[Hemodynamic and methabolic aspects of sodium nitroprusside pharmacodynamics during buccal administration in patients with arterial hypertension of cerebral ischemic genesis]

The authors presented in the article efficiency of new formulation of Natrium Nitroprusodum used buccaly in patients with cerebral-ischemic form of arterial hypertention and stage II hypertention. It has been shown both in an acute experiment and after monothrerapy having been used. The medication proved to have positive effect on brachiocephalic vessel blood flow indices in patients of both groups using pulse doplergraphy. The use of Natrium Nitroprussidum used buccaly in patients with cerebral-ischemic form of arterial hypertention and hyportensive disease differentiates in terms of indices characterising the formation, transport and utilisation of energetic products, products of POL and antioxidant ferments.

Increasing bioavailability of silymarin using a buccal liposomal delivery system: preparation and experimental design investigation

Silymarin is a natural lipotropic agent of low bioavailability from oral products. The aim of our study is to prepare buccal liposomal delivery system of silymarin with higher bioavailability. The effect of lecithin:cholesterol molar ratio on the percentage drug encapsulated was investigated. The influence of fluctuating the amount of added drug was also determined. The effect of additives such as positive charge inducer, negative charge inducer and surfactants was studied using two different 2(3) full factorial designs. Furthermore, additives used to optimize liposomal product were also investigated for their optimal concentrations, release properties and in vitro permeation and absorption through chicken cheek pouch. Optimal liposomal encapsulation efficiency was found at 7:4 lecithin to cholesterol molar ratio. A decrease in entrapment efficiency with increasing cholesterol content was observed. Tween 20 or Tween 80 beyond 0.5 molar ratio decreased the entrapment efficiency. Positively charged liposomes showed superior entrapment efficiency over neutral and negatively charged liposomes. Release studies as well as permeation and absorption studies showed that hybrid liposomes prepared according to formula 3 containing lecithin, cholesterol, stearyl amine and Tween 20 in 9:1:1:0.5 molar ratio, respectively, gave the best drug absorption and permeation. It showed steady state permeation through chicken cheek pouch for 6h. This is expected to improve the bioavailability of silymarin in the developed liposomal buccal delivery system, as the results show an increase in drug penetration compared to free drug powder.

Factors influencing the discomfort of intraoral needle penetration

This study with 24 volunteers compared the discomfort produced by needle penetration in different parts of the palatal mucosa. In addition, comparing a fresh needle to one that was used for a previous penetration in the same patient, we assessed the influence of the status of the needle on insertion discomfort during buccal mucosal penetration. The results showed that needle penetration in the anterior hard palate was more uncomfortable than in the posterior palate. Although men could not differentiate between fresh and used needles for a second buccal mucosal penetration, women reported a significant increase in discomfort with used needles.

The use of mucoadhesive polymers in buccal drug delivery

Buccal delivery of the desired drug using mucoadhesive polymers has been the subject of interest since the early 1980s. Advantages associated with buccal drug delivery have rendered this route of administration useful for a variety of drugs. This review highlights the use of mucoadhesive polymers in buccal drug delivery. Starting with a review of the oral mucosa, mechanism of drug permeation, and characteristics of the desired polymers, this article then proceeds to cover the theories behind the adhesion of bioadhesive polymers to the mucosal epithelium. Additionally, we focus on the new generation of mucoadhesive polymers such as thiolated polymers, followed by the recent mucoadhesive formulations for buccal drug delivery.

A comparison of buccal midazolam and rectal diazepam for the acute treatment of seizures

In this study, the authors aimed to evaluate buccal midazolam as a practical and safe alternative medication for children who suffer from seizures in the emergency setting and in home practice or anywhere. The effects and side effects of buccal midazolam and rectal diazepam were compared in the treatment of acute convulsions in 43 children, ranging in age from 2 months to 12 years who were seen at the emergency service of the children hospital. Midazolam was given on the even days of the month and diazepam was given on the odd days. In the midazolam group, the seizures of 18/23 (78%) patients terminated in 10 minutes; however 5/23 (22%) patients did not respond. In the diazepam group 17/20 (85%) patients responded in 10 minutes, but 3/20 (15%) did not respond. Midazolam was found to be as effective as diazepam and the difference was not statistically significant (p<0.05). Response periods of the 2 drugs showed no significant difference (p>0.05). The need for a second drug for seizures that did not stop with the first drug was equal, and the difference was not statistically significant (p>0.05). They did not observe any serious complications. In conclusion, buccal midazolam is safe and as effective as rectal diazepam for the treatment of seizures.

