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PubMed2004

Heavy metal content of ayurvedic herbal medicine products.

CONTEXT: Lead, mercury, and arsenic intoxication have been associated with the use of Ayurvedic herbal medicine product (HMPs). OBJECTIVES: To determine the prevalence and concentration of heavy metals in Ayurvedic HMPs manufactured in South Asia and sold in Boston-area stores and to compare estimated daily metal ingestion with regulatory standards. DESIGN AND SETTING: Systematic search strategy to identify all stores 20 miles or less from Boston City Hall that sold Ayurvedic HMPs from South Asia by searching online Yellow Pages using the categories markets, supermarkets, and convenience stores, and business names containing the word India, Indian cities, and Indian words. An online national directory of Indian grocery stores, a South Asian community business directory, and a newspaper were also searched. We visited each store and purchased all unique Ayurvedic HMPs between April 25 and October 24, 2003. MAIN OUTCOME MEASURES: Concentrations (microg/g) of lead, mercury, and arsenic in each HMP as measured by x-ray fluorescence spectroscopy. Estimates of daily metal ingestion for adults and children estimated using manufacturers' dosage recommendations with comparisons to US Pharmacopeia and US Environmental Protection Agency regulatory standards. RESULTS: A total of 14 (20%) of 70 HMPs (95% confidence interval, 11%-31%) contained heavy metals: lead (n = 13; median concentration, 40 microg/g; range, 5-37,000), mercury (n = 6; median concentration, 20,225 microg/g; range, 28-104,000), and/or arsenic (n = 6; median concentration, 430 microg/g; range, 37-8130). If taken as recommended by the manufacturers, each of these 14 could result in heavy metal intakes above published regulatory standards. CONCLUSIONS: One of 5 Ayurvedic HMPs produced in South Asia and available in Boston South Asian grocery stores contains potentially harmful levels of lead, mercury, and/or arsenic. Users of Ayurvedic medicine may be at risk for heavy metal toxicity, and testing of Ayurvedic HMPs for toxic heavy metals should be mandatory.

Arsenic↗
PubMed2002

Products of the determination of the iodine value with iodine monobromide.

The iodine value (iodine number) is an important analytical characteristic of fats and oils. Leading pharmacopeias determine it using iodine monobromide (Hanus method). We used methyl oleate as a simple analog of unsaturated triacylglycerols to identify the products. After performing the reaction in deuterated solvents under pharmacopeial conditions, NMR spectroscopy revealed the presence of the 9, 10-diiodo, 9, 10-dibromo, and 9, 10-bromoiodo adducts, leaving no educt olefin. The prescribed subsequent addition of potassium iodide led to the formation of methyl 9, 10-diiodo and bromoiodo stearate in equal amounts.

Bromides↗
PubMed1994

The bioavailability of diclofenac from enteric coated products in healthy volunteers with normal and artificially decreased gastric acidity.

The relative bioavailability of four monolithic enteric coated (MEC) diclofenac products was compared in 16 healthy volunteers. Only one generic product was fully bioequivalent with the reference product Voltaren with regard to AUC, Cmax, and tlag. Two products showed significant differences in tlag. In a second experiment with eight volunteers the influence of increased gastric pH (ranitidine treatment) on the two mutually most differing products was studied. They showed equivalence in AUC, but not in Cmax. Analysis of tlag suggests that the product with the low tlag disintegrates within the non-acid stomach, whereas the product with the long tlag passes the non-acid stomach intact. Several in vitro dissolution tests were conducted. The European Pharmacopeia test did not detect any differences between the products. At pH 5, both with and without mechanical stress, only the product with the shortest tlag released diclofenac. The in vivo results were best predicted by the in vitro dissolution tests performed at several fixed pH values with mechanical stress.

Adolescent↗
PubMed2005

Glycoform characterization of intact erythropoietin by capillary electrophoresis-electrospray-time of flight-mass spectrometry.

