Enhanced topical paromomycin delivery for cutaneous leishmaniasis treatment: Passive and iontophoretic approaches.

Conventional treatments for cutaneous leishmaniasis, a neglected vector-borne infectious disease, can frequently lead to serious adverse effects. Paromomycin (PAR), an aminoglycoside antibiotic, has been suggested for the topical treatment of disease-related lesions, but even when formulated in high drug-loading dosage forms, presents controversial efficacy. The presence of five ionizable amino groups hinder its passive cutaneous penetration but make PAR an excellent candidate for iontophoretic delivery. The objective of this study was to verify the feasibility of using iontophoresis for cutaneous PAR delivery and to propose a topical passive drug delivery system that could be applied between iontophoretic treatments. For this, in vitro iontophoretic experiments evaluated different application durations (10, 30, and 360 min), current densities (0.1, 0.25, and 0.5 mA/cm2), PAR concentrations (0.5 and 1.0 %), and skin models (intact and impaired porcine skin). In addition, 1 % PAR hydrogel had its penetration profile compared to 15 % PAR ointment in passive transport. Results showed iontophoresis could deliver suitable PAR amounts to dermal layers, even in short times and with impaired skin. Biodistribution assays showed both iontophoretic transport and the proposed hydrogel delivered higher PAR amounts to deeper skin layers than conventional ointment, even though applying 15 times less drug. To our knowledge, this is the first report of PAR drug delivery enhancement by iontophoresis. In summary, the association of iontophoresis with a topical application of PAR gel seems appropriate for improving cutaneous leishmaniasis treatment.

Lychnophora ericoides Mart. (Brazilian arnica) ethanol extract accelerates the skin wound healing process: Evidence for its mechanism of action.

BACKGROUND: Lychnophora ericoides Mart, also known as the Brazilian arnica or fake arnica, belongs to the Asteraceae family. Leaves and roots are used in alcoholic and hydroalcoholic preparations for the treatment of wounds, inflammation, and pain. PURPOSE: The present study aimed to investigate the effects of L. ericoides ethanolic extract (EELE) on cutaneous wound healing and the mechanisms of action involved. METHODS: A total of 72 C57BL/6 mice were randomly divided into four groups of six animals each. An excisional wound was made in the dorsal region of each mouse. The test groups were topically treated with the vehicle, a positive control commercial reference drug, EELE ointment (5%), and EELE ointment (10%). The treatments were applied over 14 days. The wound area was measured every two days to verify the wound closure kinetics. On days 3, 7, and 14 the wound tissue samples were processed for Hematoxylin and Eosin, Masson-Trichrome, and Toluidine blue staining. The expression of renin-angiotensin system (RAS) components, the vascular growth factor-A (VEGF-A), the basic fibroblast growth factor (FGF-2), and type I collagen genes were evaluated. Phytochemical analyses were performed using HPLC-DAD and HPLC-MS/MS. RESULTS: The EELE (10%) significantly reduced the wound area compared to the treatments used for the other groups. Histological analysis demonstrated that wounds treated with L. ericoides for 14 days developed improved anatomical skin features, healed with hair follicles and sebaceous glands, increased collagen production and angiogenesis, and decreased the number of mast cells at the injury site. Real-time PCR data demonstrated that groups treated with EELE (10%) showed increased Type I collagen, VEGF-A, FGF-2, and AT1R and decreased ACE II and receptor MAS. The healing action of L. ericoides may be related to the presence of phenolic compounds, such as phenolic acids, chlorogenic acid derivatives, and C-glycoside flavonoids. CONCLUSION: Topical treatment with EELE increases important factors for wound healing: FGF, VEGF, collagen formation, and the expression of the proliferative axis of the renin-angiotensin system. For the first time, the present study shows the healing action of L. ericoides at the molecular level in an animal model. This process can be used as an alternative therapy for wound healing and the development of herbal therapy.

IL1ß/ TNFα/COX-2/VEGF axis responsible for effective healing potential of C-glucoside xanthone (mangiferin) based ointment in immunocompromised rats.

