The combined administration of LNC-encapsulated retinoic acid and calcitriol stimulates oligodendrocyte progenitor cell differentiation in vitro and in vivo after intranasal administration

Intranasal administration is an efficient strategy for bypassing the BBB, favoring drug accumulation in the brain, and improving its efficiency. Lipid nanocapsules (LNC) are suitable nanocarriers for the delivery of lipophilic drugs via this route and can be used to encapsulate lipophilic molecules such as retinoic acid (RA) and calcitriol (Cal). As the hallmarks of multiple sclerosis (MS) are neuroinflammation and oligodendrocyte loss, our hypothesis was that by combining two molecules known for their pro-differentiating properties, encapsulated in LNC, and delivered by intranasal administration, we would stimulate oligodendrocyte progenitor cells (OPC) differentiation into oligodendrocytes and provide a new pro-remyelinating therapy. LNC loaded with RA (LNC-RA) and Cal (LNC-Cal) were stable for at least 8 weeks. The combination of RA and Cal was more efficient than the molecules alone, encapsulated or not, on OPC differentiation in vitro and decreased microglia cell activation in a dose-dependent manner. After the combined intranasal administration of LNC-RA and LNC-Cal in a mouse cuprizone model of demyelination, increased MBP staining was observed in the corpus callosum. In conclusion, intranasal delivery of lipophilic drugs encapsulated in LNC is a promising strategy for myelinating therapies.

Understanding the impact of formulation design on microstructure and drug release from porous microparticle-based tretinoin topical gels

For proportionally formulated intermediate strengths of a topical product, the relationship of drug release across multiple strengths of a given product is not always well understood. The current study aims to assess the proportionality of tretinoin release rates across multiple strengths of tretinoin topical gels when manufactured using two different methods to understand the impact of formulation design on drug product microstructure and tretinoin release rate. Two groups of tretinoin gels of 0.04 %, 0.06 %, 0.08 % and 0.1 % strengths were manufactured. Gels in Group I were prepared by incorporating 4-10 % g/g of 1 % w/w tretinoin-loaded microparticles into a gel base. Gels in Group II were manufactured using 10 % g/g of the microparticles that were loaded with increasing amounts (0.4-1 % w/w) of tretinoin. The two groups of gels were characterized by evaluating microstructure using a polarized microscope, rheology using an oscillatory rheometer, and drug release using Vison® Microette™ Hanson vertical diffusion cells. The microscopic images were used to discriminate between the two groups of gels based on the abundance of microparticles in the gel matrix observed in the images. This abundance increased across gels of Group I and was similar across gels of Group II. The rheology parameters, namely viscosity at a shear rate of 10 s-1, shear thinning rate, storage, and loss modulus, increased across gels of Group I, and were not significantly different across gels of Group II. The release rate of tretinoin from the drug products was proportional to the nominal strength of the drug product in both Group I and Group II, with a correlation coefficient of 0.95 in each case, although the absolute release rates differed. Overall, changing the formulation design of tretinoin topical gels containing porous microparticles may change the physicochemical and structural properties, as well as the drug release rate of the product. Further, keeping the formulation design consistent across all strengths of microparticle-based topical gels is important to achieve proportional release rates across multiple strengths of a given drug product.

Causes and risk factors for early death in adult patients with acute promyelocytic leukemia: a real-life experience

INTRODUCTION

Early Death (ED) remains challenging in newly diagnosed acute promyelocytic leukemia (APL), especially in developing countries. The clinical and laboratory profile at diagnosis were evaluated and causes and risk factors were investigated in adult APL patients.

METHOD

A retrospective real-life analysis of 141 medical records was performed of patients diagnosed with APL between 2007 and 2018, whether they were treated with the IC-APL 2006 protocol or not. Risk factors were assessed by univariate and multivariate analysis.

MAIN RESULTS

Overall, 112 patients were included in the study. ED occurred in 22.3% of cases, surpassing clinical trial reports, with non-protocol-eligible patients presenting notably higher rates (60%), potentially due to their clinical status. Hemorrhage (60%) and infection (33.3%) were the leading causes of ED. Univariate analysis associated ED to the ECOG score; white blood cell (WBC) count; body mass index; levels of hemoglobin, albumin, uric acid, and creatinine, aPTT and INR and FLT3 mutations. Multivariate analysis identified ECOG score ≥2 and elevated WBC count as independent risk factors.

CONCLUSION

ED remains a substantial challenge in APL, especially in real-world settings with hemorrhage and infection being the leading causes. ECOG status and WBC count emerged as independent risk factors, while age and platelet count lacked a 30-day prognostic correlation. Evaluating prognostic enhancement tools in controlled trials and real-life settings is pivotal to improving APL outcomes.

Tretinoin improves the anti-cancer response to cyclophosphamide, in a model-selective manner

BACKGROUND

Chemotherapy is included in treatment regimens for many solid cancers, but when administered as a single agent it is rarely curative. The addition of immune checkpoint therapy to standard chemotherapy regimens has improved response rates and increased survival in some cancers. However, most patients do not respond to treatment and immune checkpoint therapy can cause severe side effects. Therefore, there is a need for alternative immunomodulatory drugs that enhance chemotherapy.

METHODS

We used gene expression data from cyclophosphamide (CY) responders and non-responders to identify existing clinically approved drugs that could phenocopy a chemosensitive tumor microenvironment (TME), and tested combination treatments in multiple murine cancer models.

RESULTS

The vitamin A derivative tretinoin was the top predicted upstream regulator of response to CY. Tretinoin pre-treatment induced an inflammatory, interferon-associated TME, with increased infiltration of CD8 + T cells, sensitizing the tumor to subsequent chemotherapy. However, while combination treatment significantly improved survival and cure rate in a CD4+ and CD8+ T cell dependent manner in AB1-HA murine mesothelioma, this effect was model-selective, and could not be replicated using other cell lines.

CONCLUSIONS

Despite the promising data in one model, the inability to validate the efficacy of combination treatment in multiple cancer models deprioritizes tretinoin/cyclophosphamide combination therapy for clinical translation.

Real-World Adverse Events Associated with Encapsulated Benzoyl Peroxide/Tretinoin, 3%/0.1%, and Encapsulated Benzoyl Peroxide, 5

Encapsulated benzoyl peroxide, 5%, for rosacea and a combined formulation of encapsulated benzoyl peroxide/tretinoin, 3%/0.1%, for acne vulgaris, utilize microencapsulation, a process by which active pharmaceutical agents are enclosed in inert, permeable silica shells that provide a buffer between the drug and the skin. The silica shells allow a gradual release of the drug while also allowing combinations of active ingredients that would not otherwise be possible. This technology allows benzoyl peroxide and tretinoin to be combined in the same vehicle without risking the benzoyl peroxide-mediated oxidative destruction of tretinoin. In the current study, we queried the Galderma pharmacovigilance database to quantify and categorize adverse events associated with using these products in the USA during a 12-month period from May 2022 through April 2023. The adverse events were generally mild and restricted to local irritation, pruritus, burning sensation, and erythema. The real-world incidence and type of adverse events reported by the community for encapsulated benzoyl peroxide/tretinoin, 3%/0.1%, and benzoyl peroxide, 5%, were consistent with the safety and tolerability findings from the phase III clinical studies of these treatments.

