Emulsions with alkyl polyglucosides as carriers for off-label topical spironolactone - safety and stability evaluation

Assessing and Predicting Physical Stability of Emulsion-Based Topical Semisolid Products: A Review

The emulsion-based topical semisolid dosage forms present a high degree of complexity due to their microstructures which is apparent from their compositions comprising at least two immiscible liquid phases, often times of high viscosity. These complex microstructures are thermodynamically unstable, and the physical stability of such preparations is governed by formulation parameters such as phase volume ratio, type of emulsifiers and their concentration, HLB value of the emulsifier, as well as by process parameters such as homogenizer speed, time, temperature etc. Therefore, a detailed understanding of the microstructure in the DP and critical factors that influence the stability of emulsions is essential to ensure the quality and shelf-life of emulsion-based topical semisolid products. This review aims to provide an overview of the main strategies used to stabilize pharmaceutical emulsions contained in semisolid products and various characterization techniques and tools that have been utilized so far to evaluate their long-term stability. Accelerated physical stability assessment using dispersion analyzer tools such as an analytical centrifuge to predict the product shelf-life has been discussed. In addition, mathematical modeling for phase separation rate for non-Newtonian systems like semisolid emulsion products has also been discussed to guide formulation scientists to predict a priori stability of these products.

Silk peptide-hyaluronic acid based nanogels for the enhancement of the topical administration of curcumin

The present study focused on the development of Cur-loaded SOHA nanogels (Cur-SHNGs) to enhance the topical administration of Cur. The physiochemical properties of Cur-SHNGs were characterized. Results showed that the morphology of the Cur-SHNGs was spherical, the average size was 171.37 nm with a zeta potential of −13.23 mV. Skin permeation experiments were carried out using the diffusion cell systems. It was found that the skin retention of Cur-SHNGs was significantly improved since it showed the best retention value (0.66 ± 0.17 μg/cm²). In addition, the hematoxylin and eosin staining showed that the Cur-SHNGs improved transdermal drug delivery by altering the skin microstructure. Fluorescence imaging indicated that Cur-SHNGs could effectively deliver the drug to the deeper layers of the skin. Additionally, Cur-SHNGs showed significant analgesic and anti-inflammatory activity with no skin irritation. Taken together, Cur-SHNGs could be effectively used for the topical delivery of therapeutic drugs.

Compatibility of Personalized Formulations in Cleoderm™, A Skin Rebalancing Cream Base for Oily and Sensitive Skin

Inflammatory skin conditions are prevalent in the general population and are a source of much concern for those who suffer from them. Acne is an extremely common condition and can significantly impact the quality of life of affected patients. Rosacea is another common dermatological disorder that often affects the face and can present with flushing, irritated skin, and pimples. In addition to being key for acne and rosacea, inflammation can also play a role in prematurely aging skin and contributes to the formation of wrinkles. Given the prevalence and patient impact of dermatological conditions on the face, such as those previously described, there is a demand for personalized medicines to manage these conditions when commercially available options are unsuitable, unavailable, or insufficient to fully resolve the condition. When designing an appropriate personalized therapy for a patient, both the vehicle and the active pharmaceutical ingredient choices are key to the success of the treatment. Cleoderm™ is a topical cream designed for use as a vehicle for the preparation of dermatological treatments by compounding pharmacies. Its ingredient profile was specifically curated to be gentle on the skin, allowing its use as a vehicle for compounded preparations that may be applied to sensitive and affected skin. In this bracketed study, benzoyl peroxide, cyproterone acetate, estriol, metronidazole, niacinamide, progesterone, retinoic acid, spironolactone, and tranexamic acid were selected, due to their known applications for dermatological skin conditions. To evaluate the compatibility and stability of Cleoderm™ in these formulations, high-performance liquid chromatography, followed by antimicrobial effectiveness testing, were performed for 180 days. For most formulations, a beyond-use date of 180 days was observed when stored at room temperature, except for retinoic acid, which had a beyond-use date of 30 days. Through the outcomes of this study, we concluded that Cleoderm™ presents increased convenience for both the compounding pharmacist and the patient, suggesting that it is an adequate candidate vehicle for compounding different dermatological formulations with adequate stability, presenting itself as a good alternative to commercially available treatments that cannot be personalized.