Present study was conducted to undermine the wound healing potential of mangiferin vis a vis its molecular dynamics in immunocompromised excisional rat model. 120 rats were randomly and equally divided into five groups viz. group I (Healthy control), group II (Immunocompromised control), group III (Immunocompromised group treated with silver sulphadiazine), group IV (Immunocompromised group treated with 2.5 %Mangiferin) and group V (Immunocompromised group treated with 5 %Mangiferin). Immuno compromised state was achieved following intramuscular injection of Hydrocortisone @ 80 mg/kg body weight. Study was conducted for a period of 28 days. Six animals from each group were humanely sacrificed at weekly interval till day 28th of study. Planimetric analysis, biochemical studies viz. hydroxyproline assay, total protein and DNA content, antioxidative potential through LPO assay was done along with molecular studies involving expression profiling of IL1ß, TNFα and COX-2 and Immunohistochemistry of angiogenic marker i.e. VEGF was performed to undermine the pharmacodynamics of mangiferin. Histopathological studies including H&E and Masson's Trichome was also performed to study histoarchitectural changes in wound healing and reparative process following application of mangiferin ointment. Study revealed significant (P ≤ 0.05) reduction in wound area measurement and significant (P ≤ 0.05) increase in wound contraction (%) following mangiferin administration in immunocompromised rats. Hydroxyproline, DNA and total protein showed significant (P ≤ 0.05) increase in skin tissues of mangiferin treated immunocompromised rats. LPO assay revealed significant (P ≤ 0.05) reduction in mangiferin treated animals. Histopathological studies of skin tissues revealed complete restoration advocating grade III of healing in 2.5% mangiferin treated group. Higher expression and strong signal intensity of VEGF was noticed in 2.5% mangiferin treatment group along with significant (P ≤ 0.05) upregulation IL1ß and TNFα on day 7 in 2.5% mangiferin treatment group with significant (P ≤ 0.05) down regulation of COX-2 in mangiferin treatment group as compared to other groups i.e. group II and III. It is concluded from our study that mangiferin facilitates wound healing through improved wound closure, organized deposition of collagen deposition and granulation matrix formation.

Topical Simvastatin Improves Lesions of Diffuse Normolipemic Plane Xanthoma by Inhibiting Foam Cell Pyroptosis.

Xanthoma pathogenesis is speculated to be associated with oxidized low-density lipoprotein (ox-LDL) deposition, although this remains unclear. Most patients with diffuse plane xanthomas present elevated blood lipid levels, and they benefit from treatment with oral lipid-lowering agents. However, there is no available treatment for diffuse normolipemic plane xanthoma (DNPX). In this study, for the first time, we used a topical simvastatin ointment to treat DNPX in three pediatric patients and observed favorable results. Immunofluorescence staining showed that the pyroptotic pathway was significantly attenuated after topical simvastatin application on the skin lesions of the patients. As ox-LDL deposition was observed in the lesions, we used ox-LDL to build a foam cell model in vitro. In the ox-LDL-induced foam cell formation, simvastatin consistently inhibited pyroptotic activation and inflammation in the macrophages. Additionally, the overexpression of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) or 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase (HMGCR), the known target of statins, reversed the effects of simvastatin. Moreover, gasdermin D (GSDMD) or HMGCR knockdown inhibited ox-LDL-induced pyroptosis. Furthermore, the immunoprecipitation results confirmed the interaction between NLRP3 and HMGCR, and this interaction was inhibited by simvastatin. In conclusion, we demonstrated that topical application of simvastatin ointment might be a promising treatment for DNPX skin lesions and that this therapeutic effect may be related to pyroptosis inhibition via HMGCR inhibition in foam cells. Moreover, xanthoma pathogenesis might be associated with ox-LDL deposition and inflammation.

Zizhu Ointment Accelerates Wound-Healing of Diabetic Ulcers through Promoting M2 Macrophage Polarization via Downregulating the Notch4 Signaling Pathway.

Objective: The long-term clinical practice shows that Zizhu ointment (ZZO) is an empirical formula for the treatment of diabetic ulcers (DUs). In this study, we investigated the underlying mechanism of ZZO in the treatment of DU mice. Methods: Through streptozotocin induction and high-fat diet, a DU mouse model was established and ZZO was given for treatment. The activation of Notch4 signaling was examined by immunofluorescence staining, RT-PCR, as well as Western blotting. Flow cytometry was performed to detect the counts of F4/80+ cells, M1 and M2 macrophages, as well as the expression of CD11c, CD206, etc. The role of Notch4 in wound healing in diabetic mice was verified by Notch4 inhibitors and agonists. Results: Accelerated wound healing and decreased expression levels of Notch4 and its target genes and ligands were observed in diabetic mice treated with ZZO. ZZO promoted M2 macrophage polarization, downregulated the expression of proinflammatory factors, and upregulated the levels of anti-inflammatory factors. The same tendency was observed in diabetic mice after treatment with Notch4 inhibitors. Knockout of Notch4 accelerated the wound healing rate as well. Conclusions: ZZO accelerates wound healing of diabetic mice through inhibiting the activation of Notch4 signaling, promoting M2 macrophage polarization, and alleviating inflammation.

