On-Demand Reversible UV-Triggered Interpenetrating Polymer Network-Based Drug Delivery System Using the Spiropyran-Merocyanine Hydrophobicity Switch.

A reversible switchable on-demand UV-triggered drug delivery system (DDS) based on interpenetrating polymer networks (IPNs) with silicone as the host polymer and spiropyran (SP)-functionalized guest polymer is designed and demonstrated. The photo-responsive IPNs provide a new triggered drug delivery concept as they exploit the change in intermolecular interactions (work of adhesion) among the drug, matrix, and solvent when the incorporated hydrophobic SP moieties transform into the hydrophilic merocyanine form upon light irradiation without degradation and disruption of the DDS. The change in how the copolymer composition (hydrophilicity and content) and the lipophilicity of the drug (log P) affect the release profile was investigated. A thermodynamic model, based on Hansen solubility parameters, was developed to design and optimize the polymer composition of the IPNs to obtain the most efficient light-triggered drug release and suppression of the premature release. The developed IPNs showed excellent result for dopamine, l-dopa, and prednisone with around 90-95% light-triggered release. The model was applied to study the release behavior of drugs with different log P and to estimate if the light-induced hydrophobic-to-hydrophilic switch can overcome the work of adhesion between polymers and drugs and hence the desorption and release of the drugs. To the best of our knowledge, this is the first time that work of adhesion is used for this aim. Comparing the result obtained from the model and experiment shows that the model is useful for evaluating and estimating the release behavior of specific drugs merocyanine, IPN, DDS, and spiropyran.

A systematic review of the infectious complications of colchicine and the use of colchicine to treat infections.

OBJECTIVE: Colchicine has been used historically as an anti-inflammatory agent for a wide range of diseases. Little is known regarding the relationship between colchicine use and infectious disease outcomes. The objective of this study was to systematically examine infectious adverse events associated with colchicine usage and the clinical use of colchicine for infectious diseases. METHODS: A systematic review was conducted in accordance with PRISMA methodology. PubMed, EMBASE, Scopus and Cochrane Library databases were searched (up to 12th October, 2020) for interventional and observational studies that included colchicine usage associated with infectious adverse events or infectious disease outcomes. RESULTS: A total of 9,237 studies were initially identified and after exclusions, 36 articles comprising 21 interventional studies and 15 observational studies were included in this systematic review. There were 19 studies that reported infectious adverse events and 17 studies that examined the efficacy of colchicine in treating infectious disease. Only two out of six studies reported a significant benefit using colchicine in the management of viral liver disease. There was some evidence colchicine is beneficial in managing COVID-19 by reducing time to deterioration, length of stay in hospital and mortality. Colchicine had some benefit in managing malaria, condyloma accuminata and verruca vulgaris, viral myocarditis and erythema nodosum leprosum based on case-series or small, pilot clinical studies. Two of the clinical trials and five of the observational studies reported significant associations between infections adverse events and colchicine usage. Risk of pneumonia was found in three studies and post-operative infections were reported in two studies. Risks of urinary tract infections, H. pylori and C.difficile were only reported by one study each. CONCLUSION: There is a current lack of clinical evidence that colchicine has a role in treating or managing infectious diseases. Preliminary studies have demonstrated a possible role in the management of COVID-19 but results from more clinical trials are needed. There is inconclusive evidence that suggests colchicine is associated with increased risk of infections, particularly pneumonia.

Late-onset ulnar neuritis following treatment of lepromatous leprosy infection.

Neuritis is a frequent complication of Myocobacteria leprae infection and treatment due to the variety of mechanisms through which it can occur. Not only can mycobacterial invasion into peripheral nerves directly cause damage and inflammation, but immune-mediated inflammatory episodes (termed leprosy reactions) can also manifest as neuritis at any point during infection. Treatment of leprosy reactions with thalidomide can also lead to neuritis due to an adverse drug effect. Neuritis can emerge years after initial diagnosis and treatment, although it is most frequently found at time of diagnosis or early into the treatment course. Treatment of neuritis is dependent on high-dose corticosteroid therapy as well as therapy for suspected underlying etiology. Here, we present a case of ulnar neuritis presenting in a patient with lepromatous leprosy four years after treatment of initial infection, with subsequent improvement after corticosteroid burst while maintained on thalidomide therapy.

Triamcinolone acetonide-loaded PLA/PEG-PDL microparticles for effective intra-articular delivery: synthesis, optimization, in vitro and in vivo evaluation.

Nowadays the use of sustainable polymers as poly-lactic acid (PLA) and poly-δ-decalactone (PDL) in drug delivery is advantageous compared to polymers derived from fossil fuels. The present work aimed to produce microparticles (MPs) derived from novel sustainable polymers, loaded with triamcinolone acetonide (TA) for treatment of rheumatoid arthritis via intra-articular (IA) delivery. PDL was synthesized from green δ-decalactone monomers and co-polymerized with methoxy-polyethylene glycol (mPEG) forming PEG-PDL with different molecular weights. The Hansen's solubility parameters were applied to select the most compatible polymer with the drug. An o/w emulsion/solvent evaporation technique was used for MPs fabrication, using 3 [3] full factorial design. Selection of the optimized MPs was performed using Expert Design® software's desirability function. The optimized formulations were characterized using scanning electron microscope, powder X-ray diffraction, differential scanning calorimetry, infrared spectroscopy and in vitro release studies. The inhibition percents of inflammation and histopathological studies were assessed in complete Freund's adjuvant-induced rats' knee joints evaluating the effect of IA injections of selected MPs compared to the free drug suspension. Solubility studies revealed high compatibility and miscibility between TA and PEG-PDL1700, which was blended with PLA for convenient MPs formation. The in vitro characterization studies confirmed the formation of drug-copolymer co-crystals. The in vivo studies ensured the superiority of the newly designed composite MPs in inflammation suppression, compared to the free drug suspension and PLA MPs as well. The present study proved the advantage of using sustainable polymers in a novel combination for effective drug delivery and suggesting its usefulness in designing versatile platforms for therapeutic applications.

N-acetylcysteine in dermatology.

N-acetylcysteine is a mucolytic drug which is commonly used as an antidote for acetaminophen toxicity. It is a thiol compound, which acts as a donor of cysteine, leading to replenishment of glutathione and thus acts as an antioxidant. It also has anti-inflammatory effects, alters the levels of neurotransmitters, inhibits proliferation of fibroblasts and keratinocytes and causes vasodilatation. Due to these actions, n-acetylcysteine has found use in several dermatologic conditions in systemic and topical form. The drug has been used as an adjuvant in the management of conditions such as toxic epidermal necrolysis, drug hypersensitivity syndrome, trichotillomania, skin picking disorders and onychotillomania, ichthyoses, contact dermatitis, atopic dermatitis, melasma, pseudoporphyria, connective tissue diseases, wound healing and alopecia. It also has a role in protection from radiation-induced skin damage including photo-ageing, photocarcinogenesis and radiation dermatitis. Most indications in dermatology are supported by case reports, small case series and small trials. Higher quality of evidence is needed for its wider use. The drug is cheap and is generally safe with few adverse effects. Thus a greater role is possible for use of n-acetylcysteine in various skin conditions. This review explores the various uses of n-acetylcysteine in the field of dermatology, the evidence supporting the same, the possible mechanisms of action and the adverse effects of the drug.