Topical Tretinoin in the Management of Thick-skinned Rhinoplasty Patients

Background

Despite the increasing popularity of cosmetic surgeries, some patients still experience skin problems, particularly those with thick nasal skin. Isotretinoin is a commonly used drug for severe acne, and its effects on rhinoplasty aesthetic results have recently been studied. This placebo-controlled clinical trial aimed to investigate the effects of topical tretinoin gel on the cosmetic outcomes of rhinoplasty in patients with thick nasal skin.

Methods

Forty-nine individuals were randomly allocated to either the treatment group or the control group in Mashhad, Iran from 2019 to 2021. The treatment group received topical tretinoin gel (0.05%) beginning on the 31st postoperative day and continued for six months, while the control group received a usual dermatological recommendation as a placebo. Patients were assessed during the first, third, and sixth months after the intervention, and their cosmetic results were evaluated by an expert surgeon and dermatologist.

Results

There were no significant differences in baseline features between the two groups. The median score given by the surgeon was not significantly different between the groups. However, the median score given by the dermatologist was significantly higher in the treatment group during the first, third, and sixth months (P<0.001). Patient satisfaction scores were also significantly higher in the treatment group during the third and sixth months compared to the control group. (P=0.02 and 0.01, respectively).

Conclusion

Topical tretinoin gel could effectively reduce acne in patients with thick nasal skin after rhinoplasty and increase patient satisfaction in the early months following surgery. However, it did not significantly affect final cosmetic outcomes.

Design and Evaluation of Tretinoin Fatty Acid Vesicles for the Topical Treatment of Psoriasis

The goal of the current study was to explore the potential benefits of Tretinoin (Tre) fatty acid vesicles (Tre-FAV) as a prospective antipsoriatic topical delivery system. This promising system can counteract the drug challenges in terms of its extremely low aqueous solubility, instability, skin irritation, and serious systemic adverse effects. Tre-loaded fatty acid vesicles were successfully developed and entirely characterised. The selected formulation was investigated for in vitro release, ex vivo skin retention and psoriasis efficacy studies. The characterisation results of Tre-FAV showed it has a globular shape with a particle size of 126.37 ± 1.290 nm (0.188 ± 0.019 PDI). The entrapment efficiency and zeta potential were discovered to be 84.26 ± 0.816% and -28.9 ± 1.92 mV, respectively. Encapsulation of the drug in the fatty acid vesicles was also strengthened by differential scanning calorimetric and powder FTIR diffraction studies. In vitro release results showed that Tre-FAV significantly increased skin absorption and retention in comparison to the Tre solution. The topical application of Tre-FAV to a mouse model confirmed that it has superior in vivo antipsoriatic properties in terms of well-demarcated papules, erythema and reduced epidermal thickness in comparison to other treatments. The weight of the spleen and the levels of the cytokines IL-17 and IL-6 decreased after treatment. In conclusion, FAV dramatically increased the water solubility and skin permeability of Tre and its anti-psoriasis activity.

Photoaging and Topical Rejuvenation

Photoaging is a complex process of skin changes associated with chronic ultraviolet exposure. Prevention with photoprotection and treatment with topical retinoids are the core components of a topical antiaging regimen. Other topicals such as hydroquinone, vitamin C, niacinamide, and alpha hydroxyl acid can be added based on specific concerns. However, caution must be used with some of these products as the stability and absorption are major considerations. A simple topical regimen will reduce irritability and enhance compliance.

Oral Isotretinoin Treatment in Rhinoplasty: A Review

The achievement of best outcome in rhinoplasty is very important for both of the patients and plastic surgeons. Since the skin characteristics (e.g. nasal thickness and sebaceous hypertrophy) has clear role on the result, many related interventions have been proposed in recent decades to gain an appropriate result. Accordingly, isotretinoin firstly introduced to treat some type of acne, has been suggested controversially to be used in rhinoplasty. Although the early uncertain studies implied on its side effects, the recent more powerful studies and evidences indicate that isotretinoin is remarkably effective to obtain proper outcome. Nevertheless, its prescription to patients need to be evaluated and personalized. More discussion on this regard are presented in the text.

Long-term follow-up results of cytarabine-containing chemotherapy for acute promyelocytic leukemia

BACKGROUND/AIMS

We evaluated the feasibility and long-term efficacy of the combination of cytarabine, idarubicin, and all-trans retinoic acid (ATRA) for treating patients with newly diagnosed acute promyelocytic leukemia (APL).

METHODS

We included 87 patients with newly diagnosed acute myeloid leukemia and a t(15;17) or promyelocytic leukemia/retinoic acid receptor alpha (PML-RARα) mutation. Patients received 12 mg/m2/day idarubicin intravenously for 3 days and 100 mg/m2/day cytarabine for 7 days, plus 45 mg/m2/day ATRA. Clinical outcomes included complete remission (CR), relapse-free survival (RFS), overall survival (OS), and the secondary malignancy incidence during a 20-year follow-up.

RESULTS

The CR, 10-year RFS, and 10-year OS rates were 89.7%, 94.1%, and 73.8%, respectively, for all patients. The 10-year OS rate was 100% for patients that achieved CR. Subjects were classified according to the white blood cell (WBC) count in peripheral blood at diagnosis (low-risk, WBC < 10,000/mm3; high-risk, WBC ≥ 10,000/mm3). The low-risk group had significantly higher RFS and OS rates than the high-risk group, but the outcomes were not superior to the current standard treatment (arsenic trioxide plus ATRA). Toxicities were similar to those observed with anthracycline plus ATRA, and higher than those observed with arsenic trioxide plus ATRA. The secondary malignancy incidence after APL treatment was 2.7%, among the 75 patients that achieved CR, and 5.0% among the 40 patients that survived more than 5 years after the APL diagnosis.

CONCLUSION

Adding cytarabine to anthracycline plus ATRA was not inferior to anthracycline plus ATRA alone, but it was not comparable to arsenic trioxide plus ATRA. The probability of secondary malignancy was low.

Efficiency of hypericum perforatum, povidone iodine, tincture benzoin and tretinoin on wound healing

Different topical agents have been used to accelerate wound healing. The purpose of this study is to compare the safety and efficacy of topical application of the extract of Hypericum perforatum (HPE), povidone iodine (PI), tincture benzoin (TB) and tretinoin (T) on surgical wound healing. Ten adult female, Wistar albino rats were included in the study. HPE, PI, TB and T solutions were applied on the wounds. After seven days, tissue samples were collected and inflammatory cells, re-epithelialization, granulation tissue, angiogenesis, collagen accumulation, hemorrhage and lysis of cells were investigated histopathologically. No dermal toxicity was noted. HPE, TB, PI have all showed good epithelialization and granulation, but HPE showed the most advanced stage of healing within a short period of time. HPE had significantly higher values of re-epithelialization and collagen accumulation, but lower inflammatory cell count and granulation tissue. TB had the second best in re-epithelialization, collagen accumulation and the highest granulation tissue. PI induced better reepithelialization and granulation than the control group with remarkable cell lysis. As a result, HPE can be a safe, effective, and cheap agent that can be used for surgical wounds.