Comparison of In Vitro and In Vivo Percutaneous Absorption Across Human Skin Using BAY1003803 Formulated as Ointment and Cream.

Direct comparisons between skin absorption data and clinical pharmacokinetic data are rare. Here we use the lipophilic nonsteroidal selective glucocorticoid receptor agonist BAY1003803 to make such a comparison. The objective is to find the extent to which measurements of skin permeation in vitro can be used to predict the corresponding permeation in vivo for human pharmacokinetics of topically applied substances. BAY1003803 was prepared in various formulations: ointment, hydrophilic cream, lipophilic cream, and milk. Its ability to permeate healthy human skin was measured in vitro in static diffusion cells, and percutaneous absorption as well as dermal delivery was measured thereafter, for 2 selected formulations, in vivo in healthy volunteers. Absorption in vivo comparing ointment and lipophilic cream was correlated with expectation based on the dermal delivery obtained in vitro. A 2.17-fold higher systemic exposure to BAY1003803 was achieved by the ointment formulation. This is well in line with the predicted exposure difference of 2.74 based on the in vitro data. In conclusion, in vitro skin absorption studies using human skin are suitable for the prediction of systemic exposure and formulation effects in vivo; they can therefore be applied to guide the design of clinical investigations of dermatological preparations.

Ex vivo (human skin) and in vivo (minipig) permeation of propylene glycol applied as topical crisaborole ointment, 2.

Crisaborole ointment, 2%, is a non-steroidal phosphodiesterase 4 inhibitor for the treatment of mild-to-moderate atopic dermatitis. It contains 9% w/w propylene glycol (PG). Although PG is generally considered to be safe when used as a pharmaceutical excipient or food additive, the European Medicines Agency has recommended maximum daily limits for PG exposure. To determine the potential skin permeation of PG from crisaborole ointment, ex vivo human skin (normal abdominal skin from healthy volunteers without atopic dermatitis) and in vivo minipig experiments (dermal application on unabraded or abraded skin) were performed. Over a 24-h period, the extent of PG permeation in the ex vivo human skin experiment was 3.7% for crisaborole ointment. In the in vivo minipig study, the bioavailability of PG after dermally applied crisaborole ointment was 3.56% for unabraded skin and 3.65% for abraded skin. Experimental values from this study can serve to provide scientific justification for using a product's specific absorption value, as opposed to a maximum absorption of 100%, when attempting to estimate systemic exposure of PG from a topical product.

Mechanical Properties of Topical Anti-Psoriatic Medicines: Implications for Patient Satisfaction with Treatment.

Different types of topical preparations are available as anti-psoriatic medicines, semisolid formulations being the preferred dosage forms for the treatment of body lesions. The mechanical characterization of these semisolid formulations is seldom reported, although mechanical features have been recognized to play an important role in treatment acceptability and adherence. The aim of this study was to characterize the mechanical properties of semisolid topical formulations commercially available for psoriasis treatment. One complementary aim was to evaluate patient satisfaction with topical treatment and discuss the results according to the mechanical features of the dosage form. Eight ointments (O 1-8), five creams (C 1-5), one oleogel (G1), and one excipient (E1-petrolatum) were characterized for textural properties (spreadability and penetration tests) and flow behavior. Power law model was fitted to the results. A questionnaire for the assessment of satisfaction with topical medicines used for psoriasis treatment over 6 months was developed and applied to 79 psoriasis patients. All the tested formulations presented a shear-thinning behavior with power law indexes (n) lower than 1. Ointments were distinct from the other dosage forms, since they presented higher consistency coefficients (K), firmness, and adhesiveness and this was evidenced by hierarchical cluster analysis, which identified two clusters based on the mechanical properties. Cluster 1 included the ointments and petrolatum and the cluster 2 enclosed the creams and the gel. The clusters were associated with several attributes classified by patients as analyzed with Fisher's exact test. In all cases, higher satisfaction was observed for cluster 2. The knowledge obtained regarding the influence of the dosage form on the degree of satisfaction with the treatment could be helpful in supporting the selection of the dosage form in clinical practice and thus improve treatment adherence and clinical outcomes. The differences observed between the mechanical properties of the formulations studied may be also relevant to the industry, as guidance to the development of new medicines.

