Papers by Christian Surber
The aim of the present thesis was the in vivo investigation of the topical bioavailability of a m... more The aim of the present thesis was the in vivo investigation of the topical bioavailability of a model glucocorticosteroid, triamcinolone acetonide (TACA), using tape stripping. The layer by layer removal of the stratum corneum by tape stripping enables the quantification of drug amounts penetrated into the stratum corneum over time. This dermatopharmacokinetic (DPK) approach has been subject of fervent discussions in the past years, and concern about adequacy and reproducibility of the technique has been expressed. Yet, the successful performance of reliable and reproducible tape stripping investigations highly depends on the use of a standardized methodology and suitable analytical methods. This thesis proposed a standardized tape stripping protocol in combination with carefully validated analytical methods (Project I). After a proof of concept, the set of methods was applied in an in vivo investigation of the influence of different factors on topical bioavailability. Both pharmaco...
International Journal of Cancer, Dec 3, 2014
Nonsteroidal anti-inflammatory drugs (NSAIDs) have been assigned a promising role in the chemopre... more Nonsteroidal anti-inflammatory drugs (NSAIDs) have been assigned a promising role in the chemoprevention of various malignancies. However, epidemiological data on the association between NSAID use and nonmelanoma skin cancer (NMSC) are limited. To explore whether patients regularly exposed to systemic NSAIDs are at a reduced risk of basal cell carcinoma (BCC) or squamous cell carcinoma (SCC), we conducted a population-based case-control analysis using the Clinical Practice Research Datalink, a United Kingdom primary care database. We identified 65,398 patients with incident BCC and 7,864 patients with incident SCC diagnosed between 1995 and 2013 and matched 1 and 4 NMSC-free controls to each BCC and SCC case, respectively, on age, sex, general practice, calendar time and years of history in the database. We compared prior NSAID exposure between cases and controls using multivariate conditional logistic regression analyses controlling for several potential confounders. Overall, we found no association between NSAID use and BCC, but when looking exclusively at users of single NSAID substances there was a suggestion of a reduced BCC risk in regular users of aspirin and ibuprofen (adjusted odds ratio [adj. OR]: 0.92, 95% confidence interval [CI]: 0.85-0.99 and adj. OR: 0.61, 95% CI: 0.48-0.78, respectively). The risk of SCC was slightly decreased in regular users of any NSAIDs (adj. OR: 0.89, 95% CI: 0.82-0.97), with the strongest risk reduction observed in current users of coxibs (adj. OR: 0.77, 95% CI: 0.62-0.95). These findings provide evidence that patients predisposed to NMSC might benefit from chemoprevention with NSAIDs.
Experimental Dermatology, Nov 23, 2015
American Journal of Drug Delivery, 2003
Praxis, Feb 1, 2012
At discharge of a 72 year old epileptic patient from the hospital, the clinician prescribed the s... more At discharge of a 72 year old epileptic patient from the hospital, the clinician prescribed the switch from Orfiril® to Lamictal®. The general practitioner misinterpreted the confusing medication list and made handwritten changes. Later on, family members of the patient observed a discrepancy between the handwritten comments of the general practitioner and the medication list of the clinician. The medication could be re-evaluated in cooperation with the hospital pharmacy and the general practitioner. An early interdisciplinary collaboration would help improving patient safety.
Microvascular Research, Mar 1, 1999
Outpatients with essential hypertension were randomized to receive antihypertensive treatment wit... more Outpatients with essential hypertension were randomized to receive antihypertensive treatment with either mibefradil or enalapril. Ambulatory blood pressure measurement (ABPM) and video capillary microscopy of the finger nailfold were performed at baseline and after 12 weeks of treatment. In the enalapril group (n ؍ 21) baseline ABP was 156 ؎ 12/100 ؎ 9 mm Hg and decreased to 140 ؎ 17/89 ؎ 10 mm Hg after 12 weeks. In the mibefradil group (n ؍ 22) mean 24-h ABP decreased from 159 ؎ 14/102 ؎ 7 to 140 ؎ 10/89 ؎ 7 mm Hg. Capillary blood cell velocity (CBV) without treatment was 0.90 ؎ 0.58 mm/s (mean ؎ SD) and 0.83 ؎ 0.46 mm/s at rest and 0.30 ؎ 0.22 and 0.21 ؎ 0.20 mm/s immediately after local finger cooling in the mibefradil and the enalapril group, respectively. In the Enalapril group CBV at week 12 was 0.99 ؎ 0.60 mm/s (n.s.) at rest and 0.40 ؎ 0.28 mm/s immediately after local cooling (P ؍ 0.005 compared to 0.21 ؎ 0.20 mm/s without treatment). Twelve weeks after initiation of treatment CBV was 0.76 ؎ 0.48 mm/s (n.s.) at rest and 0.31 ؎ 0.28 mm/s (n.s.) immediately after local cooling in the mibefradil group. Finger nailfold CBV immediately after local finger cooling was increased by enalapril compared to baseline. The T-channel-inhibiting calcium antagonist mibefradil did not change CBV in finger nailfold capillaries.
