Dermal and Transdermal Drug Delivery Systems
Tapash K. Ghosh in Dermal Drug Delivery, 2020
This chapter reviews progress in the development of dermal and transdermal delivery systems. Both dermal and transdermal drug therapy for local and systemic effect require the active agent to be delivered to the site of action. Skin permeation and enhancement technologies, together with delivery systems, have been the regular subject of updates and reviews, as have the differences between diseased and normal stratum corneum. It has been known for some time that permeation across the skin is controlled mainly by the tortuous but continuous intercellular lipid of the stratum corneum. The authors investigated the comparative skin permeation and found that the permeation of desogestrel was significantly greater than that of levonorgestrel. The intercellular lipid lamellae are highly structured, very stable and provide a highly effective barrier to chemical penetration and permeation. While permeation of ondansetron through pig skin from a base gel was low, the addition of isopropyl myristate or camphor improved delivery.
The Arab influence
Michael J. O’Dowd in The History of Medications for Women, 2020
The mighty Arabian empire was founded by the prophet Mohammed and his emirs (the name given to independent chieftains and descendants of his daughter Fatima). The Arab physicians ‘translated the Greek authors, commented upon them, popularized them and, to their lasting glory, transmitted Greek Medicine — augmented with their own clinical experience — to the Europeans’. In the Arabian schools of medicine, principal courses held were clinical medicine, pharmacology and therapeutics. Arabian medicine gave birth to alchemy and these early chemists explored the notion of an ‘elixir of life’ that would cure all diseases and confer immortality. Arab physicians prescribed camphor to cause impotence and to ‘coagulate’ (stop) nocturnal seminal emissions. Over the years, many expressions were used for the involuntary loss of reproductive fluid, including oneirogmus, pollutio nocturni somni, somnia veneris . Nutmeg and mace were first introduced into Europe by Arabian physicians in the middle of the twelfth century. They described the use of nutmeg in an analgesic pessary.
Development of a Method for Organic Firearm Discharge Residue Detection
James Smyth Wallace in Chemical Analysis of Firearms, Ammunition, and Gunshot Residue, 2008
Development of a Method for Organic Firearm Discharge Residue Detection The requirements of a method for detecting organic FDR were that it would not be detrimental to the existing particle analysis method, that the results would be meaningful, and that it should integrate into the two individual existing systems for the detection of explosive and firearm residue, thereby creating a system which could, if desired, routinely analyze all samples for organic explosives and organic and inorganic FDR. Because a large proportion of our casework involves the use of ammunition with single-based propellants, it was desirable to investigate the possibility of using GC/MS to detect constituents of propellant that are not detectable using our existing explosive residue analysis system. Such constituents include DPA, MC, EC, camphor, and phthalates. Because these constituents are originally present in relatively small amounts (typically 0.5% to 2.0%), compared to the level of NG in double-based propellants, it would be necessary to optimize all aspects of the system, namely, the extraction and cleanup/concentration procedures in addition to the instrumental parameters.
The Effects of Camphor, Eucalyptus and Menthol Vapour on Nasal Resistance to Airflow and Nasal Sensation
Published in Acta Oto-Laryngologica, 1983
A. Burrow, R. Eccles, A. S. Jones
The effects of five minutes exposure to camphor, eucalypths or menthol vapour on nasal resistance to airflow and nasal sensation of airflow were compared with the effects of exercise on the nose. Inhalation of camphor, eucalyptus or menthol had no effect on nasal resistance to airflow but the majority of subjects reported a cold sensation in the nose with the sensation of improved airflow. Exercise caused a decrease in nasal resistance but did not induce any nasal sensation of cold or improved airflow. The results indicate that camphor, eucalyptus and menthol stimulate cold receptors in the nose. The clinical significance of nasal sensation of airflow is discussed.
Sodium Carbonate Prevents NK Cell Conditioning by Interfering with the US Signal
Published in International Journal of Neuroscience, 1994
Carolyn Rogers, Vithal Ghanta, Sossiena Demissie, Nancy Hiramoto, Raymond Hiramoto
The conditioned enhancement of natural killer (NK) cell activity can be blocked by the injection of sodium carbonate solution prior to the association of the camphor odor conditioned stimulus (CS) with the polyinosinic: polycytidylic acid (poly 1:C) unconditioned stimulus (US). We have experimentally dissociated the memory which is formed for camphor odor from that developed for the association of camphor with the US. The memory for the odor of camphor can be allowed to develop one day before the administration of the unconditioned stimulus. Sodium carbonate appears to act within the central nervous system to block the association of the unconditioned stimulus with the conditioned stimulus. The data also suggest that in conditioning of NK cell activity, there are two specific sites for memory of the response, one for the conditioned stimulus and the other for the association of the unconditioned stimulus with the conditioned stimulus.
Preparation and evaluation of dual-mode floating gastroretentive tablets containing itraconazole
Published in Drug Delivery, 2014
Ju-Young Kim, Yun-Seok Rhee, Chun-Woong Park, Jung-Myung Ha, Eun-Seok Park
The aims of the present study were to prepare new dual-mode floating gastroretentive tablets (DF-GRT) containing itraconazole (ITR) and to evaluate influence of the dosage forms on pharmacokinetic parameters of ITR. The solubility of ITR was enhanced around 200 times (from 1.54 to 248.38 µg/mL) by preparing solid dispersion (SD) with hydroxypropylmethyl cellulose. Buoyancy of DF-GRT containing ITR-SD was established by both camphor sublimation and gas generation. Camphor sublimation decreased density of DF-GRT by making pores in tablet matrix, which led to elimination of lag time for floating. Carbon dioxide generated by sodium bicarbonate and citric acid helped to maintain buoyancy of DF-GRT. Therefore DF-GRT floated on the medium without lag time until disintegrated entirely during in vitro release study. They released 89.11% of the drug at 2 h. Residual camphor was
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