Investigation of mineral content of root canal dentin after the application of various antibiotic paste using energy-dispersive X-ray detector.

The purpose of this study was to evaluate mineral content of root canal dentin after treatment with different antibiotic pastes including the mixture of metronidazole, ciprofloxacin, doxycycline, cefaclor, amoxicillin, or minocycline. Fifty extracted maxillary canine teeth were randomly divided into five groups (n = 10 teeth for each group). Root canals were prepared Reciproc rotary files. Canals were irrigated using 5 ml 5% NaOCl and 1 ml 15% EDTA. Each tooth in all groups were longitudinally splitted into two pieces as a control and experimental samples. Each experimental group received following antibiotic paste; double antibiotic paste (DAP) and triple antibiotic paste with doxycycline (TAPd), TAP with cefaclor (TAPc), TAP with amoxicillin (TAPa), and TAP with minocycline (TAPm) for 21 days. The Ca, P, Mg, Ca, and K levels, and the Ca/P ratio was analyzed by a scanning electron microscope (SEM) equipped using a Bruker energy-dispersive X-Ray (EDX) detector. Data were analyzed with independent samples t-test, one-way anova, and Duncan tests. Ca and Ca/P ratio showed a statistically significant increase TAP with amoxicillin and cefaclor (p < .05). DAP, TAPd, and TAPm did not change the mineral levels (p > .05). TAPa and TAPc with increased the Ca level and Ca/P ratio of the root canal dentin which consequently positively influences the revascularization process.

Development of a Topical 48-H Release Formulation as an Anti-scarring Treatment for Deep Partial-Thickness Burns.

The purpose of this study was to develop pirfenidone (PF) ointment formulations for a dose finding study in the prophylactic treatment of deep partial-thickness burns in a mouse model. A preformulation study was performed to evaluate the solubility of PF in buffers and different solvents and its stability. Three different formulations containing 1, 3.5, and 6.5% w/w PF were prepared and optimized for their composition for testing in mice. Optimized formulations showed promising in vitro release profiles, in which 20-45% of PF was released in the first 7 h and 70-90% released within 48 h. The rheological properties of the ointment remained stable throughout storage at 25 ± 2°C/60% RH. Animal studies showed treatments of burn wounds during the inflammatory stage of wound healing with PF ointments at different drug concentrations had no adverse effects on reepithelization. Moreover, 6.5% PF ointment (F3) reduced the expression of pro-inflammatory cytokines IL-12p70 and TNFα. This study suggests that hydrocarbon base ointment could be a promising dosage form for topical delivery of PF in treatment of deep partial-thickness burns.

Influence of plasma on the physical properties of ointments with quercetin.

Effects of two independent variables - the content of quercetin (0 or 1 or 1.5 or 5 %) and the content of plasma (0 or 2 or 4 or 6 %) - on the organoleptic properties and rheological parameters of model formulations prepared on an amphiphilic base were estimated. The consistency of all ointments was uniform, and the content of quercetin and plasma lay within the predefined range. Tested ointments are non-Newtonian systems. The content of quercetin and plasma was found to have a significant effect on the rheological properties of the ointments. An increase in the content of plasma in ointments was accompanied by a significant increase in their hardness, viscosity and shear stress and a reduction of their spreadability. The best rheological properties were shown by formulation F-3, containing 1.5 % of quercetin and 2 % of plasma.

The reservoir effect of topical steroids in vitiliginous skin: A cross-sectional study.