Development and validation of derivative UV spectroscopic method for simultaneous estimation of nicotinamide and tretinoin in their binary mixtures and pharmaceutical preparations

An accurate, precise, sensitive, and simple spectroscopic method was developed and validated for simultaneous quantification analysis of tretinoin (TRT) and nicotinamide (NCT) with a ratio of 1:40 (TRT: NCT) in a synthetic mixture from dermal pharmaceutical preparations (solution and cream). Wavelengths were chosen in the first and second-order derivatives which are valid for the determination of NCT with the existence of TRT and excipients of the tested pharmaceutical preparations. Wavelength 253 nm was picked for the first-order derivative. Wavelengths 245 and 269 nm were picked for the second derivative. All previous wavelengths were zero-crossing points for TRT and its pharmaceutical preparations. Zero-order spectroscopy was used to determine TRT at the wavelength 348 nm, where no interference with NCT or any substance in the previous pharmaceutical preparation. The linearity range was studied and found to be 20–120 μg/mL and 0.5–5.0 μg/mL for NCT and TRT respectively. The correlation coefficient was 0.9995–0.9999 for NCT and 0.9998–0.9999 for TRT. The limit of detection (LOD) and the limit of quantification (LOQ) of NCT were 1.510 μg/mL and 4.590 μg/mL respectively at the wavelength 269 nm of the second-order derivative.

Use of Retinoids in Topical Antiaging Treatments: A Focused Review of Clinical Evidence for Conventional and Nanoformulations

Nowadays, numerous skincare routines are used to rejuvenate aging skin. Retinoids are one of the most popular ingredients used in antiaging treatments. Among the representatives of retinoids, tretinoin is considered the most effective agent with proven antiaging effects on the skin and can be found in formulations approved as medicines for topical treatment of acne, facial wrinkles, and hyperpigmentation. Other retinoids present in topical medicines are used for various indications, but only tazarotene is also approved as adjunctive agent for treatment of facial fine wrinkling and pigmentation. The most commonly used retinoids such as retinol, retinaldehyde, and retinyl palmitate are contained in cosmeceuticals regulated as cosmetics. Since clinical efficacy studies are not required for marketing cosmetic formulations, there are concerns about the efficacy of these retinoids. From a formulation perspective, retinoids pose a challenge to researchers as a result of their proven instability, low penetration, and potential for skin irritation. Therefore, novel delivery systems based on nanotechnology are being developed to overcome the limitations of conventional formulations and improve user compliance. In this review, the clinical evidence for retinoids in conventional and nanoformulations for topical antiaging treatments was evaluated. In addition, an overview of the comparison clinical trials between tretinoin and other retinoids is presented. In general, there is a lack of evidence from properly designed clinical trials to support the claimed efficacy of the most commonly used retinoids as antiaging agents in cosmeceuticals. Of the other retinoids contained in medicines, tazarotene and adapalene have clinically evaluated antiaging effects compared to tretinoin and may be considered as potential alternatives for antiaging treatments. The promising potential of retinoid nanoformulations requires a more comprehensive evaluation with additional studies to support the preliminary findings.

The efficacy and safety of topical Tretinoin combined with Superficial X-ray therapy (SXRT) in treating Periungual warts

BACKGROUND

There are multiple treatment modalities for Periungual warts (PWs), although most are destructive and painful, limiting their application. Radiotherapy is a non-invasive method suitable for treating PW patients with contraindications to invasive procedures.

OBJECTIVE

To investigate the efficacy and safety of topical Tretinoin combined with Superficial X-ray therapy (SXRT) in treating PWs.

METHODS

This study included patients with 65 PWs who underwent treatment and a 3-month follow-up. 24 PWs were subjected to SXRT alone (group A). The remaining 41 PWs were subjected to SXRT combined with the application of the Tretinoin cream from the first day (group B). The overall clinical response rate, recurrence rates, cosmetic outcomes, and adverse events were observed during the follow-up period.

RESULTS

The complete clearance rate (75% vs. 92.7% in groups A and B, respectively) and healing times (19.9 vs. 16.0 days in groups A and B, respectively) between the two groups were significantly different (P<0.046 and 0.04), indicating the combination treatment is more effective. Notably, there was no damaging or permanent deformation on the nail, and the other adverse effects were mild and bearable.

CONCLUSION

Topical Tretinoin combined with SXRT therapy is an effective strategy for treating PWs, with minor side effects. It is painless and with excellent cosmetic outcomes.

Evidence for the Efficacy of Over-the-counter Vitamin A Cosmetic Products in the Improvement of Facial Skin Aging: A Systematic Review

BACKGROUND

Skincare retailers sell a plethora of retinol-containing products, ranging from serums and moisturisers to masks and eye creams.

OBJECTIVE

The purpose of this review is to critically appraise the randomized, double-blind, vehicle-controlled trials of the use of over-the-counter retinol products in the treatment of facial skin aging in order to assess evidence regarding their efficacy.

METHODS

A PubMed search was conducted for relevant clinical trial publications, using the terms "retinoid," "tretinoin," "retinol," "retinal," "retinaldehyde," and "skin."

RESULTS

Nine randomized, double-blind, vehicle-controlled clinical trials were found. Four of these trials reported no statistically significant differences between the retinol-containing treatment and vehicle. The remaining five trials provide weak evidence for retinol potentially having a mild ameliorating effect on fine facial skin wrinkle lines only. However, these five trials showed major methodological flaws, which were critically analyzed in this review, calling into question the validity of any positive results.

CONCLUSION

It can be suggested that, in the case of retinols, the "positive" trials should not inform clinical decision-making but rather may serve as tools for advertising. Until at least one high-quality clinical trial of retinol-containing products in the treatment of (photo-)aged skin is published, there is very little, if any, trustworthy evidence available to support the use of over-the-counter cosmetic retinol-containing products to improve the appearance of aged skin.

Efficacy assessments of tretinoin-loaded nano lipid carriers in acne vulgaris: a double blind, split-face randomized clinical study

Here, we assessed the efficacy and safety of Nano lipid carrier (NLC) drug delivery system containing tretinoin (NLC-TRE) in comparison with the conventional 0.05% tretinoin cream (TRE cream) in mild to moderate acne vulgaris. A stable and appropriate NLC-TRE formulation was prepared using a high-pressure homogenizer and particle characterization and physicochemical properties were evaluated under accelerated conditions. Efficacy assessment was performed via a split-face clinical study, by comparing the number of acne lesions, porphyrin production and skin biophysical parameters in both sides of the face randomly treated with NLC-TRE and TRE cream. Plasma concentration of tretinoin after topical application of NLC-TRE was measured for primary safety evaluation. We acquired a stable, spherical nanoparticles with particle size of 118.5 nm, PI equal to 0.485 and ZP of - 44.7 mV. The rate of decrease of acne lesions was significantly higher in NLC- TRE side (p value < 0.001). The size and intensity of porphyrin production in pilosebaceous follicles were significantly reduced only on NLC-TRE side (p value < 0.01). The plasma concentration of the tretinoin, after 8 weeks' application remained lower than the toxic levels. The NLC-TRE formula provides better efficiency and good loading capacity of TRE in the drug delivery system.

