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PubMed2006

Development and in vitro evaluation of expandable gastroretentive dosage forms based on compressed collagen sponges.

The objective of this study was to develop and evaluate new collagen gastroretentive dosage forms (GRDFs) which expand in the stomach after contact with gastric fluids. The GRDFs should remain in the stomach for a prolonged period of time due to their size. The dosage forms were prepared from collagen sponges. The sponges were manufactured by freeze-drying a riboflavin-containing collagen solution. A computer controlled material supply was constructed to transport precompressed collagen into a tablet machine. A second type of tablet was manufactured by combining compressed collagen sponges with hydrophilic matrix layers of hydroxypropylmethylcellulose. Matrix layers containing captopril or aciclovir were developed. In vitro experiments were performed with both types of dosage forms. The collagen tablets expand within a few minutes after contact with artificial gastric juice and form a drug delivery system with a size of 8 mm x 18 mm x 60 mm. Riboflavin is released over 16 h. If two layer tablets are used, the release of aciclovir or captopril can be controlled by the composition of the sustained release layer.

Acyclovir↗
PubMed2006

Ethnic or racial differences revisited: impact of dosage regimen and dosage form on pharmacokinetics and pharmacodynamics.

Ethnic or racial differences in pharmacokinetics and pharmacodynamics have been attributed to the distinctions in the genetic, physiological and pathological factors between ethnic/racial groups. These pharmacokinetic/pharmacodynamic differences are also known to be influenced by several extrinsic factors such as socioeconomic background, culture, diet and environment. However, it is noted that other factors related to dosage regimen and dosage form have largely been ignored or overlooked when conducting or analysing pharmacokinetic/pharmacodynamic studies in relation to ethnicity/race. Potential interactions can arise between the characteristics of ethnicity/race and a unique feature of dosage regimen or dosage form used in the study, which may partly account for the observed pharmacokinetic/pharmacodynamic differences between ethnic/racial groups. Ethnic/racial differences in pharmacokinetics/pharmacodynamics can occur from drug administration through a specific route that imparts distinct pattern of absorption, distribution, transport, metabolism or excretion. For example, racial differences in the first-pass metabolism of a drug following oral administration may not be relevant when the drug is applied to the skin. On the other hand, ethnic/racial difference in pharmacokinetics/pharmacodynamics can also happen via two different routes of drug delivery, with varying levels of dissimilarity between routes. For example, greater ethnic/racial differences were observed in oral clearance than in systemic clearance of some drugs, which might be explained by the pre-systemic factors involved in the oral administration as opposed to the intravenous administration. Similarly, changes in the dose frequency and/or duration may have profound impact on the ethnic/racial differences in pharmacokinetic/pharmacodynamic outcome. Saturation of enzymes, transporters or receptors at high drug concentrations is a possible reason for many observed ethnic/racial discrepancies between single- and multiple-dose regimens, or between low- and high-dose administrations. The presence of genetic polymorphism of enzymes and/or transporters can further complicate the analysis of pharmacokinetic/pharmacodynamic data in ethnic/racial populations. Even within the same dosage regimen, the use of different dosage forms may trigger significantly different pharmacokinetic/pharmacodynamic responses in various ethnic/racial groups, given that different dosage forms may exhibit different rates of drug release, may release the drug at different sites, and/or have different retention times at specific sites of the body. It is thus cautioned that the pharmacokinetic/pharmacodynamic data obtained from different ethnic/racial groups cannot be indiscriminately compared or combined for analysis if there is a lack of homogeneity in the apparent 'extrinsic' factors, including dosage regimen and dosage form.

Cross-Cultural Comparison↗
PubMed2006

A nondestructive technique to determine the rate of oxygen permeation into solid dosage forms.

The current study investigated the use of electron paramagnetic resonance (EPR) spectroscopy as a nondestructive method to quantify the partial pressure of oxygen (PO2) in tablets and hard shell capsules. Lithium phthalocyanine crystals (LiPC) were placed inside the dosage forms. The peak-to-peak linewidth of the first derivative of the LiPC EPR spectra was measured and, by calibration tables, the oxygen partial pressure, pO2, within the dosage form was determined. The intra-dosage form pO2 was followed as a function of time after changing the exterior gas stream composition. Results showed initial oxygen concentrations comparable to atmospheric levels in all tablets and capsules investigated. Oxygen rapidly permeated into unsealed gelatin and cellulosic hard shell capsules. Banding at the cap/body joint significantly reduced the oxygen permeation rate. Oxygen also rapidly permeated into tablet compacts, regardless of the compressional force used during tableting, while application of a polymeric film significantly decreased the rate of oxygen permeation. This EPR technique was shown to be a suitable nondestructive method to study oxygen permeation kinetics in solid dosage forms.

