To systematically review the impact of patent expiry on drug price and market share, and provide evidence-based reference for promoting the balanced development of innovative drugs and generic drugs in China.

PubMed, Scopus, the Cochrane Library, CNKI, WanFang Data and VIP databases were searched to identify studies on the impact of patent expiration on the prices and market shares of original or generic drugs from inception to September 31, 2019. After relevance screening and data extraction, a standardized assessment was performed by two independent reviewers. Then, qualitative analysis was applied to evaluate the impact of patent expiration on the prices and market shares of original or generic drugs.

A total of 26 literatures were included, 10 of which were related to changes in drug prices and market shares after the expiration of patents, 14 related to changes in drug prices, and 2 related to changes in market shares. The identified studies indicated that the market shares of generic drugs ranged from 56% to 92% 1~8 years after patent expiry, and drug prices decreased to 20%~98% of the brand drug price 1~10 years after patent expiry. The prices of original prices were rigid and varied within 25%, while some even increased after generic drugs' entry.

After the expiration of patent, the overall drug prices decrease, and the original drugs show a certain price rigidity. The market share of generic drugs is increasing over time. The number of generic competitors, price discounts, and current generic drug policies could have an impact on the speed of generic substitution.

To evaluate the biowaiver of domestic bisoprolol fumarate tablets using computer simulations and parallel artificial membrane permeability assay (PAMPA).

First, DDDplus^TM software was used to evaluated the effects of physical parameters of API and excipients on dissolution behavior of bisoprolol fumarate tablets. Second, population simulation using Gastroplus^TM software was used to predict the absorption behavior of the drug with different release rates (t_85%=15~120 min) and obtain the release rate range which had no effect on bioequivalence. Third, the membrane permeation curves of domestic bisoprolol fumarate tablets, bisoprolol fumarate raw material and reference preparation were determined to evaluate the influence of excipients on permeation rate and predict their bioequivalence.

The results of DDDplus^TM simulation indicated that the in vitro dissolution behavior of bisoprolol fumarate tablets did not change when the particle size of API and excipients, or the amount of excipients, or the particle size of excipients changed. The results of population simulation revealed that the drug preparation could be bioequivalent to the reference preparation as long as it was completely dissolved in 90 minutes. In the jejunum model solution, the membrane permeation rate curve showed that excipients did not affect the membrane permeation behavior of the drug, and the test preparation is bioequivalent with the reference preparation. There was no significant difference in ρ_max and AUC_0→t.

The application of computer simulations and PAMPA can provide evidence for the biowaiver study of bisoprolol fumarate tablets.

To compare the difference of immune response induced by egg-based and cell-based H1N1 influenza vaccines.

C57BL/6 mice were injected subcutaneously with H1N1 influenza vaccines produced from eggs or MDCK cells, respectively. The cellular and humoral immune responses induced by two type of vaccines were detected by using methods such as serological test, intracellular cytokine staining and multiplex cytokine detection assay.

In terms of humoral immunity, the serum titer of the cellular vaccine group was basically the same as that of the chicken embryo vaccine group. As to cellular immunity, the secretion level of immune-related cytokines in the cellular vaccine group was more significant.

Due to the different culture media, the two monovalent influenza vaccines have certain differences in the induction of immune response. Cellular vaccine has the advantage of inducing multiple immune responses, and the combination of other advantages of cellular technology indicates that the use of cellular technology will become a trend to produce influenza vaccine. This study is helpful to evaluate the immune level in mice induced by monovalent influenza vaccines prepared with different substrates.

To investigate the effects of five missing components in the Decoction of Wuling Powder on astrocyte edema and aquaporin4 (AQP4) expression after oxygen glucose deprivation and reoxygenation.

Astrocytes were divided into normal group, model group, cinnamaldehyde (CIN) group, alisol B 23-acetate (ALB) group, ergosterol (ERG) group, pachymic acid (PA) group, atractylenolide Ⅰ (ATR) group, medicinal chemical composition (MCC) group and ozagrel (ozagrel, OZA) group. MTT method was used to evaluate the drug's inhibitory rate on the cells, the lactate dehydrogenase (LDH) leakage rate was used to reflect the degree of cell damage, and Western blot method was used to determine the expression change of AQP4.

After 2 hours of oxygen glucose deprivation and 6 hours of reoxygenation, the LDH leakage rate was significantly increased (P<0.01). ALB at a concentration of 10 μg·mL^-1, PA and ATR at 0.01 μg·mL^-1, and MCC at 0.1 μg·mL^-1 could significantly reduce the increase in the leakage rate of reoxygenation LDH after oxygen glucose deprivation (P<0.01). The expression of AQP4 under oxygen and glucose deprivation and reoxygenation conditions showed significant differences among the groups. Compared with the normal group, the expression of AQP4 in the model group was significantly increased after oxygen glucose deprivation under reoxygenation conditions (P<0.01). Compared with the model group, the expression trends of AQP4 in the CIN, ALB, ERG, PA, ATR and MCC groups under reoxygenation conditions after oxygen glucose deprivation were similar, but the AQP4 protein expressions in the CIN, ALB, ERG, PA, ATR, and MCC groups were all significantly reduced (P<0.01).

The five main missing components in the decoction of Wuling Powder can significantly reduce the astrocyte edema after 2 hours of oxygen deprivation and 6 hours of reoxygenation, which may be related to the decrease of AQP4 protein expression level.