Emulgel for improved topical delivery of Tretinoin: Formulation design and characterization

OBJECTIVES

The chief objective of the present research was to reduce local side effects by reducing the dose, controlling the release, and improving the stability by developing and optimizing tretinoin (TRT)-loaded topical emulgel formulation.

METHODS

TRT emulgel (TE) was prepared and optimized at varying ratios of excipients and using 3² optimal response surface design (ORSD). The TRT emulgel was optimized based on TRT content and in vitro release profile of TRT from formulated emulgel batches. The optimized TRT was characterized for physical properties, pH, viscosity, spreadability, extrudability, photomicroscopy, in vitro anti-acne, in vivo skin irritation, in vivo anti-inflammatory activity, and stability study.

RESULTS

The FTIR and DSC analysis revealed the compatibility between TRT and formulation excipients of emulgel. The batch F5 of emulgel formulation displayed maximum drug content (98.69±1.26%), and controlled TRT release (78.27±0.69%). Thus, batch F5 was selected as an optimized batch for further characterization. The photomicroscopic analysis of optimized TE exhibited the presence of spherical globules. The pH and viscosity of optimized TE were found to be 6.20±0.12 and 3240cP respectively. Besides, the optimized TE showed good spreadability and extrudability. The in vitro anti-acne activity against Propionibacterium acne (P. acne) of optimized TE (diameter of zone of inhibition 34.54±0.26mm) was found to be the comparatively same as that of marketed Sotret® gel (diameter of zone of inhibition 36.13±0.43mm). Moreover, no sign of irritation was observed in rats treated with optimized TE indicating the safety of TE. Furthermore, the optimized TE displayed significant (p<0.01) in vivo anti-inflammatory activity when compared to marketed gel. Besides, optimized TE was found to be stable when stored in cool conditions for three months.

CONCLUSION

Thus, the emulgel could be a promising approach for the topical delivery of TRT with improved performance and reduced side effects.

All-trans retinoic acid in anticancer therapy: how nanotechnology can enhance its efficacy and resolve its drawbacks

Introduction: All-trans retinoic acid (ATRA, tretinoin) is the main drug used in the treatment of acute promyelocytic leukemia (APL). Despite its impressive activity against APL, the same could not be clinically observed in other types of cancer. Nanotechnology can be a tool to enhance ATRA anticancer efficacy and resolve its drawbacks in APL as well as in other malignancies.Areas covered: This review covers ATRA use in APL and non-APL cancers, the problems that were found in ATRA therapy and how nanoencapsulation can aid to circumvent them. Pre-clinical results obtained with nanoencapsulated ATRA are shown as well as the two ATRA products based on nanotechnology that were clinically tested: ATRA-IV® and Apealea®.Expert opinion: ATRA presents interesting properties to be used in anticancer therapy with a notorious differentiation and antimetastatic activity. Bioavailability and resistance limitations impair the use of ATRA in non-APL cancers. Nanotechnology can circumvent these issues and provide tools to enhance its anticancer activities, such as co-loading of multiple drug and active targeting to tumor site.

Treating Melanoma in Situ During a Pandemic with Telemedicine and a Combination of Imiquimod, 5-Fluorouracil, and Tretinoin

The recent coronavirus disease 2019 (COVID-19) pandemic has created a quandary for the physician in terms of evaluating and treating cutaneous skin cancers, particularly melanomas. At the onset of the pandemic, many planned medical and surgical visits for skin cancers were postponed. Physicians and patients have had to balance the risk of exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with that of worsening morbidity and mortality due to delays in skin cancer treatments. We present a male patient who had two melanoma-in-situs (MISs) that were treated during the COVID-19 pandemic with a combination of topical imiquimod 5% cream, 5-fluorouracil 2% solution, and tretinoin 0.1% cream. The successful treatments occurred without in-person visits and with the aid of telemedicine. Although surgery is the standard for the treatment of melanoma in situ, this case demonstrates an effective viable treatment modality for MIS during a pandemic situation.

Computational Drug Repositioning Identifies Potentially Active Therapies for Chordoma

BACKGROUND

Chordomas are aggressive bone tumors that often recur despite maximal resection and adjuvant radiation. To date there are no Food and Drug Administration (FDA)-approved chemotherapies. Computational drug repositioning is an expanding approach to identify pharmacotherapies for clinical trials.

OBJECTIVE

To identify FDA-approved compounds for repurposing in chordoma.

METHODS

Previously identified highly differentially expressed genes from chordoma tissue samples at our institution were compared with pharmacogenomic interactions in the Comparative Toxicogenomics Database (CTD) using ksRepo, a drug-repositioning platform. Compounds selected by ksRepo were then validated in CH22 and UM-Chor1 human chordoma cells in Vitro.

RESULTS

A total of 13 chemical compounds were identified in silico from the CTD, and 6 were selected for preclinical validation in human chordoma cell lines based on their clinical relevance. Of these, 3 identified drugs are FDA-approved chemotherapies for other malignancies (cisplatin, cytarabine, and lucanthone). Cytarabine, a deoxyribonucleic acid polymerase inhibitor approved for the treatment of various leukemias, exhibited a significant concentration-dependent effect against CH22 and UM-Chor1 cells when compared to positive (THZ1) and negative (venetoclax) controls. Tretinoin exhibited a significant concentration-dependent cytotoxic effect in CH22, sacral chordoma-derived cell lines but to a much lesser extent in UM-Chor1, a cell line derived from skull base chordoma.

CONCLUSION

Cytarabine administration reduces the viability of human chordoma cells. The equally effective reduction in viability seen with tretinoin seems to be cell line dependent. Based on our findings, we recommend the evaluation of cytarabine and tretinoin in an expanded set of human chordoma cell lines and animal models.

Structure elucidation of silica-based core-shell microencapsulated drugs for topical applications by cryogenic scanning electron microscopy

We present here a technology to microencapsulate drugs by the sol-gel process, and cryo-SEM methodology that allows the nanostructural characterization of the formed capsules in their native state without any artifacts, related to their drying prior to imaging. The methodology utilizes three signals generated by the electron beam scanning the specimen: Secondary electrons, backscattered electrons, and x-rays. The first gives topographical information of the fracture-surface of the thermally-fixed specimen, the second gives contrast between elements of different atomic numbers, and the third allows the identification of those elements. Combined, the three signals provide full microstructural characterization of the studied specimen. Using this methodology, we were able to demonstrate that the sol-gel technology does indeed enable the encapsulation of two hydrophobic active molecules with a silica shell. This technology allows the active ingredient in the drug product to slowly migrate from the microcapsule onto the skin, thus obtaining the desired effect with minimal side-effects, as was exhibited in several clinical studies. The successful application of the cryo-SEM methodology in this case, demonstrates that it can be used to characterize a wide range of liquid-phase suspensions, in their native state, with minimal specimen preparation or imaging artifacts.