Glycosylated proteins often show a large variation in their glycosylation pattern, complicating their structural characterization. In this paper, we present a method for the accurate mass determination of intact isomeric glycoproteins based on capillary electrophoresis-electrospray-time of flight-mass spectrometry. Human recombinant erythropoietin has been chosen as a showcase. The approach enables the on-line removal of nonglycosylated proteins, salts, and neutral and negatively charged species. More important, different glycosylation forms are separated both on the base of differences in the number of negatively charged sialic acid residues and the size of the glycans. Thus, 44 glycoforms and in total about 135 isoforms of recombinant human erythropoietin, taking also acetylation into account, could be distinguished for the reference material from the European Pharmacopeia. Distinct glycosylation differences for samples from different suppliers are clearly observed. Based on the accurate mass an overall composition of each single isoform is proposed, perfectly in agreement with data on glycan and glycopeptide analysis. This method is an ideal complement to the established techniques for glycopeptide and glycan analysis, not differentiating branching or linkage isoforms, but leading to an overall composition of the glycoprotein. The presented strategy is expected to improve significantly the ability to characterize and quantify isomeric glycoforms for a large variety of glycoproteins.

Doping in Sports↗
PubMed2004

Comorbidity in bipolar disorder: a framework for rational treatment selection.

Bipolar disorders are heterogeneous disorders often requiring multimodality treatment. The expanding pharmacopeia for bipolar disorders invites the need for a treatment framework that both recognizes and anticipates the multidimensionality and comorbidity of the illness. No available neurotherapeutic agent is singularly efficacious for the complete mélange of bipolar symptomatology. An apparent paradox has emerged in the management of bipolar disorder; whilst results from rigorous controlled monotherapy trials suggest that a disparate assortment of neurotherapeutic agents are efficacious in distinct phases of bipolar disorder, the majority of tertiary-treated bipolar patients receive polypharmacotherapeutic regimens. The evidentiary base for polypharmacotherapy is sparse and has recently become an area of active research focus. In the interim, clinicians are encouraged to invoke an organizational schema for the treatment of bipolar disorder that considers the spectrum of effectiveness of putative and established mood stabilizers. This schema should be further informed by the treatment data for comorbid and accessory conditions. The authors propose a schema to provide the impetus for further work in the area.

Antimanic Agents↗
PubMed1995

An individualized approach to the hypertensive patient with renal disease: six illustrative case studies.

One of the biggest challenges in medicine is the area of therapeutics, wherein the physician attempts to match the needs of the individual patient with a specific agent from the pharmacopeia, at the dose that might be best suited to treat the individual's problem. A great deal of the art of medicine is involved in this "matching process," in which the scientific aspects of diagnosis and therapy meet with the physician's knowledge of clinical pharmacology. The abbreviated case histories of six patients who came to the author with specific questions regarding therapy of their hypertension and renal impairment illustrate the fact that one of any number of therapies might have reduced blood pressure in these patients, but in each, there was a specific reason to attempt a single approach first. If physicians could better understand and extrapolate the results of clinical research to the treatment of specific patients, choice of therapy might become more successful.

Adrenergic alpha-Antagonists↗
PubMed1994

Evaluation of absorbable poly(ortho esters) for use in surgical implants.

