Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “BIOPHARMACEUTICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 775 records · Page 43Linked to original sources
PubMed1994

The molecular biology of production cell lines.

The emergence of a wide variety of biological expression systems for the large-scale production of therapeutic proteins has shifted the focus from vectors to host organisms. Although expression systems now span bacteria, fungi, plants, insects, and mammalian cells, the vast majority of recombinant-derived biopharmaceuticals at the present time have been produced in Escherichia coli and in mammalian cells. This promises to change as the economic benefits of the newer systems permit the development of a new generation of proteins heretofore considered unfeasible for commercial development. Despite the impressive results which have been observed for many of the newer systems, there are many commercial considerations which suggest that E. coli and CHO cell expression systems may continue to dominate the manufacture of biopharmaceuticals for a long time to come.

Animals↗
PubMed1991

The use of particle concentration fluorescence immunoassay technology for the analysis of rDNA products.

The electrophoretic and immunological techniques typically used to detect potentially useful biopharmaceutical proteins are sensitive with detection limits in the nanogram range. However, quantitation of a recombinant protein can be cumbersome, and involve large numbers of samples throughout process optimization schemes. Although electrophoretic methods (i.e., SDS-PAGE and Western blots) now avail themselves to quantitation by densitometry, these techniques are time consuming because of the lack of appropriate automated systems. Biological activity assays, when available, often require relatively pure material and are not suitable for analyzing and quantitating impure or semi-purified samples, typical of the fermentation milieu. The optimization of several rDNA-derived protein systems from both prokaryotic and eukaryotic hosts has been completed using PCFIA, a rapid, sensitive system with high throughput. The development of Particle Concentration Fluorescence Immunoassay (CFIA) procedures for several of these rDNA-derived proteins of interest as potential biopharmaceuticals (e.g., alpha-1-antitrypsin, tPA, soluble CD4, and a malaria vaccine candidate) are discussed.

Binding, Competitive↗
PubMed2002

The review of drug applications submitted to the European Medicines Evaluation Agency: frequently raised objections, and outcome.

OBJECTIVE: To study the issues raised during the review of drug applications submitted to the European Medicines Evaluation Agency for approval in the European Union and to identify important predictors of outcome. METHODS: All consecutive applications submitted since September 1997 and which had reached an outcome by May 2001 were included. The factors considered in this exploratory analysis were: year of submission, anatomical therapeutic chemical classification (ATC code), type of medicinal product (biopharmaceuticals vs. new chemical entities), and common "major objections" raised during the review. Predictors were identified using multivariate logistic regression on outcome (positive opinion vs. negative opinion or withdrawal). Examples have been provided to illustrate some of the weaknesses of the applications received, the types of objections raised by the reviewers, and the strategies used to address them. RESULTS: This series consisted of 111 successive applications for which the review had started between September 1997 and April 2000. It included 73 (66%) new chemical entities and 38 (34%) biopharmaceuticals, the most represented agents being anti-neoplastic and immunomodulating agents, and anti-infectives for systemic use, with 25 (22%), and 19 (17%) applications, respectively. Overall the proportion of drug applications that failed to reach a positive outcome was 32/111 (29%). The most frequent major objections raised were those related to the safety database and to serious adverse events. These clinical safety objections were raised in 54 (48.6%) applications. Another frequent objection was the clinical efficacy objection on the lack of adequate randomised controlled trials, which was raised in 47 (42.3%) applications. This clinical efficacy objection was the only factor that was retained after multivariate selection (P<0.01). The odds of a positive outcome for an application lacking adequate randomised controlled trials were: 0.46 (95% confidence interval 0.29-0.71) times the odds of an application without this objection (P=0.0006). CONCLUSIONS: Despite the existence of various mechanisms that allow important deficiencies to be resolved, failure to establish clinical efficacy due to the lack of adequate randomised controlled trials remained problematic, leading to a high risk of rejection.

Clinical Trials as Topic↗
PubMed2005

Stabilization and improved in vivo performance of amorphous etoricoxib using Gelucire 50/13.