Fabrication and characterization of tretinoin-loaded nanofiber for topical skin delivery

Background

Tretinoin or all-trans retinoic acid is used in the treatment of acne vulgaris and photo-aging. This work aims to develop tretinoin-loaded nanofibers as a potential anti-acne patch and to investigate its physicochemical characteristics.

Method

Nanofibers were produced via electrospinning method and surface topography was evaluated by Field Emission Scanning Electron Microscopy (FESEM). The functional groups of polymer and the drug molecule and the possible interactions were studied by Fourier Transform Infrared Spectroscopy (FTIR). Drug release studies were carried out by total immersion method at 25 °C and 32 °C. Tretinoin stability was evaluated at room temperature and fridge for 45 days. The possibility of synergistic antibacterial activity of tretinoin and erythromycin combination was investigated on Staphylococcus aureus (ATCC® 25923™) and (ATCC® 29213™) by Kirby Bauer disc diffusion method.

Results

Uniform fibers without drug crystals were fabricated via electrospinning. Drug-loaded nanofibers show inherent stability under various storage conditions. Electrospun nanofibers showed a prolonged release of tretinoin. The stability of formulations in FT was higher than RT. Disc diffusion tests did not show any synergism in the antibacterial activity of erythromycin when used in combination with tretinoin.

Conclusion

It can be anticipated that the easy fabrication, low costs and dosing frequency of the construct reported here provide a platform that can be adapted for on-demand delivery of tretinoin.

Graphical abstract

Manipulation of retinoic acid signaling in the nucleus accumbens shell alters rat emotional behavior

Novel targets for depression and anxiety disorders are necessary for the development of more effective pharmacotherapeutics. Our previous study found that the retinoic acid (RA) signaling pathway is the signaling pathway most enhanced in the nucleus accumbens (NAc) shell, a region important for depression, anxiety, and addiction. Genetic manipulations of RA signaling in the NAc affecting addiction-related behavior prompted our study of the role of retinoic acid signaling in depression-related and anxiety-related behavior using in vivo RNA interference. Knockdown of the retinoic acid degradation enzyme cytochrome p450 family 26 subfamily b member 1 (Cyp26b1) in the nucleus accumbens shell increased depression-related behavior while decreasing anxiety-like behavior. Knockdown of the retinoic acid binding protein, cellular RA binding protein 2 (Crabp2), also increased depression-related behavior. Knockdown of another RA binding partner fatty acid binding protein 5 (Fabp5), did not alter these behaviors. These results further support the contention that RA signaling in the NAc shell can affect emotional behavior and that targeting some components of this pathway could be a promising avenue for developing novel treatments for depression and anxiety.

Liquid chromatography method to assay tretinoin in skin layers: validation and application in skin penetration/retention studies

A liquid chromatography (LC) method for the quantification of tretinoin (TTN) in different matrices (adhesive tape, cotton and porcine skin layers, stratum corneum, viable epidermis, and dermis) was validated and applied in in vitro porcine skin penetration/retention studies. This study proposes, for the first time, a method for assaying TTN in separated porcine skin layers (stratum corneum, viable epidermis, and dermis). The skin studies were carried out using tape stripping and cutaneous retention techniques. The procedures for the extraction of TTN from dermatological formulations (creams and gels) and biological and non-biological matrices used with the tape stripping and retention techniques were also evaluated. The LC method consisted of a mobile phase composed of a mixture of methanol, water, and glacial acetic acid (85:15:1, v/v); a C18 column used as the stationary phase; a flow rate of 1.0 mL min⁻¹; an injection volume of 100 μL; and TTN detection at 342 nm. The method was linear in the range of 0.05–15.00 μg mL⁻¹ (r = 0.9999), and it was precise and accurate. The limit of detection (LOD) and limit of quantification (LOQ) were 0.0165 μg mL⁻¹ and 0.0495 μg mL⁻¹, respectively. TTN was extracted from different matrices, showing good precision [relative standard deviation (RSD) of <5%] and accuracy (89.4–113.9%). This method was successfully applied in the evaluation of TTN skin retention/permeation from dermatological formulations (cream and gel). A higher penetration of TTN through the skin was achieved with the gel rather than the cream, showing the influence of the dosage form. Therefore, the developed method can easily be applied in porcine skin penetration/retention studies of dermatological formulations containing TTN, and it is able to discriminate the behaviours of the different formulations.

Preparation and Characterization of Solid Lipid Nanoparticles-Based Gel for Topical Delivery

Solid lipid nanoparticles (SLNs) have been extensively investigated for effective delivery of both hydrophilic and lipophilic drugs by topical route. There are several scalable techniques for the preparation of SLNs such as homogenization, microemulsion template, and solvent emulsification diffusion. This chapter describes step-wise methodology for the preparation and characterization of SLNs using solvent emulsification diffusion method. Tretinoin, a lipophilic entity, was chosen as a model drug. The critical aspects and the important interpretations with respect to the preparation and characterization of SLNs are reported in "Notes" section.

[Mechanism of cleft palate in C57BL/6N mice induced by retinoic acid]

Objective: To investigate the mechanism of cleft palate in mice induced by excessive all-trans retinoic acid (atRA). Methods: The pregnant mice were randomly divided into atRA-treated group (n=27) and control group (n=27). atRA-treated group was given by gavage a single dose of atRA (100 mg/kg) at 8: 00 AM on gestation day 10 (GD10) and the control group was given by gavage the isopyknic corn oil. At GD13-GD15, the fetal mice palate development was observed by HE staining. The mouse embryonic palatal mesenchymal cell proliferation was detected by 5-bromo-2-deoxyuridine (BrdU) immunohistochemistry. The expressions of Smad2, phospho-Smad2 (p-Smad2), Smad4 and Smad7 in mouse embryonic palatal mesenchyme were analyzed by Western blotting. Results: At GD13-GD15, compared with the control, the ratio of BrdU-positive cells in the palatal mesenchyme of atRA-treated fetuses decreased significantly (P<0.05), especially at GD14, atRA inhibition rate was (65.4±1.7)%. Moreover, atRA decreased the levels of p-Smad2 and Smad4 in embryonic palate mesenchymal cells, whereas the expression of Smad7 was significantly increased at GD14 and GD15. Conclusions: atRA may lead to cleft palate by inhibiting the activation of Smad signaling pathway and affecting the proliferation of palatal mesenchymal cells.