Capsules↗
PubMedDate not supplied

Comparative pharmacokinetic analysis of a novel sustained release dosage form of valproic acid in dogs.

A new sustained release dosage form of valproic acid (VPA) was developed. The new sustained release dosage form was administered (twice, with and without food) to five dogs in comparison to a standard tablet (Depakine, Labaz) and an i.v. preparation of the drug. Drug level monitoring in the plasma was performed by a GLC assay. Results indicate that the sustained release formulation exhibited a more prolonged and uniform absorption rate, yielded more sustained plasma levels after ingestion, and showed an overall bioavailability of 0.84 (95 per cent C.I. = 0.72, 0.96) relative to an equivalent dose of a conventional tablet.

Animals↗
PubMed1993

Solid oral dosage forms.

The oral route of drug administration is the most convenient for patients, with tablets emerging as the most popular solid oral dosage form used today. Standard compressed, controlled-release and coated tablets are the most common form of solid oral dosages. A wide range and diversity of ingredients are often included in tablet formulations. A knowledge of the difference between tablet and capsule formulations should enable nurses to improve patient compliance with respect to solid oral dosage forms.

Administration, Oral↗
PubMed1977

High-performance liquid chromatographic analysis of isoniazid and its dosage forms.

A high-performance liquid chromatographic analysis is described for isoniazid as a drug entity and in its tablet and injectable dosage forms. After incorporation of the drug or dosage form in a solvent mixture and addition of an internal standard, tribenzylamine, an aliquot is chromatographed using a pellicular silica gel medium followed by UV spectrophotometric detection at 254 nm. The response of the chromatographic system was linear over a concentration range corresponding to 20-200% of the labelled amount of isoniazid. Comparison of the results with those obtained by the official USP XIX method indicates similar accuracy and precision. The advantages of the proposed method are its simplicity and rapidity, its potential for automation, and its specificity. The specificity was demonstrated in the presence of potential degradation products of isoniazid, other drugs used with isoniazid in combination dosage forms, and an adduct formed by the reaction of isoniazid with lactose in the tablet.

Chemical Phenomena↗
PubMed2005

Pharmacokinetics of an immediate release, a controlled release and a two pulse dosage form in dogs.

Clinical studies have shown that circadian patterns influence the pharmacokinetics of certain drugs used in the treatment of different diseases. For such drugs, the bioavailability is influenced by the time of administration. The objective of this study was to investigate differences in the pharmacokinetic patterns between a pulsatile drug delivery system using a pulsatile capsule, an immediate release tablet and a controlled release tablet. Metoprolol was chosen as a model drug because of its high solubility and high permeability pattern throughout the GI tract. The dosage forms were administered to four dogs and the plasma levels were measured using LC-MS/MS. Pharmacokinetic parameters were determined for each dosage form. Fluctuations in the plasma time curves over the observation period indicated that physiological factors like motility have an influence on the drug absorption. The comparison of the plasma time curves of the dosage forms showed that each dosage form caused significant differences in the drug plasma levels. The pulsatile drug delivery capsule caused two defined C(max) values for each dose between 1-1.75 and 2.5-3.5h. Implications for the use of a pulsatile drug delivery device for chronopharmacotherapy are discussed. Pulsatile drug delivery offers a promising way for chronopharmacotherapy if the time of administration and pulse time are adjusted to the circadian pattern.

Administration, Oral↗
PubMed2002

Anti-asthmatic drugs and dosage forms in children: a cross-sectional study.