Journal of The American Academy of Dermatology, Jul 1, 1990
Journal of The American Academy of Dermatology, Jul 1, 2020
Background: Neutralizing (buffering) lidocaine 1%/epinephrine 1:100,000 solution (Lido/Epi) with ... more Background: Neutralizing (buffering) lidocaine 1%/epinephrine 1:100,000 solution (Lido/Epi) with sodium hydrogen carbonate (NaHCO3) (also called sodium bicarbonate) is widely used to reduce burning sensations during infiltration of Lido/Epi. Optimal mixing ratios have not been systematically investigated. Objectives: To determine whether a Lido/Epi:NaHCO3 mixing ratio of 3:1 (investigational medicinal product 1) causes less pain during infiltration than a mixing ratio of 9:1 (IMP2) or unbuffered Lido/Epi (IMP3). Methods: Double-blind, randomized, placebo-controlled, crossover trial (n = 2 × 24) with 4 investigational medicinal products (IMP1-4). Results: The 3:1 mixing ratio was significantly less painful than the 9:1 ratio (P = .044). Unbuffered Lido/Epi was more painful than the buffered Lido/Epi (P = .001 vs IMP1; P = .033 vs IMP2). IMP4 (NaCl 0.9% [placebo]) was more painful than any of the anesthetic solutions (P = .001 vs IMP1; P = .001 vs IMP2; P = .016 vs IMP3). In all cases, the anesthesia was effective for at least 3 hours. Limitations: Results of this trial cannot be generalized to other local anesthetics such as prilocaine, bupivacaine, or ropivacaine, which precipitate with NaHCO3 admixtures. Conclusions: Lido/Epi-NaHCO3 mixtures effectively reduce burning pain during infiltration. The 3:1 mixing ratio is significantly less painful than the 9:1 ratio. Reported findings are of high practical relevance, given the extensive use of local anesthesia today.
Chest, Jun 1, 2007
Background: Subjects with asthma do not meet medical requirements for professions such as firefig... more Background: Subjects with asthma do not meet medical requirements for professions such as firefighting. Objective: To prospectively determine the diagnostic value of respiratory symptoms and various tests used in the assessment of asthma in a cohort of firefighters. Methods: A questionnaire, spirometry, direct and indirect airway challenge tests, exhaled nitric oxide, and skin-prick tests were administered prospectively to 101 of 107 firefighters employed in Basel, Switzerland. Asthma was defined as the combination of respiratory symptoms with airway hyperresponsiveness. Results: Six of 101 firefighters (6%) had physician-diagnosed asthma, which could be confirmed in 4 firefighters. In contrast, asthma was diagnosed in 14% (14 of 101 firefighters). Wheezing was the most sensitive symptom for the diagnosis of asthma (sensitivity, 78%; specificity, 93%). Other respiratory symptoms showed a higher specificity than wheezing but a markedly lower sensitivity. Bronchial airway challenge with mannitol was the most sensitive (92%) and specific (97%) diagnostic test for asthma. Using a cutoff point of 47 parts per billion, nitric oxide had a similar specificity (96%) but lower sensitivity (42%) compared to the direct (methacholine) and indirect (mannitol) airway challenge tests. Conclusion: Asthma was considerably underdiagnosed in firefighters. The combination of a structured symptom questionnaire with a bronchial challenge test allows to identify patients with asthma and should routinely be used in the assessment of active firefighters and may be of help when evaluating candidates for this profession.
British Journal of Cancer, May 29, 2014
Background: Little is known about the epidemiology of basal cell carcinoma (BCC). Methods: Using ... more Background: Little is known about the epidemiology of basal cell carcinoma (BCC). Methods: Using the Clinical Practice Research Datalink, we calculated annual incidence rates. In a case-control analysis, we examined lifestyle factors and comorbidities. Results: Incidence rose significantly between 2000 and 2011. Basal cell carcinoma risk was increased in alcohol drinkers (slightly) and immunocompromised patients, but reduced in smokers and individuals with abnormal weight. Conclusions: Basal cell carcinoma places a growing public health burden. Lifestyle factors do not play a major role in pathogenesis, but immunosuppression is important.
PubMed, Sep 1, 1993
The oral administration of retinoids such as etretinate and acitretin (Ro 10-1670, CAS 55079-83-9... more The oral administration of retinoids such as etretinate and acitretin (Ro 10-1670, CAS 55079-83-9), provides a successful therapeutic approach in various cutaneous diseases characterized by disturbed keratinization, e.g. psoriasis. Nevertheless oral therapy is often associated with systemic adverse effects. This makes a topical form with no or reduced systemic side effects desirable. Direct application of a topical acitretin formulation to the skin might result in therapeutic skin concentrations while minimizing systemic exposure. In the hairless guinea pig and in the rhesus monkey the percutaneous absorption of [14C]acitretin from an isopropylmyristate formulation (160 micrograms acitretin/2.5 cm2/animal) were investigated in vivo. After a 24 h exposure drug concentration in the skin was higher in the hairless guinea pig (620 ng-eq/g wet tissue) than in the rhesus monkey (380 ng-eq/g wet tissue). A similar observation was made comparing the 24 h absorption data determined as amount of drug excreted. The results are compared with in vitro absorption data using skin from the same species.