Tretinoin-loaded lipid-core nanocapsules overcome the triple-negative breast cancer cell resistance to tretinoin and show synergistic effect on cytotoxicity induced by doxorubicin and 5-fluororacil

Nanostructured drug delivery systems have been extensively studied, mainly for applications in cancer therapy. The advantages of these materials include protection against drug degradation and improvement in both the relative solubility of poorly water soluble drugs as in targeting of therapy, due to the enhanced permeability and retention effect on tumor sites. In this work, we evaluate the antitumor activity of tretinoin-loaded lipid core nanocapsules (TT-LNC) in a tretinoin-resistant breast cancer cell-line, MDA-MB- 231, as well as the synergistic effect of combination of this treatment with 5-FU or DOXO. The inhibition of cell growth was assayed by MTT reduction. Live/Dead assay and DAPI staining evaluated cytotoxicity. Apoptosis was evaluated by Annexin V-PE/7AAD and the effect of chronic exposure was evaluated by colony formation assay. TT-LNC reduced the cell viability even at lower concentrations (1μM) and displayed synergistic effect with 5-FU or DOXO on cytotoxicity and colony formation inhibition. Our work shows a possibility of using nanocapsules to improve the antitumoral activity of TT for its use either alone or in combination with other chemotherapeutic drugs, especially considering the chronic effect.

Efficacy and tolerability of a double-conjugated retinoid cream vs 1.0% retinol cream or 0.025% tretinoin cream in subjects with mild to severe photoaging

BACKGROUND

Topical retinoids are used to treat the visible signs of photoaging. While efficacious, they are irritating.

OBJECTIVE

Evaluate the effectiveness and tolerability of a double-conjugate retinoid cream (AlphaRet Overnight Cream; AHA-Ret) in improving visible signs of photoaging vs 1.0% retinol or 0.025% tretinoin.

METHODS

A 12-week, split-face, randomized trial was conducted in 48 female subjects, aged 30-65 years with mild to severe photodamage. AHA-Ret was applied to one side of the face and either retinol (n=24) or tretinoin (n=24) to the other side (PM). Expert blinded evaluation of images and Nova measurements occurred at 4, 8, and 12 weeks. Tolerability was assessed throughout the study.

RESULTS

Forty-seven subjects completed the study. AHA-Ret demonstrated significant reductions in average severity from baseline: Fine Lines/Wrinkles (P<.001; all time points); Erythema (P=.004, P<.0001; 8 and 12 weeks, respectively); Dyschromia (P<.0001; all time points); Skin Tone (P<.0001; all time points), and Pore Size (P=.035, P<.0001; 8 and 12 weeks, respectively). AHA-Ret induced less Erythema vs retinol at 8 (P=.008) and 12 (P<.02) weeks. AHA-Ret was noninferior to prescription tretinoin in all categories at 4 and 8 weeks, and for Fine Lines/Wrinkles, Erythema, Dyschromia, and Skin Tone at 12 weeks. Improvements in Hydration occurred at every time point with AHA-Ret only (P<.04, P<.03, P<.01). Less irritation was reported with AHA-Ret vs retinol or tretinoin.

CONCLUSIONS

Treatment with a double-conjugate retinoid cream demonstrated early reductions in photodamage and improvements in Hydration. AHA-Ret induced less Erythema vs retinol and was more tolerable vs retinol and tretinoin.

Why Topical Retinoids Are Mainstay of Therapy for Acne

Acne-focused dermatology expert groups have consistently recommended that most patients with acne be treated with a combination of topical retinoid and antimicrobial therapy. This is based on clinical data as well as evidence that these drug classes have different and complementary mechanisms of action that target multiple aspects of acne's complex pathophysiology. Recent evidence-based guidelines for acne, including those from the American Academy of Dermatology (AAD) and the European Dermatology Forum (EDF), have agreed that retinoids have an essential role in this widespread disease. The AAD states "retinoids are the core of topical therapy for acne because they are comedolytic, resolve the precursor microcomedone lesion, and are anti-inflammatory;" further, they "allow for maintenance of clearance." Despite uniform recommendation for use of topical retinoids, a recent study of prescribing practices from 2012 to 2014 indicated that dermatologists prescribed retinoids just 58.8% of the time while non-dermatologists prescribed them for only 32.4% of cases. In this article, we review the reasons supporting retinoids as the mainstay of acne therapy and discuss some of the perceived barriers that may be limiting use of this important drug class. Further, we discuss how and when titrating retinoid concentrations may be utilized in clinical practice.

FUNDING

Galderma International.

[Effects of 13-cis-retinoic acid combined with interferon-α2b in mantle cell lymphoma cell lines (Jeko-1) in vitro]

目的

探讨13-顺式维甲酸/异维甲酸（13cRA）、干扰素α2b（IFN-α2b）单独及联合应用对套细胞淋巴瘤（MCL）细胞增殖抑制和诱导凋亡的作用及其机制。

方法

13cRA、IFN-α2b单独及其联合应用于MCL细胞株Jeko-1细胞，应用CCK-8法检测不同药物处理方案对细胞增殖的影响，Annexin Ⅴ/PI双重染色法检测其对细胞凋亡的影响，流式细胞术（FCM）检测其对细胞周期的影响，Western blot法检测细胞周期蛋白D1（Cyclin D1）及凋亡途径相关蛋白caspase-9、Rb的表达。

结果

①单用13cRA、IFN-α2b及联合应用均对Jeko-1细胞增殖有抑制和诱导凋亡作用（P值均<0.05）；13cRA（100 µmol/L）+ IFN-α2b（10 000 IU/ml）联合组对细胞的增殖抑制率在第1天为（69.37±8.31）%，细胞凋亡率在第5天为（99.87±0.12）%（联合用药协同系数为0.735），均高于阳性对照组的（63.34±4.22）%和（87.80±3.22）%，差异均有统计学意义（P值均<0.05）；抑制增殖与促凋亡作用均呈药物浓度和时间依赖性，并引起G₁期+G₂期细胞比例的明显增加（P<0.05），S期细胞明显减低（P<0.05）。②单用13cRA、IFN-α2b及联合应用均能下调Jeko-1细胞Cyclin D1及Rb蛋白的表达水平，促进caspase-9裂解。

结论

单用13cRA、IFN-α2b及联合应用均对Jeko-1细胞有抑制增殖和诱导凋亡效应，可降低S期细胞比例，使细胞停滞于G₁、G₂期，两药联合应用有协同作用；其作用可能与下调Cyclin D1、Rb蛋白的表达水平及激活caspase-9有关。

Nanostructured lipid carriers for the topical delivery of tretinoin

Cosmetic skin care products currently in the market demonstrate an increasing trend toward antiaging products. Selection of the right formulation approach is the key to successful consumer acceptance. Nanostructured lipid carriers (NLCs) for dermal application can render added benefits to the formulation. Tretinoin a derivative of vitamin A, is a retinoid with anti-aging and anti-acne potential. The present study was aimed at formulating NLCs of tretinoin for reducing the skin irritation potential, increasing the drug loading capacity and prolonging the duration of action. The NLCs were optimized using the response surface methodology based on the particle size. Preliminary study, suggested the use of stearic acid, oleic acid, Tween 80 and Span 60 as solid lipid, liquid lipid and surfactants respectively formed a stable dispersion. NLCs of tretinoin were prepared by hot melt microemulsion and hot melt probe sonication methods. The properties of the optimized NLCs such as morphology, size, Zeta potential, stability and in vitro drug release were investigated. Tretinoin loaded NLCs in carbopol gel showed a sustained release pattern with isopropyl alcohol as the receptor fluid compared to the marketed gel using Franz diffusion cells. Eight prepared gel formulations tested were found to follow the Higuchi model of drug release. Stability studies indicated that the formulations stored at refrigeration and room temperature showed no noticeable differences in the drug content and release profiles in vitro, after a period of 4 weeks. In vivo skin irritation test on male Wister rats indicated no irritation or erythema after application of the NLCs loaded gel repeated for a period of 7 days compared to the application of marketed tretinoin gel which showed irritation and slight erythema within 3 days. The results showed that the irritation potential of tretinoin was reduced, the drug loading was increased and the drug release was prolonged by the incorporation into the NLCs.