BACKGROUND: Prolonged and frequent use of topical steroids may lead to decrease in efficacy as well as many local adverse effects. Stratum corneum has a unique property of reservoir effect. AIMS: To study the reservoir effect of topical steroids in a steroid-responsive condition which may enable a decrease in the dosing frequency of topical steroids. METHODS: A cross-sectional study design was used. Patients with at least three vitiliginous patches of more than 2 cm 2 present over the trunk or limbs were included. Exclusion criteria were topical or systemic corticosteroid use within the previous 4 weeks, antihistamine use within the previous 7 days, history of any allergy in the past and immunosuppression. Clobetasol propionate cream was applied on the first vitiliginous area (site A) and fluticasone propionate ointment was applied on the second vitiliginous area (site B). The third vitiliginous area, site C (control site) was left without applying any medication. Histamine-induced wheal suppression test was performed on each site, at the same time of the day, on every consecutive day following steroid application, until the values obtained at sites A and B approached those obtained at site C. SPSS software for Windows, version 16.0 was used for statistical analysis. The mean and standard deviation of the various studied parameters were calculated for various treatment groups and compared using analysis of variance (ANOVA) test. RESULTS: Forty patients were included in the study. The average wheal volumes and average erythema sizes at sites A and B were significantly smaller than the corresponding values at site C for up to 5 days after applying medication (P < 0.001). LIMITATIONS: The presence of a cutaneous reservoir of topical steroid was confirmed based on its suppressive effect on the wheal and flare response to histamine. It is not certain that the concentration that suppresses histamine-induced wheal and flare is sufficient for therapeutic efficacy in vitiligo. CONCLUSION: The reservoir effect of topical clobetasol propionate and fluticasone propionate persisted for 5 days in vitiliginous skin. Hence, it may be possible to reduce the frequency of topical steroid application in vitiligo.

In vitro penetration properties of solid lipid nanoparticles in intact and barrier-impaired skin.

Treatment of skin diseases implies application of a drug to skin with an impaired epidermal barrier, which is likely to affect the penetration profile of the drug substance as well as the carrier into the skin. To elucidate this, the effect of skin barrier damage on the penetration profile of a corticosteroid applied in solid lipid nanoparticles (SLN) composed of different lipids, varying in polarity, was studied. The studies were carried out in vitro using impaired and intact porcine ear skin, and the SLN were compared with a conventional ointment. It was shown that a significantly higher amount of corticosteroid remained in the skin, intact as well as barrier impaired, when SLN was used as a vehicle. In general, the penetration profile of the drug substance into the skin was affected by the type of lipid used in the formulation and related to lipid polarity and drug substance solubility. When formulated in SLN and applied to intact skin, the permeation of the drug substance across the skin was significantly reduced, as compared to the ointment. Altogether, in both barrier-impaired and intact skin, a higher amount of drug substance remained in the skin during application of SLN for 6, 16, and 24h, as compared to the ointment. These results emphasize the applicability of SLN to create a drug reservoir in skin, with the drug localized distinctively in the stratum corneum.

Development and evaluation of colloidal modified nanolipid carrier: application to topical delivery of tacrolimus.

Low solubility of tacrolimus in carrier matrix and subsequent poor in vivo bioavailability was overcome by constructing modified nanolipid carrier (MNLC) as a novel approach. The aim of this study was to develop MNLC with enhanced drug solubility in carrier lipid matrix using lipophilic solubilizers for topical delivery. Comprehensive characterization of tacrolimus-loaded MNLC (T-MNLC) was carried out for particle size, morphology, and rheology. Lipid modification resulted in the formation of less perfect crystals offering space to accommodate the dissolved drug leading to high entrapment efficiency of 96.66%. Compatibility and mixing behavior of carrier constituents was evaluated using DSC, FT-IR, and (1)H NMR. T-MNLC displayed sufficient stability that could be attributed to possibility to reduce total lipid concentration in carrier. T-MNLC-enriched gels showed significantly higher in vitro drug release, skin permeation, and in vivo bioavailability with dermatopharmacokinetic approach in guinea pigs compared to commercial ointment, Protopic® as reference. Penetration-enhancing effect was confirmed using gamma scintigraphy in vivo in rats. Radioactivity remained localized in skin at the application site avoiding unnecessary biodisposition to other organs with prospective minimization of toxic effects. Skin irritation studies showed T-MNLC to be significantly less irritating than reference. Research work could be concluded as successful development of novel T-MNLC using lipophilic solubilizers to increase the encapsulation efficiency of colloidal lipid carriers with advantage of improved performance in terms of stability and skin localization.

Ex vivo skin absorption of terpenes from Vicks VapoRub ointment.