PURPOSE: Amorphous drugs have gained importance because of their advantageous biopharmaceutical properties; however, their stabilization remains a challenge. The purpose of this work was to stabilize the amorphous form of etoricoxib (ET) by using a low excipient/drug ratio to improve drug dissolution and thus bioavailability. METHODS: The effect of Gelucire and polyvinylpyrrolidone (PVP) on stabilization and bioavailability of amorphous etoricoxib (AET) was studied. X-ray powder diffractometry, differential scanning calorimetry, and scanning electron microscopy were used to study the physical state of the drug. Dissolution studies were performed for melt granules of AET with Gelucire 50/13 (MG-AET) and solid dispersion with PVP (SDP) to differentiate dissolution performance. A stability study on samples was conducted for 3 months to evaluate the physical state of the drug and its dissolution in the formulation. The in vivo performance of the optimized and stable formulation of ET was evaluated in rat. RESULTS: Dissolution of MG-AET was significantly improved as compared to AET and SDP. Both factors, amorphization of drug and melt granulation with lipid, seemed to be important for improving dissolution. Stability data revealed that MG-AET was significantly advantageous for AET stabilization, whereas PVP was not. The amount of Gelucire required for the stabilization of one part of AET was 0.5 part (by weight), whereas even 1.5 part (by weight) of PVP failed to elicit the same result. The superior in vivo performance of MG-AET has been attributed to the altered physiochemical properties of AET and the presence of lipid in the system. CONCLUSION: Gelucire can stabilize AET and improve its biopharmaceutical performance at a low excipient/drug ratio and may provide a better alternative to conventional stabilizers such as PVP.

Animals↗
PubMedDate not supplied

Influence of fragment size on DNA quantitation using DNA-binding proteins and a sensor-based analytical system: applications in the testing of biological products.

A novel immunoassay system which rapidly quantifies picogram levels of total DNA was characterized with respect to the effects of DNA length. Nine chromatographically purified HaeIII restriction fragments of phi X174 were tested. Assay performance was found to be dependent on both the amount and length of DNA present in the sample. DNA fragments longer than 100 base pairs (bp) could be quantitatively detected with this system. Fragments shorter than 100 bp inhibited assay performance and thus could be detected through the use of inhibition studies; however, only qualitative information could be obtained. DNA fragments approximately 10 nucleotides in length had no apparent effect on assay performance. The size of the binding site (number of bases) required for each DNA-binding protein to bind to a nucleic acid fragment is suggested as an explanation for the observed influence of DNA size on assay performance. The total DNA assay was used in conjunction with a Pharmacia FPLC system to characterize the size distribution and amount of DNA in two partially purified biopharmaceutical samples. The results indicate that the majority of residual DNA in these samples is less than 600 bp in length. This technique can be used to rapidly determine the DNA size distribution in an in-process or final product biopharmaceutical sample. This data can then be used in process design and optimization for removal of residual DNA in biological products.

Animals↗
PubMed2004

Development of a PCR method for mycoplasma testing of Chinese hamster ovary cell cultures used in the manufacture of recombinant therapeutic proteins.

Chinese hamster ovary (CHO) cell cultures used to produce biopharmaceuticals are tested for mycoplasma contamination as part of the ensurance of a safe and pure product. The current U.S. Food and Drug Administration (FDA) regulatory guideline recommends using two procedures: broth/agar cultures and DNA staining of indicator cell cultures. Although these culture methods are relatively sensitive to most species, theoretically capable of detecting as few as 1-10 cfu/ml of most species, the overall procedure is lengthy (28 d), costly and less sensitive to noncultivable species. The detection of mycoplasma using the polymerase chain reaction (PCR) method has been considered an alternative method because it is relatively fast (1-2 d), inexpensive, and independent of culture conditions, however, limitations in sensitivity (limit of detection >/=1000 cfu/ml) and the risk of false positive and false negative results have prevented PCR from replacing the traditional culture methods in the industrial setting. In this report, we describe a new PCR assay for mycoplasma detection that appears to resolve these issues while being sufficiently simple and inexpensive for routine use. This assay applies readily available techniques in DNA extraction together with a modified single-step PCR using a previously characterized primer pair that is homologous to a broad spectrum of mycoplasma species known to infect mammalian cell cultures. Analysis is made easy by the detection of only a single amplification product within a narrow size range, 438-470 bp. A high sensitivity and specificity for mycoplasma detection in CHO cell production cultures is made possible through the combination of three key techniques: 8-methoxypsoralen and UV light treatment to decontaminate PCR reagents of DNA; hot-start Taq DNA polymerase to reduce nonspecific priming events; and touchdown- (TD-) PCR to increase sensitivity while also reducing nonspecific priming events. In extracts of mycoplasma DNA, the limit of detection for eight different mycoplasma species is 10 genomic copies. In CHO cell production cultures containing gentamicin, the limit of detection for a model organism, gentamicin-resistant M. hyorhinis, is 1 cfu/ml. The sensitivity and specificity of this PCR assay for mycoplasma detection in CHO cell production cultures appear similar to the currently used culture methods and thus should be considered as an alternative method by the biopharmaceutical industry.