To explore the protective effect of fermented Cordyceps Sinensis powder (Cs-4) on renal function of diabetic kidney disease rats and preliminarily investigate the mechanism.

The rat model of diabetic kidney disease was replicated by high-sugar and high-fat diet feeding combined with intraperitoneal injection of streptozotocin (40 mg·kg^-1). The model rats were randomly divided into model group, low (300 mg·kg^-1), medium (600 mg·kg^-1) and high dose (1 200 mg·kg^-1) of Cs-4 groups and positive drug group (irbesartan, 15 mg·kg^-1). At the same time, the normal group (receiving ordinary diet) and the high-sugar and high-fat groups (receiving high-sugar and high-fat diet) were set up, and they were given intraperitoneal injection of the same dose of citrate buffer. Rats in each group were administered by intragastric (ig) administration once a day for 8 consecutive weeks. At the end of the experiment, urine was collected within 24 hours, and the fasting plasma glucose level was measured. Serum and kidney were collected, and kit method was used to detect blood urea nitrogen, serum creatinine, superoxide dismutase, malondialdehyde, total cholesterol, triglycerides, low density lipoprotein, high density lipoprotein, interleukin 6, interleukin 8, tumor necrosis factor α, high sensitivity c-reactive protein, free fatty acid, glycated serum protein, monocyte chemotactic protein 1, transforming growth factor β1 in serum and urinary creatinine, urinary protein, microalbuminuria content of rats in each group, and pathological and morphological changes of kidney tissue were observed by hematoxylin-eosin staining.

Compared with the model group, all dose groups of Cs-4 reduced kidney weight, kidney weight/body weight ratio, fasting plasma glucose, blood urea nitrogen, serum creatinine, urinary protein, microalbuminuria, total cholesterol, and low density lipid, malondialdehyde, interleukin 6, interleukin 8, tumor necrosis factor α, high-sensitivity c-reactive protein, free fatty acids, glycated serum protein, monocyte chemotactic protein 1, transforming growth factor β1 levels and increased body weight, urinary creatinine, creatinine clearance rate, high density lipoprotein, and superoxide dismutase levels to varying degrees (P<0.05, P<0.01), and the high-dose group of Cs-4 had a more significant effect, and could improve the morphological damage of kidney tissue to varying degrees.

Cs-4 has a certain protective effect on kidney damage in diabetic kidney disease rats, and its mechanism may be related to reducing blood glucose, regulating blood lipids, improving oxidative stress and inflammation levels, and inhibiting the degree of renal fibrosis.

To obtain a series of multi-target inhibitors with better anti-inflammatory activity by using 1-benzoyl-4-(phenoxyacetyl) piperazine as the lead compound followed by further structure optimization.

Substituted benzoic acid was used as a starting material, and 18 target compounds were synthesized through substitution and acylation reactions. The inhibitory effects of all compounds on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α and interleukin (IL)-6 secretion in RAW264.7 cells were measured, and molecular docking was performed on the compounds with better anti-inflammatory activity.

The structures of all the compounds were confirmed by ¹H NMR, ¹³C NMR and HRMS. Compounds 3d and 8k demonstrated better inhibitory activity on TNF-α secretion, and compounds 3b and 3d showed better inhibitory activity on IL-6 secretion.

Compound 3d has good inhibitory activity on TNF-α and IL-6 secretion in RAW264.7 cells induced by LPS, and is worthy of further study.

To identify the potential impurities generated during manufacturing of recombinant Arg³⁴-GLP-1 [7-37].

After fermentation, the broth extract was analyzed by HPLC, then the main product Arg³⁴-GLP-1 [7-37] and impurities were separated and purified by ion exchange chromotography and preparative HPLC respectively. The main product was treated by extreme conditions such as high temperature, acid and alkali experiments in order to figure out how the impurities were generated. MALDI-TOF, protein sequencing and other methods were used to identify the structures of impurities.

The purity of the main product reached 97.9% after purification by anion exchange chromatography and preparation of liquid phase. Three main impurities were isolated and purified to 91.4%, 99.2%, and 96.7%. Their MWs of [M+H]⁺ were 1 033.544 6, 2 744.239 7, and 3 112.447 5 as determined by MALDI-TOF. Through the destructive test and the amino acid sequences of Arg³⁴-GLP-1 [7-37] it was speculated that the possible sequences of impurity 1, impurity 3, and impurity 9 may be E-F-I-A-W-L-V-R, H-A-E-G-T-F-T-S-D-V-S-S-Y-L-E-G-Q-A-A-K-E-F-I-A-W, H-A-E-G-T-F-T-S-D-V-S-S-Y-L-E-G-Q-A-A-K-E-F-I-A-W-L-V-R. Comparison of the components before and after purification showed that the above three main impurities were generated by the fermentation process, and the contents of these impurities would increase significantly by extreme conditions. The structure analysis and mechanism investigation of the three impurities analyzed in this study were all published for the first time.

Since recombinant Arg³⁴-GLP-1 [7-37] is unstable in high temperature, peracid and alkali, and oxidizing environments, care should be taken to avoid these conditions in order to prevent degradation of the main product during purification. This paper shows some pitfalls to avoid for the research of GLP-1 and its analogs peptides.