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PubMed1994

Bioequivalence of pyrantel pamoate dosage forms in healthy human subjects.

Drugs that are largely restricted to the gastro-intestinal tract (GIT) for their therapeutic efficacy and that are not substantially absorbed into the body are usually inadequately studied in terms of systemic bioavailability. The possibility of systemic effects requires that bioavailabilities be studied to ensure against enhanced toxicity resulting from formulation differences. Pyrantel pamoate falls into this category. High-performance liquid chromatography was employed in this study to determine plasma levels of pyrantel in nine healthy human subjects after administration of tablet and suspension dosage forms. Mean peak plasma concentrations of 37.56 +/- 9.37, 35.89 +/- 8.94, and 36.22 +/- 10.10 ng mL-1 were obtained following administration of 750 mg pyrantel pamoate in three different formulations. The mean tmax values were 2.02 +/- 0.12, 2.05 +/- 0.356, and 2.05 +/- 0.339 h respectively for the above dosage forms; the respective AUC0-9 values were 81.01 +/- 12.97, 94.59 +/- 17.18, and 101.47 +/- 19.59 h ng mL-1. There was no statistically significant difference between the bioavailabilities of the dosage forms tested. Large inter-subject variations were observed. One subject experienced abdominal discomfort and one experienced dizziness. It was not possible to clearly correlate individual variations in absorption with the observed adverse effect because the number of incidents was low (two out of 27 treatments).

Adult↗

PubMed2005

Biowaiver monographs for immediate release solid oral dosage forms: ranitidine hydrochloride.

Literature and experimental data relevant to the decision to allow a waiver of in vivo bioequivalence testing for the approval of immediate release (IR) solid oral dosage forms containing ranitidine hydrochloride are reviewed. According to the current Biopharmaceutics Classification System (BCS), ranitidine hydrochloride should be assigned to Class III. However, based on its therapeutic and therapeutic index, pharmacokinetic properties and data related to the possibility of excipient interactions, a biowaiver can be recommended for IR solid oral dosage forms that are rapidly dissolving and contain only those excipients as reported in this study.

Administration, Oral↗

PubMed2003

Novel gastroretentive dosage forms: evaluation of gastroretentivity and its effect on levodopa absorption in humans.

PURPOSE: To design novel expandable gastroretentive dosage form (GRDFs) and evaluate their gastroretentive properties. Then, to assess the pharmacokinetics of levodopa compounded in such a GRDF in healthy volunteers. METHODS: Thin (<0.07 cm), large-dimensioned (> or = 5 x 2.1 cm), multi layer dosage forms (DFs) with different rigid polymeric matrices an mechanical properties were folded into gelatin capsules and wer administered to healthy volunteers with a light breakfast. GRDF unfolding and physical integrity were evaluated in vitro and in vivo (by gastroscopy and radiology). The pharmacokinetics of levodopa GRDF were compared to Sinemet CR in a crossover design. RESULTS: The combination of rigidity and large dimension of the GRDFs was a decisive parameter to ensure prolonged gastroretentivity (> or = 5 h). Large-dimension DFs lacking rigidity had similar gastroretentivity as a nondisintegrating tablet (10 mm). The GRDF rapidly unfolded and maintained their mechanical integrity. The absorption phase of levodopa was significantly prolonged following GRDF administration in comparison to Sinemet CR. CONCLUSIONS: The combination of size and rigidity of the novel GRDF enables a significant extension of the absorption phase of a narrow absorption window drug such as levodopa. This approach is an important step toward the implementation of such GRDFs in the clinical setting.

Administration, Oral↗

PubMed1979

Analysis of dienestrol and its dosage forms by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) analysis is described for dienestrol as a drug substance and in cream, foam, and tablet dosage forms. After incorporation of the drug or dosage form into a solvent mixture containing an internal standard, biphenyl, an aliquot was chromatographed using a reversed-phase medium, followed by UV spectrophotometric detection at 254 nm. The response of the chromatographic system was linear over a concentration range corresponding to 50-200% of the labeled amount of dienestrol. Satisfactory accuracy and precision were confirmed by analyzing cream by the standard addition method. The advantages of the HPLC method are its simplicity, speed, and sensitivity, which permit direct analysis of single-dose quantities of dienestrol.

