Patient instructions suspensions

Pharmaceutical scientists have developed improved suspension dosage forms to overcome problems of poor physical stability and patient-perceived discomfort attributed to some active ingredients. An important development aspect of any suspension is the ability to resuspend easily any settled particles prior to instillation in the eye and ensure that a uniform dose is delivered. It would be ideal to formulate a suspension that does not settle since the patient may not always follow the labeled instructions to shake well before using. However, this is usually not feasible or desirable since the viscosity required to retard settling of the insoluble particles completely would likely be excessive for a liquid eyedrop. The opposite extreme, of allowing complete settling between doses, usually leads to a dense layer of agglomerated particles that are difficult to resuspend. 

A pharmacist dispensed 4 fluidounces of an antacid suspension with instructions that the patient take two tablespoonfuls of the medication four times a day. How long will the medication last ... 

A patient has been instructed to take 15 mL of Vistaril (hydroxyzine pamoate) oral suspension every six hours for four doses daily. How many days will two 6 fluidounce bottles of the suspension last ... 

An oral suspension that contains 100,000 units/ml of nystatin is given fom times a day. Premature and low-birth-weight neonates should receive 1 mL of this preparation, infants 2 mL, and children or adults 4 to 6 mL per dose. Older children and adults should be instructed to swish the drug around the mouth and then swallow. If not otherwise instructed, the patient may expectorate the bitter liquid and fail to treat the infected mucosa in the posterior pharynx or esophagus. Nystatin suspension is usually effective for oral candidiasis of the immunocompetent host. Other than the bitter taste and occasional complaints of nausea, adverse effects are uncommou. A 200,000-unit troche (mycostatin pastilles) is available for the treatment of oral candidiasis, and a 500,000-unit oral tablet is sold for the treatment of nonesophageal membrane G1 candidiasis. 

Patients are always instructed to shake their pMDl prior to inhalation because of the potential problem of separation of drug particles from the suspension (21). Berg (22) visually demonstrated the importance of shaking a MDI prior to inhalation. She was able to transfer budesonide suspension from a pMDI to a pMDI with a glass canister that allowed the behavior of the micronized drug sus-... 

The main choice will be between an oral solution and an oral suspension. For some active substances an emulsion or solubilisate is the appropriate form. However in some cases (e.g. because of an intermediate solubility of the active substance) the pharmacist will have no other option than to dispense an oral solid dosage form and instruct the patient how to manipulate it safely (see Sect. 37.6.2). Proper consideration of the options may prevent formulation mistakes with probably severe consequences. This especially applies to the unreflected use of suspending bases for rendering an oral solid into an oral liquid. 

Active substances with intermediate solubility may cause the greatest challenge. When the solubility is too low for a solution but too high for a suspension (because the risk of crystal growth, see Sect. 18.1.6) the best option seems to be to choose a solid dosage form in combination with instructions for the patient how to handle in case of swallowing problems. 

In contrast to DPIs the basic design of MDI hardware is well described in the literature [23, 24]. Most MDIs apparently have a simpler design than DPIs and a key advantage of MDI systems is their low cost per dose. They are portable, convenient and have widespread acceptance by patients and clinicians. Basically they all have the same operational principle and furthermore all MDIs deliver a constant fine particle dose (independent of the flow rate). Whereas they have a relatively low resistance to airflow and this all makes the inhalation instruction less dependent oti the individual type of MDI. The most relevant differences between types are in the actuator design and medicine formulation (solution or suspension), in which the type of propellant and the presence of co-solvents play an important role because of their influence on the (plume) velocity with which the aerosol is released from the actuator and rate of droplet evaporation. 

Many preparations for individual patients concern reconstitution of licensed products. Examples are dissolving and diluting a powder for injection or creating an antibiotic suspension. Again, quality is incorporated by standardising the instructions applied. 

Faecal tagging is performed with a 40% weight/ volume barium suspension (Tagitol V , E-Z-EM). The patients only have to drink a total of 60 ml 20 ml at breakfast, lunch and dinner respectively. The patients are instructed to drink the barium at once after the meal. 

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