Recent reports describe an unfavorable noninfective inflammatory response to acidic degradation products in clinical applications of bone fixation devices fabricated from bulk hydrolyzing polyglycolides and polylactides (PGA and PLA). The work described here suggests that poly(ortho esters) (POEs) offer an alternative. By comparison, hydrophobic POEs degrade predominately via surface hydrolysis, yielding first a combination of nonacidic degradation products, followed by alcoholic and acidic products gradually over time. POE specimens proved acutely nontoxic in United States Pharmacopeia tests of cellular, intracutaneous, systemic, and intramuscular implant toxicity. Hot-molded specimens degraded slowly in saline, retaining 92% initial stiffness (1.6 GPa flexion) and retaining 80% initial strength (66 MPa flexion) in 12 weeks. Degradation was almost unaffected by decreasing saline pH from 7.4 to 5.0. This demonstrated the relative hydrophobicity of POEs, since incorporation of small amounts of acid within the polymer markedly increases the degradation rate. Degradation rates were increased substantially by dynamic mechanical loading in saline. This may be true for other degradable polymers also, but no data could be found in the literature. Presumably, tensile loading opens microcracks, allowing water to enter. Solvent cast POE films were strong in tension (30 + MPa tensile yield) and reasonably tough (12-15% elongation to yield). Higher molecular weight films (41-67 kDa) showed no degradation in mechanical properties after 31 days in physiological buffer at body temperature. A 27-kDa film offered similar initial strength and stiffness but began showing mechanical degradation at 31 days. The films showed a decrease in weight with exposure time but no change in either molecular weight or water absorption at 31 days, further supporting the observation that POE degrades by surface hydrolysis rather than by bulk hydrolysis.

Animals↗
PubMed1990

In vitro properties of crosslinked, reconstituted collagen sheets.

Reconstituted, 100-microns-thick collagen sheets were crosslinked with either UV light, chromium, or cysteine for use as a burn covering. The sheets were also exposed to a "surface agent" (hydroxyproline, fibronectin, or soluble basement membrane matrix containing Type IV collagen) as a preliminary step in planned adherence studies. Since some chemicals render the collagen toxic, the modified sheets were tested for cytotoxicity using human keratinocytes and fibroblasts. Autoradiography and 3H-thymidine incorporation were used to quantitate the proliferative rate of these cells in vitro. There was a universal depression of keratinocyte incorporation of 3H-thymidine following a 1-day exposure to any collagen sheet when compared to cells not exposed to any collagen. This effect had lessened by 5 days' exposure to the collagen. Conversely, the fibroblasts the collagen. Conversely, the fibroblasts showed an enhancement in rate of incorporation after 1-day exposure, especially for cells exposed to collagen sheets cross-linked by UV light. This effect had also lessened by 5 days' exposure. Autoradiography showed few significant variations for any of the cells exposed for either time period. Chromium leaching was determined, with no values greater than 30% of the allowable maximum set by both the British and American Pharmacopeia.

Animals↗
PubMed2005

Single crystal and powder diffraction characterization of three polymorphic forms of Acitretin.

Acitretin [all-trans-9-(4-methoxy-2,3,6-trimethylphenyl)-3,7-dimethyl-2,4,6,8-nonatetraenoic acid or 3-methoxy-2-methyl-17-nor-1,2,3,4-tetradehydroretinoic acid], a widely marketed oral synthetic retinoid, introduced for clinical use as effective therapy against psoriasis, was found to crystallize in three polymorphic modifications (hereafter, I, II, and III), the crystal structures of which have been determined by single-crystal diffractometry (form I) or X-ray powder diffraction methods (form II and III) from conventional laboratory data only. In these latter cases, real space techniques (simulated annealing and whole-profile pattern matching) have been employed. Polymorph I crystallizes in space group P2(1), Z = 8, with unit cell parameters a = 7.894(1), b = 58.454(6), c = 8.161(1) angstroms, beta = 102.04(1) degrees, and V = 3682.9(8) angstroms3. Polymorph II crystallizes in space group P2(1)/n, Z = 4, with unit cell parameters a = 13.999(2), b = 10.714(1), c = 12.465(2) angstroms, beta = 98.76(5) degrees, and V = 1847.9(3) angstroms3. Polymorph III crystallizes in space group P2(1)/c, Z = 4, with unit cell parameters a = 3.0751(4), b = 4.0487(4), c = 14.956(2) angstroms, beta = 100.41(7) degrees, and V = 1831.3(4) angstroms3. Polymorph I, found to be identical with that deposited in the European Pharmacopeia, shows four crystallographically independent Acitretin molecules, arranged in pairs through conventional hydrogen-bonded carboxylic dimers; also in form II, carboxylic dimers are observed, located on crystallographic inversion centres, while in form III, a catameric arrangement of the carboxylic residues, winding up about the rather short monoclinic axis, generates one-dimensional chains of hydrogen-bonded Acitretin molecules. Thermal analysis showed that form I can be quantitatively transformed into form II by moderate heating near 200 degrees C, under vacuum. These results show that ab initio structural studies from conventional laboratory X-ray powder diffraction (XRPD) data are fully providing the opportunity to investigate the structural aspects of moderately complex substances also in the absence of single crystals, disclosing the crystal chemistry of a few polymorphs of pharmaceutically relevant species.