Chromatography, High Pressure Liquid↗

PubMed2002

Simultaneous determination of metronidazole and miconazole in pharmaceutical dosage forms by RP-HPLC.

A reversed-phase high performance liquid chromatography (RP-HPLC) method with UV detection is described for the simultaneous determination of metronidazole and miconazole in pharmaceutical dosage forms. Chromatography was carried out on a C18 reversed-phase column, using a mixture of methanol-water (40+60, v/v) as a mobile phase, at a flow rate of 1.0 ml min(-1). Sulfamethoxazole was used as an internal standard and detection was performed using a diode array detector at 254 nm. The method produced linear responses in the concentration ranges 10-70 and 1-20 microg ml(-1) with detection limits 0.33 and 0.27 microg ml(-1) for metronidazole and micanozole, respectively. This procedure was found to be convenient and reproducible for analysis of these drugs in ovule dosage forms.

Chromatography, High Pressure Liquid↗

PubMed1999

Coated dosage forms for colon-specific drug delivery.

Coating materials used in the manufacture of colon-specific solid oral dosage forms include polymers with a pH-dependent solubility that rely on the difference in pH between the small and the distal large intestine (pH-controlled release), polymers with a slow or pH-dependent rate of swelling, dissolution or erosion that take advantage of the constant small intestinal transit time (time-controlled release), polymers that are degradable by the microbial enzymes in the colon (enzyme-controlled release) and polymers that form firm layers that are destroyed by an increase of the luminal pressure in the colon caused by peristaltic waves (pressure-controlled release). This review gives an overview of coated dosage forms that have been developed to achieve colon specificity.

Journal Article↗

PubMed2004

Stability of lisinopril in two liquid dosage forms.

BACKGROUND: Lisinopril is used in pediatric patients with hypertension. It is not commercially available as a liquid. Little is known about the stability of lisinopril in extemporaneously prepared liquid dosage forms. OBJECTIVE: To determine the stability of lisinopril in 2 oral suspensions stored at 4 and 25 degrees C in plastic prescription bottles. METHODS: Five bottles contained methylcellulose 1%:simple syrup NF (1:13) and the other 5 bottles had Ora Plus-Ora Sweet (1:1) at a lisinopril concentration of 1 mg/mL. Three samples were collected from each bottle at 0, 7, 14, 28, 42, 56, 70, and 91 days and analyzed by stability-indicating HPLC analytical method (n = 15). RESULTS: At 4 degrees C, the mean +/- SD concentration of lisinopril remained >95.1 +/- 1.8% of the initial concentration in the methylcellulose formulation and 95.1 +/- 3.2% of the initial concentration in the Ora Plus-Ora Sweet formulation throughout the 91-day study period. At 25 degrees C, the mean concentration of lisinopril remained >92.4 +/- 2.2% of the initial concentration in the methylcellulose formulation for 8 weeks and 95.8 +/- 2.3% of the initial concentration in the Ora Plus-Ora Sweet formulation throughout the 91-day study period. No changes in physical appearance in any samples were seen during this period. CONCLUSIONS: Lisinopril can be prepared in either of 2 liquid dosage forms and stored for at least 13 weeks under refrigeration and 8 weeks at room temperature.

Administration, Oral↗

PubMedDate not supplied

Liquid chromatographic determination of methocarbamol in injection and tablet dosage forms: collaborative study.

A reverse phase liquid chromatographic method was developed for determining methocarbamol in injection and tablet dosage forms. The injections require dilution only; the tablets require a filtration step before introduction into the chromatograph. Response for methocarbamol was linear over the range 0-18 micrograms, using an ultraviolet detector at 274 nm. Recoveries by the author ranged from 96.1 to 101.9% for authentic injection formulations and 98.0 to 101.0% for authentic tablet formulations. A collaborative study of the method by 6 laboratories resulted in standard deviations of 1.70 and 2.22 for injection and tablet dosage forms, respectively. The method has been adopted official first action.

