Voluntary licensing of long-acting HIV prevention and treatment regimens: using a proven collaboration- and competition-based mechanism to rapidly expand at-scale, sustainable, quality-assured and affordable supplies in LMICs.

INTRODUCTION: Emerging long-acting (LA) prevention and treatment medicines, technologies and regimens could be game-changing for the HIV response, helping reach the ambitious goal of halting the epidemic by 2030. To attain this goal, the rapid expansion of at-scale, sustainable, quality-assured, and affordable supplies of LA HIV prevention and treatment products through accelerated and stronger competition, involving both originator and generic companies, will be essential. To do this, global health stakeholders should take advantage of voluntary licensing of intellectual property (IP) rights, such as through the United Nations-backed, not-for-profit Medicines Patent Pool, as a proven mechanism to support broad access to existing HIV medicines across low- and middle-income countries (LMICs). DISCUSSION: While voluntary licensing may unlock the possibility for generic competition to take place ahead of patent expiry, there are additional elements-of amplified importance for more complex LA HIV medicines-that need to be taken into consideration. This paper discusses 10 enablers of voluntary licensing of IP rights as a model to rapidly expand at-scale, sustainable, quality-assured, and affordable supplies of LA HIV prevention and treatment regimens in LMICs: Identifying promising LA technology platforms and drug formulations at an early developmental stage and engaging with patent holders Consolidating a multidisciplinary network and strengthening early-stage coordination and collaboration to foster innovation Embedding public health considerations in product design and delivery Building innovative partnerships for product development and commercialization Raising awareness of and creating demand for emerging LA products Estimating the market size, ensuring sufficient competition and protecting sustainability Using technology transfer and hands-on technical support to reduce product development timelines and costs Exploring de-risking mechanisms and financial incentives to support generic manufacturers Optimizing strategies for generic product development and regulatory filings Aligning and coordinating efforts of stakeholders across the value chain. CONCLUSIONS: Rapid access to emerging LA prevention and treatment regimens and technologies can be facilitated by voluntary licensing-catalyzed and supplemented by enabling collaborative and non-duplicative efforts of various other stakeholders. This can effectively lead to improved-accelerated and cheaper-access to quality-assured medicines for populations in LMICs.

Photolysis of (3-methyl-2H-azirin-2-yl)-phenylmethanone: direct detection of a triplet vinylnitrene intermediate.

The photoreactivity of (3-methyl-2H-azirin-2-yl)-phenylmethanone, 1, is wavelength-dependent (Singh et al. J. Am. Chem. Soc. 1972, 94, 1199-1206). Irradiation at short wavelengths yields 2P, whereas longer wavelengths produce 3P. Laser flash photolysis of 1 in acetonitrile using a 355 nm laser forms its triplet ketone (T(1K), broad absorption with λ(max) ~ 390-410 nm, τ ~ 90 ns), which cleaves and yields triplet vinylnitrene 3 (broad absorption with λ(max) ~ 380-400 nm, τ = 2 µs). Calculations (B3LYP/6-31+G(d)) reveal that T(1K) of 1 is located 67 kcal/mol above its ground state (S(0)) and has a long C-N bond (1.58 Å), and the calculated transition state to form 3 is only 1 kcal/mol higher in energy than T(1K) of 1. The calculations show that 3 has significant 1,3-carbon iminyl biradical character, which explains why 3 reacts efficiently with oxygen and decays by intersystem crossing to the singlet surface. Photolysis of 1 in argon matrixes at 14 K produced ketene imine 7, which presumably is formed from 3 intersystem crossing to 7. In comparison, photolysis of 1 in methanol with a 266 nm laser produces mainly ylide 2 (λ(max) ~ 380 nm, τ ~ 6 µs, acetonitrile), which decays to form 2P. Ylide 2 is formed via singlet reactivity of 1, and calculations show that the first singlet excited state of the azirine chromophore (S(1A)) is located 113 kcal/mol above its S(0) and that the singlet excited state of the ketone (S(1K)) is 85 kcal/mol. Furthermore, the transition state for cleaving the C-C bond in 1 to form 2 is located 49 kcal/mol above the S(0) of 1. Thus, we theorize that internal conversion of S(1A) to a vibrationally hot S(0) of 1 forms 2, whereas intersystem crossing from S(1K) to T(1K) results in 3.

Photochemical functionalization of polymer surfaces for microfabricated devices.

Herein we report the topochemical modification of polymer surfaces with perfluorinated aromatic azides. The aryl azides, which have quaternary amine or aldehyde functional groups, were linked to the surface of the polymer by UV irradiation. The polymer substrates used in this study were cyclic olefin copolymer and poly(methyl methacrylate). These substrates were characterized before and after modification using reflection-absorption infrared spectroscopy, sessile water contact angle measurements, and X-ray photoelectron spectroscopy. Analysis of the surface confirmed the presence of aromatic groups with aldehyde or quaternary amine functionality. Enzyme immobilization and patterning onto polymer surfaces were studied using confocal microscopy. Enzymatic digests of protein were carried out on modified probes manufactured from thermoplastic substrates, and the resulting peptide analysis was completed using matrix-assisted laser desorption/ionization mass spectrometry. The use of functionalized perfluorinated aromatic azides allows the surface chemistry of thermoplastics to be tailored for specific lab-on-a-chip applications.

Core-modified porphyrins. Part 6: Effects of lipophilicity and core structures on physicochemical and biological properties in vitro.