OBJECTIVE: To describe the choice of drugs as well as the dosage forms of anti-asthmatic drugs in children with regard to different age groups. METHODS: Cross-sectional study based on computerized pharmacy dispensing records of 1999 for children aged 0-16 years in the north of the Netherlands. All children were selected and divided in the following age groups: 0-1, 2-5, 6-11 and 12-16-year-olds. RESULTS: Inhaled beta 2-agonists and inhaled corticosteroids were the most widely used anti-asthmatic drugs in all age groups (respectively 59 and 58 users per 100 anti-asthmatic using 0-16 year-olds). Cromones were rarely used. Up to four years of age the use of treatment with aerosol inhalers increased simultaneously with a decrease of oral dosage forms. The use of dry powder inhalers started at the age of approximately 4 years old and increased to about 85% of the users at the age of 11, with the strongest increase around the age of 6 and 7. CONCLUSION: The choice of drugs and dosage forms corresponds with what might be expected based on guidelines for the treatment of asthma in children, except for the high use of deptropine in the youngest age group. Anti-asthmatic drugs for preventive treatment are used so frequently without beta 2-agonists that questions about possible overtreatment need to be raised.

Administration, Inhalation↗
PubMed2004

Phase transformation considerations during process development and manufacture of solid oral dosage forms.

The quality and performance of a solid oral dosage form depends on the choice of the solid phase, the formulation design, and the manufacturing process. The potential for process-induced solid phase transformations must be evaluated during design and development of formulations and manufacturing processes. This article briefly reviews the basic principles of polymorphism, defines the classes of phase transformation and the underlying transformation mechanisms, and discusses respective kinetic factors. The potential phase transformations associated with common unit operations employed in manufacturing solid oral dosage forms are highlighted. Specific examples are given to illustrate the importance of solid phases, and process-induced phase transitions in formulation and process development.

Acetaminophen↗
PubMed1995

Morphologic examination of rabbit nasal mucosa after the nasal administration of insulin peanut oil suspension and a powder dosage form with soybean-derived sterylglucoside.

Soybean-derived sterylglucoside mixture (SG) is a potentially effective absorption enhancer for the nasal absorption of insulin. Insulin is a peanut oil suspension dosage form and in a powder dosage form with SG were administered into the rabbit nasal cavity. After 0.5 or 1 h, nasal mucosa was taken from the nasal cavity and side effects were examined by an optiphoto light microscope. The insulin in the peanut oil suspension produced a histological change in the nasal epithelium mucosae, as well as mucodermal phlogistic cellular infiltration. The peanut oil suspension with SG showed side effects slightly stronger than without SG. SG alone and the insulin powder dosage form with SG produced no signs of inflammation, erosion or squamous metaplasia. The results from this study indicate that SG can be considered safe.

Administration, Intranasal↗
PubMedDate not supplied

Performance characteristics of methods of analysis used for regulatory purposes. I. Drug dosage forms. D. High pressure liquid chromatographic methods.

Precision parameters of high pressure liquid chromatographic methods approved by AOAC for the analysis of drug dosage forms were recalculated on a consistent statistical basis, using the computer program "FDACHEMIST." Eleven collaborative studies of 12 compounds in 66 dosage forms analyzed by an average of 9 laboratories per study, with a total of 1150 determinations, were reviewed. For the approved methods and methods awaiting approval (9 studies, 11 compounds, 54 dosage forms, and 959 determinations), the average repeatability relative standard deviation (within-laboratory; RSDo) was 1.0%; reproducibility relative standard deviation (among-laboratories, including within-; RSDx) was 2.5%; the ratio RSDo/RSDx was an unusually low 0.40, with an average outlier rate of 0.6% of the reported values. The line of best fit for RSDx plotted against - log concentration increases with decreasing concentration, extending approximately from RSDx = 2% at 100% concentration to RSDx = 3.6% at 0.01% concentration, a change in RSDx of about 0.4% for each 10-fold decrease in concentration, independent of analyte and matrix.

Chromatography, High Pressure Liquid↗
PubMed2002

The clinical efficacy of piroxicam fast-dissolving dosage form for postoperative pain control after simple lumbar spine surgery: a double-blinded randomized study.

