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PubMed2001

Design and in vitro evaluation of a mucoadhesive oral delivery system for a model polypeptide antigen.

A novel mucoadhesive drug carrier system has been generated which protects a model polypeptide antigen from degradation by the most abundant intestinal proteases. The enzyme inhibitors antipain, chymostatin and elastatinal, respectively, were covalently attached to the mucoadhesive polymer sodium carboxymethylcellulose (NaCMC) and the inhibitory efficacy of the resulting polymer-inhibitor conjugates was evaluated in vitro. When these inhibitor conjugates were combined with the thiolated polymer polycarbophil-cysteine (PCP-Cys), 95.8 +/- 3.8% (mean +/- SD, n = 3) of the incorporated model antigen ovalbumin (OVA) was protected from enzymatic degradation within 90 min incubation in the presence of an artificial intestinal fluid containing the pancreatic serine proteases trypsin, chymotrypsin and elastase. Replacing the CMC-inhibitor conjugates in the dosage form by unmodified CMC significantly reduced the protective effect to 78.8 +/- 4.7% (mean +/- SD, n = 3), whereas incorporation of the model antigen in a CMC dosage form omitting PCP-Cys protected 72.5 +/- 3.2% (mean +/- SD, n = 3) of OVA from degradation within a 90 min incubation period. Further, the incorporation of PCP-Cys resulted in higher cohesiveness within the dosage form and controlled drug release of the antigen for a time period of more than 9 h. Results suggest that a delivery system combining thiolated polymer and polymer-inhibitor conjugates improves the metabolic stability of the model polypeptide antigen and may therefore be a useful tool for oral protein vaccination.

Acrylic Resins↗
PubMed1988

Design and implementation of a cost-accounting system in hospital pharmacy.

The design and implementation of a cost-accounting system in a hospital pharmacy department is described. Pharmacy resource use (labor, drugs, supplies, and overhead), or pharmacy's intermediate products, was clearly defined in terms of dosage forms (10 groupings representing variable labor and supplies) and drug products (more than 100 categories that incorporate cost and volume of use for 3000 line items). Costs were defined as variable or nonvariable (fixed), based on whether they were related to a specific medication order. Labor was divided into variable and fixed components. Time standards were developed using time and motion studies. Variable labor hours were determined as follows: specified hours (the volume of each dosage form multiplied by the standard time for each dosage form); nonspecified hours (time not directly associated with production); hours worked (specified plus nonspecified hours); and hours paid (hours worked plus sick leave and vacation). A standard cost for each drug product was based on the weighted average of volume and cost of the individual line items. The total drug budget was constructed by multiplying the standard cost for each drug product times the projected volume for each drug product. The pharmacy budget was developed by calculating the number and mix of pharmacy products used in association with the projected number and type of cases for the fiscal year. The monthly pharmacy budget reports were assembled with data from the payroll, billing, and cost-accounting systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Accounting↗
PubMed1990

[A new antianginal preparation: isosorbide-5-mononitrate].

Repeated treadmill exercise tests were used in 20 patients with stable exercise-induced angina in order to comparatively examine various dosage forms of isosorbide-5-mononitrate (IMN) and isosorbide dinitrate (ID) during their single administration. The antianginal effect of conventional IMN tablets (Monisid, Bulgaria) lasted about 5 hours and 1-2 hours longer than that shown by long-acting tablets (Olicard, FRG) and lasted on an average of 12 hours. There was a correlation between the antianginal effect of IMN and its blood concentration. A significant individual variability was observed in the potency of all the dosage forms of IMN and ID under study. The dosage form of IMN had antianginal effects that were similar and even superior to those exhibited by ID.

Angina Pectoris↗
PubMed2005

AC biosusceptometry in the study of drug delivery.