Thiaporphyrins 2-8 were prepared as analogues of 5,20-diphenyl-10,15-bis[4-(carboxymethyleneoxy)-phenyl]-21,23- dithiaporphyrin (1) to examine the effect of structural modifications: substituent changes in meso aryl groups of dithiaporphyrins with one water-solubilizing group (2-5), dihydroxylation of a pyrrole double bond and reduction to dihydroxychlorins (6 and 7), and the removal of two meso aryl groups to give unsubstituted meso positions (8). The impact of these structural modifications was measured in both physicochemical (UV spectra, generation of singlet oxygen, lipophilicity, and aggregate formation) and biological properties (dark toxicity and phototoxicity, cellular uptake, and subcellular localization). Mono-functionalized porphyrins had much higher lipophilicity than di-functionalized porphyrin 1 and, consequently, formed more aggregates in aqueous media. The formation of aggregates might lower the efficiency of lipophilic porphyrins as photosensitizers. Interestingly, dihydroxylation of a core pyrrole group in the dithiaporphyrin core did not affect either the absorption spectrum or the efficiency for generating singlet oxygen. The phototoxicity of dihydroxydithiachlorins mainly depended on their intracellular uptake. The potent phototoxicity of 6, IC(50)=0.18muM, was attributed to the extraordinarily high uptake. The intracellular uptake of 6 was about 7.6 times higher than 1. In contrast, thiaporphyrin 8 with only two meso aryl groups was less effective as a photosensitizer, perhaps due to poorer uptake and a lower quantum yield for the generation of singlet oxygen.

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Superior mesentric artery syndrome is a rare cause of high small bowel obstruction, caused by compression of the transverse part of the duodenum in between the superior mesentric artery and aorta. Patients present with chronic abdominal pain, vomiting and weight loss. We report a case of superior mesenteric artery syndrome, managed laparoscopically with laparoscopic duodenojejunostomy.

2-cyano-lup-1-en-3-oxo-20-oic acid, a cyano derivative of betulinic acid, activates peroxisome proliferator-activated receptor gamma in colon and pancreatic cancer cells.

Betulinic acid (BA) is a phytochemical triterpenoid acid from bark extracts and is cytotoxic to cancer cells and tumors. We modified the A-ring of BA to give a 2-cyano-1-en-3-one moiety and the effects of the 2-cyano-lup-1-en-3-oxo-20-oic acid (CN-BA), 2-cyano derivative of BA, and its methyl ester (CN-BA-Me) were investigated in colon and pancreatic cancer cells. Both CN-BA and CN-BA-Me were highly cytotoxic to Panc-28 pancreatic and SW480 colon cancer cells. CN-BA and CN-BA-Me also induced differentiation in 3T3-L1 adipocytes, which exhibited a characteristic fat droplet accumulation induced by peroxisome proliferator-activated receptor gamma (PPARgamma) agonists. Based on these results, we investigated the activities of CN-BA and CN-BA-Me as PPARgamma agonists using several receptor-mediated responses including activation of transfected PPARgamma-responsive constructs, induction of p21 in Panc-28 cells and induction of caveolin-1 and Krüppel-like factor 4 in colon cancer cells. The results clearly demonstrated that both CN-BA and CN-BA-Me activated PPARgamma-dependent responses in colon (caveolin-1) and pancreatic (p21) cancer cells, whereas induction of KLF4 by these compounds in colon cancer cells was PPARgamma independent and also dependent on cell context. The PPARgamma agonist activities of CN-BA and CN-BA-Me were structure-, response/gene- and cell context-dependent suggesting that these compounds are a novel class of selective PPARgamma modulators with potential for clinical treatment of colon and pancreatic cancer.

Photoinduced C-N bond cleavage in 2-azido-1,3-diphenyl-propan-1-one derivatives: photorelease of hydrazoic acid.

Photolysis of 3-azido-1,3-diphenyl-propan-1-one (1a) in toluene yields 1,3-diphenyl-propen-1-one (2), whereas irradiation of 3-azido-2,2-dimethyl-1,3-diphenyl-propan-1-one (1b) results in the formation of mainly 2,2-dimethyl-1,3-diphenyl-propan-1-one. Laser flash photolysis (308 nm) of 1a,b in acetonitrile reveals a transient absorption (lambda max = approximately 310 nm) due to the formation of radicals 4a and 4b, respectively, which have lifetimes of approximately 14 micros at ambient temperature. TD-DFT calculations (B3LYP/6-31+G(d)) reveal that the first and second excited states of the triplet ketone (T1K (n,pi*) and T2K (pi,pi*)) in azide 1a are almost degenerate, at approximately 74 and 76 kcal/mol above the ground state (S0), respectively. Similarly, azide 1b has T1K and T2K 75 and 82 kcal/mol above S0, respectively. The calculated transition state for cleaving the C-N bond is located 71 and 74 kcal/mol above S0 in azides 1a and 1b, respectively. The calculated bond dissociation energies for breaking the C-N bond are 55 and 58 kcal/mol for azides 1a and 1b, respectively, making C-N bond breakage accessible from T1K in azides 1 at ambient temperature. In comparison, the irradiation of azides 1 in argon matrices at 14 K lead to the formation of the corresponding triplet alkyl nitrenes (1-n), via intramolecular energy transfer from T2K. The characterization of 1-n was supported by isotope labeling, IR spectroscopy, and molecular modeling.