CRC Press eBooks, Nov 2, 2005
PubMed, Dec 1, 2015
With aging, skin undergoes progressive structural and functional degeneration that leaves it pron... more With aging, skin undergoes progressive structural and functional degeneration that leaves it prone to a wide variety of bothersome and even serious conditions and diseases. As skin conditions and diseases may affect all ages from cradle to grave, a disproportionate burden will clearly fall on the elderly and may significantly impact on quality of life (QoL). With a reduced ability of the skin to regenerate, the elderly are at an increased risk of skin breakdowns from even the simplest insults. It is therefore vital that skin care in the late adulthood is seen as a priority among both clinicians and caregivers. The scientific literature on diagnosing and assessing age-related skin conditions and diseases is vast; however, when it comes to preventive care and treatment, the scientific data available is less profound, and the recommendations are often based on personal experience, opinions or at best on consensus documents rather than on scientific data retrieved from controlled clinical trials. In addition to the absence of the scientific data, the imprecise terminology to describe the topical products, as well as the lack of understanding the essence of the vehicle, contributes to vague and often unhelpfully product recommendations. This paper aims to elucidate some basic principles of skincare, the choice of skincare products and their regulatory status. The paper discusses adherence to topical therapies, percutaneous absorption in the elderly, and skin surface pH and skin care. Lastly, it also discusses skin care principles in selected age related skin conditions and diseases.
PubMed, 2003
Unconventional (i.e. alternative, traditional, or complementary) treatments are used by many indi... more Unconventional (i.e. alternative, traditional, or complementary) treatments are used by many individuals for a variety of symptoms and disorders. Reports on fraudulent products used for unconventional treatments are not uncommon. These include herbal remedies offered as "natural" while containing non-labeled synthetic pharmacological ingredients or even toxic agents, patients not being informed of active ingredients, products containing no active substances, or unqualified individuals or "clinics" delivering dangerous advice or treatment. Reports on tainted topical products remain rare due to the high analytical demands necessary to detect minimal traces of unknown ingredients, the fact that patients often use medications from different sources, and patient over-reliance on the effectiveness of folk remedies or advertised claims. The patients' assumption of receiving a safe and effective therapy by "natural" products has shown to be unreliable. The authors urge that quality standards for "natural" and pharmaceutical products should be the same and that only qualified professionals should deliver treatment and medical advice.
Current problems in dermatology, 2021
Since the beginning of the development of sunscreen products, efforts have been made to measure a... more Since the beginning of the development of sunscreen products, efforts have been made to measure and quantify the protection performance of such products. Early on an in vivo method was established that allowed statements on the sun protection performance in humans. Later, by establishing defined basic and experimental conditions, the method became internationally standardized delivering the well-known sun protection factor (SPF). The method was widely used and is nowadays regarded as a gold-standard method. Further standardized methods were added shortly thereafter. However, shortcomings such as the confined radiation spectra used by the methods, the invasiveness, the complexity in their application, as well as their time- and cost-intensity promoted the development of alternative methods. The shortcomings were recently followed by another, namely, the large interlaboratory variances of the sun protection metrics SPFISO 24444. This all together shows that there is a justifiable need to explore the potential of alternative methods, to complement the existing methods, to serve as equivalents, or even to replace it in the future. Based on the work of Uhlig and coworkers, the authors propose to test the suitability of the alternative methods and their possible equivalency to the reference methods in a broad-based investigation, taking into account possible interlaboratory variances. A research program - developed by a consortium - is in public planning where stakeholders from research, industry, authorities, and the public can come together to facilitate and further advance standardization of the measurement of the sun protection performance. The authors give an insight into historical, technical--conceptual, and future developments of methods for -determining the protective performance of sun protection products.
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Papers by Christian Surber
are applied directly to the affected skin resulting in a local,
prolonged and intimate contact of product and skin
> The vehicle choice is based on the nature of the dermatosis
(size, location and skin condition)
> Vehicle polarity (hydrophilic vehicles on hydrophilic skin,
lipophilic vehicles on dry skin) and vehicle viscosity (low
viscosity on large and high viscosity on small skin areas) lead to
an optimal contact between vehicle and affected skin and allow
an uncomplicated application and distribution
> A realistic application quantity is rarely more than 5 mg/cm2.
For semi-solid dosage forms, the Finger Tip Unit (400-500mg)
and for more liquid dosage forms mechanical dosage aids (e.g.,
pump with weight data per pump stroke) both with dosing
tables/instructions are recommended