Conventionally, pharmaceutical substances are administered orally because the gastrointestinal tract possesses the appropriate features for drug absorption. Nevertheless, the gastrointestinal tract physiology is complex and influenced by many factors. These factors must be completely understood for the optimization of oral drug delivery systems. Although in vitro tests provide information about release and drug absorption profiles, in vivo studies are essential, due to the biological variability. Several techniques have been employed in an attempt to conveniently characterize the behavior of solid dosage forms in vivo. The noninvasive biomagnetic technique of alternate current biosusceptometry (ACB) has been used in studies focusing on gastrointestinal motility and, more recently, to evaluate the performance of magnetic dosage forms. This article will discuss the main characteristics of AC biosusceptometry and its applicability for determination of the relationship between the human gastrointestinal tract and orally administered pharmaceutical dosage forms.

Drug Delivery Systems↗
PubMed1991

Comparative efficacy of intravaginal prostaglandin E2 in the gel and suppository forms for cervical ripening.

Thirty-seven patients admitted for labor induction and presenting with unfavorable cervical features were randomized in a single-blind fashion to receive either 3 mg of prostaglandin E2 in an intravaginal gel or a 2-mg dose in a vaginal suppository. With the aid of previously reported placebo data, the intent was to compare the two dosage forms in terms of their ability to promote cervical ripening, and to see which dosage form was more effective in terms of influencing the overall incidence of cesarean section. The two groups showed a comparable improvement (alpha = 0.05) in cervical condition over that of the placebo group, with the mean Bishop score increasing by 2.0 points in the gel group, 2.5 points in the suppository group, and 0.7 points in the placebo group. As the suppository contained a lower dose of drug than the gel, the data support the concept that the type of drug vehicle and dosage form are important variables affecting product performance. No statistically significant difference in the incidence of cesarean section was noted between the two groups or between either group and placebo. This may be attributable to the small sample size and the relatively high proportion of women diagnosed as having cephalopelvic disproportion/failure to progress. Additional studies are warranted.

Administration, Intravaginal↗
PubMed1988

[Study of general toxic properties and side effects of polymethylsiloxane and gentamicin immobilized on it].

A long-acting dosage form for local use of gentamicin immobilized on polymethylsiloxane, a silicon organic adsorbent was developed. It combined the antimicrobial spectrum of gentamicin and the local sorption-detoxication action of the matrix. In acute and chronic experiments on 5 species of laboratory animals it was shown that polymethylsiloxane had no general toxic action on the animals, no damaging action on their internal organs, did not affect their functions and the state of the biological fluids, had no pyrogenic or allergenic effect. During gentamicin immobilization on polymethylsiloxane there was observed no increase in the antibiotic toxicity as compared to the nonimmobilized dosage form of the antibiotic. Further study of the immobilized dosage form of gentamicin is advisable.

Animals↗
PubMed1996

In vitro evaluation of magaldrate antacid efficacy in the presence of some drugs and its effect on their dissolution rates: Part I.

A comparison of the antacid efficacy of magaldrate powder and its dosage forms on an equal weight basis by an in vitro technique revealed that: suspensions > chew tablets > powder. This was also evidenced by acid neutralizing capacity test USP XXIII, which also showed that riopan and rioplus suspensions were equipotent. All tested doses of different antacid dosage forms were found to regulate acid level to pH 3.0 within 10 seconds. This rapidity of action depends on its dose, dosage forms, and extent of chewing the tablets. The antacid efficacy of tested antacid was not affected by the concomitant presence of two tablets of duspatalin, faverin and panadol (group I) or their equivalent weights of pure powders, whilst, the duration of action, buffering capacity and total acid consumption was significantly suppressed with two dosage units of inderal, aspirin, and indocid (group II) or their equivalents of pure powder. However, antacid tested was still regulating gastric acid level within the comfort zone for a period of 70-110 min, and possessing (20.01-25.10 mEq/g) with group (II). These results are consistent with that obtained from acid neutralizing capacity test. The dissolution of magaldrate was pH dependent, with fast magnesium release and sustained aluminum hydroxide conversion. A significant (p < 0.05) retardation of the release rates of group (II), whilst, a non significant (p > 0.05) effect on that of group (I) was observed in the presence of different doses of antacid tested in all dissolution media. The presence of riopan suspension (20 ml) had a significant suppression on the release rates in all systems.

