Allopurinol is a xanthine oxidase inhibitor used to decrease high blood uric acid levels. Allopurinol is specifically used to prevent gout, prevent specific types of kidney stones, and for the high uric acid levels that can occur with chemotherapy. Allopurinol acts on purine catabolism, without disrupting the biosynthesis of purines. It reduces the production of uric acid by inhibiting the biochemical reactions immediately preceding its formation. Allopurinol is a structural analog of the natural purine base, hypoxanthine. It is an inhibitor of xanthine oxidase, the enzyme responsible for the conversion of hypoxanthine to xanthine and of xanthine to uric acid, the end product of purine metabolism in man. Allopurinol is metabolized to the corresponding xanthine analog, oxypurinol (Allopurinol), which also is an inhibitor of xanthine oxidase. Allopurinol is taken by mouth or injected into a vein. Common side effects, when used by mouth, include itchiness and rash. Common side effects when used by injection include vomiting and kidney problems.

Potassium citrate is indicated for the management of renal tubular acidosis with calcium stones, hypocitraturic calcium oxalate nephrolithiasis of any etiology, uric acid lithiasis with or without calcium stones. WhenPotassium citrate is given orally, the metabolism of absorbed citrate produces an alkaline load. The induced alkaline load in turn increases urinary pH and raises urinary citrate by augmenting citrate clearance without measurably altering ultrafilterable serum citrate. Thus, potassium citrate therapy appears to increase urinary citrate principally by modifying the renal handling of citrate, rather than by increasing the filtered load of citrate. Potassium citrate is used as a food additive (E 332) to regulate acidity.

Bibrocathol (trade names Noviform and Posiformin) is a well-established topical antiseptic for the treatment of acute eyelid diseases like blepharitis. Eye ointments containing 2 or 5 % bibrocathol and the excipients liquid paraffin, white soft paraffin, and lanolin have been marketed since 1967 for the treatment of eye irritation, chronic blepharitis, and uninfected corneal injuries. Reports of clinical experience with bibrocathol for inflammation of the edge of the palpebra exist since the beginning of the 20th century. Until recently, no controlled, randomized clinical studies according to the guidelines for Good Clinical Practice for Trials on Medical Products for Human Use (GCP) as defined by the International Conference on Harmonisation (ICH) have been performed with bibrocathol 2 % ointment, as these were not required for marketing authorization in the 1960s. A first double-blind, prospective, controlled, GCP-compliant clinical study was recently performed to assess the efficacy of bibrocathol 5 % (Noviform®) in acute blepharitis. It demonstrated superior efficacy of bibrocathol 5 % ointment as compared to an ointment vehicle (placebo) after 2 weeks of treatment as assessed by a combined measure of slit-lamp examination results and patients’ subjective complaints.

Bibrocathol (trade names Noviform and Posiformin) is a well-established topical antiseptic for the treatment of acute eyelid diseases like blepharitis. Eye ointments containing 2 or 5 % bibrocathol and the excipients liquid paraffin, white soft paraffin, and lanolin have been marketed since 1967 for the treatment of eye irritation, chronic blepharitis, and uninfected corneal injuries. Reports of clinical experience with bibrocathol for inflammation of the edge of the palpebra exist since the beginning of the 20th century. Until recently, no controlled, randomized clinical studies according to the guidelines for Good Clinical Practice for Trials on Medical Products for Human Use (GCP) as defined by the International Conference on Harmonisation (ICH) have been performed with bibrocathol 2 % ointment, as these were not required for marketing authorization in the 1960s. A first double-blind, prospective, controlled, GCP-compliant clinical study was recently performed to assess the efficacy of bibrocathol 5 % (Noviform®) in acute blepharitis. It demonstrated superior efficacy of bibrocathol 5 % ointment as compared to an ointment vehicle (placebo) after 2 weeks of treatment as assessed by a combined measure of slit-lamp examination results and patients’ subjective complaints.

Arhalofenate is a uricosuric drug which lowers serum urate by blocking its reabsorption by the proximal tubules of the kidney. Arhalofenate activity is mediated by inhibition of URAT1, OAT4 and OAT10. Additionally, arhalofenate has been suggested to exert potent anti-inflammatory activity. Arhalofenate has completed Phase 2 and is ready to advance to Phase 3 as a novel potential treatment for gout. The drug was also tested in patients with type 2 diabetes mellitus (phase III study), where it demonstrated its ability to lower glucose level, acting as a selective, partial PPAR-gamma agonist. However, the development of arhalofenate as an anti-diabetic drug was terminated.

AstraZeneca developed disufenton (NXY-059), a free radical trapping agent, for the treatment of ischaemic stroke and other brain injuries. Nevertheless, large clinical trial (3306 versus 1722 patients) was neutral, providing no evidence for the efficacy of disufenton sodium in patients with stroke. One study using rat cortical brain slices concluded that NXY-059 improved neuronal survival. However, another study in mouse neuroblastoma cells reported no effect. Another study reported that NXY-059 restored endothelial blood-brain. Histological analyses revealed several therapeutic advantages associated with disufenton sodium treatment following acute acoustic trauma, including reductions in inner and outer hair cell loss; reductions in acute acoustic trauma-induced loss of calretinin-positive afferent nerve fibers in the spiral lamina; and reductions in fibrocyte loss within the spiral ligament. However, AstraZeneca terminated the development program.

(+)-selfotel ((+)-CGS-19755) is an enantiomer of selfotel, a competitive antagonist at N-methyl-D-aspartate (NMDA)-preferring receptors. The inhibition of NMDA-evoked ACh release from rat striatal slices is stereospecific, with the (+)-enantiomer less potent than the (-)-enantiomer.

Totrombopag is an orally bioavailable, nonpeptide, small-molecule thrombopoietin receptor agonist. It induces proliferation and differentiation of megakaryocytes and progenitor cells, ultimately increasing the production of platelets. Totrombopag has been investigated in healthy volunteers in a phase 1, single-blind, randomized fashion to cause a dosedependent increase in platelet count with demonstrated safety. There were no serious adverse events, no significant changes in laboratory or cardiovascular safety parameters and there was no observed relationship between the incidence or severity of adverse events and dose. Most adverse events were mild in intensity and self-limiting. Totrombopag was developed for the treatment of immune thrombocytopenic purpura.

Leteprinim is the synthetic purine. It has both anti-excitotoxic neuroprotective properties and enhances the regenerative response of surviving neurons within the central nervous system. Moreover, the experiments in vitro and in vivo reveal that leteprinim can be administered after an excitotoxic event and still produce neuroprotection. This is clearly crucial for any drug designed to treat stroke or any acute central nervous system injury. Therefore, leteprinim has the pharmacological properties required by a drug intended to treat acute stroke as well as a spinal injury. It may be useful in reducing brain injury; it possesses clinical relevance for the treatment of hypoxic-ischemic encephalopathy in the newborn. Leteprinim has the therapeutic potential for use in clinical trials in the treatment of neuronal deterioration in depression.