Acitretin↗
PubMed1983

A highly sensitive pyrogen test for antibiotics I: detection of trace amounts of endotoxin in injectable sodium ampicillin preparations.

The rabbit pyrogen test (specified in the pharmacopeia) and the Limulus amebocyte lysate (LAL) test are influenced by high concentrations of certain antibiotics. Therefore, it has not been possible to detect trace amounts of endotoxin which may contaminate these antibiotics. To detect trace amounts of endotoxin in injectable sodium ampicillin, an ultrafiltration technique was utilized which removed the antibiotic and left a solution which contained predominantly the endotoxin. After ultrafiltration, a trace amount of pyrogen (which otherwise could not be detected) was found using both the rabbit pyrogen and the LAL tests. The endotoxin was also determined quantitatively using a chromogenic endotoxin reagent which is made by combining the Limulus amebocyte lysate and a synthetic substrate with a suitable chromophore.

Ampicillin↗
PubMed1985

Preparations of agglomerated crystals of polymorphic mixtures and a new complex of indomethacin-epirizole by the spherical crystallization technique.

Agglomerated crystals of indomethacin and epirizole were prepared by the spherical crystallization technique. The solvent used was ethanol-water-chloroform, ethyl acetate-water, or ethyl acetate-aqueous sodium chloride. From the ethanol-chloroform-water system, we obtained agglomerated crystals of a polymorphic mixture of the beta form of indomethacin (original form, gamma) and amorphous epirizole. When the mole percent of epirizole loaded into the system was less than 63 and 38% for the ethyl acetate-water and ethyl acetate-aqueous sodium chloride systems, respectively, the agglomerated crystals consisted of a polymorphic mixture of the alpha form of indomethacin and amorphous epirizole. When the respective mole percent of epirizole loaded was more than 65 and 43% in the aforementioned systems, a new complex of indomethacin-epirizole (molecular ratio equal to 2:1) was obtained. Recovery of complex from the drugs loaded in the ethyl acetate-aqueous sodium chloride system was higher than that in the ethyl acetate-water system, as a result of a salting-out effect. The solubility of indomethacin in the agglomerated complex in a solution of 30% aqueous ethanol and in disintegration test solution no. 2 (composition, 0.05 M KH2PO4 plus 0.0236 M, NaOH, pH 6.8), specified in the Japanese Pharmacopeia X (JPX), was higher than in the physical mixture (molecular ratio of indomethacin to epirizole equal to 2:1). In the ethanol solution, indomethacin was transformed into the gamma form during dissolution, and a decrease in solubility occurred. The process of dissolution of the tablet of the agglomerated complex was described by zero-order kinetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Calorimetry, Differential Scanning↗
PubMed1987

Comprehensive high-performance liquid chromatographic methodology for the determination of thiothixene in bulk drug, finished product, and dissolution testing samples.

An HPLC methodology is described which enables the quantitation of thiothixene (N,N-dimethyl-9-[3-(4-methyl-1-piperazinyl)-propylidene]thioxanthe ne-2- sulfonamide) in bulk drug, finished product, and dissolution samples using a single analytical column (SiAl: a mixture of silica and alumina). The Z (cis) and the less pharmacologically active E (trans) isomers of thiothixene, as well as synthetic precursors and degradants, are well resolved within a short chromatographic run. A minor modification of the mobile phase allows direct injection and quantitation of low-concentration samples in a simulated gastric fluid (SGF) dissolution medium. The method is capable of supplanting the three separate procedures currently included in the thiothixene monograph of the U.S. Pharmacopeia XXI.