STUDY DESIGN: A prospective, randomized, double-blinded clinical trial was conducted. OBJECTIVE: To study the efficacy of piroxicam fast-dissolving dosage form in reducing postoperative pain after simple lumbar spine surgery. SUMMARY OF BACKGROUND DATA: Many reports mention the use of nonsteroidal antiinflammatory drug for relieving postoperative pain, but study still is lacking on their use in spine surgery. METHODS: For this study, 50 patients who underwent discectomy or one-level laminectomy were randomly sampled into two groups: 21 patients in the placebo control group and 29 patients in the study group. In addition to a normal postoperative analgesic regimen, each patient received placebo or piroxicam fast-dissolving dosage form (2 tablets administered sublingually 1 to 3 hours before surgery). This regimen was repeated with 2 tablets after 24 hours, then 1 tablet after 48 hours. Postoperative pain was evaluated every 6 hours by a visual analog scale for 3 days. The amount of morphine usage was measured on postoperative days 1, 2, and 3. Postoperative variables such as blood loss, length of wound, and time of operation also were recorded. RESULTS: There was no difference between the groups with respect to age, weight, height, gender, and type of operation. The postoperative pain of the study group, as measured by visual analog scale, showed significant improvement (P < 0.05) during the postoperative period 12 to 42 hours after surgery. The study group used less morphine, but their usage showed no significant difference on postoperative days 1, 2, and 3. When the visual analog scale between the types of operation was compared, the scale for the discectomy group was better than that for the laminectomy group. The results of the postoperative variables showed no difference between the groups in terms of postoperative blood loss, length of wound, and time of operation. CONCLUSIONS: Sublingual administration of piroxicam fast-dissolving dosage form after simple spine surgery is effective and efficient in relief of postoperative pain. Because of its low side effects and high toleration, piroxicam fast-dissolving dosage form may be considered as an alternative for postoperative pain control during the early postoperative period.

Administration, Sublingual↗
PubMed1998

Evaluation and comparison of dissolution data derived from different modified release dosage forms: an alternative method.

Dissolution testing is an essential requirement for the development, establishment of in vitro dissolution and in vivo performance (IVIVR), registration and quality control of solid oral dosage forms. The objective of the present study was to investigate the effect of delivery system positioning in accordance with the USP 23-recommended dissolution methods and the proposed modification on drug release from controlled release systems having different operating release mechanisms, namely, swellable floatable, swellable sticking and osmotic pump. The delivery systems were evaluated by placing each dosage form either in the dissolution vessel in accordance with the USP 23 methods or over/below a designed ring/mesh device for achieving full surface exposure to the dissolution medium for sticking or floatable systems respectively. Results indicate that the overall release profiles from the sticking and floatable systems of theophylline are sensitive to their positioning in the dissolution vessel (P<0.05). Furthermore, release of diltiazem hydrochloride from the sticking system also demonstrated sensitivity (P<0.05). In contrast, the floatable dosage form of this latter drug with the application of a helical wire sinker, or when it was placed below the ring/mesh assembly, or by allowing the dosage form to float, did not show sensitivity (P>0.05) for the overall release behavior. This was attributed to the greater solubility of diltiazem hydrochloride (50% solubility in water at 25 degreesC) in comparison to theophylline which is a sparingly soluble drug (0.85% solubility in water at 25 degreesC). Drug release from the osmotic pump appeared to be identical under the given experimental conditions (P>0.05). Statistical analysis of data was performed by comparing the t50%, t70%, t90%; mean dissolution times (MDT50%, MDT70%, MDT90%); the "difference factor, f1" and "similarity factor, f2". It is concluded that the results derived from the application of the "similarity factor, f2" are superior to the individual time points (e.g. tx%) and MDTx% values in differentiating between overall release patterns or the border line release profile differences. It also became apparent that in the case of the swellable sticking systems full surface exposure to the dissolution medium results in greater release rate. For the osmotic pump the required osmotic pressure threshold necessary for constant rate drug delivery appears to have reached independent of the hydrodynamic conditions. A successful and more accurate evaluation of dissolution data can be derived when full surface exposure is considered and this can be accomplished by dissolution method modification with the aid of the designed ring/mesh assembly.

Algorithms↗
PubMed2003

A multi-mechanistic drug release approach in a bead dosage form and in vivo predictions.