Tetracaine oral gel in patients treated with radiotherapy for head-and-neck cancer: final results of a phase II study

PURPOSE

We performed a phase II study to assess feasibility, pain relief, and toxicity of a tetracaine-based oral gel in the treatment of radiotherapy (RT)-induced mucositis.

METHODS AND MATERIALS

Fifty patients treated with RT for head-and-neck cancer with clinical evidence of acute oral mucositis of grade>or=2 were scheduled to receive the tetracaine gel. A questionnaire evaluating the effect of the gel was given to all subjects.

RESULTS

In 38 patients (79.2%), a reduction in oral cavity pain was reported. Thirty-four patients (82.9%) reported no side effect. Seventy-one percent of patients had no difficulties in gel application. Unpleasant taste of the gel and interference with food taste were noticed in 5 (12%) and 16 patients (39%), respectively. Planned RT course was interrupted less frequently in patients who reported benefit from gel application than in patients who did not (p=0.014). None of the patients who experienced pain relief needed a nasogastric tube, opposite to the patients who did not report any benefit from gel application (p=0.001).

CONCLUSION

Tetracaine oral gel administration seemed feasible and safe while reducing RT-induced mucositis-related oral pain in a sizeable proportion of treated head-and-neck cancer patients. A trial designed to compare efficacy of this gel vs. standard treatment is warranted.

PK-PD modeling of buprenorphine in cats: intravenous and oral transmucosal administration1

The pharmacokinetics and thermal antinociceptive effects of buprenorphine after intravenous (i.v.) or oral transmucosal (OTM) administration were studied in six adult cats. Plasma buprenorphine concentrations were measured using radioimmunoassay in a crossover study after a dose of 20 microg/kg given by the i.v. or OTM route. Oral pH was measured. Blood for drug analyses was collected before, and at 1, 2, 4, 6, 10, 15, 30, and 60 min and at 2, 4, 6, 8, 12, and 24 h after treatment. Thermal thresholds were measured before treatment, then following treatment every 30 min to 6 h, every 1 hour to 12 h and at 24 hours postadministration. Plasma buprenorphine concentration effect relationships were analyzed using a log-linear effect model. Oral pH was 9 in each cat. Peak plasma buprenorphine concentration was lower and occurred later in the OTM group but median bioavailability was 116.3%. Thermal thresholds increased significantly between 30 and 360 min in both groups. Peak effect was at 90 min and there was no difference at any time between the two groups. There was distinct hysteresis between plasma drug concentration and effect in both groups. Overall, OTM administration of buprenorphine is as effective as i.v. treatment and offers a simple, noninvasive method of administration which produces thermal antinociception for up to 6 h in cats.

Development of three layered buccal compact containing metoprolol tartrate by statistical optimization technique

The objective of this work to evaluate the effect of formulation variables on release properties and bioadhesive strength in development of three layered buccal compact containing highly water-soluble drug metoprolol tartrate (MT) by statistical optimization technique. Formulations were prepared based on rotatable central composite design with peripheral polymer ratio (carbopol 934P: HPMC 4KM) and core polymer ratio (HPMC 4KM: sodium alginate) as two independent formulation variables. The three layered buccal compact comprises a peripheral layer, core layer and backing layer. Four dependent (response) variables were considered: bioadhesion force, percentage MT release at 8 h, T50% (time taken to release 50% of drug) and release exponent (n). The release profile data was subjected to curve fitting analysis for describing the release mechanism of MT from three layered buccal compact. The main effects and interaction terms was quantitatively evaluated by quadratic model. The decrease in MT release was observed with an increase in both the formulation variables and as the carbopol: HPMC ratio increases the bioadhesive strength also increases. The desirability function was used to optimize the response variables, each having a different target and the observed responses were highly agreed with experimental values. The results demonstrate the feasibility of the model in the development of three layered buccal compact containing highly water-soluble drug MT.