Aluminum Hydroxide↗
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↗
PubMed2003

Press-coating of immediate release powders onto coated controlled release tablets with adhesives.

A novel adhesive coating was developed that allows even small quantities of immediate-release (IR) powders to be press-coated onto controlled-release (CR), coated dosage forms without damaging the CR coating. The process was exemplified using a pseudoephedrine osmotic tablet (asymmetric membrane technology, AMT) where a powder weighing less than 25% of the core was pressed onto the osmotic tablet providing a final combination tablet with low friability. The dosage form with the adhesive plus the press-coated powder showed comparable sustained drug release rates to the untreated dosage form after an initial 2-h lag. The adhesive layer consisted of an approximately 100- microm coating of Eudragit RL, polyethylene glycol (PEG) and triethyl citrate (TEC) at a ratio of 5:3:1.2. This coating provides a practical balance between handleability before press-coating and good adhesion.

Adhesives↗
PubMed1976

Development of polylactic/glycolic acid delivery systems for use in treatment of narcotic addiction.

Implantable polylactic/glycolic acid matrix systems have successfully provided the sustained release of naltrexone to mice for periods of up to 200 days. In vitro and in vivo release rates have been determined by measuring chemical concentrations in pH 7 buffer solution and urine, respectively, and in vivo efficacy has been measured by direct challenge with morphine (Dewey-Harris mouse tail-flick test). Dosage forms of small implantable cylinders, 1/16'' diameter, (25 mg/rod, one rod/mouse) containing 33% by weight naltrexone pamoate in 90 L(+)/10 polylactic/glycolic acid have sustained the delivery of chemical for 20 days. Delivery of chemical from dosage forms of 1/16'' diameter spherical beads (3 mg/bead, 3 beads/mouse) containing 33% by weight naltrexone base in 90 L(+)/10 polylactic/glycolic acid was sustained for 60 days. Earlier a similar bead type dosage form of 75 L(+)/25 polylactic/glycolic acid containing 50% by weight naltrexone base and coated with the pure polymer provided controlled release for 25 days. Polymerization conditions which incorporate the use of pharmacologically suitable catalysts and yield products reproducibly have have been delineated. Techniques for sterilization of the final implant have been screened.

Animals↗
PubMed2006

Spectrophotometric determination of gatifloxacin in pure form and in pharmaceutical formulation.

Simple, rapid, and extractive spectrophotometric methods were developed for the determination of gatifloxacin (GT) in bulk and pharmaceutical dosage form. These methods are based on the formation of yellow ion-pair complexes between the basic nitrogen of the drug and three sulphonphthalein acid dyes, namely; bromocresol green (BCG), bromocresol purple (BCP), bromophenol blue (BPB) and bromothymol blue (BTB) in phthalate buffer pH 3.0, 3.4 and 3.2, using BCG, BCP and (BPB or BTB), respectively. The formed complexes were extracted with chloroform and measured at 415, 417, 412 and 414 nm for BCG, BPB, BCP and BTB, respectively. The analytical parameters and their effects on the reported systems are investigated. The reactions were extremely rapid at room temperature and the absorbance values remains unchanged at 48 h for all reactions. Beer's law was obeyed in the ranges 2.0-20, 2.0-14 and 2.0-16 microg mL(-1) for BCG, BCP and (BPB or BTB), respectively. The composition of the ion pairs was found 1:1 by Job's method. Beer's law validation, accuracy, precision, limits of detection, limits of quantification. The proposed methods have been applied successfully for the analysis of the drug bulk form and its dosage form. The results were in good agreement with those obtained by the official and reported methods.

Buffers↗
PubMed1996

[Energy-dispersive X-ray analysis of pharmaceutical formulations].

