Spectrophotometric determination of folic acid in pharmaceutical preparations by coupling reactions with iminodibenzyl or 3-aminophenol or sodium molybdate-pyrocatechol

Novel coupling reagents are used for the simple and sensitive spectrophotometric determination of folic acid either in pure form or in its pharmaceutical preparations. The methods are based on the probable diazotization of the p-aminobenzoylglutamic acid obtained after reductive clevage of folic acid, followed by either coupling with iminodibenzyl to give a violet product with lambda(max) of 580nm or coupling with 3-aminophenol to produce an orange yellow-colored product with lambda(max) of 460nm. Sodium molybdate and pyrocatechol are used in the third method and the pale red-colored product formed has a lambda(max) of 490nm. The methods are highly reproducible and have been applied to the determination of folic acid in tablets and the results compare favorably with the official method. Common excipients used as additives in pharmaceutical preparations do not interfere in the proposed methods.     

Purification and characterization of human lung calmodulin-independent cyclic AMP phosphodiesterase

A high-affinity calmodulin-independent cyclic AMP phosphodiesterase was purified to homogeneity from human lung tissue. This enzyme has a molecular weight of 60,000, a sedimentation coefficient of 3.2–3.4 S, and an isoelectric pH of 4.6–4.8. Neither Ca²⁺ nor calmodulin (in the presence or absence of added Ca²⁺) stimulates the enzymatic activity. This enzyme appears to be very similar to that described previously from dog kidney (W. J. Thompson, P. M. Epstein, and S. J. Strada, (1979) Biochemistry18, 5228–5237). Hydrolysis of cyclic AMP is greatly enhanced by Mg²⁺ (25–30× at 10 mm Mg²⁺) and Mn²⁺ (20× at 10 mm Mn²⁺). Zn²⁺, Cu²⁺, and Co²⁺ are ineffective at these concentrations. Cyclic AMP is the exclusive substrate with a K_m of 0.7–0.8 μm. The I₅₀ of cyclic GMP is 1 mm using 1 μm cyclic AMP as substrate. In contrast, aminophylline, MIX, and SQ 20009 have I₅₀s of 0.28, 0.021, and 0.001 mm, respectively). The purified enzyme is susceptible to temperature inactivation and protease degradation. Significant (10%) inhibition is seen at 37 °C for 20 min. Trypsin, at 0.1 μg/ml, destroys 50% of the activity in 30 min at 25 °C. Our observations concerning its lability to temperature and proteases coupled with its lack of response to calmodulin suggest this enzyme is a basic catalytic subunit of other cyclic AMP phosphodiesterases present within human lung tissue.     

Detection of indicator pathogens from pharmaceutical finished products and raw materials using multiplex PCR and comparison with conventional microbiological methods

A multiplex PCR assay was devised and compared with standard conventional methods for quality evaluation of pharmaceutical raw materials and finished products with low levels of microbial contamination. Samples which were artificially contaminated with <10 colony forming units of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella species and possibly contaminated samples were incubated for 16 h with different enrichment media. Primers that deduce 559 bp fragment of the 16S rRNA gene was employed in amplifying E. coli species, similarly invasion protein gene with 275 bp fragment size was used as target for detecting Salmonella spp., in case of S. aureus a 461 bp amplicon from m-RNA nuclease gene, and an 709 bp fragment from oprL gene was used for amplifying P. aeruginosa. The detection limits for artificially contaminants by multiplex PCR was 1 CFU/g, where as in case of conventional method the detection limit was >2 CFU/g. Similarly, when tested with possibly contaminated samples, 35% were detected for E. coli, Salmonella spp., S. aureus and P. aeruginosa species with multiplex PCR, while only 21% were detected with standard conventional microbial methods. Multiplex PCR assay provides sensitive and reliable results and allows for the cost-effective detection of all four bacterial pathogens in single reaction tube.     

基于社会网络分析和共词分析的制药技术领域研究

目的:深入研究制药技术领域的发展态势。方法:本研究以Pub Med数据库中收录的制药技术领域研究论文为研究对象,采用社会网络分析、共词分析等定量方法,结合药学专业知识的定性分析,从论文数量年度分布、国家/地区分布及合作网络、研究主题等多个角度开展研究。结果:研究发现:第一,全球制药技术领域共有研究论文95381篇,近几年正处于快速发展阶段;第二,论文发表集中在美国、中国和日本等国家;第三,在定量分析的基础上,结合药学专业知识,共得到15个研究主题,包括点击化学、晶型药物、纳米微球药物等。结论:美国在制药技术领域处于主导地位,中国发文量已经具备一定优势,但发文量和国际影响力与美国相比还是存在较大差距;通过对制药技术领域研究主题的深入分析可以全面把握制药技术领域的研究现状和发展态势。     