Spray-dried Amioca® starch/Carbopol® 974P mixtures as buccal bioadhesive carriers

In the present study, spray-dried Amioca starch/Carbopol 974P mixtures were evaluated as potential buccal bioadhesive tablets. Carbopol (C 974P) concentrations from 5 to 75% were tested. All spray-dried mixtures showed a comparable or better bioadhesive capacity compared to a reference formulation (DDWM/C 974P 95/5). The bioadhesive capacities of Amioca/Carbopol 974P mixtures were improved by spray-drying. All spray-dried mixtures showed significantly higher work of adhesion values compared to their equivalent physical mixtures. The influence of Carbopol concentration on the in vivo adhesion time of placebo tablets and in vitro miconazole nitrate release was tested. The ratio Amioca/C 974P 70/30 showed the longest in vivo adhesion time (24.5+/-8.5 h). Lower and higher C 974P concentrations had a shorter in vivo adhesion time. The mixtures containing between 15 and 30% C 974P could all sustain the in vitro miconazole nitrate release over 20 h. Again, lower and higher C 974P concentrations showed a faster in vitro miconazole release. The drug loading capacity of a spray-dried mixture containing 20% C 974P was investigated in vivo in dogs using testosterone as model drug. The spray-dried mixture could be loaded with 60% drug without loosing its in vivo bioadhesive and pharmacokinetic properties.

Initial Injection Pressure for Dental Local Anesthesia: Effects on Pain and Anxiety

This study quantitatively assessed injection pressure, pain, and anxiety at the start of injection of a local anesthetic into the oral mucosa, and confirmed the relationship between injection pressure and pain, as well as between injection pressure and anxiety. Twenty-eight healthy men were selected as subjects and a 0.5-inch (12 mm) 30-gauge disposable needle attached to a computer-controlled local anesthetic delivery system (the Wand) was used. A 0.5 mL volume of local anesthetic solution was injected submucosally at a speed of either 30 or 160 s/mL. Three seconds after the start of local anesthetic injection, injection pressure was measured and pain and anxiety were assessed. Injection pressure was measured continuously in real time by using an invasive sphygmomanometer and analytical software, and pain was assessed on the Visual Analogue Scale and anxiety on the Faces Anxiety Scale. A significant correlation was evident between injection pressure and pain (rs = .579, P = .00124) and between intensity of injection pressure and state anxiety (rs = .479, P = .00979). It is therefore recommended that local anesthetic be injected under low pressure (less than 306 mm Hg) to minimize pain and anxiety among dental patients.

Short communication: serum and tissue concentrations of vitamin D metabolites in beef heifers after buccal dosing of 25-hydroxyvitamin D3

Sixteen crossbred (British x Continental; average un-shrunk body weight = 507.9 kg; SD = 45.6 kg) beef heifers fed a steam-flaked corn-based finishing diet with melengestrol acetate (0.4 mg/heifer daily) included to suppress estrus were used in a completely random design to evaluate the efficacy of buccal administration of 0, 10, 100, or 1000 mg of 25-hydroxyvitamin D3, (25-OH D3). Serum Ca, P, Mg, 25-OH D3, 1,25-dihydroxyvitamin D [1,25-(OH)2 D3], albumin, and protein were measured 24 h before dosing (-24 h), at dosing (0 h), and 6 and 24 h after dosing, after which the cattle were slaughtered at a commercial facility. Samples of kidneys, liver, longissimus lumborum, and triceps brachii were collected and evaluated for concentrations of 1,25-(OH)2 D3. With -24 and 0 h as baseline covariates, a significant time x treatment interaction was observed for serum 25-OH D3 and Ca concentrations, but not for serum 1,25-(OH)2 D3. Supplemental 25-OH D3 doses of 100 and 1000 mg significantly increased serum 25-OH D3 at 24 h after dosing, 1,25-(OH)2 D3 at 6 and 24 h after dosing, and serum Ca at 24 h after dosing. Similarly, buccal dosing of 1000 mg of supplemental 25-OH D3 significantly increased (approximately 2- to 3-fold) concentrations of 1,25-(OH)2 D3 in the kidney, liver, and longissimus lumborum relative to the other 3 treatments but not in triceps brachii. Serum albumin, protein, P, and Mg were not affected by treatment. Based on these results, buccal administration of 100 and 1000 mg 25-OH D3 increased vitamin D3 metabolites in serum and tissues, and it should be an effective method of delivering the vitamin.

Best evidence topic report. Buccal midazolam as an alternative to rectal diazepam for prolonged seizures in childhood and adolescence

A short cut review was carried out to establish whether buccal midazolam is better than rectal diazepam for treating prolonged seizures in childhood and adolescence. Eight papers were found using the reported search, of which two presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these best papers are tabulated. A clinical bottom line is stated.