Energy-dispersive X-ray analysis (EDS) coupled to a scanning electron microscopy (SEM) could represent a valuable tool in the study of solid dosage forms. In particular, EDS can be useful in the control of conventional pharmaceutical formulations by determining the presence and the distribution of characteristic compounds. More recently, the growth in the development of modified release dosage forms needed the determinations of parameters affecting the drug delivery. Among these, drug distribution, elements involved in crosslinking procedures and coatings of "reservoir" systems could easily and rapidly evaluated by EDS analysis. In this paper, we report the theoretical aspects and some applications of the EDS technique especially concerning controlled release dosage forms in order to show the versatility of such an analytical method which could be widely used in the future.

Chemistry, Pharmaceutical↗
PubMed1997

Stereoselective disposition of suspensions of conventional and wax-matrix sustained release ibuprofen microspheres in rats.

PURPOSE: The aim of the study is to evaluate stereoselective in vivo disposition of suspensions of conventional and wax-matrix sustained release ibuprofen microspheres in rats. METHODS: Male wistar rats were dosed i.v. with 20 mg/kg, or orally with conventional suspension, and three suspension formulations of sustained release microspheres (having three different particle sizes) of racemic ibuprofen. Blood samples were analyzed stereoselectively by reverse phase HPLC. RESULTS: The mean Cmax for (S)- and (R)-ibuprofen decreased with increased particle size of the drug or microspheres in the suspension dosage forms, while the Tmax increased with increased particle size. The mean S/R ratio (AUC0-48) of the suspensions decreased with increase in particle size of the drug or microspheres and these ratios (for both conventional and sustained formulations) were higher than that of the i.v., an indication of presystemic inversion. Decrease in the ratios with increased particle size is suggestive of formulation dependent inversion. The plasma concentration-time data of the sustained release formulations showed bimodal profiles, irrespective of the particle size of the microspheres. The second peak observed after 8 hours is indicative of colonic absorption. CONCLUSIONS: Stereoselective disposition of ibuprofen microspheres showed higher bioavailability compared to the conventional suspension. Bimodal disposition is influenced by dosage form while presystemic inversion is both site-specific, and dosage form dependent.

Administration, Oral↗
PubMed1989

Physiological pharmacokinetic model of adriamycin delivered via magnetic albumin microspheres in the rat.

The influence of magnetic albumin microspheres on the disposition of adriamycin was evaluated. Adriamycin concentrations were monitored in multiple rat tissues for 48 hr after its intra-arterial administration (2 mg/kg) as a solution and associated with magnetic albumin microspheres. The magnetic dosage form was targeted to a predefined tail segment with a magnetic field strength of 8000 G applied for 30 min after dosing. A physiological pharmacokinetic model was used to describe the disposition of adriamycin following its administration from either dosage form. The model developed for the data resulting from administration of adriamycin as a solution served as a foundation for the model developed for adriamycin resulting from the administration of adriamycin associated with the magnetic dosage form. The model for adriamycin following administration of the magnetic microspheres required additional relationships to describe the transport of adriamycin associated with the microspheres. For both models, the predicted adriamycin concentrations were in adequate agreement with the observed values. The present investigation demonstrates the use of a physiological pharmacokinetic modeling method to represent drug kinetics following its administration via a targeted drug delivery system.

Albumins↗
PubMed1975

Development of polylactic/glycolic acid delivery systems for use in treatment of narcotic addiction.

Implantable polylactic/glycolic acid matrix systems have successfully provided the sustained release of naltrexone to mice for periods of up to 200 days. In vitro and in vivo release rates have been determined by measuring chemical concentrations in pH 7 buffer solution and urine, respectively, and in vivo efficacy has been measured by direct challenge with morphine (Dewey-Harris mouse tail-flick test). Dosage forms of small inplantable cylinders, 1/16 inch diameter, (25 mg/rod, one rod/mouse) containing 33 per cent by weight naltrexone pamoate in 90 L(+)/10 polylactic/glycolic acid have sustained the delivery of chemical for 200 days. Delivery of chemical from dosage forms of 1/16 inch diameter spherical beads (3 mg/bead, 3 beads/mouse) containing 33 per cent by weight naltrexone base in 90 L(+)/10 polylactic/glycolic acid was sustained for 60 days. Earlier a similar bead type dosage form of 75 L(+)/25 polylactic/glycolic acid containing 50 per cent by weight naltrexone base and coated with the pure polymer provided controlled release for 25 days. Polymerization conditions which incorporate the use of pharmacologically suitable catalysts and yield products reproducibly have beendelineated. Techniques for sterilization of the final implant have been screened.