Multi-faceted strategy based on enzyme immobilization with reactant adsorption and membrane technology for biocatalytic removal of pollutants: A critical review

In the modern era, the use of sustainable, environmentally friendly alternatives for removal of recalcitrant pollutants in streams resulting from industrial processes is of key importance. In this context, biodegradation of phenolic compounds, pharmaceuticals and dyes in wastewater by using oxidoreductases offers numerous benefits. Tremendous research efforts have been made to develop novel, hybrid strategies for simultaneous immobilization of oxidoreductase and removal of toxic compounds. The use of support materials with the options for combining enzyme immobilization with adsorption technology focused on phenolic pollutants and products of biocatalytic conversion seems to be of particular interest. Application of enzymatic reactors based on immobilized oxidoreductases for coupling enzyme-aided degradation and membrane separation also attract still growing attention. However, prior selection of the most suitable support/sorbent material and/or membrane as well as operational mode and immobilization technique is required in order to achieve high removal efficiency. Thus, in the framework of this review, we present an overview of the impact of support/sorbent material on the catalytic properties of immobilized enzymes and sorption of pollutants as well as parameters of membranes for effective bioconversion and separation. Finally, future perspectives of the use of processes combining enzyme immobilization and sorption technology as well as application of enzymatic reactors for removal of environmental pollutants are discussed.     

Fertiliser products from new sanitation systems: Their potential values and risks

The plant nutrients consumed in human society today are lost through the established wastewater treatment systems in industrialised countries as well as via insufficient or non-existent handling of sewage in the developing world. New sanitation systems have been designated to overcome this failure. The source separated wastewater streams collected within these systems contain a high nutrient content, and can be used as fertiliser as well as soil conditioner after appropriate storage and/or treatment. Application in agriculture with existing techniques is feasible. However, pathogens and pharmaceuticals contained in these fertiliser types are a potential hazard. Nevertheless, storage and appropriate treatment can minimise the risks. The products deriving from these systems have a high potential to preserve available plant nutrient resources and deficiencies in agriculture as well as being able to substitute synthetic plant nutrients and at the same time prevent unwanted environmental nutrient over-enrichment.     

Sustainable biocatalytic synthesis of L-homophenylalanine as pharmaceutical drug precursor

Over the past decade, L-homophenylalanine is extensively used in the pharmaceutical industry as a precursor for production of angiotensin-converting enzyme (ACE) inhibitor, which possesses significant clinical application in the management of hypertension and congestive heart failure (CHF). A number of chemical methods have been reported thus far for the synthesis of L-homophenylalanine. However, chemical methods generally suffer from process complexity, high cost, and environmental pollution. On the other hand, enantiomerically pure L-homophenylalanine can be obtained elegantly and efficiently by employing biocatalytic methods, where it appears to be the most attractive process in terms of potential industrial applications, green chemistry and sustainability. Herein we review the biocatalytic synthesis of vital L-homophenylalanine as potentially useful intermediate in the production of pharmaceutical drugs in environmentally friendly conditions, using membrane bioreactor for sustainable biotransformation process. One envisages the future prospects of developing an integrated membrane bioreactor system with improved performance for L-homophenylalanine production.     

Comparative evaluation of gastrointestinal blood loss in the feces of rats following pepto-bismol liquid and aspirin administration

Acetylsalicylic acid (aspirin) can irritate the gastrointestinal tract of man and of animals ultimately resulting in hemorrhagic erosions and ulcers. Since Pepto-Bismol liquid also contains salicylates (primarily bismuth subsalicylate), the relative sensitivity of the GI tract of the rat to hemorrhage and subsequent blood loss in response to Pepto-Bismol and to aspirin was determined. The appearance of blood in the feces of male Sprague-Dawley rats 22 hr after the peroral administration of aspirin or Pepto-Bismol at equivalent salicylate doses was measured spectrophotometrically using the modified benzidine assay. Aspirin, administered in total salicylate doses of 38.4, 57.5, 76.7 or 153 mg/kg caused a dose-dependent increase in blood loss ranging from 53 to 276 μl/kg body weight, the latter 2 values being significantly different from control. Pepto-Bismol at total salicylate doses of 38.4, 57.5 or 76.7 mg/kg failed to cause blood loss. Neither Pepto-Bismol nor aspirin obscured recovery of orally-dosed blood in rat feces. The sensitivity of the benzidine assay allowed for the quantitative assessment of 5 μl or less blood per gram of feces. It was concluded that at equivalent salicylate dose levels, Pepto-Bismol, unlike aspirin, did not cause a dose-dependent increase in blood in the feces of rats, suggesting that salicylates should not be collectively categorized as inducing gastric mucosal damage.