Randomized trial of mifepristone and buccal or vaginal misoprostol for abortion through 56 days of last menstrual period

OBJECTIVE

Mifepristone-misoprostol medical abortion has been approved in the United States since 2000. U.S. providers have preferred to use vaginal misoprostol because of evidence that such a regimen is more effective in later gestations. Buccal administration of misoprostol may be equally effective and more acceptable to some women.

METHODS

This open-label, randomized trial was conducted at two sites in Rochester, NY, and involved healthy women with pregnancies through 56 days since the last menstrual period (LMP) as indicated by sonogram. Women received mifepristone 200 mg orally and were randomized to use 800 mug of misoprostol either buccally or vaginally 1 to 2 days later. They returned within 15 days for repeat sonogram. If the woman's pregnancy had not been completely aborted by day 36, a suction abortion was performed. The primary outcome was a complete abortion without surgical intervention.

RESULTS

Four hundred forty-two women were enrolled in the study, and complete data were available on 429. The efficacy rate was 95% (205/216) in the buccal group and 93% (199/213) in the vaginal group (chi(2)=0.43, p=.51). Nausea was the most commonly reported side effect, affecting 70% in the buccal group and 62% in the vaginal group. There were no differences in the satisfaction with the overall procedure between the buccal (92%) and the vaginal groups (95%) (chi(2)=1.87, p=.17).

CONCLUSION

Buccal administration of misoprostol after low-dose mifepristone for medical abortion appears to be a highly effective and acceptable alternative compared with vaginal administration for medical abortion in pregnancies through 56 days LMP.

Evaluation of relatively low dose of oral transmucosal ketamine premedication in children: a comparison with oral midazolam

BACKGROUND

Oral Transmucosal ketamine (lollipop) has been shown to be an effective, harmless preoperative medication for children. However, its efficacy was not compared with commonly used premedication drugs. We, therefore, compared the efficacy of oral transmucosal ketamine with oral midazolam for premedication in children.

METHODS

Fifty-five children (2-6 years of age) were randomized to receive orally either a lollipop containing 50 mg of ketamine (the group K; n = 27) or syrup containing 0.5 mg.kg(-1) of midazolam (the group M; n = 28) before minor surgery. A five points-sedation score (1 = asleep to 5 = agitated; scores 2 and 3 were defined as 'effective') on arrival in the operating room and a three points-acceptance score of separation from the parents and a three points-mask cooperation score at induction of anesthesia (1 = easy to 3 = markedly resistant; score 3 was defined as 'poor') were used.

RESULTS

Sedation scores in group K were significantly higher than those in group M (P = 0.012), and the incidence of 'effective' in sedation was significantly lower in group K than in group M (P = 0.036). The incidence of 'poor' at separation from the parents and for mask cooperation was significantly higher in group K than in group M (P = 0.017, P = 0.019, respectively).

CONCLUSION

These results indicate that a relatively low dose of oral transmucosal ketamine premedication provides no benefits over oral midazolam in children.

Safety and efficacy of buccal midazolam versus rectal diazepam for emergency treatment of seizures in children: a randomised controlled trial

BACKGROUND

Rectal diazepam and buccal midazolam are used for emergency treatment of acute febrile and afebrile (epileptic) seizures in children. We aimed to compare the safety and efficacy of these drugs.

METHODS

A multicentre, randomised controlled trial was undertaken to compare buccal midazolam with rectal diazepam for emergency-room treatment of children aged 6 months and older presenting to hospital with active seizures and without intravenous access. The dose varied according to age from 2.5 to 10 mg. The primary endpoint was therapeutic success: cessation of seizures within 10 min and for at least 1 hour, without respiratory depression requiring intervention. Analysis was per protocol.

FINDINGS

Consent was obtained for 219 separate episodes involving 177 patients, who had a median age of 3 years (IQR 1-5) at initial episode. Therapeutic success was 56% (61 of 109) for buccal midazolam and 27% (30 of 110) for rectal diazepam (percentage difference 29%, 95% CI 16-41). Analysing only initial episodes revealed a similar result. The rate of respiratory depression did not differ between groups. When centre, age, known diagnosis of epilepsy, use of antiepileptic drugs, prior treatment, and length of seizure before treatment were adjusted for with logistic regression, buccal midazolam was more effective than rectal diazepam.