Chromatography, High Pressure Liquid↗
PubMed1988

Simultaneous determination of tamoxifen citrate and its E isomer impurity in bulk drug and tablets by high-performance liquid chromatography.

A new stability-indicating HPLC method that is highly selective for the separation of E and Z isomers of tamoxifen citrate [(Z)-2-[p-(1,2-diphenyl-1-butenyl)phenoxy]-N,N-dimethylethylamine citrate] is described. The method can be used to assay tamoxifen citrate and the E isomer impurity in both bulk drug and tablets. The chromatographic system consists of a 5-microns octadecyl silica column and a mobile phase composed of an aqueous phosphate buffer (pH 2.0) and acetonitrile. N,N-Dimethyloctylamine is used as an additive in the mobile phase for improving the peak shape of tamoxifen citrate. Compared with the existing official U.S. and British Pharmacopeia methods, the new method offers the following advantages: better resolution between the E and Z isomers, shorter analyses time, stability indication, and a less aggressive mobile phase that results in a longer column life.

Chromatography, High Pressure Liquid↗
PubMed1989

Effects of sinker shapes on dissolution profiles.

In dissolution testing, according to the U.S. Pharmacopeia, a nonreactive stainless steel wire helix is typically used to sink dosage forms that would otherwise float. The objective of this investigation was to determine if other sinker shapes will influence the rate, extent, or variability of dissolution. Criteria for the optimal sinker were defined. Various new sinker designs were fabricated, tested, and classified. Four classes of sinker shapes were defined: longitudinal, lateral, screen enclosures, and internal weights. Longitudinal sinkers contact the dosage forms on the long axis. Lateral sinkers either wrap around or contact capsule dosage forms in the middle, such as the line where the top and bottom halves of a capsule shell come together. Screen enclosures are of two types: either a wire cage, which holds the entire capsule, or a circular piece of wire screen placed on top of the capsule. Internal weights consist of two steel ball bearings, one inserted into each end of the capsule. The investigation consisted of four studies: (1) visual observation of the dissolution performance using 12 different sinkers; (2) the effect on drug release from nine classified sinkers on two different capsule formulations; (3) side-by-side comparison between the selected optimal longitudinal U clip and the wire helix lateral type sinkers; and (4) hydrodynamic effects caused by the use of the longitudinal U clip and the wire helix lateral type sinkers in the absence of capsule shells. We concluded that capsules sunk with either of the two longitudinal sinkers, the U clip or the paper clip, have faster, more complete dissolution and less variable results than did lateral type sinkers.(ABSTRACT TRUNCATED AT 250 WORDS)

Capsules↗
PubMed1992

Influence of higher rates of agitation on release patterns of immediate-release drug products.

The dissolution procedure serves as a quality control test to assure batch-to-batch uniformity and bioequivalence of a product once the bioavailability of the product has been established. It can also be used to detect manufacturing and/or process variations that could reduce product bioavailability. Dissolution testing must be conducted at an appropriate agitation rate. Tests conducted at high agitation rates may lose the ability to differentiate between good and bad products. Although the effect of high agitation rates has been known for some time, several immediate-release drug products still have United States Pharmacopeia (USP) monograph dissolution procedures that require very high agitation rates. A systematic survey was conducted on marketed tablets of chloroquine phosphate, griseofulvin, hydroxychloroquine sulfate, isocarboxazide, primaquine phosphate, and sulfadiazine. Each of these products has a USP monograph requiring a dissolution test at a paddle speed of 100 rpm. To study the influence of agitation rate on the dissolution rate of these products, dissolution studies were conducted at paddle speeds of 50, 75, and 100 rpm with the USP apparatus 2 (paddle method). The dissolution rate increased with an increase in the agitation rate from 50 to 75 rpm. However, no significant increase in the dissolution rate was noted with an increase in the agitation rate from 75 to 100 rpm. The data support the position that the higher agitation rate of 100 rpm is not necessary for a quality control procedure or a compendial standard for the products tested.