Animals↗
PubMed1981

Development of drug delivery systems for use in treatment of narcotic addiction.

The long term goal of the NIDA narcotic antagonist program of developing an implantable, biodegradable, naltrexone/PLGA matrix system which will sustain the delivery of naltrexone to biological systems for one month has been achieved. The dosage forms which provide the desired delivery characteristics are 1.5 mm diameter beads composed of 70% by weight naltrexone base in 40,000 molecular weight, 90L/10G poly (L(+)-lactic-co-glycolic acid). Other dosage forms, including 1.5 mm diameter rods which provide 6 months' naltrexone release, finely divided injectable powders which provide up to 30 days' naltrexone release, and 1.5 mm diameter rods which provide 2 weeks' sustained delivery of morphine, have also been investigated. In vitro and in vivo release rates have been determined by measuring chemical concentrations in pH 7 buffer solution and urine, respectively. In vivo efficacy of naltrexone sustained delivery devices has been measured by direct challenge with morphine (Dewey-Harris mouse tail-flick test) and inhibition of morphine self-administration in monkeys. Good Manufacturing Practices documentation has been developed and used to produce a large batch of the 1.5 mm diameter naltrexone bead dosage forms at an FDA-registered pharmaceutical manufacturer. These beads, produced at the University of North Carolina School of Pharmacy, are awaiting use in human clinical trials.

Animals↗
PubMed1995

[Bioadhesives: rationale, state of the art and therapeutic potential].

Pharmaceutical research is going on the way to formulate drugs in dosage forms and delivery systems able to improve their biopharmaceutical properties. For some routes of administration, among them the transmucosal ones, such improvements may be reached by increasing the time and the nature of the contact between mucosal tissues and drug dosage forms via chemical or physical bioadhesive links. Biopharmaceutical AFI Study Group efforts were oriented in analyzing the actual state of the art in the field of bioadhesive drug delivery. Rationals of use of drug dosage forms with bioadhesive properties, analytical method of control of bioadhesion (both in vitro and in vivo) and therapeutical potentialities are the matter of this review.

Animals↗
PubMedDate not supplied

Pharmacokinetics and bioavailability of theophylline following enema and suppository administration in man.

The pharmacokinetics and bioavailability of theophylline from a commercial oral elixir of theophylline, a rectal suppository of aminophylline, and a rectal enema of theophylline monoethanolamine was compared in six normal subjects. Using a complete crossover design, the fasted subjects received a single dose of each dosage form. Blood and saliva samples were collected at frequent time intervals for 24 h, and the plasma assayed for theophylline by a specific thin-layer chromatography densitometric method. No statistically significant differences existed among the three dosage forms with respect to Cmax and AUC corrected for the elimination rate constant and the dose (mg kg-1). However, tmax was significantly larger for the suppository. While the rate of absorption was significantly slower for the suppository, no differences in the extent of absorption existed among the three dosage forms. A one-compartment open model with apparent first-order absorption adequately described the plasma concentration-time data for the elixir and enema, whereas the suppository data were best fitted by a one-compartment open model with apparent zero-order absorption and a lag time. A rate-limiting, concentration-independent release of drug from the base most likely accounts for the slow absorption of theophylline from the suppository. While the saliva:plasma ratio remained fairly constant for most of the study period, the large variability found during the absorption phase following drug administration limits the usefulness of this parameter as a monitor of theophylline plasma concentrations.

Adult↗