Animals↗
PubMed2006

CJD PrPsc removal by nanofiltration process: application to a therapeutic immunoglobulin solution (Lymphoglobuline).

The characteristic of transmissible spongiform encephalopathies (TSE) is an accumulation of partially protease resistant (PrP(res)) abnormal prion protein (PrP(sc)). This pathological prion protein is very resistant to conventional inactivation methods. The risk of transmission of TSE, such as Creutzfeldt-Jakob disease (CJD), by biopharmaceutical products prepared from human cells must be taken into account. The nanofiltration process has been proved to be effective in removing viruses and scrapie agent. The major advantages of this technique are flexibility and efficacy in removing infectious particles without altering biopharmaceutical characteristics and properties. This study focused on the removal of human PrP(sc) by means of a nanofiltration method after spiking a Lymphoglobuline solution with a CJD brain homogenate. Lymphoglobuline equine anti-human thymocyte immunoglobulin is a selective immunosuppressive agent acting mainly on human T lymphocytes. The therapeutic indications are: immunosuppression for transplantation: prevention and treatment of graft rejection; treatment of aplastic anemia. In our study, CJD homogenate was spiked at three different dilutions (low, moderate and high) in the Lymphoglobuline product. The nanofiltration process was performed on each sample. Using the western blot technique, the PrP(res) signal detected in nanofiltrates was compared to that obtained with a reference scale (dilution series of CJD brain homogenate in Lymphoglobuline detected by western blot and elaborated on 3.3 log). After nanofiltration, the PrP(res) western blot signal was detected with a significant reduction in the less dilute sample, whereas the signal was undetectable in the two other samples. These are the first data in CJD demonstrating a clearance between 1.6 and 3.3 log with a Lymphoglobuline recovery of over 93%. The nanofiltration process confirms its relative efficacy in removing human CJD PrP(sc).

Animals↗
PubMed2004

Influence of physicochemical properties and intestinal region on the absorption of 3-fluoro-2-pyrimidylmethyl 3-(2,2-difluoro-2-(2-pyridyl)ethylamino)-6-chloropyrazin-2-one-1-acetamide, a water insoluble thrombin inhibitor, in dogs.

In this paper, we describe the physicochemical and biopharmaceutical properties of 3-fluoro-2-pyrimidylmethyl 3-(2,2-difluoro-2-(2-pyridyl)ethylamino)-6-chloropyrazin-2-one-1-acetamide, a direct thrombin inhibitor (1, Fig. 1). Three crystalline forms were characterized and studies were planned to investigate the absorption characteristics of the three selected crystalline forms. Due to the short half-life observed in preclinical species, regional absorption studies were also conducted to support potential controlled release formulation development. Results showed that the absorption of 1 was dependent on the surface area of the particles administered as suspensions and was independent of the crystal forms. From Caco-2 cell transport studies, it was determined that the permeability of 1 was high. Based on the low aqueous solubility it would be classified as a class 2 compound in the Biopharmaceutics Classification System. Regional absorption results suggested that the compound was absorbed along the gastrointestinal tract in Beagle dogs, however colonic absorption appeared to be reduced by slower dissolution.

Acetamides↗
PubMed2004

Adenoviral vector mediates high expression levels of human growth hormone in the milk of mice and goats.

