Formulation, long-term physicochemical and microbiological stability of 15% topical resorcinol for hidradenitis suppurativa

OBJECTIVES

Topical resorcinol 15% is a self-treatment for painful hidradenitis suppurativa nodules and abscesses with good results in reducing pain and lesion duration. The aim of this study is to establish a 15% topical resorcinol formula, to develop a physicochemical and microbiological stability study and to further determine the compounding shelf-life in different package conditions following the European Pharmacopoeia (Ph. Eur.) specifications.

METHODS

Physicochemical and microbiological stability studies of the formulation were conducted for 12 months at room temperature (25°C±2°C) in different package conditions: aluminium tubes (aluminium A7-99.7% varnish DF-6172), plastic tubes (low density polyethylene) and amber plastic containers (polyethylene terephthalate). High performance liquid chromatography (HPLC) was developed as a method of indicating the stability of the resorcinol formulation. A microbiological growth assay was also validated according to the Ph. Eur. Physical properties were inspected to determine parameters such as odour, colour, pH, emulsion phase and extensibility index and its evolution.

RESULTS

The HPLC method was validated according to the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines. At day 365, visual inspection remained unchanged only for preparations packaged in aluminium tubes. The pH did not vary by more than 0.3 units in all conditions. The extensibility index decreased in the preparations packaged in plastic and amber plastic containers. HPLC analysis conducted over 1 year did not show a degradation greater than 7% of resorcinol in the preparation in plastic and aluminium packages. The ability of ATCC strains to grow in resorcinol formulation was confirmed under the suitability test. Resorcinol packed in aluminium tubes achieved microbiological stability at day 365.

CONCLUSIONS

Only the formulation package in aluminium tubes showed physicochemical and microbiological stability of resorcinol for 12 months at room temperature (25°C±2°C).

Clinically Inspired Skin Lesion Classification through the Detection of Dermoscopic Criteria for Basal Cell Carcinoma

Background and Objective. Skin cancer is the most common cancer worldwide. One of the most common non-melanoma tumors is basal cell carcinoma (BCC), which accounts for 75% of all skin cancers. There are many benign lesions that can be confused with these types of cancers, leading to unnecessary biopsies. In this paper, a new method to identify the different BCC dermoscopic patterns present in a skin lesion is presented. In addition, this information is applied to classify skin lesions into BCC and non-BCC. Methods. The proposed method combines the information provided by the original dermoscopic image, introduced in a convolutional neural network (CNN), with deep and handcrafted features extracted from color and texture analysis of the image. This color analysis is performed by transforming the image into a uniform color space and into a color appearance model. To demonstrate the validity of the method, a comparison between the classification obtained employing exclusively a CNN with the original image as input and the classification with additional color and texture features is presented. Furthermore, an exhaustive comparison of classification employing different color and texture measures derived from different color spaces is presented. Results. Results show that the classifier with additional color and texture features outperforms a CNN whose input is only the original image. Another important achievement is that a new color cooccurrence matrix, proposed in this paper, improves the results obtained with other texture measures. Finally, sensitivity of 0.99, specificity of 0.94 and accuracy of 0.97 are achieved when lesions are classified into BCC or non-BCC. Conclusions. To the best of our knowledge, this is the first time that a methodology to detect all the possible patterns that can be present in a BCC lesion is proposed. This detection leads to a clinically explainable classification into BCC and non-BCC lesions. In this sense, the classification of the proposed tool is based on the detection of the dermoscopic features that dermatologists employ for their diagnosis.

Effectiveness and safety of topical 15% resorcinol in the management of mild-to-moderate hidradenitis suppurativa: A cohort study

Antibiotics remain one of the main treatment alternatives in mild-to-moderate hidradenitis suppurativa. The use of topical 15% resorcinol reduces antibiotic pressure and the generation of resistance. However, knowledge on its efficacy and safety is limited. This single-center, prospective, follow-up cohort study evaluated topical 15% resorcinol every 12-h response at 16 weeks. Those individuals with mild-to-moderate hidradenitis suppurativa (Hurley I-II) who started treatment with topical resorcinol monotherapy between April 2019 and May 2020 were eligible for follow-up. The primary endpoint for effectiveness was the proportion of patients who achieved an overall clinical response (complete or partial response) at week 16, evaluated as intention-to-treat. Responses were measured according to the Hidradenitis Suppurativa Clinical Response index. Target lesion size was measured clinically and by ultrasonography. Quality of life was assessed through the Dermatology Life Quality Index (DLQI) questionnaire. Safety was measured by recording the adverse events reported during the follow-up period. A total of 32 patients were enrolled (mean age, 40.1 years [95% confidence interval, 35.7-44.4]; women, 20 [62.5%]; Hurley I, 17 [53.1%]). Under the intention-to-treat analysis, 68.8% (n = 22) of the patients achieved a clinical response. A ≥50% reduction in the size of the main lesion was observed in 56.3% of the patients (n = 18). Some 65.6% (n = 21) of the patients had a ≥50% reduction (improvement) in their baseline DLQI score. Fifty percent of patients who completed the follow-up period experienced adverse events, all of which were local, mild, and transient and did not lead to discontinuation of resorcinol. To conclude, in this cohort study, topical 15% resorcinol was shown to be effective for mild-to-moderate hidradenitis suppurativa and to have a positive impact on quality of life with an acceptable safety profile.