Single and Dual Drug Release Patterns from Shellac Wax-Lutrol Matrix Tablets Fabricated with Fusion and Molding Techniques

The objective of this investigation was to prepare the shellac wax matrix tablets by fusion and molding technique incorporated with Lutrol in different ratios to modify the hydrophobicity of matrix tablet. The matrix tablets with single drug were loaded either with propranolol hydrochloride or hydrochlorothiazide as hydrophilic and hydrophobic model drugs, and a dual drug formula was also prepared. The single and dual drug release patterns were studied in a dissolution apparatus using distilled water as medium. Propranolol hydrochloride released from matrix was easier than hydrochlorothiazide. Drug release from shellac wax matrix could be enhanced by incorporation of Lutrol. However retardation of drug release from some matrix tablets was evident for the systems that could form dispersion in the dissolution medium. The gel network from high content of Lutrol was hexagonal which was a dense and more compact structure than the other structures found when low amounts of Lutrol were present in the formula. Therefore, the formulae with high content of Lutrol could prolong drug release more efficiently than those containing low content of Lutrol. Hence shellac wax matrix could modulate the drug release with the addition of Lutrol. Sustainable dual drug release was also obtained from these developed matrix tablets. Thus shellac wax-Lutrol component could be used as a potential matrix tablet prepared with fusion and molding technique with excellent controlled drug release.     

Clinical efficiency of a natural resin fluoride varnish (Shellac F) in reducing dentin hypersensitivity

Summary  Previous in vitro permeability and scanning electron microscopic studies have demonstrated the effectiveness of a new natural based-resin varnish (Shellac F) in dentin permeability reduction and effective tubule occlusion. The aim of this randomized double-blind, controlled, split mouth 8-week clinical study was to evaluate the efficiency of Shellac F in reducing dentin hypersensitivity. Ten patients (eight women: two men) completed the study. A quadrant including at least one hypersensitive tooth (Visual Analog Scale – VAS = 15 mm to air blast) was considered as a unit and randomly assigned to different groups for Shellac F, Duraphat^®, Isodan^®. Three applications of each material were completed at days 0, 1 and 7. The subjective response was assessed by tactile and thermal/evaporative methods. Data were collected at baseline and after the first application, at 15 min, 1, 7, 14, 28 and 56 days. Analysis was based on Kruskall–Wallis test, Wilcoxon signed rank test and the method of the least square means. No statistically significant difference was noted between Shellac F and the two control materials. Regardless of the type of stimulus, Shellac F showed significant immediate and progressive continuous efficiency in reducing dentin hypersensitivity until 56 days (VAS of 14 ± 12 mm and provoking pain force of 89 ± 12 cN, respectively, compared with 38 ± 23 mm and 41 ± 10 cN at baseline), corresponding to a highly effective relief dentin hypersensitivity. Shellac F reduced dentin hypersensitivity and did not differ from the two desensitizing agents used as controls.     

Novel method for screening of enteric film coatings properties with magnetic resonance imaging

The aim of the study is to present the concept of novel method for fast screening of enteric coating compositions properties without the need of preparation of tablets batches for fluid bed coating. Proposed method involves evaluation of enteric coated model tablets in specially designed testing cell with application of MRI technique. The results obtained in the testing cell were compared with results of dissolution studies of mini-tablets coated in fluid bed apparatus. The method could be useful in early stage of formulation development for screening of film coating properties that will shorten and simplify the development works.     

虫胶的理化性质与肠溶性能关系及其改善方法

市售虫胶种类繁多,以往仅认为药用虫胶应为无砷、漂白、透明。在实际应用中常发现肠溶性能不稳定,包衣工艺过程不易控制,致使不同厂的产品或不同批号的肠溶性能各有差异。Wagner报道氨制虫胶片久置崩解时间延长。桧桓认为虫胶肠溶片的片心影响它的崩解时间,而虫胶衣本身是稳定的。Hick则认为虫胶久置后产生聚合,表现为冷醇不溶物增加,碘价降低,诸说不一。本文对虫胶的理化性质与肠溶性能关系及附加剂对改善虫胶肠溶性能进行了探讨。     

[Artículo traducido] Alergia de contacto a shellac. Estudio transversal retrospectivo con datos del Registro Español de Investigación en Dermatitis de Contacto y Alergia Cutánea (REIDAC)

IntroductionShellac is a known allergen present mainly in cosmetics used on the eyelids and lips, although new sources of exposure have recently been described. Our objective was to assess the use of shellac as a contact allergen in Spain and the clinical profile of patients allergic to shellac.MethodsThis retrospective cross-sectional study included patients patch tested for shellac between 2018 and 2021 from the Spanish Registry of Contact Dermatitis and Cutaneous Allergy (REIDAC).ResultsA total of 980 patients were patch tested for shellac (20% in ethanol), and 37 (3.77%, 95% confidence interval [CI], 2.58–3.97%) showed positive results. Most of these patients were tested for shellac due to a suspicion of cosmetic contact dermatitis. Seven patients with present relevance were found, five with relation to cosmetics, and the other two with an occupational background of food handling. The reaction index for shellac was 0.51 and the positivity ratio was 67.56% (95% CI, 52.48–82.65%).ConclusionsShellac appears to be a prevalent allergen in patients with suspected contact dermatitis related with cosmetics or foodstuff. However, further studies are needed to validate its use in other patients.     

Contact Allergy to Shellac. Retrospective Cross-Sectional Study With Data From the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy (REIDAC)

IntroductionShellac is a known allergen present mainly in cosmetics used on the eyelids and lips, although new sources of exposure have recently been described. Our objective was to assess the use of shellac as a contact allergen in Spain and the clinical profile of patients allergic to shellac.MethodsThis retrospective cross-sectional study included patients patch tested for shellac between 2018 and 2021 from the Spanish Registry of Contact Dermatitis and Cutaneous Allergy (REIDAC).ResultsA total of 980 patients were patch tested for shellac (20% in ethanol), and 37 (3.77%, 95% confidence interval [CI], 2.58–3.97%) showed positive results. Most of these patients were tested for shellac due to a suspicion of cosmetic contact dermatitis. Seven patients with present relevance were found, five with relation to cosmetics, and the other two with an occupational background of food handling. The reaction index for shellac was 0.51 and the positivity ratio was 67.56% (95% CI, 52.48–82.65%).ConclusionsShellac appears to be a prevalent allergen in patients with suspected contact dermatitis related with cosmetics or foodstuff. However, further studies are needed to validate its use in other patients.