The production of large quantities of complex proteins with biopharmaceutical purposes is the main drawback for their more extensive use. Here we demonstrated that a direct instillation of a recombinant adenoviral vector containing an expression cassette for the human growth hormone gene into the mammary gland of mice and goats allowed for the efficient secretion of human growth hormone in the milk. Through this approach we were able to express human growth hormone at maximal levels of 2.8 mg/ml in the milk of mice and up to 0.3 mg/ml in goat milk. We found that the expression levels were closely dependent on both the degree of differentiation of the secretory epithelium and on the adenoviral dose used. Here we demonstrated that the direct transduction of mammary epithelial cells by means of a recombinant adenovirus could be a suitable alternative to transgenic technology for the production of recombinant proteins of biopharmaceutical interest.

Adenoviridae↗
PubMed2006

Role of antioxidants in prophylaxis and therapy: A pharmaceutical perspective.

Antioxidants are emerging as prophylactic and therapeutic agents. These are the agents, which scavenge free radicals otherwise reactive oxygen species and prevent the damage caused by them. Free radicals have been associated with pathogenesis of various disorders like cancer, diabetes, cardiovascular diseases, autoimmune diseases, neurodegenerative disorders and are implicated in aging. Several antioxidants like SOD, CAT, epigallocatechin-3-O-gallate, lycopene, ellagic acid, coenzyme Q10, indole-3-carbinol, genistein, quercetin, vitamin C and vitamin E have been found to be pharmacologically active as prophylactic and therapeutic agents for above mentioned diseases. Antioxidants are part of diet but their bioavailability through dietary supplementation depends on several factors. This major drawback of dietary agents may be due to one or many of the several factors like poor solubility, inefficient permeability, instability due to storage of food, first pass effect and GI degradation. Conventional dosage forms may not result in efficient formulation owing to their poor biopharmaceutical properties. Principles of novel drug delivery systems need to be applied to significantly improve the performance of antioxidants. Novel drug delivery systems (NDDS) would also help in delivery of these antioxidants by oral route, as this route is of prime importance when antioxidants are intended for prophylactic purpose. Implication of NDDS for the delivery of antioxidants is largely governed by physicochemical characteristics, biopharmaceutical properties and pharmacokinetic parameters of the antioxidant to be formulated. Recently, chemical modifications, coupling agents, liposomes, microparticles, nanoparticles and gel-based systems have been explored for the delivery of these difficult to deliver molecules. Results from several studies conducted across the globe are positive and provided us with new anticipation for the improvement of human healthcare.

Administration, Oral↗
PubMed2006

Competitive bioreactor hens on the horizon.

The hen has long held promise as a low-cost, high-yield bioreactor for the production of human biopharmaceuticals in egg whites using genetic engineering. Two separate reports have recently appeared indicating the production of substantial levels of human monoclonal and single chain antibodies (>3 mg and >150 mg, respectively) in eggs of transgenic hens. These promising findings indicate that the hen is close to becoming a competitive manufacturing platform for the production of human biopharmaceuticals.

Animals↗
PubMed2006

A genetic redox sensor for mammalian cells.

Nutrient and oxygen availability are key metabolic parameters for biopharmaceutical manufacturing. In order to enable mammalian cells to manifest their intracellular nutrient and oxygen levels we engineered a genetic sensor circuitry which converts signals impinging on the cellular redox balance into a robust reporter gene expression readout. Capitalizing on the Streptomyces coelicolor redox control system, consisting of REX modulating ROP-containing promoters in an NADH-dependent manner, we designed a mammalian dual sensor transcription control system by fusing REX to the generic VP16 transactivation domain of Herpes simplex, which reconstitutes an artificial transactivator (REDOX) able to bind and activate chimeric promoters assembled by placing a ROP operator module 5' of a minimal eukaryotic promoter (P(ROP)). When nutrient levels were low and resulted in depleted NADH pools REDOX-dependent P(ROP)-driven expression of secreted (human-secreted alkaline phosphatase; SEAP) or intracellular (Renilla reniformis luciferase; rLUC) reporter genes was high as a consequence of increased REDOX-P(ROP) affinity. Conversely, at hypoxic conditions leading to high intracellular NADH levels, strongly reduced REDOX-P(ROP) interaction mediated low-level transgene expression in Chinese hamster ovary (CHO-K1) cells. Other molecules (for example, 2,4-dinitrophenol, cyanide or hydrogen peroxide) which are known to imbalance the intracellular NADH/NAD+ poise could also be detected using the REDOX-P(ROP) sensor circuitry. REDOX's sensor capacity (nutrient and oxygen levels) operated seamlessly in transgenic CHO-K1 cell derivatives adapted for growth in serum-free suspension cultures and enabled precise monitoring of the population's metabolic state. As the first genetic metabolic sensor designed for mammalian cells, REDOX may foster advances in process development and biopharmaceutical manufacturing.

