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Monographs of Topical Drugs that Have Caused Contact Allergy/Allergic Contact Dermatitis
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
In a prospective study, 29 patients with hypertension were treated with clonidine-TTS. In the study period of 3 months, local skin reactions suspected to be allergic occurred in 11 (38%) of the patients. Patch testing with all components of clonidine-TTS in 7 of these individuals confirmed contact allergy to clonidine in 6 and a reaction to polyisobutylene in the TTS in the 7th patient (4). With continued treatment and inclusion of more patients, these authors reported 15 (47%) allergic reactions in 32 patients treated. Not all of them were patch tested, but those who were all reacted positively to clonidine (apart from the one reacting to polyisobutylene) (6).
Development of Topical and Transdermal Dosage Forms
Published in Tapash K. Ghosh, Dermal Drug Delivery, 2020
Three major groups of adhesives are usually used in transdermal products. Those are: Polyisobutylene/polybutylene, acrylic and silicone. On rare occasions, hydrophilic adhesives and block copolymer based hot-melt pressure sensitive adhesives have been used. Polyisobutylene is a synthetic polymer produced by the low-temperature polymerization of isobutylene in liquid ethylene, methylene chloride or hexane, using an aluminum-chloride or boron-trifluoride catalyst and may contain a suitable stabilizer. Tackifiers provide tack and specific adhesion qualities to the adhesive mass. Plasticizers soften the adhesive mass. Both tackifiers and plasticizers act as viscosity enhancers and modify the flow properties of the polyisobutylene. The modifiers such as hydrocarbon resins and low molecular weight polyisobutylenes may also be used to improve adhesion/flow properties32.
Topical and Transdermal Formulation Development
Published in Marc B. Brown, Adrian C. Williams, The Art and Science of Dermal Formulation Development, 2019
Marc B. Brown, Adrian C. Williams
When used for extended times, patches can cause skin irritation. This is partly a result of the permeant, but also because patches tend to be occlusive with consequent hydration of the stratum corneum; whilst hydrating the stratum corneum is valuable for increasing drug delivery, it also poses some difficulties in the longer term. On extended use, the hydrated stratum corneum can encourage microbial growth, and the wet tissue can also adversely affect the adhesive performance. Both the polyisobutylene and polysiloxane adhesives have good water vapour permeability properties and hence reduce problems associated with long-term tissue occlusion. However, the polysiloxanes, whilst offering low toxicity and generally good skin compatibility, can themselves be irritating. One further problem, notable in drug in adhesive formulations, is that the drug can migrate through the adhesive layer on storage. This is usually not a problem with the acrylic-based polymers, but it is evident with polyisobutylene adhesives. Where this phenomenon has occurred, with delivery of scopolamine and clonidine, the migrated drug has formed an “adhesive depot” which provides a drug burst or pulse prior to pseudo steady-state delivery; the manufacturers have shown this to be a valuable method for overcoming initial drug:skin binding.
Development and evaluation of a drug-in-adhesive transdermal delivery system for delivery of olanzapine
Published in Expert Opinion on Drug Delivery, 2022
Traditionally, transdermal drug delivery systems are broadly classified into two types: matrix-based TDS and reservoir-based TDS. Matrix-type TDS contain the active solubilized or suspended in a blend of adhesives, chemical enhancers, and other excipients. On the other hand, reservoir-type TDS contain a blend of components in a liquid or semi-solid form in a heat-sealed reservoir formed between a backing membrane and a semipermeable membrane. However, matrix-type TDS are preferred and recommended by the FDA over reservoir-type TDS due to some serious limitations with reservoir-type TDS such as leakage from the reservoir leading to dose dumping [10]. Generally, matrix TDS are drug-in-adhesive transdermal patches that include lipophilic drugs either dissolved or dispersed in pressure-sensitive adhesives (PSAs). The most commonly used PSAs for transdermal drug delivery systems are acrylates, silicone, or polyisobutylene (PIB) PSAs [11]. The objective of our study is to develop a drug-in-adhesive matrix-type drug in adhesive TDS that can exert a slow and sustained release of OZP for 3 days. The TDS will be noninvasive and improve patient adherence
Ketamine-polymer based drug delivery system for prolonged analgesia: recent advances, challenges and future prospects
Published in Expert Opinion on Drug Delivery, 2021
Surabhi Singh, Amit Kumar, Gaurav Mittal
A polymeric transdermal drug-in-reservoir skin patch based on ketamine has been designed by Tang et al. [79] comprising a backing layer, a reservoir layer, a rate-controlling membrane, an adhesive layer, and a release liner. The backing layer was made up of polyesters such as Scotchpak 9736 or polyurethane film, or polyethylene film such as CoTran 9720. The reservoir layer includes ketamine in combination with gel forming agents such as hydroxypropylcellulose (HPC) or hydroxypropyl methyl cellulose (HPMC) or polyvinyl pyrrolidone (PVP such as BASF’s Kollidon) or polyacrylic acid (such as Carbopol) or sodium CMC (carboxyl methyl cellulose), or a combination. The adhesive layer comprised a pressure sensitive adhesive, for example, a polyisobutylene (PIB) adhesive or a silicone polymer adhesive, or an acrylate copolymer adhesive. The rate-controlling membrane was a microporous membrane of polypropylene film or polyethylene-vinyl-acetate (EVA) film, or a combination. The sustained release profile of ketamine from transdermal drug delivery device was monitored in vitro using human cadaver skin and the results indicated that tunable ketamine release could be achieved varying from 18 h to 7 days.
Status epilepticus after C-4 ingestion: using liquid chromatography to quantify toxicity
Published in Clinical Toxicology, 2019
Robert Garcia, Amir Karimian, Chase Donaldson, Kerry Preston, Shawna Scully
C-4 is a commonly used military explosive comprised of the explosive compound cyclotrimethylenetrinitramine, or Research Department Explosive (RDX), along with stabilizing rubbers. Its composition is 91% RDX, 5.3% dioctyl sebacate or dioctyl adipate, 2.1% polyisobutylene, and 1.6% mineral oil. Oral ingestion of C-4 is documented among some service members, and it has been known to elicit a euphoria similar to alcohol [1,2]. As this practice grew in popularity during the Vietnam War, military medical providers began to see the increasingly toxic effects of the RDX component of C-4: nausea, renal injury, and convulsions [3–5]. Since then, cases of C-4 poisoning have decreased in frequency with no reports published since 2009. However, some soldiers in explosive ordnance disposal (EOD) units in the US Army still acknowledge its consumption as a rite of passage. Here, we present a case of status epilepticus after consumption of C-4 with seizures persisting for two days and correlate the clinical course with serum concentrations.