Our previous study has successfully prepared a combination of immediate release, enteric coated, and controlled release (CR) beads and mathematically modeled in vitro drug release characteristics of the combination based on the release profiles of individual beads. The objectives of the present study are to evaluate the combination and individual beads in vivo and to mathematically model in vivo drug input characteristics of the combination based on the in vivo input of individual beads. Beagle dogs were used as an animal model, and theophylline as a model drug. In vivo percent drug absorbed at different times (input function) after administration of a capsule bead dosage form was calculated using the Wagner-Nelson deconvolution method using intravenous injection of theophylline in each dog as a reference. The in vivo input functions of individual beads were each fitted to appropriate mathematical equations. The in vivo input function of the bead combination dosage form was calculated based on the individual mathematical equations (expected), and verified experimentally in vivo (experimental). The results showed that all bead dosage forms behave in vivo as defined in vitro. Enteric coated beads significantly delay the time to reach the maximum concentration of drug (tmax=4.9 h) compared to uncoated immediate release beads (2 h). The lag time of enteric coated beads is 1.1 h. CR beads showed both longer tmax (6 h) and mean residence time (MRT=9.7 h) compared to the uncoated immediate release beads (tmax=2 h and MRT=7.1 h) as designed in vitro. The in vivo input functions for the three individual beads can be fitted to equations as a function of square root of time. The combined bead dosage form showed tmax of 2.4 h and MRT of 7.9 h. The experimental and expected in vivo input profiles agreed to within +/- 12% (residues at individual data points). Our results suggest that the drug input function of a combined multi-mechanism oral dosage form can be predicted from the in vivo performance of individual formulations using the dog as an in vivo model.

Administration, Oral↗
PubMed1998

Drug-delivery products and the Zydis fast-dissolving dosage form.

Many patients find it difficult to swallow tablets and hard gelatin capsules and do not take their medication as prescribed. It is estimated that 50% of the population is affected by this problem which results in a high incidence of non-compliance and ineffective therapy. The difficulty is experienced in particular by paediatric and geriatric patients, but it also applies to people who are ill in bed and to those active working patients who are busy or travelling, especially those who have no access to water. Such problems can be resolved by means of the Zydis dosage form which does not require water to aid swallowing. The Zydis fast-dissolving dosage form is a unique freeze dried medicinal tablet, made from well known and acceptable materials. When Zydis units are put into the mouth, the freeze dried structure disintegrates instantaneously releasing the drug which dissolves or disperses in the saliva. The saliva containing the dissolved or dispersed medicament is then swallowed and the drug is absorbed in the normal way. Some drugs are absorbed from the mouth, pharynx and oesophagus as the saliva passes down into the stomach. In these cases, the bioavailabilities of drugs from Zydis formulations are significantly greater than those observed from standard dosage forms. This paper deals with the formulation and process technology of the Zydis dosage form. The bioavailability characteristics of Zydis products are summarized, and in particular, the design of Zydis products for the enhancement of oral bioavailability and the improvement of clinical activity, through transmucosal delivery and pregastric absorption, is discussed.

Administration, Oral↗
PubMed1990

Development and characterization of a lyophilized dosage form of IL-1 beta.

The development and characterization of a lyophilized dosage form for recombinant Interleukin-1 beta is described. Included in the evaluation of the drug product are accelerated and long-term stability studies utilizing a number of biophysical techniques (reverse-phase HPLC, SDS-PAGE, isoelectric focusing and ELISA). Data collected with these methods were examined for correlations with biological activity assessments provided by an in-vitro cell culture system (mouse thymocyte proliferation). Results of these studies demonstrate that a lyophilized dosage form of Interleukin-1 beta can be prepared which retains its potency for at least 1 year when stored at ambient temperature. The analytical methodology used to assess the physicochemical integrity of the protein provided a sensitive and reproducible means of predicting changes in biological activity.

Animals↗
PubMed1990

Gastrointestinal transit of nondisintegrating, nonerodible oral dosage forms in pigs.

Gastrointestinal (GI) transit data necessary as "baseline" or "control" information were collected using pigs as animal models preliminary to bioavailability studies of new sustained action formulations. Density and size effects of nondisintegrating dosage forms on GI transit were investigated. Initially, enteric-coated nondisintegrating magnesium hydroxide caplets (density, 1.5 g/ml; size, 19.6 x 9.5 mm; weight, 1.2 g) were utilized in seven pigs. Prolonged gastric residence (greater than 5 days) occurred in every case for this dosage form. Therefore, nondisintegrating caplets of three densities (1.25, 1.45, and 2.3 g/ml) and three different sizes (large, 20 x 10 mm; medium, 10 x 10 mm; small, 5 x 10 mm) were studied in two more pigs. Roentgenography was used to visualize passage of caplets through the GI tract. Heidelberg pH capsules (size, 8 x 20 mm; density, 1.61 g/ml) were also used in this study. Total GI transit times range from 2 to 33 days for 22 administrations of these nondisintegrating dosage forms. Pigs are found to not be an appropriate model for evaluating bioavailability of nondisintegrating controlled-release dosage forms because total GI transit time (especially gastric transit) is much too long.

Animals↗