Azelaic acid loaded chitosan and HPMC based hydrogels for treatment of acne: formulation, characterization, in vitro-ex vivo evaluation

In this study, hydrogels containing azelaic acid were developed using chitosan or HPMC (1-7%) for local treatment of acne vulgaris. Physicochemical properties such as viscosity, pH and mechanical properties were evaluated. In vitro release and ex vivo permeability studies were performed using Franz diffusion cell system. The pH of the hydrogels were highly compatible with the skin pH and varied between 4.38-5.84. The cumulative release percentages of the hydrogels at the end of 6 hours were 65-78%, whereas the marketed product yielded 50% drug release. According to the ex vivo permeability results, azelaic acid accumulated in the skin were found to be 9.38 ± 0.65% (marketed cream), 19.53 ± 1.06% (K3), 10.96 ± 1.91% (H6). The antiacne studies with Cutibacterium acnes revealed that K3 (29.45 ± 0.95) and H6 (32.35 ± 0.15) had higher inhibition zones compared to the marketed cream (24.50 ± 0.90). Additionally, the gels were found to be highly stable as a result of the stability studies for 6 months. Among the hydrogels that were prepared based on experimental findings, K3 (3% Chitosan) and H6 (6% HPMC) represented elevated in vitro release profile, higher permeability and increased antiacne activity. The findings of this research suggest that the developed hydrogels might be an alternative to the marketed product.

Spironolactone hyaluronic acid enriched cerosomes (HAECs) for topical management of hirsutism: in silico studies, statistical optimization, ex vivo, and in vivo studies

Spironolactone (SP) is a potassium sparing diuretic with antiandrogenic properties. This study aimed at formulating SP into hyaluronic acid enriched cerosomes (HAECs) for topical management of hirsutism. HAECs were prepared by ethanol injection method, according to D-optimal design, after a proper in silico study. HAECs were evaluated by measuring their entrapment efficiency (EE%), particle size (PS), and polydispersity index (PDI). Optimal hyaluronic acid enriched cerosomes (OHAECs) were subjected to further in vitro and ex-vivo and in-vivo studies. The in silico study concluded better interactions between SP and phosphatidyl choline in presence of hyaluronic acid (HA) and high stability of their binding in water. The prepared HAECs had acceptable EE%, PS, and PDI values. The statistical optimization process suggested OHAEC containing 10.5 mg ceramide III and 15 mg HA, utilizing Kolliphor^® RH40. OHAEC had EE% and PS of 89.3 ± 0.3% and 261.8 ± 7.0 nm, respectively. OHAEC was stable for up to 3 months. It also showed a mixed tubular and vesicular appearance under transmission electron microscope. The ex vivo and in vivo studies concluded better skin deposition and accumulation of SP from OHAEC. The histopathological study demonstrated the safety of OHAEC for topical application. Therefore, OHAEC could be considered as effective system for topical application of SP to manage hirsutism, with prolonged action, coupled with minimized side effects.

Topical Treatment of Human Skin and Cultured Keratinocytes with High-Dose Spironolactone Reduces XPB Expression and Induces Toxicity

Spironolactone (SP) is used to treat a variety of disparate disease states ranging from heart failure to acne through antagonism of the mineralocorticoid and androgen receptors. Although normally taken as an oral medication, recent studies have explored the topical application of SP onto the skin. However, because SP induces the proteolytic degradation of the XPB protein, which plays critical roles in DNA repair and transcription, there may be safety concerns with the use of topical SP. In this study, we show that the topical application of a high concentration of either SP or its metabolite canrenone onto human skin ex vivo lowers XPB protein levels and induces toxic responses in the epidermis. Interestingly, although SP and canrenone both inhibit cell proliferation, induce replication stress responses, and stimulate apoptotic signaling at high concentrations in cultured keratinocytes in vitro, these effects were not correlated with XPB protein loss. Thus, high concentrations of SP and canrenone likely inhibit cell proliferation and induce toxicity through additional mechanisms to XPB proteolytic degradation. This work suggests that care may need to be taken when using high concentrations of SP directly on human skin.