Chromatography, Liquid↗

PubMed2005

[Preparation and investigation of gemfibrozil + dimethyl-beta-cyclodextrin products and solid dosage forms].

Gemfibrozil is a lipid-regulating active substance. Dimethyl-beta-cyclodextrin products were prepared from this sparingly soluble pharmacon by means of methods such as physical mixing, kneading, spray drying and ultrasonication. Solid dosage forms (hydroxypropylmethyl cellulose /HPMC/ capsules and tablets) were prepared from the selected products on the basis of their dissolution profile and the in vitro membrane diffusion results. This publication details the results of electronmicroscopic morphological studies, particle size analysis and wetting contact angle determinations, and also the preparation and examination of the resulting solid dosage forms.

Diffusion↗

PubMed1984

Development of a standardized analysis strategy for basic drugs, using ion-pair extraction and high-performance liquid chromatography - III. Analysis of pharmaceutical dosage forms.

The usefulness of the standardized analysis strategy previously described for the determination of basic drugs in pharmaceutical dosage forms is evaluated. Several examples which typify experience in applying the strategy are reported. Ion-pair extraction techniques are compared with each other and with a classical extraction method in terms of their efficiency. The extraction technique with di(2-ethylhexyl)-phosphoric acid (HDEHP) is found to be the method of choice. The use of an internal standard is recommended. The selection of a suitable compound is greatly facilitated by referring to the chromatographic properties. It is shown that it is not necessary for the analyte and internal standard to be structurally similar. The combination of the HDEHP extraction technique with the preferred HPLC systems has been shown to be very useful in the routine analysis of pharmaceutical dosage forms.

Journal Article↗

PubMed2004

Development of a sustained release dosage form for alpha-lipoic acid. II. Evaluation in human volunteers.

Within this study an oral sustained release dosage form of alpha-lipoic acid (thioctic acid) has been generated and evaluated in healthy volunteers. A granulate comprising 56.8% alpha-lipoic acid and 43.2% chitosan acetate was compressed to tablets (weight: 0.45 g; diameter: 10.0 mm; thickness: 4 mm). Three of these tablets were administered at once orally to each volunteer. Prior to administration and then every hour for 12 hours blood samples were taken from the antebrachial vein. alpha-Lipoic acid concentrations in plasma were quantified via precolumn derivatization and reversed-phase high-performance liquid chromatography (HPLC). Results demonstrated that an increased plasma level of alpha-lipoic acid can be achieved by this formulation for at least 12 hours. Within this time period at least two maximum plasma concentrations were reached. The first one is based on the release of alpha-lipoic acid, which is not ionically and therefore only loosely bound to chitosan, whereas a second maximum is based on the release of the drug during the enzymatic degradation of the chitosan matrix in the colon. The AUC(0-12) was determined to be 183.8 +/- 101.4 microg x min/mL (mean +/- SD; n = 8). Because of the pulsed sustained release of alpha-lipoic acid, the dosage form described here seems to be highly beneficial in order to stimulate the glucose uptake in the case of diabetes type II.

Adult↗

PubMed2005

Pharmacokinetic/pharmacodynamic (PK/PD) evaluation of a once-daily treatment using ciprofloxacin in an extended-release dosage form.

OBJECTIVE: To evaluate the suitability of a once-a-day dosing regimen of ciprofloxacin using a new extended-release dosage form based on PK/PD principles. METHODS: Ciprofloxacin's serum concentrations were measured after administration of 500 mg immediate-release twice-daily, and 1,000 mg extended-release once-daily to 19 healthy volunteers. Pharmacokinetic parameters were determined using non-compartmental and compartmental data analysis. Measured serum concentration profiles were linked to ciprofloxacin's effect against Escherichia coli (MIC 0.013 mg/l) from in vitro kill curve studies where the pharmacokinetics of ciprofloxacin were simulated and change in number of bacteria (CFU/ml) versus time was monitored. Resulting parameters were used to compare expected kill curves for the two dosing regimens based on measured ciprofloxacin concentrations. RESULTS: Fitting the data using an appropriate PK/PD model resulted in a set of mean pharmacodynamic parameters (bacterial growth rate constant, k0, maximum kill rate constant, Kmax, and EC50). The model included a novel term to account for a change in kill rate after approximately 4 h when Kmax decreased in concentration-dependent matter. The model allowed excellent curve fits of all ciprofloxacin concentrations investigated. Comparison of expected kill curves with the immediate-release versus extended-release treatments showed similar outcome. Both treatments resulted in a decrease in CFU/ml > 5 log units over 24 h. CONCLUSION: Results indicate that once-a-day dosing of equal total daily doses with the new and more compliance-friendly extended-release dosing form will be therapeutically equivalent to once-a-day dosing with traditional immediate-release dosage forms for treatment of infections with this microorganism.