INTERPRETATION

Buccal midazolam was more effective than rectal diazepam for children presenting to hospital with acute seizures and was not associated with an increased incidence of respiratory depression.

Transbuccal tablets of carbamazepine: formulation, release and absorption pattern

Tranbsuccal drug administration is an attractive method, as it has several advantages especially with respect to peroral delivery. Here we report: i) the aptitude of carbamazepine (CBZ) to penetrate porcine buccal mucosa and reconstituted human oral (RHO) epithelium; ii) three different tablet formulations for transbuccal administration; iii) the drug release rate from tablets. CBZ permeation through the buccal mucosa was investigated by using two different bi-compartmental open models: Franz cells for porcine buccal mucosa and Transwell diffusion cells system for RHO epithelium. Results, expressed as drug flux (Js) and permeability coefficients (Kp), indicated that CBZ well penetrates the membrane and arrives in the acceptor phase. Js and Kp resulted 7x10(-2) mg/cm2h and 0.23 cm/h for in vitro experiments and 1.81 x 10(-2) mg/cm2h and 4.57 x 10(-2) cm/h for ex vivo experiments. The flux is extensively affected by the membrane thickness. The CBZ release from three different formulations of tablets, prepared with loaded microspheres, loaded matrices, and conventional compressed physical mixture of components was studied. Using the new formulated "non-conventional" tablets prolonged drug release was obtained. Loaded matrix tablets discharged CBZ faster than microsphere tablets (17% and 12% in about 2.5 h respectively). Results indicate the possibility of administering CBZ on buccal mucosa.

Development of a mucoadhesive and permeation enhancing buccal delivery system for PACAP (pituitary adenylate cyclase-activating polypeptide)

The buccal mucosa providing direct entry into the systemic circulation appears to be a potential site for the delivery of PACAP (pituitary adenylate cyclase-activating polypeptide), a new therapeutic agent in the treatment of type 2 diabetes. In order to reach a sufficient buccal bioavailability a drug delivery system with strong permeation enhancing and mucoadhesive properties is needed. In this study the enhancing effect of a strongly mucoadhesive chitosan-thioglycolic acid (TGA) conjugate in combination with reduced glutathione (GSH) on the permeation of PACAP across the buccal mucosa was investigated. The apparent permeability coefficient (P(app)) of PACAP in buffer only was (5.7 +/- 3.1) x 10(-8), while in the presence of chitosan-TGA conjugate (1%) a P(app) of (20.0 +/- 3.4) x 10(-8) was achieved. The combination of chitosan-TGA (1%) with GSH (2%) led to an improvement of the P(app) up to (57.3 +/- 31.7) x 10(-8). Release studies of PACAP demonstrated that a controlled release can be provided from tablets consisting of chitosan-TGA at a pH of 5, whereas more than twice as much was released from chitosan-TGA tablets pH 4. According to the combination of permeation enhancing properties, controlled drug release and the mucoadhesive character, chitosan-TGA conjugates represent a promising tool for the buccal administration of PACAP.

Buccal drug delivery

Buccal formulations have been developed to allow prolonged localised therapy and enhanced systemic delivery. The buccal mucosa, however, while avoiding first-pass effects, is a formidable barrier to drug absorption, especially for biopharmaceutical products (proteins and oligonucleotides) arising from the recent advances in genomics and proteomics. The buccal route is typically used for extended drug delivery, so formulations that can be attached to the buccal mucosa are favoured. The bioadhesive polymers used in buccal drug delivery to retain a formulation are typically hydrophilic macro-molecules containing numerous hydrogen bonding groups. Newer second-generation bioadhesives have been developed and these include modified or new polymers that allow enhanced adhesion and/or drug delivery, in addition to site-specific ligands such as lectins. Over the last 20 years a wide range of formulations has been developed for buccal drug delivery (tablet, patch, liquids and semisolids) but comparatively few have found their way onto the market. Currently, this route is restricted to the delivery of a limited number of small lipophilic molecules that readily cross the buccal mucosa. However, this route could become a significant means for the delivery of a range of active agents in the coming years, if the barriers to buccal drug delivery are overcome. In particular, patient acceptability and the successful systemic delivery of large molecules (proteins, oligonucleotides and polysaccharides) via this route remains both a significant opportunity and challenge, and new/improved technologies may be required to address these.