Animals↗
PubMed1999

Setting bioequivalence requirements for drug development based on preclinical data: optimizing oral drug delivery systems.

The recently proposed Biopharmaceutics Classification System can be used to classify drugs and set standards for scale-up and post-approval changes as well as standards for in vitro/in vivo correlation for immediate and controlled release products. This classification scheme is based on determining the underlying process that is controlling the drug absorption rate and extent, namely, drug solubility and intestinal membrane permeability. Theoretical analysis and experimental results suggest that a permeability/solubility classification scheme can be used to set more rationale drug standards. In particular, high solubility/high permeability, rapidly dissolving drugs may be regulated on the basis of a single point rapid dissolution test while low solubility dissolution rate limited drugs can be regulated based on an in vitro dissolution test that reflects the in vivo dissolution process. This dissolution test may include multiple time points, media change, as well as surfactants in order to reflect the in vivo dissolution process and would be used by the manufacturer for requesting a waiver from a bioequivalence (BE) trial. For controlled release products, the regulation of bioequivalence standards is more complex due to the potential differences in position-dependent permeability/solubility and metabolism of drugs along the gastrointestinal tract. These differences may result in drug absorption rates that are highly transit time dependent. This paper will present the current status of the biopharmaceutic drug classification scheme, the underlying developed data base and its application to optimizing IR and CR products.

Administration, Oral↗
PubMed2000

New clinical applications of transdermal testosterone delivery in men and women.

This paper reviews recent progress in the development and clinical application of testosterone transdermal delivery systems designed for physiological replacement therapy in men and women. The biopharmaceutic goal of physiologic replacement therapy is to produce serum levels and circadian patterns of testosterone and its active metabolites that mimic the normal physiology of testosterone in the particular target population. For the treatment of adult hypogonadal men, the nightly 24 h application of the Androderm testosterone transdermal system (5 mg per day) achieves this goal - as demonstrated in a series of clinical pharmacokinetic studies. For the treatment of adolescent males, physiologic replacement can be approximated by modifying the dose and duration of Androderm application so as to mimic the patterns of nocturnal testosterone secretion observed during puberty. With the objective of providing physiological replacement for women with diminished testosterone production, an experimental testosterone matrix transdermal system (TMTDS) has been developed and is currently undergoing clinical evaluation. In parallel with the development of testosterone transdermal systems, physicians have been investigating a number of conditions, in both males and females, where testosterone production is diminished and replacement therapy may be beneficial. Three of these new clinical applications will be illustrated - the use of Androderm for the treatment of adolescent males with beta-thalassemia, the use of Androderm for the treatment of HIV+ men, and the use of the TMTDS for the treatment of HIV+ women. From the biopharmaceutic and clinical perspectives, the development of testosterone transdermal systems represents an important achievement in controlled drug delivery.

Administration, Cutaneous↗
PubMed2001

Predicting the impact of physiological and biochemical processes on oral drug bioavailability.