Adult↗

PubMed1996

Gastrointestinal physiology-regulated dogs for bioavailability evaluation of an oral controlled-release dosage form composed of pulsatile release granules.

Gastrointestinal (GI) physiology-regulated beagle dogs (regulated dogs) were regulated by a combined treatment using intramuscular pentagastrin and intravenous atropine sulfate. In the regulated dogs, the gastric pH was shifted to around 2, and the GI transit time was prolonged to approximate that in humans. Pranoprofen, an acidic anti-inflammatory agent, was granulated around sucrose seeds, and then coated with low substituted hydroxypropyl cellulose used as a swelling agent to afford plain granules (A-granule). Then, A-granule was coated stepwise with ethyl cellulose used as an outer shell material to afford two kinds of pulsatile release granules (B- and C-granules). In the dissolution study using pH 1.2 and 6.8 media, A-, B- and C-granules exhibited lag times of 0, 1 and 2h, respectively. Even in intact beagle dogs, the absorption profiles for A- and B-granules corresponded with those expected from the dissolution profiles. In contrast, the bioavailability of C-granule was only 35% in the intact dogs, but was 55% in the regulated dogs. Thus, the absorption of pranoprofen from pulsatile release granules after a longer lag time should be influenced by the location in the GI tract. Next, a controlled-release (CR) dosage form of pranoprofen was tentatively prepared by combining A-, B- and C-granules at the ratio of 3:4:3 (w/w in contents of pranoprofen). The bioavailability of the CR dosage form was significantly diminished in the intact dogs, being about 70% as much as that in the regulated dogs. Therefore, the regulated dogs would be superior to the intact dogs in avoiding the underestimation of the bioavailability of a CR dosage form with a pulsatile release property.

Animals↗

PubMed1985

Tissue vitamin E levels in newborn rabbits after pharmacologic dosing. Influence of dose, dosage form, and route of administration.

Tissue levels of alpha-tocopherol and alpha-tocopheryl acetate were measured in neonatal rabbits using high-performance liquid chromatography after administration of 100 mg/kg once or daily of either alpha-tocopherol or alpha-tocopheryl acetate subcutaneously, orally, or intravenously. Tissues were analyzed at 1, 3, and 6 days after daily dosing was begun. Tissue levels of alpha-tocopherol increased after each dose of alpha-tocopherol; the liver had much higher concentrations than other tissues after subcutaneous or oral administration. Alpha-tocopherol and alpha-tocopheryl acetate given orally produced similar tissue levels of alpha-tocopherol. Intravenous administration of alpha-tocopherol resulted in high concentrations of alpha-tocopherol in the liver, whereas intravenously administered alpha-tocopheryl acetate produced high concentrations of alpha-tocopheryl acetate in the lung. Following intravenous administration of alpha-tocopheryl acetate, only 2-4% of the total vitamin E present in the lung was alpha-tocopherol. From these results we conclude that total dose, dosage form, and route of administration of vitamin E have major influences on tissue vitamin E levels and whether the predominant molecular form is alpha-tocopherol or alpha-tocopheryl acetate. Assuming vitamin E tissue levels and molecular form determine tissue antioxidant activity, total dose, dosage form, and route of administration of vitamin E affect the potential clinical benefits that may result from pharmacologic vitamin E therapy in newborn infants.