Comparing vaginal and buccal misoprostol when used after methotrexate for early abortion

OBJECTIVE

The primary objective of this study was to determine if buccal misoprostol was as effective as vaginal misoprostol in medical abortions. The secondary objectives were to compare side effects and acceptability.

METHODS

This was a randomized controlled trial of 600 microg misoprostol by the buccal or vaginal routes used 3 to 6 days after 50 mg/m2 methotrexate. The participants were women presenting for abortion at 49 days or less gestation. The outcome measures were the number of women who had aborted by Day 8, side effects and acceptability.

RESULTS

Day 8 completion rate was 53.5% for the buccal route and 67.5% for the vaginal route (p = 0.012). Side effects were similar in the two groups except that there was more burning with the buccal route. Overall acceptability and route acceptability were similar in the two groups.

CONCLUSIONS

When used after methotrexate for early abortion, the vaginal route for misoprostol is more effective and preferred to the buccal route.

Formulation and in vitro evaluation of prednisolone buccoadhesive tablets

In this research, the effect of mucoadhesive polymers such as hydroxyl propyl methyl cellulose (HPMC) with viscosity grade 60 and 500 mPas, sodium carboxy methyl cellulose (NaCMC) and carbopol 934 (Cp 934) alone or in combination with each other on the release profile of prednisolone was studied and mucoadhesion strength of these buccoadhesive formulations was evaluated. The results showed that the release of prednisolone from HPMC with viscosity grade 60 mPas and Cp 934 alone was fast and their mucoadhesion strengths was low. On the other hand, the release rates of prednisolone from the HPMC viscosity grade 500 mPas and NaCMC and mucoadhesion strengths were moderate and suitable. The results showed that with different blends of HPMC viscosity grade 500 mPas or NaCMC and Cp 934 with increasing in HPMC or NaCMC/Cp 934 ratio a remarkable decrease in the rate of drug release and an appreciable increase in the mucoadhesion strength was observed. Except from the formulations prepared with HPMC viscosity grade 60 and 500 mPas, other formulation had more fluctuations in release profiles and their kinetics of release were not fitted to zero order model.

Enhanced Buccal Mucosal Retention and Reduced Buccal Permeability of Estradiol in the Presence of Padimate O and Azone®: A Mechanistic Study

In previous experiments, it was suggested that the reduction in estradiol (E2) buccal permeability after pretreatment with some skin penetration enhancers was attributed to enhanced membrane storage. To verify this, further in vitro permeability experiments were performed and the kinetics of E2 buccal mucosal uptake and permeability was assessed. Porcine buccal mucosa was pretreated with the skin penetration enhancers octisalate, padimate O (PO), or Azone (AZ) and placed in modified Ussing chambers. The disappearance of E2 from the donor chamber and appearance of E2 in the receptor chamber was then monitored over 4 h. The final concentration of E2 associated with the buccal mucosa and donor chamber walls in the presence of each enhancer was also determined. The rate of E2 disappearance from the donor chamber was 3.1-fold greater than the rate of E2 appearance in the receptor chamber, indicating significant membrane storage of E2. Pretreatment with PO and AZ significantly increased the rate of E2 disappearance and reduced the rate of E2 appearance in the receptor chamber. The corresponding enhancement in E2 tissue concentration after PO and AZ pretreatment was 1.7- and 3-fold, respectively. However, PO and AZ also increased the amount of E2 adsorbed to the walls of the donor chamber, which contributed to the reduction in E2 flux through the buccal mucosa.

Pharmacodynamics and pharmacokinetics of recombinant hirudin via four non-parenteral routes

One of recombinant hirudin variants, rHV2, a polypeptide used as an anticoagulant agent in clinic, was administered to anesthetized rats via intratracheal, buccal, nasal and rectal routes. Prolongation in clotting time and thrombin time was measured to calculate pharmacological bioavailability. Plasma concentration of rHV2 was determined using a chromogenic thrombin substrate assay and pharmacokinetic parameters were obtained on the basis of a non-compartmental model. Intravenous administration was also performed as the gold standard by which the other routes were compared. Difference in pharmacological bioavailability (P.A.), bioavailability (F) and absorption rate of rHV2 was found for the four non-parenteral routes. The rank order for both P.A. and F was intratracheal>nasal>buccal>rectal. Absorption was more rapid after both intratracheal and rectal administration (tmax approximately 20-40 min), compared with that after nasal and rectal administration. It is evident that the pulmonary route is preferable to other three routes for successful systemic delivery of rHV2.