BACKGROUND: The pharmaceutical market offers a wide range of inhalant drug products applied on the skin that contain essential oils and/or their isolated compounds, i.e. terpenes. Because there are few data concerning the skin penetration of terpenes, especially from complex carriers, the goal of this study was to determine the ex vivo skin absorption kinetics of chosen terpenes, namely eucalyptol, menthol, camphor, alpha-pinene, and beta-pinene, from the product Vicks VapoRub. MATERIAL/METHODS: Human cadaver skin was placed in a flow-through diffusion chamber and the product was applied for 15, 30, and 60 min. After the application time the skin was separated into layers using a tape-stripping technique: three fractions of stratum corneum and epidermis with dermis, and terpenes amounts in the samples were determined by gas-chromatography. RESULTS: The investigated terpenes showed different absorption characteristics related to their physicochemical properties and did not permeate through the skin into the acceptor fluid. Eucalyptol had the largest total accumulation in the stratum corneum and in the epidermis with dermis, while alpha-pinene penetrated into the skin in the smallest amount. CONCLUSIONS: The short time in which saturation of the stratum corneum with the terpenes occurred and the high accumulation of most of the investigated terpenes in the skin layers proved that these compounds easily penetrate and permeate the stratum corneum and that in vivo they may easily penetrate into the blood circulation.

Intraocular ophthalmic ointment following clear corneal phacoemulsification: Clinical implications.

We report 4 cases of apparent ophthalmic ointment in the anterior chamber after sutureless clear corneal phacoemulsification and posterior chamber intraocular lens implantation. The cases, as well as previous literature, indicate that ointment for topical use can be well tolerated in the eye, although glaucoma and uveitis can be potential negative outcomes. Possible risk factors, some of which may be related to current rates of endophthalmitis after clear corneal cataract surgery, and methods to prevent intraocular ophthalmic ointment after cataract surgery are discussed.

Surgical removal of intraocular antibiotic ointment after routine cataract phacoemulsification.

We report surgical removal of a droplet of intraocular chloramphenicol ointment in a 70-year-old man who had routine small-incision phacoemulsification. A spherical droplet of ointment adherent to the intraocular lens was noted 2 months postoperatively. The source was considered to be the immediate postoperative conjunctival fornix chloramphenicol ointment. Gonioscopy revealed tiny droplets adherent to the peripheral iris and angle. The droplet was surgically explanted using a minimally traumatic technique with a lens glide and ophthalmic viscosurgical device through an enlarged clear corneal incision and sent intact for laboratory biochemical analysis. The patient maintained good vision without evidence of uveitis or secondary glaucoma at 1 year of follow-up. This uncommon case also raises issues about the need for immediate postoperative antibiotic ointment for endophthalmitis prophylaxis and phacoemulsification thermal wound effects on the integrity of self-sealing clear corneal incisions.

Skin penetration and metabolism of topical glucocorticoids in reconstructed epidermis and in excised human skin.

PURPOSE: To investigate pharmacokinetic differences between the nonhalogenated double ester prednicarbate (PC) and the fluorinated monoester betamethasone 17-valerate (BM17V) their metabolism in human keratinocytes and fibroblasts as well as their permeation and biotransformation in reconstructed epidermis and excised human skin was compared. Special attention was given to the 17-monoesters because of their high receptor affinity and antiproliferative effects. METHODS: Glucocorticoid penetration was determined using Franz diffusion cells, quantifying metabolite concentrations by HPLC. Chemical stability and reactivity of the monoesters was determined by molecular modeling analysis. RESULTS: PC accumulated in the stratum corneum. A considerable amount of penetrating PC was hydrolyzed by viable keratinocytes to prednisolone 17-ethylcarbonate (PI7EC), P17EC permeated the skin very rapidly when compared to BM17V. Overall P17EC concentrations in viable tissue were low. Inside of the acceptor fluid, but not within the tissue, P17EC was converted to the more stable prednisolone 21-ethylcarbonate (P21EC). CONCLUSIONS: The inactivation of highly potent, but also cell toxic, 17-monoesters to almost inactive 21-congeners seen with isolated cell monolayers appears less important in the skin. In vitro determination of the dermal 17-monoesters concentrations may allow the prediction of the atrophogenic risk in man. BM17V levels exceeding P17EC concentration about 6-fold may contribute to its lower tolerance when compared to PC.

HPLC-fluorescence determination of unconjugated estrogens in pharmaceuticals.

A fluorimetric liquid chromatographic method (lambda(ex) = 280 nm; lambda(em) = 312 nm) was developed for measurements of unconjugated estrogens (estradiol and estriol) in pharmaceutical dosage forms using a reversed-phase column with water acetonitrile at different composition as mobile phase. The in vitro release profiles of three different estradiol transdermal therapeutic systems were determined through a medical-grade silicone rubber subdermal implant material membrane, using a modified Franz diffusion apparatus at 37 degrees C in presence of PEG 400. The HPLC method possesses advantages of rapidity, simplicity and accuracy.