Animals↗

PubMed2005

Estimation of trans-resveratrol in herbal extracts and dosage forms by high-performance thin-layer chromatography.

A simple, sensitive and precise high-performance thin-layer chromatographic (HPTLC) method of analysis of trans-resveratrol in Polygonum cuspidatum root extracts and in dosage forms was developed and validated. The separation was carried out on a TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase, eluted with chloroform-ethylacetate-formic acid (2.5 : 1 : 0.1) as mobile phase. Densitometric analysis of trans-resveratrol was carried out in the absorbance mode at 313 nm. This system was found to give compact spot for trans-resveratrol (Rf value of 0.40+/-0.03). A good linear regression relationship between peak areas and the concentrations was obtained over the range of 0.5-3.0 microg/spot with correlation coefficient 0.9989. The limit of detection and quantification was found to be 9 and 27 ng/spot. The method was validated for precision and recovery. The spike recoveries were within 99.85 to 100.70%. The RSD values of the precision in the range 0.37-1.84%. The proposed developed HPTLC method can be applied for identification and quantitative determination of trans-resveratrol in herbal extracts and dosage forms.

Chromatography, High Pressure Liquid↗

PubMed1997

Determination of pentobarbital and pentobarbital sodium in bulk drug substance and dosage forms by high-performance liquid chromatography.

High performance liquid chromatography (HPLC) is used to determine impurities in pentobarbital (I) and pentobarbital sodium (II) and to determine the strength of the drug substance and dosage forms. Separations were achieved using a Nucleosil C-18 column (5 microns) measuring 4.6 mm x 15 cm and an eluent containing 0.01 M phosphate buffer at pH 3.5:acetonitrile (72:28). The column is eluted isocratically and UV detection is used at 214 nm. Impurities are determinable in the drug substance at levels > or = 0.01%. Assay precision (relative standard deviations) for impurities in I and II ranged from +/- 36% to +/- 1.3% at levels of 0.01-1.46%. The external standard method is used for quantitating impurities in I and II. The determination of strength in drug substances I and II and in dosage forms (elixir, solution, capsules and suppositories) used the internal standard method. Precision for the strength determination ranged from +/- 0.26 to +/- 1.6%. The accuracy of the procedure was evaluated by addition and recovery of I and II to placebos. Recoveries were quantitative at 50-150% addition levels. Variation in parameters of the separation were made to evaluate the robustness of the HPLC separations.

Acetonitriles↗

PubMed1984

Quantitation of metronidazole in pharmaceutical dosage forms using high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method for the quantitation of metronidazole in pharmaceutical dosage forms has been developed. The method is accurate and precise with an RSD of 0.68%, based on six readings. The excipients present in various dosage forms did not interfere with the assay procedure. A solution of metronidazole decomposed using heat showed 0% potency.

Chromatography, High Pressure Liquid↗

PubMed2005

Influence of dosage forms on pharmacokinetics of daidzein and its main metabolite daidzein-7-O-glucuronide in rats.

AIM: To investigate the influence of dosage forms on the pharmacokinetics of daidzein and its main metabolite daidzein-7-O-glucuronide in Wistar rats. METHODS: After administration of two typical dosage forms (daidzein solution and suspension), the concentrations of daidzein and daidzein-7-O-glucuronide were determined by an LC-MS-MS method. The pharmacokinetic parameters were calculated and analyzed statistically using the Student's t-test. RESULTS: Absorption of daidzein after administration of daidzein solution (tmax=0.46 h) was more rapid than that of the suspension (tmax=5.00 h). The peak plasma concentrations of daidzein after administration of daidzein solution and suspension were 601.1 microg/L and 127.3 microg/L, respectively, and those of daidzein-7-O-glucuronide were 3000 microg/L and 192.6 microg/L, respectively. The absolute bioavailabilities of free daidzein in rats after administration of daidzein solution and suspension were 12.8% and 6.1%, respectively, which were calculated to be 47.0% and 12.2%, respectively, in the form of total daidzein (free plus conjugated daidzein). CONCLUSION: Absorption of daidzein solution was better than absorption of suspension (P<0.05).

Animals↗