Skin Diseases: A Review

Treatment of skin ailments through systemic administration is limited due to toxicity and patients discomfort. Hence, lower risk of systemic side effects from topical dosage forms like ointments, creams, emulsions and gels is more preferred for the treatment of skin disease. Application of lipid based carriers in drug delivery in topical formulations has recently become one of the major approaches to improve drug permeation, safety, and effectiveness. These delivery systems include liposomes, ethosomes, transfersomes, Nanoemulsions (NEs), Solid Lipid Nanoparticles (SLNs) Nanostructured Lipid Carriers (NLCs) and micelles. Most of the liposomes and SLNs based products are in the market while some are under investigation. Transcutaneous delivery of therapeutics to the skin layer by novel lipid based carriers has enhanced topical therapy for the treatment of skin ailments. This article covers an overview of the lipid-based carriers for topical uses to alleviate skin diseases.

Nanoemulgel: A Promising Phase in Drug Delivery

Recently, the delivery of hydrophobic/ poorly water-soluble drugs has been a challenging task. Various strategies have been developed to counter the former along with other prime issues, such as stability, bioavailability etc. However, only few formulations have been successful in addressing the problems and nanoemulgel is a standout among them. Nanoemulgels are appropriate candidates for drug delivery because of their dual character i.e. the presence of an emulsion in the nano scale and a gel base, both combined as a single formulation. The nanoemulsion component of the nanoemulgel conforms protection to the active moiety by preventing the enzymatic degradation and certain reactions like hydrolysis. The gel base attributes thermodynamic stability to the emulsion by increasing the viscosity of the aqueous phase by decreasing the interfacial and surface tension. Nanoemulgels possess rheological characteristics which are suited especially for topical delivery and other forms such as dental delivery with the aid of better patient acceptance. As the globule size is present in the nano form alongside the employment of certain penetration enhancers can increase the effectiveness of the formulation by enhancing the permeability and diffusibility. Reports suggest that certain commercially available topical dosage forms have a low spreading coefficient in comparison with the nanoemulgel thereby focusing on the application of nanoemulgels in the field of dermatology, although paving way for various other fields have not been thoroughly exploited. This comprehensive review highlights the benefits of nanoemulgel as a potential carrier for drug delivery with an overview of few illustrations supporting the cause.

Formulation and evaluation of different topical dosage forms for wound healing properties

The aim of the present work was to compare the wound healing efficacy of different topical dosage forms such as β cyclodextrin complex gel, liposomal gel, and ointment on the rat model. Simvastatin was used as a drug, β cyclodextrin was used as a complexing agent to enhance solubility, L α Phosphatidylcholine as a phospholipid, and cholesterol as a stabilizing agent. Liposomes were prepared by thin-film hydration method, β cyclodextrin complexes of simvastatin were prepared by spray drying technique, and the ointment was prepared in simple method. Beta cyclodextrin gels and liposomal gels were prepared by direct incorporation of spray-dried products and lyophilized liposomes into Carbopol gel. The gel was evaluated for drug content, particle size, viscosity, spreadability, surface morphology, in-vitro drug release studies, skin irritation study, and wound healing activity studies. FTIR and DSC studies showed no chemical interaction between the drug and excipients. The particle size of β cyclodextrin complexes was in the range of 0.5 μm to 2.5 μm and for liposomes 163 nm to 725 nm. The in-vitro drug release was 96.7 % at the end of the sixth hour for β cyclodextrin gel, 29.7 % at the end of the sixth hour for liposomal gel, and 96.2 % at the end of 3 hours for ointment. Wound healing activity studies were carried out for 21 days on albino wrister rats, a period of epithelization, and rate of wound contraction was measured on 4, 8, 14, 16, and 21 days. Simvastatin ointment showed a significant effect on wound healing in the rat model compared to β-cyclodextrin gel and liposomal gel. Hence, Simvastatin ointment could be a potential dosage form for clinical utility on wound healing.

Gel formulations containing Sumbawa's horse milk with carbomer gel base

Peptides from Sumbawa horse milk are active as antibacterial and antioxidant. Horse milk has a higher content of vitamin C than cow or goat's milk, and cream products that contain milk can overcome dry skin. The Gel is one of the topical dosage forms suitable for acne medications and oily skin types. This study aimed to determine the effect of variations in horse milk content formulated in gel preparations with carbomer 1% base as gelling agents on physical characteristics (organoleptic, viscosity, pH) and antibacterial activity in Propionibacterium acnes. In this study, gel preparations were made with six different formulas on horse milk content, namely FI (2.5%), FII (5%), and FIII (10%), FIV (15%), FV (20%), and FVI (25%) with 1% carbomer base on each formula and well method were used for the antibacterial test. From the organoleptic test, it was found that in all of the gel formula had soft textured, thick white color, and distinctive aroma like horse milk. The viscosity test showed that was no significant difference, but the pH test showed a significant difference for each formula. In this study showed that all of the gel formulae did not have an inhibitory zone, which means that at each level there was no evidence of antibacterial activity in the P. acnes. So, it could be concluded that all gel formula had good gel characteristics but there was no inhibitory activity against the P. acnes.