Chloroquine↗
PubMed1993

Molecular weight identification of polyethylene glycols in pharmaceutical preparations by gel permeation chromatography.

The suitability of different Fractogel media [Fractogel TSK HW40(S), Fractogel TSK HW55(F), and Fractogel TSK HW65(F)] for the molecular weight identification of polyethylene glycols was examined. The results were compared with those obtained on two recently introduced gel filtration media (Superdex 75 prep grade and Superdex 200 prep grade); nonspecific adsorptions were observed for the latter. An aqueous gel filtration procedure was developed for the molecular weight identification of polyethylene glycols in drug formulations as an alternative method to that prescribed by the American Pharmacopeia. This procedure was optimized by a logit-log calibration method.

Chromatography, Gel↗
PubMed1994

In vitro drug release behavior of D,L-lactide/glycolide copolymer (PLGA) nanospheres with nafarelin acetate prepared by a novel spontaneous emulsification solvent diffusion method.

Nanospheres with D,L-lactide/glycolide copolymer (PLGA) were prepared as a biodegradable and biocompatible polymeric carrier for peptide drugs by a novel spontaneous emulsification solvent diffusion method. Nafarelin acetate (NA), a luteinizing hormone-releasing hormone analogue, was employed as a model peptide drug to investigate the encapsulation efficiency. The drug and PLGA, dissolved in an acetone-dichloromethane-water mixture, were poured into an aqueous solution of polyvinyl alcohol under moderate stirring at room temperature. Spontaneous emulsification arising from a rapid diffusion of acetone from the organic to the aqueous phase enables preparation of PLGA submicron spheres 200-300 nm in size. The entrapment of NA in nanospheres was improved by blending low molecular weight (Mw = 4500) PLGA with higher molecular weight PLGA due to the synergistic effect of the rapid deposition of PLGA and the ionic interaction between NA and PLGA. By coadmixing a small amount of negatively charged phospholipids such as dipalmitoyl phosphatidylglycerol or dicetyl phosphate, the leakage of water-soluble NA was further prevented. The NA encapsulated in PLGA nanospheres was more stable than native NA in acidic medium (pH = 1.2). The drug-release behavior from nanospheres suspended in the disintegration test solution no. 1 (Japanese Pharmacopeia XII) exhibited a biphasic pattern. It was found tht the initial burst of release might be due to the degradation of the PLGA chain, as monitored by gel permeation chromatography. At a later stage, the drug was released more slowly, the rate of which was determined by the diffusion of the drug in the porous matrix structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

Programmable drug release of highly water-soluble pentoxifylline from dry-coated wax matrix tablets.

The programmable release of pentoxifylline from a dry-coated wax matrix tablet containing behenic acid as wax matrix was investigated at 37 degrees C in Japanese Pharmacopeia XII 1st (pH 1.2) and 2nd (pH 6.8) fluids. The dry-coated tablet consisted of a low drug concentration (33% w/w) in the outer layer tablet and a high concentration (50-67% w/w) in the core. The drug release from the wax matrix significantly increased after penetrating the core; therefore, the drug release profiles showed specific biphasic curves. Because the contact angle of the wax matrix tablet increased with a decrease in the drug concentration, the fluid penetration in wax matrix tablet increased with an increase of the drug concentration. The time required for 75% drug release (T75) decreased with an increasing drug concentration in the core, and the T75 at pH 6.8 was slightly longer than that in pH 1.2. The larger core tablet had a shorter T75, indicating that the drug release rate was controlled by regulating the drug concentration and/or the weight of the core tablet.

Chemical Phenomena↗