Recent advances in computational methods applied to the fields of drug delivery and biopharmaceutics will be reviewed with a focus on prediction of the impact of physiological and biochemical factors on simulation of gastrointestinal absorption and bioavailability. Our application of a gastrointestinal simulation for the prediction of oral drug absorption and bioavailability will be described. First, we collected literature data or we estimated biopharmaceutical properties by application of statistical methods to a set of 2D and 3D molecular descriptors. Second, we integrated the differential equations for an advanced compartmental absorption and transit (ACAT) model in order to determine the rate, extent, and approximate gastrointestinal location of drug liberation (for controlled release), dissolution, passive and carrier-mediated absorption, and saturable metabolism and efflux. We predict fraction absorbed, bioavailability, and C(p) vs. time profiles for common drugs and compare those estimates to literature data. We illustrate the simulated impact of physiological and biochemical processes on oral drug bioavailability.

Animals↗
PubMed2000

Safety of recombinant and plasma-derived medicinals for the treatment of coagulopathies.

The introduction of advanced technologies (PCR testing, chromatography, and specific viral inactivation and removal techniques) has led to remarkable improvements in the quality and efficacy of biopharmaceutical products. The current safety strategies for both recombinant protein and PDP products depend on the extensive screening of the source material for infectious agents and the use of mild purification methods, specific mild viral-reduction techniques, GMP, QC, and QA. An appropriate system of pharmacologic vigilance is also an integral element for assuring product quality and safety in the marketplace. Such precautions make available high quality therapeutic recombinant proteins and PDP products. The risks in the clinical setting and the cost/benefit ratio must be considered in choosing a product for therapeutic use. The choice should be based on the analysis of data available for a specific product, because some variations in quality and safety can be observed in different brands. Overall, a much finer control of infectious risks has been achieved, and improvement will continue. With the new products, thrombotic episodes have become rare. Reducing immunogenic potential and improving yield to increase product supply could be the next challenges for producers of biopharmaceuticals.

Animals↗
PubMed2001

Prediction of drug transport processes using simple parameters and PLS statistics. The use of ACD/logP and ACD/ChemSketch descriptors.

A method of modelling and predicting biopharmaceutical properties using simple theoretically computed molecular descriptors and multivariate statistics has been investigated for several data sets related to solubility, IAM chromatography, permeability across Caco-2 cell monolayers, human intestinal perfusion, brain-blood partitioning, and P-glycoprotein ATPase activity. The molecular descriptors (e.g. molar refractivity, molar volume, index of refraction, surface tension and density) and logP were computed with ACD/ChemSketch and ACD/logP, respectively. Good statistical models were derived that permit simple computational prediction of biopharmaceutical properties. All final models derived had R(2) values ranging from 0.73 to 0.95 and Q(2) values ranging from 0.69 to 0.86. The RMSEP values for the external test sets ranged from 0.24 to 0.85 (log scale).

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2002

Bioavailability and in vitro oesophageal sticking tendency of hydroxypropyl methylcellulose capsule formulations and corresponding gelatine capsule formulations.

The overall aim of the present study was to widen our knowledge about the biopharmaceutical behaviour of novel hydroxypropyl methylcellulose (HPMC)-based two-piece capsules by comparing them with the classic hard gelatine capsules. Firstly, the tendency of the HPMC capsules to stick to isolated porcine oesophageal preparation was evaluated. The force needed to detach the HPMC capsules from the oesophagus was significantly lower than that for the gelatine capsules (P<0.001), which is evidently an advantage of this new dosage form. The second aim was to investigate the possibility of preparing sustained-release capsules using different powdered HPMCs as diluents (K100, K4M and K15M) and the effect of the molecular weight of HPMC powder on the in vitro and in vivo behaviour of the capsules. In addition to peroral drug administration also rectal dosing was applied. Two groups of eight healthy volunteers participated in randomised, cross-over, single-dose studies. One group was administered capsules orally and the other rectally. There were no marked differences in the bioavailability properties of either the oral or rectal HPMC capsules containing ibuprofen as model drug as compared with corresponding gelatine capsule formulations. Using different viscosity grades of HPMC powders as diluents it was possible to control the absorption rate of the model drug both from gelatine and HPMC capsules as far as the oral route was concerned. After rectal administration there were no statistically significant differences between the formulations containing different grades of HPMC powder. Only partial correlation was observed between the results of the bioavailability studies and the in vitro dissolution studies. From a biopharmaceutical point of view these two shell materials can be regarded as interchangeable.

Administration, Oral↗