Successive ratio subtraction coupled with constant multiplication spectrophotometric method for determination of hydroquinone in complex mixture with its degradation products, tretinoin and methyl paraben

A sensitive and selective stability-indicating successive ratio subtraction coupled with constant multiplication (SRS-CM) spectrophotometric method was studied and developed for the spectrum resolution of five component mixture without prior separation. The components were hydroquinone in combination with tretinoin, the polymer formed from hydroquinone alkali degradation, 1,4 benzoquinone and the preservative methyl paraben. The proposed method was used for their determination in their pure form and in pharmaceutical formulation. The zero order absorption spectra of hydroquinone, tretinoin, 1,4 benzoquinone and methyl paraben were determined at 293, 357.5, 245 and 255.2 nm, respectively. The calibration curves were linear over the concentration ranges of 4.00-46.00, 1.00-7.00, 0.60-5.20, and 1.00-7.00 μg mL(-1) for hydroquinone, tretinoin, 1,4 benzoquinone and methyl paraben, respectively. The pharmaceutical formulation was subjected to mild alkali condition and measured by this method resulting in the polymerization of hydroquinone and the formation of toxic 1,4 benzoquinone. The proposed method was validated according to ICH guidelines. The results obtained were statistically analyzed and compared with those obtained by applying the reported method.

Comparison of long-pulsed alexandrite laser and topical tretinoin-ammonium lactate in axillary acanthosis nigricans: A case series of patients in a before-after trial

BACKGROUND

Acanthosis nigricans (AN) is a brown to black, velvety hyperpigmentation of the skin that usually involves cutaneous folds. Treatment of AN is important regarding cosmetic reasons and various therapeutic modalities have been used for these purposes. The goal of this study was to compare the effectiveness of long-pulsed alexandrite laser and topical tretinoin-ammonium lactate for treatment of axillary-AN.

METHODS

Fifteen patients with bilateral axillary-AN were studied in Razi Hospital, Tehran, Iran. Diagnosis was confirmed by two independent dermatologists. Each side skin lesion was randomly allocated to either topical mixed cream of tretinoin 0.05%- ammonium lactate 12% or long-pulsed alexandrite laser. Duration of treatment was 14 weeks. At endpoint, the mean percent reduction from baseline in pigmentation area was compared between the two groups.

RESULTS

The study population consisted of 15 patients three males and 12, females. The mean age of patients was 28.5±4.9 years. The mean percent reduction was 18.3±10.6%, in tretinoin/ammonium lactate group and 25.7±11.8% in laser group (P=0.004).

CONCLUSION

These findings indicate that the application of alexandrite laser is a relative effective method for treatment of axillary-AN. However, this issue requires further studies with prolonged follow-up period.

Tretinoin Nanogel 0.025% Versus Conventional Gel 0.025% in Patients with Acne Vulgaris: A Randomized, Active Controlled, Multicentre, Parallel Group, Phase IV Clinical Trial

BACKGROUND

Conventional topical tretinoin formulation is often associated with local adverse events. Nanogel formulation of tretinoin has good physical stability and enables good penetration of tretinoin into the pilo-sebaceous glands.

AIM

The present study was conducted to assess the efficacy and safety of a nanogel formulation of tretinoin as compared to its conventional gel formulation in the treatment of acne vulgaris of the face.

MATERIALS AND METHODS

This randomized, active controlled, multicentric, phase IV clinical trial evaluated the treatment of patients with acne vulgaris of the face by the two gel formulations locally applied once daily at night for 12 wk. Acne lesion counts (inflammatory, non-inflammatory & total) and severity grading were carried out on the monthly scheduled visits along with the tolerability assessments.

RESULTS

A total of 207 patients were randomized in the study. Reductions in the total (72.9% vs. 65.0%; p = 0.03) and inflammatory (78.1% vs. 66.9%; p = 0.02) acne lesions were reported to be significantly greater with the nanogel formulation as compared to the conventional gel formulation. Local adverse events were significantly less (p = 0.04) in the nanogel group (13.3%) as compared to the conventional gel group (24.7%). Dryness was the most common adverse event reported in both the treatment groups while peeling of skin, burning sensation and photosensitivity were reported in patients using the conventional gel only.

CONCLUSION

In the treatment of acne vulgaris of the face, tretinoin nanogel formulation appears to be more effective and better tolerated than the conventional gel formulation.

New insight into the immunomodulatory mechanisms of Tretinoin in NMRI mice

OBJECTIVES

Recent evidence have proposed that Tretinoin produced in the gut preferentially promote differentiation of FoxP3+Treg cells but inhibits Th17 lymphocytes, and this may be the main immunomdulatory mechanism of Tretinoin in vivo. This study was done to investigate the effects of Tretinoin in outbred white mice after challenge with sheep red blood cells (SRBC).

MATERIALS AND METHODS

Twenty male NMRI-mice randomly allocated in two equal groups. Mice were treated with 1×10(9) SRBCs emulsified in CFA intraperitoneally twice with one weak interval. Animals were bled 5 days after last injection. Moreover, 48 hr before bleeding time, 1×10(9) SRBCs were injected into the left hind foot pad of mice. Tretinoin (25 mg/kg-every other day) were intraperitoneally injected into the treatment group from the beginning of the study and continued throughout the study. The levels of anti-SRBC antibody and the specific cellular immune responses were measured by microhemagglutination test and footpad thickness, respectively. Moreover, splenocytes were checked for proliferation rate, respiratory burst, cytokine production and FoxP3+Treg cells frequency.

RESULTS

Tretinoin markedly alleviated cellular immunity and concurrently potentiated humoral immunity after mice challenge with SRBCs. Furthermore, aside from reducing NBT reduction and lymphocyte proliferation, Tretinoin markedly suppressed the secretion of interleukin-17 and conversely, increased the production of interleukin-10. However, the level of IFN-γ and the frequency of FoxP3+Treg cells did not alter significantly.

CONCLUSION

The in vivo immunomudlatoty effects of Tretinoin may be partly due to immune deviation from pro-inflammatory cytokine interleukin-17 to anti-inflammatory cytokine interleukin-10, but not absolutely depend on the expansion of FoxP3(+)Treg cells.

High pseudotumor cerebri incidence in tretinoin and arsenic treated acute promyelocytic leukemia and the role of topiramate after acetazolamide failure

Dual differentiation therapy with arsenic trioxide and tretinoin (all-trans-retinoic acid; ATRA) for the management of low and intermediate risk acute promyelocytic leukemia has recently been recommended by the National Comprehensive Cancer Network. Some less common toxicities of the combination may have yet to be fully realized. Of ten patients we have treated thus far, five (50%) have developed pseudotumor cerebri. In one patient, temporary discontinuation of ATRA and initiation of acetazolamide controlled symptoms. In four patients, topiramate was substituted for acetazolamide to relieve symptoms and allow ATRA dose re-escalation. We conclude that providers should monitor for pseudotumor cerebri and consider topiramate if acetazolamide fails.

•

We identify five cases of pseudotumor cerebri during arsenic and tretinoin therapy.

•

We report four cases of pseudotumor cerebri successfully treated with topiramate.

•

Topiramate may have a role in the management of pseudotumor cerebri.

•

Addition of arsenic trioxide to tretinoin may potentiate pseudotumor cerebri.

Formulation of tretinoin-loaded topical proniosomes for treatment of acne: in-vitro characterization, skin irritation test and comparative clinical study

Tretinoin (TRT) is a widely used retinoid for the topical treatment of acne, photo-aged skin, psoriasis and skin cancer which makes it a good candidate for topical formulation. Yet side effects, like redness, swelling, peeling, blistering and, erythema, in addition to its high lipophilicity make this challenging. Therefore, the aim of this study was the development of TRT-loaded proniosomes to improve the drug efficacy and to increase user acceptability and compliance by reducing its side effects. Nine formulae were prepared according to 3(2) factorial design and were evaluated for their morphology, vesicle size, entrapment efficiency (EE %), and% of drug released after 5 h. Hydrogel of the candidate formula, N8G (proniosomes prepared with 0.025% TRT, and Span60: cholesterol molar ratio of 3:1 and incorporated in 1% carbopol gel) was developed and evaluated for skin irritation test and clinical study in acne patients compared to marketed product. Candidate formula showed higher efficacy and very low irritation potential when compared to marketed product in human volunteers.

Formulation and In-vitro Evaluation of Tretinoin Microemulsion as a Potential Carrier for Dermal Drug Delivery

In this study, tretinoin microemulsion has been formulated based on phase diagram studies by changing the amounts and proportions of inactive ingredients, such as surfactants, co-surfactants and oils. The effects of these variables have been determined on microemulsion formation, particle size of the dispersed phase and release profile of tretinoin from microemulsion through dialysis membrane. In released studies, static Franz diffusion cells mounted with dialysis membrane were used. Sampling was conducted every 3 h at room temperature over a period of 24 h. The amount of released drug was measured with UV-spectrophotometer and the percentage of drug released was calculated. Based on the results obtained, the oil phase concentration had a proportional effect on particle size which can consequently influence on drug release. The particle size and the amount of released drug were affected by the applied surfactants. The components of the optimized microemulsion formulation were 15% olive oil, 12% propylene glycol (as co-surfactant), 33% Tween(®)80 (as surfactant) and 40% distilled water, which was tested for viscosity and rheological behavior. The prepared tretinoin microemulsion showed pseudoplastic-thixotropic behavior. The profile of drug release follows zero order kinetics. The optimized tretinoin microemulsion showed enhanced in-vitro release profile compared to the commercial gels and creams.

Preparation and evaluation of tretinoin microemulsion based on pseudo-ternary phase diagram

PURPOSE

The aim of the present research was to formulate a transparent microemolsion as a topical delivery system for tretinoin for the treatment of acne.

METHODS

Microemulsion formulations prepared by mixing appropriate amount of surfactant including Tween 80 and Labrasol, co-surfactant such as propylene glycol (PG) and oil phase including isopropyl myristate - transcutol P (10:1 ratio). The prepared microemolsions were evaluated regarding their particle size, zeta potential, conductivity, stability, viscosity, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), refractory index (RI) and pH.

RESULTS

The results showed that maximum oil was incorporated in microemolsion system that was contained surfactant to co-surfactant ratio (Km) of 4:1. The mean droplets size range of microemulsion formulation were in the range of 14.1 to 36.5 nm and its refractory index (RI) and pH were 1.46 and 6.1, respectively. Viscosity range was 200-350 cps. Drug release profile showed 49% of the drug released in the first 8 hours of experiment belong to ME-7. Also, Hexagonal and cubic structures were seen in the SEM photograph of the microemulsions.

CONCLUSION

physicochemical properties and in vitro release were dependent upon the contents of S/C, water and, oil percentage in formulations.Also, ME-7 may be preferable for topical tretinoin formulation.

Recent advances in the diagnosis and management of childhood acute promyelocytic leukemia

Since the successful introduction of all-trans-retinoic acid (ATRA) and its combination with anthracycline-containing chemotherapy, the prognosis for acute promyelocytic leukemia (APL) has markedly improved. With ATRA and anthracycline-based-chemotherapy, the complete remission rate is greater than 90%, and the long-term survival rate is 70-89%. Moreover, arsenic trioxide (ATO), which was introduced for APL treatment in 1994, resulted in excellent remission rates in relapsed patients with APL, and more recently, several clinical studies have been designed to explore its role in initial therapy either alone or in combination with ATRA. APL is a rare disease in children and is frequently associated with hyperleukocytosis, which is a marker for higher risk of relapse and an increased incidence of microgranular morphology. The frequency of occurrence of the promyelocytic leukemia/retinoic acid receptor-alpha (PML/RARα) isoforms bcr 2 and bcr 3 is higher in children than in adults. Although recent clinical studies have reported comparable long-term survival rates in patients with APL, therapy for APL in children is challenging because of the risk of early death and the potential long-term cardiac toxicity resulting from the need to use high doses of anthracyclines. Additional prospective, randomized, large clinical trials are needed to address several issues in pediatric APL and to possibly minimize or eliminate the need for chemotherapy by combining ATRA and ATO. In this review article, we discuss the molecular pathogenesis, diagnostic progress, and most recent therapeutic advances in the treatment of children with APL.

Acrokeratosis Paraneoplastica with Adenocarcinoma of the Colon Treated with Topical Tretinoin

Acrokeratosis paraneoplastica, or Bazex syndrome, is one of the paraneoplastic syndromes. The characteristic skin lesions include palmoplantar keratoderma, psoriasiform skin lesions, hyperpigmentation, and nail dystrophy. The most common associated neoplasms are squamous cell carcinoma of the upper respiratory tract and other kinds of tumors with cervical lymph node metastasis. A 63-year-old woman presented with an 11 month history of hyperkeratotic lesions on the palms and soles. Ten months before she had been diagnosed with adenocarcinoma of the colon and undergone a left hemicolectomy. We report a case of acrokeratosis paraneoplastica associated with colon cancer which persisted after removal of the primary cancer, but resolved with topical tretinoin treatment.